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Wat is hierdie twee insekte (of ten minste een van hulle)?

Wat is hierdie twee insekte (of ten minste een van hulle)?


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Ek moet insekte vang en identifiseer vir my biologie-projek, maar ek kan nie daardie twee goggas identifiseer nie.

Kan ek die genus en die spesie kry (of dit kan net die algemene naam wees van wat hierdie tipe gogga genoem word?)

Hulle is in Chicago se voorstedelike gebied gevind.


Ek die eerste insek is 'n krieket, vroulike herfsveldkrieket,Gryllus pennsylvanicus.

Dit is wydverspreid oor 'n groot deel van Noord-Amerika. Hulle word dikwels rondom gebiede van menslike bewoning gevind.

Die kleur wissel van donker swart tot donkerbruin, hoewel sommige eksemplare 'n effense rooierige tint toon. Die swart antennas is geneig om langer as die liggaamspan van die spesie te wees.

Dit is 'n wyfie omdat dit 'n lang swartbruin ovipositor het.

Verwysings:

  1. Wikipedia

  2. pbase.com

  3. goggagids


Na vermoeiende ure se navorsing om nie eers te weet wat die tweede fout se volgorde is nie, het ek uiteindelik die tweede fout gevind as ander deel van die antwoord.

Die tweede gogga is Slender meadow katydid, Conocephalus fasciatus van orde Orthoptera, ook 'n wyfie.


Insekte wat ons voed: meer as heuningbye

Ontelbare bye-organisasies het lyste van "heuningbyfeite" wat vermaaklik is, indien nie presies feitelik nie. Baie sulke lyste beweer dat heuningbye die enigste insekte is wat voedsel produseer wat deur mense geëet word.

Dit lyk dalk waar as jy net so ver as jou plaaslike kruidenierswinkel soek, maar baie insekte versamel nektar of ander plantafskeidings wat mense graag eet. Daarbenewens produseer sommige insekte insekte wat op hul beurt weer vir kos gebruik word. Byvoorbeeld, as 'n mama-wasmot eiers lê wat tot larwes groei wat jy in botter braai en oor rys bedien, was daardie mama-mot sekerlik besig om kos vir mense te produseer. Dit is alles hoe jy daaroor dink.


Insekte & # 038 Blomme

Die mega-neusvlieg (Moegistorhynchus longirostris) van suidelike Afrika, soos sy literêre eweknie, Pinocchio, het 'n bisarre voorkoms wat 'n onderliggende waarheid openbaar. Sy proboscis, wat lyk soos 'n neus, maar is eintlik die langste monddeel van enige bekende vlieg, steek soveel as vier duim uit sy kop–vyf keer die lengte van sy by-grootte lyf. In vlug hang die lomp aanhangsel tussen die insek’ se bene en spoor ver agter sy lyf.

Vir 'n vlieg in die lug kan 'n langwerpige proboscis 'n ernstige gestremdheid lyk (verbeel jou om in die straat af te loop met 'n strooi van sewe-en-twintig voet wat uit jou mond hang). Blykbaar kan die gestremdheid egter die aerodinamiese koste werd wees. Die vreemde proboscis gee die meganeusvlieg toegang tot nektarpoele in lang, diep blomme wat eenvoudig buite bereik is vir insekte met korter monddele.

Maar dit stel 'n raaisel: waarom sou natuurlike seleksie so 'n diep buis in 'n blom bevoordeel? Nektar self het immers ontwikkel omdat dit diere lok wat stuifmeel, die sperm van die blommewêreld, van een plant na 'n ander dra. En aangesien bestuiwers so 'n noodsaaklike diens vir die blom verrig, moes evolusie nie blomgeometrieë bevoordeel het wat nektar geredelik toeganklik maak vir die bestuiwers nie?

Tog is die storie van die lang proboscis van die mega-neusvlieg en die lang, diep buise van die blomme waarop hy voed nie heeltemal so eenvoudig nie. Daar is subtiele voordele, blyk dit, om nektar toeganklik te maak vir slegs 'n paar bestuiwers, en die natuur faktoriseer daardie voordele ook in die evolusionêre vergelyking. Trouens, die evolusie van daardie twee soorte organismes, bestuiwer en bestuif, bied 'n uitstekende voorbeeld van 'n belangrike evolusionêre verskynsel bekend as ko-evolusie. Ko-evolusie kan die opkoms van bisarre of ongewone anatomieë verklaar wanneer geen eenvoudige evolusionêre reaksie op natuurlike seleksie werklik voldoende is nie. Dit kan natuurbewaarders help om spesies te identifiseer wat noodsaaklik kan wees in die instandhouding van 'n gegewe habitat. En dit kan natuurkundiges wat nuwe plante ondersoek, help om te voorspel watter soort diere hul blomme kan bestuif.

Die mede-evolusie van die meganeusvlieg en die plante wat dit bestuif is 'n verhaal van uiterste spesialisasie. Elke spesie het aangepas by veranderinge in die ander op maniere wat elkeen van hulle tot 'n sekere mate op die ander aangewese gelaat het. Die idee dat 'n plantspesie vir bestuiwing van 'n enkele diersoort afhanklik kan word, gaan terug na die geskrifte van Charles Darwin. Darwin het byvoorbeeld opgemerk, die blomspoor van die Malgassiese orgidee (Angraecum sesquipedale) bevat 'n poel nektar wat amper 'n voet binne die opening van die blom is. ('n Blomspore is 'n hol, horingagtige verlenging van 'n blom wat nektar in sy basis hou.) Deur die evolusionêre betekenis van daardie ongewone blomme te peins, het Darwin voorspel dat die orgidee aangepas moet word by 'n motbestuiwer met 'n lang proboscis.

Kritiek vir Darwin se voorspelling was sy vermoede dat bestuiwing slegs kan plaasvind as die diepte van 'n plant se blomme ooreenstem met of die lengte van 'n bestuiwer se tong oorskry. Eers dan sou die liggaam van die bestuiwer stewig genoeg teen die voortplantingsdele van die blom gedruk word om stuifmeel effektief oor te dra soos die bestuiwer gevoed word. Dus, soos steeds dieper blomme ontwikkel het deur verhoogde voortplantingsukses, sal motte met steeds langer proboscise ook, verkieslik, lank genoeg lewe om voort te plant, omdat hulle die maklikste die beskikbare voorraad voedende nektar sou bereik. Langer proboscise sou weer lei tot seleksie vir dieper blombuise.

Die resultaat sou die wederkerige evolusie van blomme en bestuiwer monddele wees. Daardie ko-evolusionêre proses sal eers ophou wanneer die nadele van 'n oordrewe eienskap die voordele daarvan gebalanseer of swaarder weeg. Gegewe genoeg tyd, kan die proses selfs nuwe spesies produseer: 'n insek wat spesialiseer in die voeding van nektar van diep blomme, en 'n diepblomplant wat gespesialiseer is om deur insekte met lang monddele bestuif te word.

In die vroeë twintigste eeu het dit gelyk asof Darwin’ se voorspelling bevestig is. 'n Reuse valkmot van Madagaskar, Xanthopan morganii praedicta, is gevang, met 'n proboscis wat meer as nege duim lank gemeet het. Alhoewel niemand eintlik gesien het hoe die insek op die blom vreet nie, is die ontdekking steeds merkwaardig, en dui sterk op die samevolusie van die orgidee en mot. Ander insekte wat verwantskappe met hoogs spesifieke plante het, soos die meganeusvlieg en ander, verwante langneusvliegspesies van Suider-Afrika, lewer selfs beter bewyse van die wederkerige bande tussen vliegtuie en hul bestuiwers.

Darwin sou verbaas gewees het dat sommige vlieë in Suider-Afrika langer tonge het as wat die meeste valkmotte het. Die vlieë’ liggame is immers verskeie kere kleiner as wat die valkmotte’ is. Vlieë word as langneus beskryf as hul monddele langer as driekwart duim is. Volgens daardie maatstaf is meer as 'n dosyn langneusvliegspesies inheems aan Suider-Afrika. Hulle behoort aan twee families. Die nemestriede, of verstrengelde vlieë (wat die mega-neusvlieg insluit), vreet uitsluitlik van nektar, terwyl die tabaniede, of perdevlieë, meestal van nektar vreet, alhoewel vroulike tabaniede aparte monddele het om bloed te suig vir hul ontwikkelende eiers.

Soos alle ander langneusvlieë, is die meganeusvlieg die enigste bestuiwer vir 'n groep onverwante plantspesies wat so 'n groep as 'n gilde bekend staan. Die plantgilde van die meganeusvlieg sluit spesies uit 'n wye verskeidenheid plantfamilies in, insluitend malvas, irisse, orgideë en viooltjies.

