Show simple item record

dc.contributor.advisorIms, Rolf
dc.contributor.authorBarstad, Trond Elling
dc.date.accessioned2016-10-28T10:36:12Z
dc.date.available2016-10-28T10:36:12Z
dc.date.issued2016-11-04
dc.description.abstractThe phenological adaptation of herbivorous insects in the Arctic may be particularly prone to the negative impact of the current global climate change. Increasing temporal dissociation with their plant resources, and to their natural enemies such as parasitoids may be detrimental for their survival. The life history adaptations for gall-inducing sawflies in the Arctic (Tenthredinidae: Nematinae: Pontania nivalis, P. glabrifrons and P. arcticornis) followed the common outline for overwintering insects. During winter hibernation, diapause intensity prevented resumption of morphogenesis in early winter and turned into a post-diapause quiescence mid-winter, in which response to temperature synchronizes spring eclosion. Hindcasts of temperature conditions in spring for the last 21 years revealed a highly significant advancement in dates of eclosion, an evidence of global warming. There were, however, large inter-annual differences in eclosion timing, which probably is caused by timing of the spring snow melt. In early spring there is a short phenological window of opportunity for oviposition on suitable willow (Salix spp).host resources. Females showed a non-discriminatory oviposition preference pattern that did not enhanced larval performance, however larval survival was high. This pattern is probably caused by a brief and early spring eclosion when host plant cues are lacking. In autumn, diapause preparation was shown to occur in response to photoperiod during pre-diapause. Pontania spp. had a remarkable phenological synchronous behaviour in which larvae start to emerge from the galls in search for overwintering sites to pupate on 5 september. Although specialist insect species may be especially prone to the negative impacts of climatic change, this study does not provide any clear indications that this applies to Pontania spp..en_US
dc.description.doctoraltypeph.d.en_US
dc.description.popularabstractFenologisk tilpasning hos plantespisende insekter i arktis kan være spesielt utsatt for klima forandringer. Dette studie har sett på livssyklus-tilpasning hos galledannende bladveps (Tenthredinidae: Nematinae: Pontania) som er vanlig å finne på vier (Salix spp.) i nordlige områder. De overvintrer som prepuppe (larve i kokong) og har en vanlig overvintringsstrategi, der temperature styrer deres fenologi om våren tilpasset vertsplanten. Estimering av tidspunkt for klekking om våren, viste tydelig tidligere klekking i perioden 1993-2013, bevis på varmere klima om våren. Larvene lever inni galler på blad hos vier i løpet av sommeren, og viser å være godt tilpasset vertsplanten med høy overlevelse. Larvene responderer til nattlengde i slutten av august og kryper ut av gallen og forpupper seg på bakken i løpet av en kort periode som starter 5 september. Dette studie viser ingen indikasjoner på at galledannende bladveps er spesielt utsatt i forhold til klima forandringer.en_US
dc.description.sponsorshipFinansiert av Tromsø Museum-Universitetsmuseeten_US
dc.descriptionThe papers I and II of this thesis are not available in Munin. <br> Paper I: Barstad, T. E. Nilssen, A. C.: “Hibernation adaptation and eclosion synchrony in leaf-galling sawflies in subarctic Norway”. Available in <a href=http://dx.doi.org/10.1007/s00300-012-1157-8>Polar Biology 2012, 35:1097-1103.</a> <br> Paper II: Barstad, T. E. Nilssen, A. C.: “Spring phenology and the response to global warming in gall-inducing sawflies”. Available in <a href=http://dx.doi.org/10.1007/s00300-015-1712-1>Polar Biology 2015, 38:1503-1513. </a>en_US
dc.identifier.isbn978-82-8266-124-9
dc.identifier.urihttps://hdl.handle.net/10037/9911
dc.language.isoengen_US
dc.publisherUiT The Arctic University of Norwayen_US
dc.publisherUiT Norges arktiske universiteten_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2016 The Author(s)
dc.subject.courseIDDOKTOR-002
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480en_US
dc.titleSeasonal adaptation, phenology and survival in gall-inducing sawflies (Tenthredinidae: Nematinae: Pontania)en_US
dc.typeDoctoral thesisen_US
dc.typeDoktorgradsavhandlingen_US


File(s) in this item

Thumbnail
Thumbnail
Thumbnail
Thumbnail

This item appears in the following collection(s)

Show simple item record