Intricate predatory decisions by a mosquito-specialist spider from Malaysia

Robert R Jackson,Rosli Hashim,Daiqin Li,Fiona R Cross,Jeremy R W Woon

doi:10.1098/rsos.140131

Abstract

Paracyrba wanlessi is a southeast Asian jumping spider (Salticidae) that lives in the hollow internodes of fallen bamboo and preys on the larvae, pupae and adults of mosquitoes. In contrast to Evarcha culicivora, an East African salticid that is also known for actively targeting mosquitoes as preferred prey, there was no evidence of P. wanlessi choosing mosquitoes on the basis of species, sex or diet. However, our findings show that P. wanlessi chooses mosquitoes significantly more often than a variety of other prey types, regardless of whether the prey are in or away from water, and regardless of whether the mosquitoes are adults or juveniles. Moreover, a preference for mosquito larvae, pupae and adults is expressed regardless of whether test spiders are maintained on a diet of terrestrial or aquatic prey and regardless of whether the diet includes or excludes mosquitoes. Congruence of an environmental factor (in water versus away from water) with prey type (aquatic versus terrestrial mosquitoes) appeared to be important and yet, even when the prey were in the incongruent environment, P. wanlessi continued to choose mosquitoes more often than other prey.

Highlights

Among ecologists, there has been a long-standing interest in predatory specialization [1,2], especially when the prey in question is an agricultural pest or a human–disease vector2014 The Authors
Preferences expressed during encounters with terrestrial prey: Paracyrba wanlessi compared with Evarcha culicivora
In encounters away from water, P. wanlessi, like E. culicivora, chose adult mosquitoes significantly more often than a variety of other terrestrial prey types, but there was a striking difference between these two species

Summary

Introduction

There has been a long-standing interest in predatory specialization [1,2], especially when the prey in question is an agricultural pest or a human–disease vector2014 The Authors. The terms ‘specialized’ and ‘generalized’ can be seriously misleading when used to 2 specify the range of prey in a predator’s natural diet. When discussing a predator’s diet, it is more instructive to acknowledge a stenophagy–euryphagy continuum, with ‘stenophagy’ referring to a narrow range of prey types in a natural diet and ‘euryphagy’ referring to a wide range. It is more appropriate to use the term ‘specialization’ in the context of specifying the level to which a predator has become especially well adapted to particular prey types [7]. Specialized adaptations may include the predator’s prey-choice behaviour and a cognitive attribute called ‘preference’ Specialized adaptations may include the predator’s prey-choice behaviour and a cognitive attribute called ‘preference’ (e.g. [8])

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