Arthropod Predation of Vertebrates Structures Trophic Dynamics in Island Ecosystems.

David C Dow,Holly P Jones,Wei Wen Wong,Rohan H Clarke,Rowan Mott,Luke R Halpin,Nicholas Carlile,Daniel I Terrington

doi:10.1086/715702

Abstract

AbstractOn isolated islands, large arthropods can play an important functional role in ecosystem dynamics. On the Norfolk Islands group, South Pacific, we monitored the diet and foraging activity of an endemic chilopod, the Phillip Island centipede (Cormocephalus coynei), and used a stable isotope mixing model to estimate dietary proportions. Phillip Island centipede diet is represented by vertebrate animals (48%) and invertebrates (52%), with 30.5% consisting of squamates, including the Lord Howe Island skink (Oligosoma lichenigera) and Günther's island gecko (Christinus guentheri); 7.9% consisting of black-winged petrel (Pterodroma nigripennis) nestlings; and 9.6% consisting of marine fishes scavenged from regurgitated seabird meals. Centipede predation was the principal source of petrel nestling mortality, with annual rates of predation varying between 11.1% and 19.6% of nestlings. This means that 2,109-3,724 black-winged petrel nestlings may be predated by centipedes annually. Petrels produce a single offspring per year; therefore, predation of nestlings by centipedes represents total breeding failure for a pair in a given year. Our work demonstrates that arthropods can play a leading role in influencing vertebrate reproductive output and modifying trophic structures and nutrient flow in island ecosystems.

Highlights

Predator-prey interactions are important processes that regulate the structure of ecological communities, population dynamics, and nutrient transfer in food webs (Paine 1966; Sih et al 1985; Krebs 2011; Ripple and Beschta 2012)
Phillip Island centipede diet is represented by vertebrate animals (48%) and invertebrates (52%), with 30.5% consisting of squamates, including the Lord Howe Island skink (Oligosoma lichenigera) and Günther’s island gecko (Christinus guentheri); 7.9% consisting of black-winged petrel (Pterodroma nigripennis) nestlings; and 9.6% consisting of marine fishes scavenged from regurgitated seabird meals
We observed one instance of envenomation of a black-winged petrel nestling by a centipede in an exposed burrow that resulted in nestling death, where the centipede did not consume the nestling at the time of observation

Summary

Introduction

Predator-prey interactions are important processes that regulate the structure of ecological communities, population dynamics, and nutrient transfer in food webs (Paine 1966; Sih et al 1985; Krebs 2011; Ripple and Beschta 2012). These processes are central to many ecological studies and provide a foundation to better understand how ecosystems function, including how natural systems can maintain critical function in the face of anthropogenic disturbance and environmental change (Yodzis 1988; Johnson et al 1996).

Methods

Results

Conclusion