首页 | 本学科首页   官方微博 | 高级检索  
   检索      


The costs of reduced feeding due to predator avoidance: potential effects on growth and fitness in Ischnura elegans larvae (Odonata: Zygoptera)
Authors:PHILIP A HEADS
Institution:Department of Biology, University of York
Abstract:ABSTRACT.
  • 1 This paper investigates the behaviour, in the laboratory, of a forager simultaneously confronted with the conflicting needs to feed and to avoid predators. The foragers were larvae of the damselfly Ischnura elegans Van der Linden, feeding on Daphnia magna Strauss. The predators were adult females of Notonecta glauca L.
  • 2 Patch choice by Ischnura larvae was significantly modified by the presence of predators. Larvae moved to feed in patches of high prey density when predators were absent but preferred dense cover, even though virtually no prey were available, when predators were present. This behaviour was not altered by hunger, up to 12 days without food. In other words, Ischnura larvae were risk averse in their foraging behaviour.
  • 3 In experiments with abundant prey available, the feeding rates of Ischnura larvae confined to a single patch were also significantly reduced by the presence of hydrodynamically and chemically detectable predators. Predators detectable only by vision had little effect.
  • 4 Calculations made from published data show that reduced larval feeding rates can lead to slower growth and development and prolonged instar durations in Ischnura elegans larvae. This may have important consequences for larval survival and adult reproductive fitness.
Keywords:Forager              Ischnura            predator              Notonecta            avoidance behaviour  feeding  growth  development  survival  fitness
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号