Al is gildelede dalk net ver verwant, het almal min of meer dieselfde eienskappe. Plante in die langneusvlieëgilde het byvoorbeeld almal lang, reguit blombuisies of spore helderkleurige blomme wat oop is gedurende die dag en geen reuk nie. Die kenmerkende eienskappe van 'n gilde vorm saam wat plantkundiges 'n bestuiwingsindroom noem. Voëlbestuifde blomme is byvoorbeeld tipies groot, rooi en geurloos, terwyl motbestuifde blomme meer geneig is om saans lank, smal, wit en geurig te wees.

Die belangrikste eienskap in die bestuiwingsindroom van die langneusvlieg (en inderdaad, in alle bestuiwingsindroome van langneusinsekte) is 'n diep, buisvormige blom- of blomspore. Een van ons (Johnson) en Kim E. Steiner van die Compton Herbarium in Claremont, Suid-Afrika, het die orgidee Disadraconis bestudeer, 'n Suider-Afrikaanse plant met 'n diep, buisvormige blomspruit. Die twee ondersoekers het die spore van sommige orgideë kunsmatig verkort in 'n habitat waar die enigste bestuiwers teenwoordig was langneusvlieë. Die plante wie se spore lank gebly het, het meer stuifmeel gekry, en was meer geneig om vrugte te produseer, as dié wie se spore verkort was.

Tog is kort blomspore nie noodwendig 'n reproduktiewe nadeel nie. Korter spore sal dit moontlik maak vir 'n groter verskeidenheid bestuiwers om toegang tot die nektar te kry, indien verskeie potensiële bestuiwers teenwoordig is. In plaas daarvan blyk langer spore net 'n voordeel te wees wanneer langtong-insekte die enigste bestuiwers is. Johnson en Steiner het gevind dat verskille in lengte van die populasies nie geblameer kan word op verskille in vog of temperatuur nie, wat hul gevolgtrekking versterk het dat die lengte van die uitloper 'n aanpassing by die plaaslike verspreidings van langtongvlieë was.

Nie net korrel lengte van die uitloper statisties met bestuiwer eienskappe nie, maar 'n direkte oorsaaklike verband kan gedemonstreer word. Johnson en Ronny Alexandersson, ’n plantkundige aan die Uppsala Universiteit in Swede, het Suid-Afrikaanse Gladiolus-blomme bestudeer wat deur langtongvalkmotte bestuif is. Wanneer die valkmot-snaveltjies lank was in vergelyking met die lengte van die blombuis, het die valkmotte nie doeltreffend stuifmeel opgetel nie, en die blomme het nie goed gereproduseer nie. Wanneer die valkmot-snaveltjies relatief kort was, is stuifmeel makliker oorgedra, en die plante was meer geneig om bevrug te word en vrugte te dra. Dus oefen die lengte van die bestuiwer se proboscis 'n sterk druk op die reproduktiewe sukses van die blomme uit.

Daardie studies en ander dui daarop dat wat Darwin van die Malgassiese orgidee voorspel het, 'n taamlik algemene verskynsel is: valkmotte en langneusvlieë het saam met hul plantmaats ontwikkel. Soos blomme buise langer geword het, so het die bestuiwers’ proboscises, en dié het op hul beurt gelei tot selfs langer blomme. Namate die lengtes van die blombuis en die insekproboscis saamvloei, ontwikkel 'n merkwaardige mate van spesialisasie. Die plante kom staatmaak vir bestuiwing op die paar insekspesies wat hul blomme’ nektar voorrade kan bereik.

Daar is voordele vir die spesialiste aan beide kante van hierdie verhouding. Die langneusvlieë kry uiteraard bevoorregte toegang tot poele nektar. En die plante wat deur langneusvlieë bestuif word, trek voordeel uit 'n byna eksklusiewe stuifmeelkoerierdiens–of ten minste een wat die risiko van aflewering by die verkeerde adres verminder. Maar spesialisering kan ook 'n riskante strategie vir die plante wees as die bestuiwers minder in getrouheid belangstel as wat die plante is. Langneusvlieë kon nie oorleef op die nektar wat hulle kon kry deur net een plantspesie te besoek nie. Die vlieë moet verskeie plantspesies besoek om die energie wat hulle benodig in te samel. Johnson en Steiner het meganeusvlieë waargeneem wat minstens vier spesies met diep blomme besoek het.

Sulke promiskue gedrag kan nadelig vir die plante wees. 'n Vlieg kan uiteindelik stuifmeel van een spesie na 'n ander spesie in die gilde dra en sodoende die stuifmeel vermors. Erger nog, die vreemde stuifmeel kan uiteindelik die stigmata, die vroulike voortplantingstrukture, van die ontvangende blomme verstop, wat verhoed dat hulle die “regte” stuifmeel kry. Maar die stigmata van plante in die gilde van die meganeusvlieg verstop nie, want onder daardie plante het nog 'n slim aanpassing by gespesialiseerde bestuiwing ontwikkel. Elke plantspesie rangskik sy helmknoppe, die manlike voortplantingstrukture, in 'n kenmerkende posisie. Op dié manier, die stuifmeel van elke spesie vas aan die bestuiwer’ se liggaam in 'n duidelike maar konsekwente, plant-spesifieke plek. Die vlieg word 'n selfs meer doeltreffende koerier wat stuifmeel van verskeie plantspesies gelyktydig, sê maar, op sy kop, bene en borskas dra.

Die risiko's van spesialisasie is nie beperk tot die blomme nie. Net soos die vlieë ontroue vennote is, is sommige blomme oneerlik om 'n nektarbeloning aan te dui. Die orgidee D. draconis is byvoorbeeld nie die mutualistiese vennoot nie. Die blom lok die mega-neusvlieg, want dit lyk soos ander lede van die vlieg’s se gilde. Maar, terwyl die vlieg die orgidee se stuifmeel dra, bied die orgidee geen nektar in ruil daarvoor nie.

Die risiko om vir so 'n truuk te val, lyk na 'n klein prys vir die vlieë om te betaal vir die voordele van spesialisasie. Maar spesialisasie dra ook 'n veel erger risiko–in werklikheid die uiteindelike risiko–vir beide lede van die vennootskap omdat die verdwyning van enige vennoot is waarskynlik die ander een, sowel as doem. Sommige plantspesies het meganismes, soos vegetatiewe voortplanting of selfbestuiwing, wat kan help om hul bevolkings op kort termyn te onderhou. Maar op die lange duur, sonder hul bestuiwers, sal die spesie stadig en onherroeplik agteruitgaan. Bestuivende insekte kan in sommige gevalle meer buigsaam wees, maar is steeds kwesbaar as 'n belangrike voedselbron verdwyn.

Ongelukkig is dit in Suider-Afrika presies wat met baie plante en hul langneusvliegmaats gebeur. Dikwels kan nie eens nouverwante insekspesies help met bestuiwing nie. Vir geaffekteerde plante beteken die verlies van 'n enkele vliegspesie uitsterwing. En voorbeelde van daardie somber waterval is reeds waargeneem. Peter Goldblatt van die Missouri Botaniese Tuin in St. Louis en John C. Manning van die Compton Herbarium het ‘berig dat baie bevolkings van langneusvlieë bedreig word deur die verlies van hul broeihabitat vir vleiland, en moontlik ook deur die verlies van ander insekte wat hulle parasiteer tydens hul larwes stadiums. In sommige habitatte produseer blomme in die langneusvlieggilde reeds geen sade nie, omdat hul bestuiwer plaaslik uitgesterf is.

Natuurkundiges het die konsepte van gildes en bestuiwersindroom vir baie jare aanvaar, en om te voorspel watter bestuiwers gereeld watter plante besoek, het iets van 'n kothuisbedryf geword. Maar presies hoe algemeen is bestuiwerspesialisasie in Suider-Afrika? Promiskuïteit kan 'n meer suksesvolle–en meer wydverspreide–strategie as spesialisasie blyk te wees, selfs onder plante wat blykbaar in identifiseerbare gildes pas.

In onlangse jare het ekoloë ontdek dat net omdat plante en insekte blykbaar 'n bestuiwingsgilde vorm, dit nie waarborg dat hulle dit nooit daarbuite waag nie. Ekoloë het byvoorbeeld opgemerk dat in jare wanneer kolibriebevolkings laag is, blomme wat gewoonlik deur kolibries bestuif word, met nektar kan vul en effektief deur bye bestuif kan word. Net so het bye vroeër gedink om in slegs een of twee plantspesies te spesialiseer, blykbaar op 'n verskeidenheid plante te vreet.

