Female Choosiness Leads to the Evolution of Individually Distinctive Males

Abstract

Individual recognition is a taxonomically widespread ability that underlies a diverse suite of behaviors including the identification of individual nest-mates, agonistic opponents, and mating partners. However, as yet relatively little is known about the circumstances under which the requisite signal diversity can evolve. Here, we develop a model describing a novel mechanism of individual identity evolution via sexual selection. Females choose among a subset of males, but can select the most attractive male only when he bears a unique identity signal. This mimics a species in which mate assessment and choice are temporally separate, such as when females observe males in direct conflict and must subsequently locate the winner. When females in our model are choosy at least 10% of the time, diversity at individuality signaling loci evolves as a by-product of selection on male attractiveness more rapidly than does diversity at equivalent loci evolving only under neutral processes. Even at lower discrimination rates, drifting signal diversity gives the female choice mechanism sufficient traction to drive up average male attractiveness. The mechanism we describe here can significantly increase signal diversity at even low rates of discrimination by females. K E Y W O R D S :Agent-based model, behavior, individual recognition, models/simulations, sexual selection, signal diversity.

The Genetic Basis of Kin Recognition in a Cooperatively Breeding Mammal

“…MUP polymorphism also provides an individual genetic signature that allows male mice to advertise their individual competitive ability through scent marks [23][24][25]. Frequency-dependent selection on MUP through roles in both inbreeding avoidance and individual recognition [52] could help to maintain variability among haplotypes necessary for the reliable recognition of closely related cooperative partners [53].…”

When does female multiple mating evolve to adjust inbreeding? Effects of inbreeding depression, direct costs, mating constraints, and polyandry as a threshold trait

“…The males available to choosing females for initial versus additional matings are restricted to subsets of the total population in two alternative ways. (i) Best‐of‐N constraint: each female is restricted to two random subsests of N males generated independently for each female, modeling externally imposed constraints on initial and additional potential mates, respectively (i.e., a “fixed sample” search, Janetos ; Wiegmann and Angeloni ; Thom and Dytham ; Edward ). Any individual male can occur once (but not more than once) within both subsets, but a female's initially chosen male cannot be in the additional subset.…”

Morphological and population genomic evidence that human faces have evolved to signal individual identity

“…Individual recognition can rely on cues alone, but if individuals benefit from being recognized then selection is expected to favor individuals to advertise their identity with distinctive phenotypes 12 , 20 , 21 . Identity signals evolve when being confused with others is costly due to misdirected behaviors including aggression 26 , mating opportunities 27 , parental care 28 , etc. Comparative and experimental evidence for identity signaling leading to increased phenotypic diversity has been documented in multiple taxa 25 , 26 , 28 , 29 but has not been investigated in humans.…”