Mate acceptance and guarding by male fiddler crabs Uca tetragonon (Herbst)

• Published in: Journal of experimental marine biology and ecology Vol. 196; no. 1; pp. 131 - 143
• Main Authors: Goshima, Seiji, Koga, Tsunenori, Murai, Minoru
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-1996
• Subjects: Egg stage; Fiddler crab; Marine; Mate assessment; Mate-guarding; Operational sex ratio; Uca tetragonon; Fiddler crab; Egg stage; Mate assessment; Mate-guarding; Operational sex ratio
• ISSN: 0022-0981; 1879-1697
• DOI: 10.1016/0022-0981(95)00127-1

The fiddler crab,
Uca tetragonon (Herbst) mates both on the surface near female-defended burrows and underground in male-defended burrows. In underground mating, which requires relatively high male investment, males attract both non-ovigerous and ovigerous females into their burrows by claw waving. Males aggressively expel some females soon after they enter their burrows and others after pair formation, but before females spawn. Finally males guard some females in their burrows until they spawn, which presumably ensures paternity. Males do not select mates of a particular body size, but they do differentially accept females with late-stage eggs, those about to release larvae and spawn another clutch. Except at the beginning of the reproductive season, few ripe non-ovigerous females are available because females spawn successively and only in moderate synchrony. By differentially accepting late stage ovigerous females, males may increase their fertilization rates because they minimize the time they spend guarding each of their mates to ensure their paternity. A male-biased operational sex ratio and a high last male advantage in sperm competition are two conditions that may have favored male choice based on female guarding time in this species.