Market forces influence helping behaviour in cooperatively breeding paper wasps

Lena Grinsted,Jeremy Field

doi:10.1038/ncomms13750

Abstract

Biological market theory is potentially useful for understanding helping behaviour in animal societies. It predicts that competition for trading partners will affect the value of commodities exchanged. It has gained empirical support in cooperative breeders, where subordinates help dominant breeders in exchange for group membership, but so far without considering one crucial aspect: outside options. We find support for a biological market in paper wasps, Polistes dominula. We first show that females have a choice of cooperative partners. Second, by manipulating entire subpopulations in the field, we increase the supply of outside options for subordinates, freeing up suitable nesting spots and providing additional nesting partners. We predicted that by intensifying competition for help, our manipulation would force dominants to accept a lower price for group membership. As expected, subordinates reduce their foraging effort following our treatments. We conclude that to accurately predict the amount of help provided, social units cannot be viewed in isolation: the surrounding market must also be considered.

Highlights

Biological market theory is potentially useful for understanding helping behaviour in animal societies
Biological market theory emphasizes the importance of partner choice and competition for cooperative partners, using the economic principles of supply and demand to predict the trade-value of commodities exchanged between trader classes[2,3,8,9]
Here we document the presence of partner choice in the cooperatively breeding paper wasp P. dominula, and demonstrate that the supply of outside options affects helping behaviour within un-manipulated social groups in the field

Summary

Introduction

Biological market theory is potentially useful for understanding helping behaviour in animal societies It predicts that competition for trading partners will affect the value of commodities exchanged. Biological market theory emphasizes the importance of partner choice and competition for cooperative partners, using the economic principles of supply and demand to predict the trade-value of commodities exchanged between trader classes[2,3,8,9]. The critical experiments to test whether market forces affect the exchange of commodities in cooperative breeders are first, to test whether there is partner choice; and second, to manipulate the outside options available, altering competition for trading partners[10,23] We carried out both tests using cooperatively breeding groups of the paper wasp Polistes dominula (Fig. 1a,b).

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Conclusion