Phenology of predation on insects in a tropical forest: temporal variation in attack rate on dummy caterpillars

0455017 - BC 2017 RIV US eng J - Journal Article
Molleman, F. - Remmel, T. - Sam, Kateřina
Phenology of predation on insects in a tropical forest: temporal variation in attack rate on dummy caterpillars.
Biotropica. Roč. 48, č. 2 (2016), s. 229-236. ISSN 0006-3606. E-ISSN 1744-7429
R&D Projects: GA ČR(CZ) GP14-32024P
Institutional support: RVO:60077344
Keywords : artificial prey * development time * functional response
Subject RIV: EH - Ecology, Behaviour
Impact factor: 1.730, year: 2016
http://onlinelibrary.wiley.com/doi/10.1111/btp.12268/abstract

Temporal patterns of attack rates on insect n tropical forest habitats have not been studied systematically, because it is very difficult to observe and record elusive predation of omnipresent and tiny insect. Yet, in communities of tropical insects, adult abundance tends to fluctuate widely, perhaps owing exactly to predator–prey dynamics. However, the identity of predators of insects in tropical forests is poorly known, and their responses to temporal variation in prey abundance have rarely been explored. We recorded incidence and shape of marks of attacks on dummy caterpillars (proxy of predation rate) in a sub-montane tropical forest in Uganda during a year-long experiment, and explored correlations with inferred caterpillar abundance. Applying the highest and lowest observed daily attack rates on clay dummies over a realistic duration of the larval stage of butterflies, indicates that the temporal variation in attack rate could cause more than 10-fold temporal variation in caterpillar survival. Inferred predators were almost exclusively invertebrates, and beak marks of birds were very scarce. Attack rates by wasps varied more over time than those of ants that were present across all seasons. Attack rates on dummies peaked during the two wet seasons, and appeared congruent with inferred peaks in caterpillar density. This suggests (1) a functional response (predators shifting to more abundant resource) or adaptive timed phenology (predators timing activity or breeding to coincide with seasonal peaks in prey abundance) of predators, rather than a numerical response (predator populations increasing following peaks in prey abundance); and (2) that predation would dampen abundance fluctuations of tropical Lepidoptera communities.
Permanent Link: http://hdl.handle.net/11104/0255762