The causes and consequences of inbreeding avoidance and tolerance in cooperatively breeding vertebrates

Abstract

Cooperative breeders provide a particularly interesting scenario for studying inbreeding. Such populations are viscous due to delayed dispersal and short dispersal distances, resulting in the build-up of relatives in the local population. This leads to a high risk of inbreeding, and consequently of inbreeding depression. This has driven the evolution of an array of inbreeding avoidance mechanisms resulting in a relatively low level of close inbreeding in the majority of cooperative breeders. However, there are a number of species where inbreeding occurs relatively frequently. The presence of regular inbreeding (in cases where inbreeding is not a result of recent population declines), suggests that inbreeding tolerance and even preference can evolve under some circumstances. Both inbreeding and inbreeding avoidance mechanisms have enormous downstream fitness consequences for cooperative breeding species. For example, they can influence reproductive dynamics leading to a monopolization of breeding opportunities by dominant individuals. Inbreeding and its avoidance are also likely to impact on the evolution of cooperative breeding itself through influencing levels of relatedness between potential cooperators. Finally, in some cooperative breeders, a high degree of inbreeding avoidance can be detrimental to population viability, and hence is of particular concern to conservationists. In this review, I discuss these issues in detail and also briefly consider recent advances in the methods available for the study of inbreeding in natural populations.

Evidence That the Microbiota Counteracts Male Outbreeding Strategy by Inhibiting Sexual Signaling in Females

“…If the energy allocated to find a female in nature is higher than the fitness reward gained by distinguishing a related female, then males should not differentiate females based on relatedness. Context-dependent kin recognition is widely used by amphibian (Blaustein and Waldman, 1992;Hokit et al, 1996;Nichols, 2017), and hymenopteran species (Hepper, 1991;Starks et al, 1998;Buczkowski and Silverman, 2005) and this could explain why kin recognition is observed only when the microbiota is altered in the laboratory in D. melanogaster.…”

A high‐quality pedigree and genetic markers both reveal inbreeding depression for quality but not survival in a cooperative mammal

“…The resulting loss of fitness can be substantial and is believed to have shaped the evolution of dispersal and mating behaviour in many species. Consequently, quantifying the severity of inbreeding depression in natural populations is essential for understanding population and evolutionary dynamics (Hedrick & Garcia-Dorado, 2016;Keller & Waller, 2002;Nichols, 2017;Szulkin, Stopher, Pemberton, & Reid, 2013).…”

Dispersal altering local states has a limited effect on persistence of a metapopulation

“…Our model of dispersal also leads to kin-based social groups which is consistent with a number of studies of avian cooperative breeding (see [10]). Of course, allowing only kin to join certain social groups does lead to inbreeding, but certain social species are known to tolerate inbreeding to some degree [19].…”