Die huistoe-les was dat die sindroomkonsep geen plaasvervanger vir noukeurige veldwaarneming is nie. Sommige ondersoekers dink selfs dat die konsep plantkundiges veroorsaak het om generaliste oor die hoof te sien. In die Noordelike Halfrond, byvoorbeeld, dui studies daarop dat veralgemening die norm is, nie die uitsondering nie. Johnson en Steiner het onlangs 'n studie voltooi wat toon dat lede van die orgideë- en asclepiade-families in die Noordelike Halfrond geneig is om elk op tussen drie en vyf bestuiwers staat te maak. In teenstelling hiermee maak plante van dieselfde families in die Suidelike Halfrond staat op net een bestuiwer elk.

So hoekom is veralgemening meer algemeen in die Noordelike Halfrond as in die Suidelike Halfrond? Miskien is die rede daarvoor dat sosiale bye, wat grootliks opportunisties is, bestuiwerfaunas in noordelike streke oorheers. In die Suidelike Halfrond, daarenteen, is sosiale bye meestal afwesig, en eerder vervang deur meer gespesialiseerde bestuiwers soos die langneusvlieë en valkmotte.

Maar dit is net 'n breë veralgemening self. Meer data oor die geografiese verspreiding van bestuiwerspesialisasie moet ingesamel word, veral in tropiese lande. Die data is noodsaaklik, nie net om die spesialisasiedebat te bevorder nie, maar ook om soveel as moontlik van hierdie unieke spesies en verwantskappe te beskerm, sodat hulle nie vir altyd verdwyn nie.


Inleiding

Min kan oor die meeste insekte gesê word maar die heuningby is 'n spesiale geval omdat bye opgelei kan word. Vroeë navorsers in die veld het bye opgelei met 'n aantal patrone wat saam aangebied is, en die bye het geleer om op die patroon te land wat hulle met reuklose suikeroplossing beloon het. Die vermoë van die bye om te herken was verwant aan 'n paar parameters wat in die patrone vertoon word, naamlik die totale lengte van rande in die patroon, die area en die kleur, asof hulle kenmerkdetektors vir rande en ook vir helderheid van areas het. Die bye het ook sekere eienskappe van die hele patroon opgespoor, naamlik of dit sirkelvormig was of radiale speke of sektore gehad het en of dit glad of hoogs ontwrig was (Hertz, 1933). In baie groot eenvoudige patrone wat vertikaal aangebied word en wat >100 grade onderlê, was die tellings vir die toetspatrone verwant aan die maksimum oorvleueling van die toetsarea met die area van die oefenpatroon (Wehner, 1969). Waarskynlik kon hierdie strategie nie misluk nie, ongeag die meganisme. Later is gevind dat die bye die posisies van areas van swart in die periferie van die beloonde patroon en net onder die beloningsgat geleer het (Horridge, 1996b). Teen die einde van die eeu het individueel gemerkte bye geleer om in 'n eksperimentele keusekamer te vlieg en een van twee patrone te kies wat vertikaal op die agterwande vertoon word (Fig. 1). Dit was gelukkig dat die patrone wat op die teikens vertoon word, 40–50 grade onderhou het. by die oog van die by op die oomblik van keuse en slegs een of twee plaaslike streke van die oog was betrokke, sodat die aantal beskikbare leidrade beperk is en die meganisme ontleed kon word. In die middel van elke patroon was 'n gaatjie, maar slegs een van hierdie gaatjies het na 'n klein kamertjie daaragter gelei, waar die bye die beloning gekry het. Die twee patrone (en die beloning) het elke 5 minute van kant verander, wat die bye gedwing het om daarna te kyk, eerder as om bloot die beloonde kant te kies. Dit is geen sin om bye op te lei en hulle dan nie te toets om te sien wat hulle geleer het nie, soos gereeld in die verlede gebeur het. Die opgeleide bye is dus vir die eerste keer groot getalle toetse in groot verskeidenheid gegee. Om te verhoed dat die bye dit in die toetse leer, is verskillende toetspatrone geïntegreer en slegs een toets is toegelaat tussen voortgesette opleidingsperiodes.


Die Spesieskonsep

  • Spesies word gewoonlik beskryf in terme van hul eienskappe, sodat organismes wat baie ooreenkomste het, as dieselfde spesie geklassifiseer word. Streng gesproke moet die definisie van 'n spesie egter meer rigied as dit wees en word dus in terme van teling gestel.
  • Oorweeg 3 moontlike definisies van 'n spesie:
    - DEFINISIE 1: ''n Groep individue wat meer aan mekaar ooreenstem as wat hulle is aan individue van ander sulke groepe.'
    - DEFINISIE 2: ''n Groep individue wat soortgelyk is aan mekaar, en wat sal kruising met ander individue binne daardie groep.'
    - DEFINISIE 3: ''n Groep individue wat aan mekaar ooreenstem, en wat sal kruising met ander individue binne die groep te produseer vrugbaar nageslag, onder natuurlike voorwaardes.'
  • Die eerste definisie word dikwels in die veldsituasie gebruik, maar dit kan lei tot wanklassifikasies. Die vroeë natuurkenners het byvoorbeeld mannetjies en wyfies van sommige voëlspesies in Australië in aparte spesies geplaas omdat hulle so verskillend van mekaar gelyk het.
  • Die tweede definisie vermy hierdie probleem, maar neem nie situasies van kruising deur spesies in ag wat lei tot onvrugbare nageslag, wat nie op die spesielyn kan dra nie - bv. 'n perd en 'n donkie kan kruisteel om 'n muil te produseer, maar muile is steriel (genoem steriel basters).
  • Die derde definisie is die mees aanvaarde en is DIE DEFINISIE WAT JY TOT GEHEUGEN MOET VERBIND.
    dit wil sê Lede van 'n spesie broei onder natuurlike toestande saam om vrugbare nageslag te produseer.
  • 'n Ander manier om dit te sê is dit spesies deel 'n gemeenskaplike genepoel - dit wil sê dat enige gene in die bevolking tussen lede uitgeruil kan word omdat hulle in staat is om te kruisteel om vrugbare nageslag te produseer.
  • Jy moet ook bewus wees van die probleme met selfs hierdie definisie - dit kan nie gebruik word met fossielspesies, of met spesies wie se paring en nageslag nie waargeneem kan word nie, of waar daar net een monster is, of met uitgestorwe spesies.

Nog 'n paar idees

Om die jeugdige deel van jou lewe onder water in 'n stroompie of dam deur te bring, is nie iets wat net die hemimetaboliese insekte doen nie. Baie holometaboliese insekte het akwatiese larwestadiums, soos die meeste Caddisflies (Trichoptera), sommige Ware vlieë – soos Muskiete en baie Neuroptera en Coleoptera.

Dit is interessant om daarop te let dat slegs een orde holometaboliese insekte (d.w.s. Coleoptera Diving Beetles, ens.) en een orde van hemimetaboliese insekte (d.w.s. Hemiptera Water Boatmen, ens.) heeltemal akwatiese spesies geproduseer het. D.w.s. spesies wie se volwassenes hoofsaaklik in of op die water leef, asook die larwes.

Soms kan jy sien dat die term 'Naiad' gebruik word om 'n waternimf te beskryf - maar dit moet nie gebruik word om 'n waterlarwe te beskryf nie.

Dit lyk nie asof insekte voortdurend groei soos ons nie, want hul velle kan nie groter word soos die insek groei nie. In plaas daarvan, elke nou en dan, gooi hulle hul ou vel af en blaas 'n nuwe groter een op - wat hulle in hul ou een opgebou het.

Dit lyk dus of hulle in 'n reeks stadiums groei. Dit is baie duideliker met die nimfe van hemimetaboliese insekte soos Stok-insekte, wat dikwels hul ou velle laat rondhang vir mense om te sien.

Die ouwêreldse swaelstert (Papilio machaon) ruspe wat vervel.

Die velle van ruspes en maaiers strek baie meer as dié van die hemimetaboliese insekte. Omdat hulle dikwels baie kleiner en eenvoudiger bene het, neem die proses van die vervelling minder tyd en word dus minder gereeld gesien.

Die meeste ruspes verloor hul vel 3 keer voordat hulle die papiestadium bereik. Hierdie afskeiding van die ou vel word 'vervelling' of 'ekdyse' genoem en alle geleedpotiges doen dit - nie net insekte nie. Die vel wat agterbly word 'n 'exuviae' genoem

Die nimfe- en larwestadiums van die meeste insekte behels verskeie, van 3 tot 15, vervellings (of velskure).

Die tyd wat spandeer word tussen die uitbroei van die eier en die 1ste vervelling van die vel word die '1ste stadium' genoem. Die tyd tussen die 1ste vervelling en die 2de vervelling word die 2de 'instar' genoem, ens.

