Male mate choice in hermit crabs: prudence by inferior males and simple preference by superior males

Abstract

In species with both male-male competition and male mate choice, inferior males may make different mate choice decisions from superior males. Males of the intertidal hermit crab, Pagurus middendorffii, are known to conduct precopulatory guarding and to adjust the threshold for guarding according to social parameters, such as encounter rate with females, competitor size and sex ratio. Larger males are stronger in male-male competition during guarding in this species. We here tested whether male of P. middendorffii initially guarding a smaller female exchanged partners when the male encountered a larger receptive female, and whether large and small males chose potential mates on the basis of body size and/or time needed for guarding when a male simultaneously encounters two females. When a male guarding a smaller receptive female encountered a larger receptive female, the male assessed the larger female and exchanged his partner only in cases of a large difference in body size between the two females, suggesting that males of this species could choose their mates based on female quality even during guarding. When a male simultaneously encountered two receptive females, small males showed the prudent mate choice by balancing female traits between larger body size and shorter time until breeding, while large males showed preference for larger females. The distinct preference exhibited by males of different size classes is concluded to be an adaptive response to the size-dependent risk of losing the female during guarding.

Male mate choice and male–male competition in the hermit crab Pagurus nigrofascia: importance of female quality

“…Intruder males of P. filholi and P. middendorffii seem to be able to gain some information about female quality from visual and chemical cues in hermit crabs (Wada et al 1999;Okamura and Goshima 2010;Wada et al 2011;Yasuda et al in press). However, our results of contest experiment in P. nigrofascia suggest that IG males might not gain sufficient information to accurately determine female quality from visual and chemical cues in the contest.…”

“…Although this perspective is true in some animals, male mate choice has recently been reported in a wide range of animals where there is intense male-male competition (Hoefler 2007;Candolin and Salesto 2009;Wada et al 2011). Males of such animals often prefer to mate with larger females due to their higher fecundity (Byrne and Rice 2006;Bel-Venner et al 2008;Baldauf et al 2009).…”

“…Male mate choice and male-male competition potentially will have effects on each other, and some theoretical models predict that competitive dominance of males could lead to variation in the direction and strength of male mate choice (Fawcett and Johnstone 2003;Härdling et al 2004;Härdling and Kokko 2005;Venner et al 2010). Wada et al (2011) demonstrated that inferior small males of the hermit crab, Pagurus middendorffii, choose not only larger females but also females that require less time to guard until prenuptial molting and/or spawning, while large superior males choose females based on their body size.…”

“…Males of P. middendorffii show both contest competition and mate choice (Wada et al 1999;Wada et al 2011). Males of the genus Pagurus engage in precopulatory guarding behavior, grasping the rim of a female shell with its minor cheliped during the breeding season (Hazlett 1972;Elwood and Neil 1992;Goshima et al 1998).…”

Effects of male size and mate quality on male-male contest in the hermit crab <i>Pagurus filholi</i>

“…Gammarus pulex RHP Elwood & Neil 1992;Wada et al 1999;Yasuda et al 2011 Pagurus filholi Yoshino et al 2004;Goshima et al 2006 P. middendorffii P. nigrofascia Wada et al 2011;Suzuki et al 2012 e.g., Wada et al 1995;Goshima et al 1998 i. Table 2 GLM, Z 3.81, P 0.001, Z 5.00, P 0.001 Table 3 Z 2.76, P 0.01…”