Social Monogamy in the Big‐Clawed Snapping Shrimp,Alpheus heterochelis

Abstract

Social monogamy has evolved independently in many taxa, and often involves biparental care of the young. Where it does not, mate guarding and shared territoriality have been invoked as causal factors. We evaluated mate guarding and shared resource defence (a common shelter) as factors that could have led to social monogamy in the snapping shrimp, Alpheus heterochelis. This species is found in male–female pairs that defend a common shelter together. Female receptivity lasts only for a few hours immediately after her periodic moult. Their monogamous pair bond may represent mate guarding or joint defence of a territory. Monogamy in A. heterochelis seems most importantly driven by the cryptic nature of the female's moult cycle. We found that males did not discriminate among females at different intermoult stages for pairing, nor did they modulate their defence of mate and shelter (vs. the risk in finding a new shelter and mate) according to female moult stage. This, together with the short period of female receptivity before her single copulation per cycle, make extended mate guarding the most efficient method for a male to secure a mating opportunity. Comparing eviction rates of paired and unpaired shelter residents by conspecific intruders provided no evidence of enhanced resource defence that would confer a selective advantage to a pair. Male presence during the moult is beneficial for the female, as searching for a male during her soft‐bodied receptive phase would put her at mortal risk. Our results show empirically for the first time that guarding may be beneficial, even if males are not able to assess the female's reproductive stage. This extends the theoretical framework for understanding the evolution of social monogamy in taxa without biparental care of young.

Kin structure, ecology and the evolution of social organization in shrimp: a comparative analysis

“…Sponge-dwelling shrimp provide an independent test of the role of kin structure in the origin of eusociality. As far as is known all alpheids are monogamous (Knowlton 1980;Rahman et al 2003;Mathews 2007), but in most species the planktonically dispersing larvae, which are typical of decapod crustaceans, prevent accumulation of kin groups. Synalpheus, however, is unusual among alpheids in that the single genus contains species that produce swimming larvae, as well as species whose eggs hatch directly into crawling juveniles.…”

Refuge size, group living and symbiosis: testing the “resource economic monopolization” hypothesis with the shrimp Betaeus lilianae and description of its partnership with the crab Platyxanthus crenulatus

“…Recent studies have uncovered an evolutionary history and phylogenetic relationships within the group more complex than originally thought (Braken et al, 2009). Furthermore, some studies on shrimps combining systematic, physiological, behavioral and/or ecological observations, have exposed most peculiar behaviors and the conditions favoring them: multiple independent origins of eusociality (Duffy, 1996;Duffy et al, 2000;Morrison et al, 2004); condition-dependent alternative mating tactics (Correa et al, 2000); extreme sex allocation in sequentialsimultaneous hermaphrodites (Baeza, 2006(Baeza, , 2007; advertising and cleaning behavior in tropical environments Grutter, 2004, 2005;; and social monogamy in discrete refuges (Knowlton, 1980;Mathews, 2003;Rahman et al, 2003;Baeza, 2008). While our knowledge of the evolutionary history and diversity of caridean shrimps has increased substantially, the behavior and ecology of many species belonging to numerous genera and families still remains unknown.…”

Evidence for high rates of in-pair paternity in the socially monogamous snapping shrimp Alpheus angulosus

“…Knowlton 1980, Mathews 2002a,b, 2003, Rahman et al 2003. In all alpheids that have been examined empirically, the social structure consists of size-matched, heterosexual pairs cohabiting and codefending a territory against all conspecific and heterospecific alpheids, and, at least for Alpheus angulosus, males and females defend their territories against conspecifics of both genders (Mathews 2002a).…”