Jy lees dalk dikwels dat 'n spesifieke spesie insek 4 stadiums het, wat beteken dat dit sy vel 4 keer vervel voordat dit die volwasse of papiestadium van sy lewe bereik. Daarom, eerder as:

Eier » Nimf » Volwasse
of
Eier » Larwe » Poppie » Volwasse

Die meeste insek lewensiklusse lyk soos volg:

Eier » Nimf 1 » Nimf 2 » Nimf 3 » Nimf 4 » Volwasse
of
Eier » Larwe 1 » Larwe 2 » Larwe 3 » Poppie » Volwasse

Dit is slegs die basiese beginsels. Vir elke algemene reël in entomologie is daar dosyne insekte wat dit anders doen.

Sommige insekte broei byvoorbeeld uit in 'n ongewone vorm van kleintjies wat 'n pronimf genoem word (sien Orthoptera). Terwyl ander, veral die Lepidoptera, 'n stadium het tussen hul laaste larwale instar en hul papie wat 'n prepoppe genoem word. Dit is basies 'n onaktiewe, nie-metamorfiese rustende toestand.


Swart Wingerdkalander

Swart wingerdkalander, Otiorhynchus sulcatus (Fabricius), Curculionidae, COLEOPTERA

BESKRYWING

Volwasse &ndash Die langwerpige swart wingerdkalander is 10 tot 11 mm lank en het 'n kort snoet. Die elytra het baie geronde knolle, elk met 'n kort seta. Die liggaam is swartbruin, die antennas is swart en effens behaard en die kop is gladder as die toraks (Figuur J).

Eier &ndash Die eier is ongeveer 0,7 mm in deursnee, met 'n gladde, blink oppervlak. Dit is wit wanneer dit eers neergesit word, maar word bruin soos dit verouder.

Larwe &ndash Soos die beenlose larwe volwasse word, veroorsaak verdikking van die torakale segmente dat sy liggaam geboë word. Die volgroeide larwe is vuilwit met 'n bruin kop.

Poppie &ndash Die papie is wit met prominente donker stekels op die kop, buik en bene.

Verspreiding &ndash Die swart wingerdkalander het die naam "vine" in sy algemene naam omdat dit in 1934 vir die eerste keer as 'n plaag van druiwe in Duitsland erken is. Omstreeks 1910 is die kewer in Connecticut gevind en het sedertdien 'n ernstige ornamentele plaag in die suide van Kanada en die noorde van Kanada geword. Verenigde State.

Gasheerplante &ndash Baie kruidagtige en houtagtige plante is gelys as gashere vir die swart wingerdkalander. Sommige van die houtagtige gashere wat verkies word, sluit hemlock, rododendron en taxus in.

Skade &ndash Swart wingerdkalanderlarwes kan die groei van 'n plant stuit deur op die wortels te voed. Groter wortels word van hul bas gestroop of omgord, of hulle het kepe wat uit hulle gekou is. Die volwasse kalanders kou die rande van die blare, sny die punte van naalde af, of verslind hele naalde (Figuur J). Die binneste, ouer blare word verkies bo die terminale groei.

Lewensgeskiedenis &ndash Swart wingerdkalanders oorwinter as volwasse larwes of as papies. 'n Paar volwassenes oorleef egter ook die winter om eiers gedurende 'n tweede seisoen te voed en te deponeer. Hierdie kalander is partenogeneties. Alhoewel een wyfie aangeteken is wat 863 eiers gelê het, is die gemiddelde aantal eiers wat deur elke wyfie neergelê is waarskynlik ongeveer 200. Gedurende die preoviposition periode, wat ongeveer 45 dae duur, voed die volwassenes die meeste. Die lang lewe van die volwassene wissel gewoonlik van 90 tot 100 dae. Eiers, wat in die grond en blaarvullis neergelê word, broei binne 2 tot 3 weke uit. Aanvanklik voed die jong larwes wortelloos maar na die derde vervelling beweeg die larwes na die groter wortels. Tydens hul ontwikkeling vervel die larwes vyf of ses keer binne aardselle in die grond wat deur die larwes gebou is voor vervelling. Na 'n rustige prepaupale stadium wat van 3 weke tot 8 1/2 maande duur, verpop die larwes. Drie weke later kom volwassenes na vore. Volwassenes voed snags en val van die plant af en maak hulle dood wanneer hulle versteur word. Hierdie kalanders kan nie vlieg nie, so hulle moet gedra word of moet na onbesmette gebiede kruip.

Vir spesifieke chemiese beheermaatreëls, sien die huidige toestand uitbreiding aanbevelings.

Swart wingerdkalander. A. Volwasse. B. Eier. C en D. Larwe. E. Skade aan rododendronblare deur volwasse kalanders.


Wat is hierdie twee insekte (of ten minste een van hulle)? - Biologie

(Rhabditida: Steinernematidae & Heterorhabditidae)

Deur David I. Shapiro-Ilan, USDA-ARS, SEFTNRL, Byron, GA &
Randy Gaugler, Departement Entomologie, Rutgers Universiteit, New Brunswick, New Jersey

Aalwurms is eenvoudige rondewurms. Kleurloos, ongesegmenteerd en sonder aanhangsels, aalwurms kan vrylewend, voorloper of parasities wees. Baie van die parasitiese spesies veroorsaak belangrike siektes van plante, diere en mense. Ander spesies is voordelig om insekplae aan te val, meestal om hul gashere te steriliseer of andersins te verswak. 'n Baie min veroorsaak insekvrektes, maar hierdie spesies is geneig om moeilik (bv. tetradomatiede) of duur (bv. mermitiede) te wees om massa te produseer, het 'n beperkte gasheerspesifisiteit teen plae van geringe ekonomiese belang, besit 'n beskeie virulensie (bv. sfaeruliede) of is andersins swak geskik om vir plaagbeheerdoeleindes te ontgin. Die enigste insek-parasitiese aalwurms wat 'n optimale balans van biologiese beheer-eienskappe besit, is entomopatogene of insekdodende aalwurms in die genera Steinernema en Heterorhabditis. Hierdie multi-sellulêre metazoane beslaan 'n biobeheermiddelgrond tussen mikrobiese patogene en predatore/parasitoïede, en word sonder uitsondering met patogene saamgevoeg, vermoedelik as gevolg van hul simbiotiese verwantskap met bakterieë.


Entomopatogene nematodes is buitengewoon dodelik vir baie belangrike insekplae, maar is tog veilig vir plante en diere. Hierdie hoë graad van veiligheid beteken dat anders as chemikalieë, of selfs Bacillus thuringiensis, aalwurmtoedienings vereis nie maskers of ander veiligheidstoerusting nie en herbetredingstyd, residue, grondwaterbesoedeling, chemiese oortreding en bestuiwers is nie probleme nie. Die meeste biologiese middels benodig dae of weke om dood te maak, maar aalwurms, wat met hul simbiotiese bakterieë werk, kan insekte binne 24-48 uur doodmaak. Tientalle verskillende insekplae is vatbaar vir infeksie, tog is geen nadelige effekte teen voordelige insekte of ander nie-teikens in veldstudies getoon nie (Georgis et al., 1991 Akhurst en Smith, 2002). Aalwurms is vatbaar vir massaproduksie en benodig nie gespesialiseerde toedieningstoerusting nie aangesien hulle versoenbaar is met standaard landbouchemiese toerusting, insluitend verskeie spuite (bv. rugsak, druk, mis, elektrostatiese, waaier en lug) en besproeiingstelsels.


Honderde navorsers wat meer as veertig lande verteenwoordig, werk daaraan om aalwurms as biologiese insekdoders te ontwikkel. Aalwurms is bemark op elke vasteland behalwe Antarktika vir die beheer van insekplae in hoëwaarde tuinbou-, landbou- en huis- en tuinnismarkte.

Steinernematiede en heterorhabditiede het soortgelyke lewensgeskiedenis. Die nie-voedende, ontwikkelingsgestopte aansteeklike jeugdige soek insekgashere en inisieer infeksies. Wanneer 'n gasheer opgespoor is, dring die aalwurms in die insek liggaamsholte binne, gewoonlik via natuurlike liggaamsopeninge (mond, anus, spirakels) of areas van dun kutikula. Een keer in die liggaamsholte, 'n simbiotiese bakterie (Xenorhabdus vir steinernematides, Fotorhabdus vir heterorhabditiede) word vrygestel uit die aalwurmderm, wat vinnig vermeerder en vinnige insekdood veroorsaak. Die nematodes voed op die bakterieë en vloeibare gasheer, en word volwassenes. Steinernematied-infektiewe jeugdiges kan mannetjies of wyfies word, terwyl heterorhabditiede ontwikkel tot selfbevrugte hermafrodiete, alhoewel daaropvolgende generasies binne 'n gasheer ook mannetjies en wyfies produseer.

