Inbreeding avoidance influences the viability of reintroduced populations of African wild dogs (Lycaon pictus).

Penny A Becker,Philip S Miller,Micaela Szykman Gunther,Michael J Somers,Jesús E Maldonado,David E Wildt,Brock Fenton

doi:10.1371/journal.pone.0037181

Abstract

The conservation of many fragmented and small populations of endangered African wild dogs (Lycaon pictus) relies on understanding the natural processes affecting genetic diversity, demographics, and future viability. We used extensive behavioural, life-history, and genetic data from reintroduced African wild dogs in South Africa to (1) test for inbreeding avoidance via mate selection and (2) model the potential consequences of avoidance on population persistence. Results suggested that wild dogs avoided mating with kin. Inbreeding was rare in natal packs, after reproductive vacancies, and between sibling cohorts (observed on 0.8%, 12.5%, and 3.8% of occasions, respectively). Only one of the six (16.7%) breeding pairs confirmed as third-order (or closer) kin consisted of animals that were familiar with each other, while no other paired individuals had any prior association. Computer-simulated populations allowed to experience inbreeding had only a 1.6% probability of extinction within 100 years, whereas all populations avoiding incestuous matings became extinct due to the absence of unrelated mates. Populations that avoided mating with first-order relatives became extinct after 63 years compared with persistence of 37 and 19 years for those also prevented from second-order and third-order matings, respectively. Although stronger inbreeding avoidance maintains significantly more genetic variation, our results demonstrate the potentially severe demographic impacts of reduced numbers of suitable mates on the future viability of small, isolated wild dog populations. The rapid rate of population decline suggests that extinction may occur before inbreeding depression is observed.

Highlights

Mating with kin has been shown to lead to decreased heterozygosity, expression of deleterious alleles, and reduced fitness due to inbreeding depression in a variety of species [1,2]
To improve our understanding of inbreeding avoidance and its consequences, we examined both real and simulated data based on a reintroduced population of African wild dogs (Lycaon pictus) in KwaZulu-Natal province (KZN), South Africa
Results from our integrated behavioural, genetic, and demographic evaluation support our hypothesis that inbreeding avoidance is present in the African wild dog, and suggest that individuals within this species have the capacity to discriminate between kin and non-kin through ‘recognition by association’

Summary

Introduction

Mating with kin has been shown to lead to decreased heterozygosity, expression of deleterious alleles, and reduced fitness due to inbreeding depression in a variety of species [1,2]. Natural selection should favour behavioural mechanisms for animals to avoid mating with kin, in species that could potentially suffer the most severe costs of inbreeding depression [8]. The first is that natal dispersal reduces contact among relatives, an approach commonly found in species like the black-tailed prairie dog (Cynomys ludovicianus) that displays male-biased dispersal and female philopatry [9]. Individuals avoid mating with relatives via three types of kin recognition: 1) familiarity (e.g., Seychelles warbler, Acrocephalus sechellensis) [11]; 2) major histocompatibility complex comparisons (e.g., house mouse, Mus musculus) [12]; or 3) phenotype matching, where an individual compares templates of close kin or itself to determine relatedness to unknown individuals (e.g., golden hamster, Mesocricetus auratus) [13]

Methods

Results

Conclusion