Male courtship cycles in three species of tropical Ilyoplax crabs (Decapoda, Brachyura, Ocypodidae)

Abstract

The courtship behaviour and cycles of male courtship activity and colouration of Ilyoplax orientalis, I. delsmani and I. gangetica were studied in the field in Malaysia and Thailand. Each species had a distinctive chela waving or beckoning display. Depending on species, the chelipeds, carapaces, or both of waving males blanched to white in contrast to the cryptic colour of nonwaving males and females. All three of these tropical Ilyoplax exhibited semilunar cycles in male waving activity at the colony level. It was confirmed for I. orientalis that individual males cycled each semilunar period between waving and non-waving phases and exhibited different behaviour toward females during these two behavioural phases.

Social behaviors of several ocypodoid crabs observed in mangrove swamps in southern Thailand

“…About 3 min later, the male emerged from the burrow and plugged the burrow by gathering surface sediments around the burrow entrance. Such underground coupling, in which the male entices the female to enter the male burrow, is the same as that reported in other dotillid crabs of the genus Ilyoplax, such as I. pusilla (Wada, 1981), I. gangetica (Kosuge et al, 1994a), and I. orientalis (Kosuge et al, 1994b).…”

“…Thereafter, the female re-emerged from the burrow and left the burrow to wander. Underground coupling through male-first entering into the burrow has been observed in other species of Ilyoplax (Wada, 1981;Kosuge et al, 1994b;Wada et al, 1996).…”

“…The wave duration ranged from 0.22 s to 0.72 s (mean: 0.45 s) (113 displays by ten males). The waving motion was the same as that described by Kosuge et al (1994b).…”

“…Among ocypodoid crabs, the families Dotillidae and Macrophthalmidae, as well as the family Ocypodidae, exhibit high levels of diversity in the mangrove swamps of Southeast Asia (Serène, 1968;Tan & Ng, 1994), but descriptions of their social behaviors such as waving displays, mating behavior, and fighting behavior are limited (Tweedie, 1950;Kosuge et al, 1994aKosuge et al, , 1994b, although the mating (Murai et al, 1995;Koga et al, 1999;Weis & Weis, 2004) and fighting (Koga et al, 1999;Tina et al, 2015) behaviors of fiddler crabs of the family Ocypodidae have often been studied . This paper presents observational notes on the social behaviors of waving display, threat display, chela-quivering display, fighting, burrow usurpation and mating, which were recorded for six dotillid species (Dotilla myctiroides, Dotillopsis brevitarsis, Ilyoplax delsmani, Ilyoplax gangetica, Ilyoplax obliqua, and Ilyoplax orientalis) and two macrophthalmid species (Macrophthalmus erato and Macrophthalmus pacificus) in mangrove swamps of southern Thailand, and these behaviors are compared with those of related species.…”

A New Species Of Ilyoplax (Decapoda, Brachyura, Dotillidae) From Panglao, The Philippines

“…Like other shore Ocypodoidea they also have evolved some complex and noteworthy behaviours, and these have been the subject of numerous studies (e.g., Wada, 1981Wada, , 1983aWada, -c, 1984Wada, , 1987aKosuge et al, 1994;Kitaura & Wada, 1998, 2006a.…”