Die lewensiklus word binne 'n paar dae voltooi, en honderdduisende nuwe aansteeklike jeugdiges kom te voorskyn op soek na vars gashere. Entomopatogene nematodes is dus 'n nematode-bakteriekompleks. Die aalwurm lyk dalk net meer as 'n biologiese spuit vir sy bakteriese vennoot, maar die verhouding tussen hierdie organismes is een van klassieke mutualisme. Aalwurmgroei en -reproduksie hang af van toestande wat deur die bakterie in die gasheerkadawer gevestig is. Die bakterie dra verder anti-immuunproteïene by om die nematode te help om gasheerverdediging te oorkom, en anti-mikrobiese middels wat kolonisasie van die kadawer onderdruk deur mededingende sekondêre indringers. Omgekeerd het die bakterie nie indringende kragte nie en is afhanklik van die aalwurm om geskikte gashere op te spoor en binne te dring.



Produksie- en bergingstegnologie

Entomopatogene aalwurms word massa geproduseer vir gebruik as bioplaagdoders met behulp van in vivo of in vitro metodes (Shapiro-Ilan en Gaugler 2002). In vivo produksie (kultuur in lewende insekgashere) vereis 'n lae vlak van tegnologie, het lae aanvangskoste, en gevolglike aalwurmkwaliteit is oor die algemeen hoog, maar kostedoeltreffendheid is laag. Die benadering kan as ideaal vir klein markte beskou word. In vivo produksie kan verbeter word deur innovasies in meganisasie en vaartbelyning. 'n Nuwe alternatiewe benadering tot in vivo methodology is production and application of nematodes in infected host cadavers the cadavers (with nematodes developing inside) are distributed directly to the target site and pest suppression is subsequently achieved by the infective juveniles that emerge. In vitro solid culture, i.e., growing the nematodes on crumbled polyurethane foam, offers an intermediate level of technology and costs. In vitro liquid culture is the most cost- efficient production method but requires the largest startup capital. Liquid culture may be improved through progress in media development, nematode recovery, and bioreactor design. A variety of formulations have been developed to facilitate nematode storage and application including activated charcoal, alginate and polyacrylamide gels, baits, clay, paste, peat, polyurethane sponge, vermiculite, and water-dispersible granules. Depending on the formulation and nematode species, successful storage under refrigeration ranges from one to seven months. Optimum storage temperature for formulated nematodes varies according to species generally, steinernematids tend to store best at 4-8 °C whereas heterorhabditids persist better at 10-15 °C.

Relative Effectiveness and Application Parameters

Growers will not adopt biological agents that do not provide efficacy comparable with standard chemical insecticides. Technological advances in nematode production, formulation, quality control, application timing and delivery, and particularly in selecting optimal target habitats and target pests, have narrowed the efficacy gap between chemical and nematode agents. Nematodes have consequently demonstrated efficacy in a number of agricultural and horticultural market segments.

Entomopathogenic nematodes are remarkably versatile in being useful against many soil and cryptic insect pests in diverse cropping systems, yet are clearly underutilized. Like other biological control agents, nematodes are constrained by being living organisms that require specific conditions to be effective. Thus, desiccation or ultraviolet light rapidly inactivates insecticidal nematodes chemical insecticides are less constrained. Similarly, nematodes are effective within a narrower temperature range (generally between 20 °C and 30 °C) than chemicals, and are more impacted by suboptimal soil type, thatch depth, and irrigation frequency (Georgis and Gaugler, 1991 Shapiro-Ilan et al., 2006). Nematode-based insecticides may be inactivated if stored in hot vehicles, cannot be left in spray tanks for long periods, and are incompatible with several agricultural chemicals. Chemicals also have problems (e.g., mammalian toxicity, resistance, groundwater pollution, etc.) but a large knowledge base has been developed to support their use. Accelerated implementation of nematodes into IPM systems will require users to be more knowledgeable about how to use them effectively.


Therefore, based on the nematodes&rsquo biology, applications should be made in a manner that avoids direct sunlight, e.g., early morning or evening applications are often preferable. Soil in the treated area should be kept moist for at least two weeks after applications. Application to aboveground target areas is difficult due to the nematode&rsquos sensitivity to desiccation and UV radiation however, some success against certain above-ground targets has been achieved and recently approaches have been enhanced by improved formulations (e.g., Shapiro-Ilan et al., 2010). In all cases, the nematodes must be applied at a rate that is sufficient to kill the target pest generally, 250,000 infective juveniles per m2 of treated area is required (though in some cases an increased or slightly decreased rate may be suitable) (Shapiro-Ilan et al., 2002). Additionally, it is important to match the appropriate nematode species to the particular pest that is being targeted (see the table below for species effectiveness).

Nematodes are formulated and applied as infective juveniles, the only free-living and therefore environmentally tolerant stage. Infective juveniles range from 0.4 to 1.5 mm in length and can be observed with a hand lens or microscope after separation from formulation materials. Disturbed nematodes move actively, however sedentary ambusher species (e.g. Steinernema carpocapsae, S. scapterisci) in water soon revert to a characteristic "J"-shaped resting position. Low temperature or oxygen levels will inhibit movement of even active cruiser species (e.g., S. glaseri, Heterorhabditis bacteriophora). In short, lack of movement is not always a sign of mortality nematodes may have to be stimulated (e.g., probes, acetic acid, gentle heat) to move before assessing viability. Good quality nematodes tend to possess high lipid levels that provide a dense appearance, whereas nearly transparent nematodes are often active but possess low powers of infection.

Insects killed by most steinernematid nematodes become brown or tan, whereas insects killed by heterorhabditids become red and the tissues assume a gummy consistency. A dim luminescence given off by insects freshly killed by heterorhabditids is a foolproof diagnostic for this genus (the symbiotic bacteria provide the luminescence). Black cadavers with associated putrefaction indicate that the host was not killed by entomopathogenic species. Nematodes found within such cadavers tend to be free-living soil saprophages.

Steinernematid and heterorhabditid nematodes are exclusively soil organisms. They are ubiquitous, having been isolated from every inhabited continent from a wide range of ecologically diverse soil habitats including cultivated fields, forests, grasslands, deserts, and even ocean beaches. When surveyed, entomopathogenic nematodes are recovered from 2% to 45% of sites sampled (Hominick, 2002).

Because the symbiotic bacterium kills insects so quickly, there is no intimate host-parasite relationship as is characteristic for other insect-parasitic nematodes. Consequently, entomopathogenic nematodes are lethal to an extraordinarily broad range of insect pests in the laboratory. Field host range is considerably more restricted, with some species being quite narrow in host specificity. Nonetheless, when considered as a group of nearly 80 species, entomopathogenic nematodes are useful against a large number of insect pests (Grewal et al., 2005). Additionally, entomopathogenic nematodes have been marketed for control of certain plant parasitic nematodes, though efficacy has been variable depending on species (Lewis and Grewal, 2005). A list of many of the insect pests that are commercially targeted with entomopathogenic nematodes is provided in the table below. As field research progresses and improved insect-nematode matches are made, this list is certain to expand.


USE OF NEMATODES AS BIOLOGICAL INSECTICIDES

Plaag
Algemene naam
Plaag
Wetenskaplike naam
Sleutel
Crop(s) targeted
Efficacious
Nematodes *
Artichoke plume moth Platyptilia carduidactyla Artichoke Sc
Armyworms Lepidoptera: Noctuidae Groente Sc, Sf, Sr
Banana moth Opogona sachari Ornamentals Hb, Sc
Banana root borer Cosmopolites sordidus Banana Sc, Sf, Sg
Billbug Sphenophorus spp. (Coleoptera: Curculionidae) Turf Hb,Sc
Black cutworm Agrotis ipsilon Turf, vegetables Sc
Black vine weevil Otiorhynchus sulcatus Berries, ornamentals Hb, Hd, Hm, Hmeg, Sc, Sg
Borers Synanthedon spp. and other sesiids Fruit trees & ornamentals Hb, Sc, Sf
Cat flea Ctenocephalides felis Home yard, turf Sc
Citrus root weevil Pachnaeus spp. (Coleoptera: Curculionidae Citrus, ornamentals Sr, Hb
Codling moth Cydia pomonella Pome fruit Sc, Sf
Corn earworm Helicoverpa zea Groente Sc, Sf, Sr
Corn rootworm Diabrotica spp. Groente Hb, Sc
Cranberry girdler Chrysoteuchia topiaria Cranberries Sc
Crane fly Diptera: Tipulidae Turf Sc
Diaprepes root weevil Diaprepes abbreviatus Citrus, ornamentals Hb, Sr
Fungus gnats Diptera: Sciaridae Mushrooms, greenhouse Sf, Hb
Grape root borer Vitacea polistiformis Grapes Hz, Hb
Iris borer Macronoctua onusta Iris Hb, Sc
Large pine weevil Hylobius albietis Forest plantings Hd, Sc
Leafminers Liriomyza spp. (Diptera: Agromyzidae) Vegetables, ornamentals Sc, Sf
Mole crickets Scapteriscus spp. Turf Sc, Sr, Scap
Navel orangeworm Amyelois transitella Nut and fruit trees Sc
Plum curculio Conotrachelus nenuphar Vrugtebome Sr
Scarab grubs** Coleoptera: Scarabaeidae Turf, ornamentals Hb, Sc, Sg, Ss, Hz
Shore flies Scatella spp. Ornamentals Sc, Sf
Strawberry root weevil Otiorhynchus ovatus Bessies Hm
Small hive beetle Aethina tumida Bee hives Yes (Hi, Sr)
Sweetpotato weevil Cylas formicarius Sweet potato Hb, Sc, Sf

