Kin competition accelerates experimental range expansion in an arthropod herbivore.

Katrien Van Petegem,Emanuel A Fronhofer,Robby Stoks,Felix Moerman,Thomas Van Leeuwen,Maxime Dahirel,Dries Bonte,Nicky Wybouw,Martijn L Vandegehuchte,Tim Coulson

doi:10.1111/ele.12887

Abstract

With ongoing global change, life is continuously forced to move to novel areas, which leads to dynamically changing species ranges. As dispersal is central to range dynamics, factors promoting fast and distant dispersal are key to understanding and predicting species ranges. During range expansions, genetic variation is depleted at the expanding front. Such conditions should reduce evolutionary potential, while increasing kin competition. Organisms able to recognise relatives may be able to assess increased levels of relatedness at expanding range margins and to increase their dispersal in a plastic manner. Using individual-based simulations and experimental range expansions of a spider mite, we demonstrate that plastic responses to kin structure can be at least as important as evolution in driving range expansion speed. Because recognition of kin or kind is increasingly documented across the tree of life, we anticipate it to be a highly important but neglected driver of range expansions.

Highlights

Cooperation and conflict are central to understanding organismal interactions and their impact on population and community dynamics[3, 6]
We formalized our hypotheses by means of a highly parameterized, but simple simulation model based on spider mite life histories and relatedness-dependent dispersal reaction norms
Despite the incorporation of uncertainties regarding condition-dependent dispersal thresholds, the model predicted range expansion to proceed at a 25.9% slower mean rate when signatures of both kin competition and spatial sorting were removed, while expansion rates were only 7.4% slower when spatial sorting was prevented, but kin competition was present (Fig. 1)

Summary

Introduction

Cooperation and conflict are central to understanding organismal interactions and their impact on population and community dynamics[3, 6]. Even when dispersal entails high costs, dispersers may be released from local competition, thereby increasing their inclusive fitness[5]. This effect is even stronger when dispersal is not a fixed genetic trait, but a conditional response[8, 9], for instance conditional on kin structure where individuals plastically adapt their dispersal strategy to current levels of relatedness[10]. Dispersal has been recognized as a central and independent trait in life history, known to have a strong impact on spatial dynamics in fragmented landscapes or during range expansions [9, 11,12,13]. We surprisingly lack knowledge about the consequences of the interaction between kin structure and conditional dispersal for ecological patterns at large spatial scales, such as range expansions

Methods

Results

Conclusion