Host-plant quality adaptively affects the diapause threshold: evidence from leaf beetles in willow plantations
2012 (English)In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 37, no 6, 490-499 p.Article in journal (Refereed) Published
1. Voltinism of herbivorous insects can vary depending on environmental conditions. The leaf beetle Phratora vulgatissima L. is univoltine in Sweden but will sometimes initiate a second generation in short-rotation coppice (SRC) willow plantations. 2. The study investigated whether increased voltinism by P. vulgatissima in plantations can be explained by (i) rapid life-cycle development allowing two generations, or (ii) postponed diapause induction on coppiced willows. 3. In the field, no difference was found in the phenology or development of first-generation broods between plantations (S. viminalis) and natural willow habitats (S. cinerea). However, the induction of diapause occurred 12 weeks later in SRC willow plantations. 4. Laboratory experiments indicated no genetic difference in the critical day-length for diapause induction between beetles originating from plantations and natural habitats. Development time was unaffected by host-plant quality but critical day-length was prolonged by almost an hour when the beetles were reared on a non-preferred willow species (S. phylicifolia). When reared on new leaves from re-sprouting shoots of recently coppiced willow plants, diapause incidence was significantly less than when the beetles were reared on mature leaves from uncoppiced plants. 5. The study suggests that P. vulgatissima has a plastic diapause threshold influenced by host-plant quality. The use of host-plant quality as a diapause-inducing stimulus is likely to be adaptive in cases where food resources are unpredictable, such as when new host-plant tissue is produced after a disturbance. SRC willows may allow two beetle generations due to longer growing seasons of coppiced plants that grow vigorously.
Place, publisher, year, edition, pages
2012. Vol. 37, no 6, 490-499 p.
Critical day-length, diapause, host-plant quality, seasonal adaptations, voltinism
Zoology Ecology Evolutionary Biology
Research subject Animal Ecology
IdentifiersURN: urn:nbn:se:su:diva-84793DOI: 10.1111/j.1365-2311.2012.01387.xISI: 000311697300007OAI: oai:DiVA.org:su-84793DiVA: diva2:581786
FunderSwedish Research Council, 621-2011-5636Biodiversity and Ecosystem Services in a Changing Climate