* At least one scientific study reported 75% suppression of these pests using the nematodes indicated in field or greenhouse experiments. Subsequent/other studies may reveal other nematodes that are virulent to these pests. Nematodes species used are abbreviated as follows: Hb=Heterorhabditis bacteriophora, Hd = H. downesi, Hi = H. indica, Hm= H. marelata, Hmeg = H. megidis, Hz = H. zealandica, Sc=Steinernema carpocapsae, Sf=S. feltiae, Sg=S. glaseri, Sk = S. kushidai, Sr=S. riobrave, Sscap=S. scapterisci, Ss = S. scarabaei.
** Efficacy of various pest species within this group varies among nematode species.



Characteristics of Some Commercialized Species


Steinernema carpocapsae: This species is the most studied of all entomopathogenic nematodes. Important attributes include ease of mass production and ability to formulate in a partially desiccated state that provides several months of room-temperature shelf-life. S. carpocapsae is particularly effective against lepidopterous larvae, including various webworms, cutworms, armyworms, girdlers, some weevils, and wood-borers. This species is a classic sit-and-wait or "ambush" forager, standing on its tail in an upright position near the soil surface and attaching to passing hosts. Gevolglik, S. carpocapsae is especially effective when applied against highly mobile surface-adapted insects (though some below-ground insects are also controlled by this nematode). S. carpocapsae is also highly responsive to carbon dioxide once a host has been contacted, thus the spiracles are a key portal of host entry. It is most effective at temperatures ranging from 22 to 28°C.

Steinernema feltiae: S. feltiae is especially effective against immature dipterous insects, including mushroom flies, fungus gnats, and tipulids as well some lepidopterous larvae. This nematode is unique in maintaining infectivity at soil temperatures as low as 10°C. S. feltiae has an intermediate foraging strategy between the ambush and cruiser type.

Steinernema glaseri: One of the largest entomopathogenic nematode species at twice the length but eight times the volume of S. carpocapsae infective juveniles, S. glaseri is especially effective against coleopterous larvae, particularly scarabs. This species is a cruise forager, neither nictating nor attaching well to passing hosts, but highly mobile and responsive to long-range host volatiles. Thus, this nematode is best adapted to parasitize hosts possessing low mobility and residing within the soil profile. Field trials, particularly in Japan, have shown that S. glaseri can provide control of several scarab species. Large size, however, reduces yield, making this species significantly more expensive to produce than other species. A tendency to occasionally "lose" its bacterial symbiote is bothersome. Moreover, the highly active and robust infective juveniles are difficult to contain within formulations that rely on partial nematode dehydration. In short, additional technological advances are needed before this nematode is likely to see substantial use.

Steinernema kushidai: Only isolated so far from Japan and only known to parasitize scarab larvae, S. kushidai has been commercialized and marketed primarily in Asia.

Steinernema riobrave: This novel and highly pathogenic species was originally isolated from the Rio Grande Valley of Texas, but has since been also been isolated in other areas, e.g., in the southwestern USA. Its effective host range runs across multiple insect orders. This versatility is likely due in part to its ability to exploit aspects of both ambusher and cruiser means of finding hosts. Trials have demonstrated its effectiveness against corn earworm, mole crickets, and plum curculio. Steinernema riobrave has also been highly effective in suppressing citrus root weevils (e.g., Diaprepes abbreviates and Pachnaeus species). This nematode is active across a range of temperatures it is effective at killing insects at soil temperatures above 35°C, and can also infect at 15 °C. Persistence is excellent even under semi-arid conditions, a feature no doubt enhanced by the uniquely high lipid levels found in infective juveniles. Its small size provides high yields whether using in vivo (up to 375,000 infective juveniles per wax moth larvae) or in vitro metodes.


Steinernema scapterisci: The only entomopathogenic nematode to be used in a classical biological control program, S. scapterisci was isolated from Uruguay and first released in Florida in 1985 to suppress an introduced pest, mole crickets. The nematode become established and presently contributes to control. Steinernema scapterisci is highly specific to mole crickets. Its ambusher approach to finding insects is ideally suited to the turfgrass tunneling habits of its host. Commercially available since 1993, this nematode is also sold as a biological insecticide, where its excellent ability to persist and provide long-term control contributes to overall efficacy.

Heterorhabditis bacteriophora: Among the most economically important entomopathogenic nematodes, H. bacteriophora possesses considerable versatility, attacking lepidopterous and coleopterous insect larvae, among other insects. This cruiser species appears quite useful against root weevils, particularly black vine weevil where it has provided consistently excellent results in containerized soil. A warm temperature nematode, H. bacteriophora shows reduced efficacy when soil drops below 20°C.

Heterorhabditis indica: First discovered in India, this nematode is now known to be ubiquitous. Heterorhabditis indica is considered to be a heat tolerant nematode (infecting insects at 30 °C or higher). The nematode produces high yields in vivo en in vitro, but shelf life is generally shorter than most other nematode species.


Heterorhabditis megidis:
First isolated in Ohio, this nematode is commercially available and marketed especially in western Europe for control of black vine weevil and various other soil insects. Heterorhabditis megidis is considered to be a cold tolerant nematode because it can effectively infect insects at temperatures below 15 °C.

Conservation strategies are poorly developed and largely limited to avoiding applications onto sites where the nematodes are ill-adapted for example, where immediate mortality is likely (e.g., exposed foliage) or where they are completely ineffective (e.g., aquatic habitats) (Lewis et al., 1998). Minimizing deleterious effects of the aboveground environment with a post-application rinse that washes infective juveniles into the soil is also a useful approach to increasing persistence and efficacy. Native populations are highly prevalent, but, other than scattered reports of epizootics, their impact on host populations is generally not well documented (Stuart et al., 2006). This is largely attributable to the cryptic nature of soil insects. Consequently, research and guidelines for conserving native entomopathogenic nematodes are in need of advancement.

Infective juveniles are compatible with most but not all agricultural chemicals under field conditions. Compatibility has been tested with well over 100 different chemical pesticides. Entomopathogenic nematodes are compatible (e.g., may be tank-mixed) with most chemical herbicides and fungicides as well as many insecticides (such as bacterial or fungal products) (Koppenhöfer and Grewal, 2005). In fact, in some cases, combinations of chemical agents with nematodes results in synergistic levels of insect mortality. Some chemicals to be used with care or avoided include aldicarb, carbofuran, diazinon, dodine, methomyl, and various nematicides. However, specific interactions can vary based on the nematode and host species and application rates. Furthermore, even when a specific chemical pesticide is not deemed compatible, use of both agents (chemical and nematode) can be implemented by waiting an appropriate interval between applications (e.g., 1 &ndash 2 weeks). Prior to use, compatibility and potential for tank-mixing should be based on manufacturer recommendations. Similarly, entomopathogenic nematodes are also compatible with many though not all biopesticides (Koppenhöfer and Grewal, 2005) interactions range from antagonism to additivity or synergy depending on the specific combination of control agents, target pest, and rates and timing of application. Nematodes are generally compatible with chemical fertilizers as well as composted manure though fresh manure can be detrimental.

Of the nearly eighty steinernematid and heterorhabditid nematodes identified to date, at least twelve species have been commercialized. A list of some nematode producers and suppliers is provided below the list emphasizes U.S. suppliers. Comparison-shopping is recommended as prices vary greatly among suppliers. Additionally, caution is again advised with regard to application rates. One billion nematodes per acre (250,000 per m2) is the rule-of-thumb against most soil insects (containerized and greenhouse soils tend to be treated at higher rates). A final caveat is that, just as one must select the appropriate insecticide to control a target insect, so must one choose the appropriate nematode species or strain. Ask suppliers about field tests supporting their recommended matching of insect target and nematode.


