Sharing of Potential Nest Sites by Etheostoma olmstedi Males Suggests Mutual Tolerance in an Alloparental Species

Abstract

When reproductive competitors tolerate or cooperate with one another, they may gain particular benefits, such as collectively guarding resources or attracting mates. Shared resources may be those essential to reproduction, such as a breeding site or nest. Using the tessellated darter, a species where males but not females compete over potential nest sites, we examined site use and sharing under controlled conditions of differing competitor density. Sharing was observed even when competitor density was low and individuals could have each occupied a potential nest site without same-sex sharing. Males were more likely to share a nest site with one other when the difference in size between them was larger rather than smaller. There was no evidence that female sharing was dependent on their relative size. Fish were generally more likely to use and share larger sites, in accordance with the greater relative surface area they offered. We discuss how one or both sharing males may potentially benefit, and how male sharing of potential nest sites could relate to female mating preferences. Tessellated darter males are known to provide alloparental care for eggs but this occurs without any social contact between the alloparent and the genetic father of the young. Thus, the suggestion that they may also share sites and maintain social contact with reproductive competitors highlights the importance of increased focus on the potential complexity of reproductive systems.

Linking male reproductive success to effort within and among nests in a co‐breeding stream fish

“…Co‐breeding behaviors are often observed in some animal taxa, particularly in fishes. For example, males of darters (Percidae) and suckers (Catostomidae) share spawning grounds and display mutual tolerance for reproduction (Díaz‐Muñoz et al, 2014; Stiver et al, 2013). However, reproductive effort of those fishes is relatively less intensive than that of nest‐building species, who invest much more effort in nest construction by collecting nesting resources.…”

“…But in some species, males co‐breed with other males by building and sharing nests (Díaz‐Muñoz et al, 2014; Gross, 1996; Taborsky, 2009). This behavior is adaptive because males in a certain group may have a better chance to increase reproductive success (Balshine et al, 2001; Riehl, 2012; Sherley, 1990; Stiver et al, 2013; Theuerkauf et al, 2009). In addition, males of some species build multiple nests sequentially in a reproductive season (Friedl & Klump, 2000; Sumasgutner et al, 2016).…”

“…Males exhibit diverse reproductive tactics, and males of some species co-breed by sharing resources and territories (Díaz-Muñoz et al, 2014;Taborsky, 1994Taborsky, , 2009. Social hierarchy is not readily evident in co-breeding males (Balshine et al, 2001;Díaz-Muñoz et al, 2014;Stiver et al, 2013). Thus, the relationship between reproductive success and behavior is elusive compared with cooperative males who form a social structure or partition their roles (Hellmann et al, 2020;Koenig & Walters, 2015;Olson & Blumstein, 2010;Taborsky, 2001).…”

Fathead minnow reproduction: Implications for commercial culture

“…They reported that in a pond, adjacent nests with eggs were as close together as 10–20 cm. Sharing of a substrate by nesting males provides them with some benefits, such as less energetically expensive conflict, mutual defense of the site, and additive efforts to attract females (Stiver, Wolff, & Alonzo, ).…”

Linking Male Reproductive Success to Effort Within and Among Nests in a Co-Breeding Stream Fish

“…This behavior is adaptive because at least some males of a group bene t from increased reproductive success (Sherley 1990 leads to individual variation in reproductive success. But the social hierarchy is not readily evident in other species, where males lek or tolerate mutually on a nest (Taborsky 1994(Taborsky , 2009Stiver et al 2013;Díaz-Muñoz et al 2014). In these co-breeding species, the relationship between reproductive success and behavior is elusive.…”