SOME COMMERCIAL PRODUCERS/SUPPLIERS*

P.O. Box 4247 CRB
Tucson, AZ 85738-1247.
Telephone: 520-825-9785,
800-827-2847
FAX: 520-825-2038

Springtown Road, P.O. Box 177
Willow Hill, PA 17271

134 West Drive
Lodi, Ohio 44254.
Telephone: 800/321-5656,
330-302-4203
FAX: 330-302-4204
FAX: 330-722-2616

Klausdorfer Str. 28-36
24223 Schwentinental
Duitsland.
Telephone:+49-4307-8295-0
FAX: +49-4307-8295-14

5100 Schenley Place
Lawrenceburg, IN 47025.
Telephone: 513-354-1482

128 Intervale Road
Burlington, VT 05401
Telephone: 888-833-1412,
802-660-3500
FAX:800-551-6712

2725A Hwy 32 West
Chico CA 95973.
Telephone: 530-895-8301,
800-895-8307
FAX: 530-895-8317

93 Priest Road
Nottingham, NH 03290-6204
Telephone: 603-942-8925
FAX 603-942-8932

3244 Hwy. 116 North
Sebastopol, CA 95472
707-823-9125
FAX: 707-823-1734

Veilingweg 17, P.O. Box 155 2650
AD Berkel en Rodenrijs
The Netherlands

Koppert (USA)28465
Beverly Road
Romulus, Michigan 48174
Telephone:1-800- 928-8827
FAX: 734 641 3799

P.O. Box 886
Bayfield, CO 81122.
Telephone: 800-526-4075
FAX: 970-259-3857.

606 Ball Street or
P.O. Box 1546,
Perry, GA 31069
Telephone: 478-988-9412,
877-967-6777
FAX: 478-988-9413.

7028 W. Waters Ave.,
Suite #264
Tampa, FL 33634-2292
Telephone: 866-215-2230.

* Mention of a proprietary product name does not imply USDA&rsquos approval of the product to the exclusion of others that may be suitable.

Akhurst, R. and K. Smith. 2002. Regulation and safety. In: Gaugler, R. (Ed.), Entomopathogenic Nematology. CABI, New York, NY, pp. 311-332.

Georgis, R. and R. Gaugler. 1991. Predictability in biological control using entomopathogenic nematodes. Journal of Economic Entomology. [Forum] 84: 713-20.

Georgis, R., H. Kaya, and R. Gaugler. 1991. Effect of steinernematid and heterorhabditid nematodes on nontarget arthropods. Environmental Entomology 20: 815-22.

Grewal, P. S., R-U, Ehlers, and D. I. Shapiro-Ilan. 2005. Nematodes as Biocontrol Agents. CABI, New York, NY.

Hominick, W. M. 2002. Biogeography. In: Gaugler, R. (Ed.), Entomopathogenic Nematology. CABI, New York, NY, pp. 115-143.

Koppenhöfer, A. M. and P. S. Grewal. 2005. Compatibility and interactions with agrochemicals and other biocontrol agents. In: Nematodes as Biocontrol Agents. CABI, New York, NY, pp. 363-381.

Lewis, E., J. Campbell, and R. Gaugler. 1998. A conservation approach to using entomopathogenic nematodes in turf and landscapes. In: Barbosa, P. (Ed.), Perspectives on the Conservation of Natural Enemies of Pest Species, Academic Press, New York, pp. 235-254.

Lewis, E.E. and P. S. Grewal. 2005. Interactions with plant parasitic nematodes. In: Grewal, P.S., Ehlers, R.-U., and Shapiro-Ilan, D.I. (Eds.), Nematodes as Biocontrol Agents. CABI, New York, NY., pp. 349-362.
Shapiro-Ilan D. I. and R. Gaugler. 2002. Production technology for entomopathogenic nematodes and their bacterial symbionts. Journal of Industrial Microbiology and Biotechnology 28: 137-146.

Shapiro-Ilan, D. I., D. H. Gouge, and A. M. Koppenhöfer. 2002. Factors affecting commercial success: case studies in cotton, turf and citrus. In: Gaugler, R. (Ed.), Entomopathogenic Nematology. CABI, New York, NY, pp. 333-356.

Shapiro-Ilan, D.I., D. H. Gouge, S. J. Piggott, and J. Patterson Fife. 2006. Application technology and environmental considerations for use of entomopathogenic nematodes in biological control. Biological Control 38: 124-133.

Shapiro-Ilan, D. I., T. E. Cottrell, R. F. Mizell, D. L. Horton, B. Behle, and C. Dunlap. 2010. Efficacy of Steinernema carpocapsae for control of the lesser peachtree borer, Synanthedon pictipes: Improved aboveground suppression with a novel gel application. Biological Control 54, 23&ndash28.


College Degree Requirements

Curriculum Requirements

The curriculum requirements of the College consist of three areas: ACE (Achievement-Centered Education), College of Agricultural Sciences and Natural Resources Core, and Degree Program requirements and electives. All three areas of the College Curriculum Requirements are incorporated within the description of the Major/Degree Program sections of the catalog. The individual major/degree program listings of classes ensures that a student will meet the minimum curriculum requirements of the College.

World Languages/Language Requirement

Two units of a world language are required. This requirement is usually met with two years of high school language.

Minimum Hours Required for Graduation

The College grants the bachelors degree in programs associated with agricultural sciences, natural resources, and related programs. Students working toward a degree must earn at least 120 semester hours of credit. A minimum cumulative grade point average of C (2.0 on a 4.0 scale) must be maintained throughout the course of studies and is required for graduation. Some degree programs have a higher cumulative grade point average required for graduation. Please check the degree program on its graduation cumulative grade point average.

Grade Rules

Removal of C-, D, and F Grades

Only the most recent letter grade received in a given course will be used in computing a student’s cumulative grade point average if the student has completed the course more than once and previously received a grade or grades below C in that course.

The previous grade (or grades) will not be used in the computation of the cumulative grade point average, but it will remain a part of the academic record and will appear on any transcript.

A student can remove from his/her cumulative average a course grade of C-, D+, D, D-, or F if the student repeats the same course at the University of Nebraska and receives a grade other than P (pass), I (incomplete), N (no pass), W (withdrew), or NR (no report). If a course is no longer being offered, it is not eligible for the revised grade point average computation process.

For complete procedures and regulations, see the Office of the University Registrar website at http://www.unl.edu/regrec/course-repeats.

Pass/No Pass

Students in CASNR may take any course offered on a Pass/No Pass basis within the 24-hour limitation established by the Faculty Senate. However, a department may specify that the Pass/No Pass status of its courses be limited to non-majors or may choose to offer some courses for letter grades only.

GPA Requirements

A minimum cumulative grade point average of C (2.0 on a 4.0 scale) must be maintained throughout the course of studies and is required for graduation. Some degree programs have a higher cumulative grade point average required for graduation. Please check the degree program on its graduation cumulative grade point average.

Transfer Credit Rules

To be considered for admission, a transfer student, Nebraska resident or nonresident, must have an accumulated average of C (2.0 on a 4.0 scale) and a minimum C average in the last semester of attendance at another college. Transfer students who have completed less than 12 credit hours of college study must submit either ACT or SAT scores.

Ordinarily, credits earned at an accredited college are accepted by the University. The College, however, will evaluate all hours submitted on an application for transfer and reserves the right to accept or reject any of them. Sixty (60) is the maximum number of hours the University will accept on transfer from a two-year college. Ninety (90) is the maximum number of hours the University will accept from a four-year college. Transfer credit in the degree program must be approved by the degree program advisor on a Request for Substitution Form to meet specific course requirements, group requirements, or course level requirements in the major. At least 9 hours in the major field, including the capstone course, must be completed at the University of Nebraska–Lincoln regardless of the number of hours transferred.

The College will accept no more than 10 semester hours of C-, D+, D, and D- grades from other schools. The C-, D+, D, and D- grades can only be applied to free electives. This policy does not apply to the transfer of grades from UNO or UNK to the University of Nebraska–Lincoln.

Joint Academic Transfer Programs

The College of Agricultural Sciences and Natural Resources has agreements with many institutions to support joint academic programs. The transfer programs include dual degree programs and cooperative degree programs. Dual degree programs offer students the opportunity to receive a degree from a participating institution and also to complete requirements for a bachelor of science degree in CASNR. Cooperative programs result in a single degree from either the University of Nebraska–Lincoln or the cooperating institution.

Dual Degree Programs

A to B Programs

The A to B Program, a joint academic program offered by the CASNR and participating community colleges, allows students to complete the first two years of a degree program at the participating community college and continue their education and study in a degree program leading toward a bachelor of science degree.

The A to B Program provides a basic knowledge plus specialized coursework. Students transfer into CASNR with junior standing.

Depending on the community college, students enrolled in the A to B Program may complete the requirements for an associate of science at the community college, transfer to the University of Nebraska–Lincoln, and work toward a bachelor of science degree.

Participating community colleges include:

  • Central Community College
  • Metropolitan Community College
  • Mid-Plains Community College
  • Nebraska College of Technical Agriculture
  • Nebraska Indian Community College
  • Northeast Community College
  • Southeast Community College
  • Western Nebraska Community College

3+2 Programs

Two specialized degree programs in animal science en veterinary science are offered jointly with an accredited college or school of veterinary medicine. These two programs permit CASNR animal science or veterinary science students to receive a bachelor of science degree from the University of Nebraska–Lincoln with a degree in animal science or veterinary science after successfully completing two years of the professional curriculum in veterinary medicine at an accredited veterinary school. Students who successfully complete the 3+2 Program, must provide transcripts and complete the Application for Degree form via MyRED. Students without MyRED access may apply for graduation in person at Husker Hub in the Canfield Administration Building, or by mail. Students should discuss these degree programs with their academic advisor.

Cooperative Degree Programs

Academic credit from the University and a cooperating institution are applied towards a four-year degree from either the University of Nebraska–Lincoln (University degree-granting program) or the cooperating institution (non University degree-granting program). All have approved programs of study.

UNL Degree-Granting Programs

A University of Nebraska–Lincoln degree-granting program is designed to provide students the opportunity to complete a two-year program of study at one of the four-year institutions listed below, transfer to CASNR, and complete the requirements for a bachelor of science degree.

Chadron State College. Chadron State College offers a 2+2 program leading to a grassland ecology and management degree program and a transfer program leading to a bachelor of science in agricultural education in the teaching option.

Wayne State College. Wayne State College offers a 3+1 program leading to a bachelor of science in plant biology in the ecology and management option and a 3+1 program leading to a bachelor of science in Applied Science.

University of Nebraska at Kearney. Transfer programs are available for students pursuing degree programs leading to a bachelor of science degree.

University of Nebraska at Omaha. Transfer programs are available for students pursuing degree programs leading to a bachelor of science degree.

Non University of Nebraska–Lincoln Degree-Granting Programs

CASNR cooperates with other institutions to provide coursework that is applied towards a degree at the cooperating institution. Pre-professional programs offered by CASNR allow students to complete the first two or three years of a degree program at the University prior to transferring and completing a degree at the cooperating institution.

Chadron State College–Range Science. The 3+1 Program in range science allows Chadron State College students to pursue a range science degree through Chadron State College. Students complete three years of coursework at Chadron State College and one year of specialized range science coursework (32 credit hours) at CASNR.

Dordt College (Iowa)–Agricultural Education: Teaching Option. This program allows students to pursue an Agricultural Education Teaching Option degree leading toward a bachelor of science in agricultural education. Students at Dordt College will complete 90 credit hours in the Agricultural Education: Teaching Option Transfer Program.

Residency

Students must complete at least 30 of the total hours for their degree using University of Nebraska–Lincoln credits. At least 18 of the 30 credit hours must be in courses offered through CASNR 1 (>299) including the appropriate ACE 10 degree requirement or an approved ACE 10 substitution offered through another Nebraska college and excluding independent study regardless of the number of hours transferred. Credit earned during education abroad may be used toward the residency requirement if students register through the University of Nebraska–Lincoln and participate in prior-approved education abroad programs. University of Nebraska–Lincoln open enrollment and summer independent study courses count toward residence.

Includes courses taught by CASNR faculty through interdisciplinary prefixes (e.g., LIFE, MBIO, ENVR, SCIL, EAEP, HRTM, ENSC) and CASNR crosslisted courses taught by non-CASNR faculty.

Online and Distance Education

There are many opportunities to earn college credit online through the University of Nebraska–Lincoln. Some of these credits may be applicable not only as elective credits but also toward the fulfillment of the College’s education requirements. Credits earned online may count toward residency. However, certain offerings may not be counted toward scholarship requirements or academic recognition criteria.

For further information, contact:

Office of Online and Distance Education
University of Nebraska–Lincoln
305 Brace Labs
Lincoln, NE 68588-0109
402-472-4681
http://online.unl.edu/

Independent Study Rules

Students wishing to take part in independent studies must obtain permission complete and sign a contract form and furnish copies of the contract to the instructor, advisor, departmental office, and the Dean’s Office. The contract should be completed before registration. Forms are available in 103 Agricultural Hall or online at the CASNR website.

Independent study projects include research, literature review or extension of coursework under supervision and evaluation of a departmental faculty member.

Students may only count 12 hours of independent study toward their degrees and no more than 6 hours can be counted during their last 36 hours earned, excluding senior thesis, internships, and courses taught under an independent study number.

Other College Degree Requirements

Capstone Course Requirement

A capstone course is required for each CASNR degree program. A capstone course is defined as a course in which students are required to integrate diverse bodies of knowledge to solve a problem or formulate a policy of societal importance.


Yellow sugarcane aphid

The yellow sugarcane aphid is bright lemon yellow and has many long hairs (Fig. 40). Two lines of black dots are usually visible down the back. This aphid feeds on the underside of sorghum leaves but produces little or no honeydew.

While feeding, yellow sugarcane aphids inject a toxic substance into the leaf. The toxin turns the seedling leaves purple and stunts plant growth (Fig. 41). Even a few yellow sugarcane aphids—two or three per leaf—can damage seedling sorghum plants.

Feeding on older plants causes the leaves to turn yellow and die.

Inspect the plants beginning the first week of emergence and twice weekly until the plants have at least five true leaves.

Treatment thresholds for yellow sugarcane aphid in forage sorghum have not been determined. Treatment thresholds for grain sorghum range from about 10 percent of the plants with one or more yellow sugarcane aphids per plant at the one-true-leaf stage, and about 40 percent of the plants with one or more yellow sugarcane aphids per plant at the three-true-leaf stage.

For detailed treatment thresholds for grain sorghum plants with one to three true leaves across a range of control costs and crop market values, see Texas A&M AgriLife publication B-1220, Managing Insect and Mite Pests of Texas Sorghum, which is available from the county Texas A&M AgriLife Extension office or online at http://www.agrilifebookstore.org/Managing-Insects-and-Mite-Pests-of-Texas-Sorghum-p/eb-1220.htm. At the threshold, consider applying an insecticide (Table 7).

Chlorpyrifos, zeta-cypermethrin, and beta-cypermethrin do not control the sugarcane aphid, which may increase after
these products are applied because of the loss of beneficial insects. If both sugarcane and yellow sugarcane aphids are present, consider Sivanto Prime or Transform.

Figure 40. Yellow sugarcane aphid showing the rows of black dots, hairs, and lemon yellow color characteristic of this species. Texas A&M AgriLife Extension Service Figure 41. Yellow sugarcane aphid damage. Greg Cronholm, Texas A&M AgriLife Extension Service

Fall Armyworm and corn earworm

Figure 42. Fall armyworm (top) and corn earworm. Pat Porter, Texas A&M AgriLife Extension Service

The larvae of fall armyworms and corn earworms (Fig. 42) feed on leaves within the whorl of the sorghum plant. When feeding in sorghum whorls, the larvae are called whorl worms. As the leaves emerge from the whorl, the feeding damage becomes evident as a series of round or ragged holes across the leaf blade.

Fall armyworms are identified by the white, inverted “Y” pattern on the face. Corn earworms have brown heads, lack the Y pattern, and have short spines along the body (Fig. 58).

To confirm that the culprit is fall armyworms or corn earworms (rather than grasshoppers, etc.), pull the whorl from the plant and unroll the leaves. The larvae and their excrement (frass) would be in the tightly rolled leaves.

Although the leaf damage looks dramatic, the forage loss from leaf feeding alone is usually insignificant, and control during the whorl stage is seldom economically justified.

Consider an insecticide treatment (Table 8) if fall armyworms are feeding on the growing point of plants less than 6 inches tall or if infestations threaten to reduce the leaf area by 30 percent or more. Before applying an insecticide, confirm that fall armyworms are still present by locating larvae in the whorl.

Controlling fall armyworms with insecticides is difficult because they are somewhat protected in the tightly rolled whorl leaves. Ground applications using 15 to 20 gallons of water per acre with nozzles directed over the top of the row increase penetration of the insecticide deep within the whorl and improve control.

Chemigation of insecticides, if approved on the label, through center pivot systems can improve the chemical’s effectiveness.

Because fall armyworm populations in- crease as the season progresses, late-planted sorghum is at greater risk of infestation than early-planted sorghum.


Kyk die video: Graad R Insekte (Oktober 2022).