Egg size and clutch size in three species of Nihonotrypaea (Decapoda: Thalassinidea: Callianassidae) from western Kyushu, Japan

Abstract

Three species of the callianassid genus Nihonotrypaea occur in the Ariake Sound estuarine system, southern Japan; they consist of two tidal-flat species (N. harmandi; N. japonica) and one boulder-beach species (N. petalura), with maximum population densities of 1440, 343, and 12 ind m−2, respectively. Nihonotrypaea harmandi and N. petalura are distributed along the coastline from the outermost part of the sound to the open sea, while N. japonica occurs in the middle part of the sound. Nihonotrypaea japonica has an extended reproductive period from late winter to autumn, while those of the other species are from late spring or summer to autumn. Interspecific comparisons were made for recently laid egg size (as volume) and clutch size (as number of eggs per female). Only in N. japonica was a seasonal egg size variation observed, being significantly larger in winter to spring (mean=0.106 mm3) than in summer (0.080 mm3). By contrast, clutch size was significantly smaller in winter to spring, resulting in nearly the same clutch volume per female (product of the mean egg volume and clutch size) between the seasons. Among the three species, the egg size was ordered as N. japonica (overall mean volume through the seasons=0.092 mm3)>>N. petalura (0.057 mm3)>N. harmandi (0.054 mm3). The clutch size was ordered as N. harmandi>N. petalura≈N. japonica. The clutch volume was ordered as N. japonica≈N. harmandi>N. petalura. The smallest clutch volume value for N. petalura female showed an opposite trend to the relative size of the major cheliped found in a previous study.

Offspring production in three freshwater crab species (Brachyura: Pseudothelphusidae) from the Amazon region and Central America

“…, KUBO et al 2006, TEROSSI et al 2010, including brachyuran crabs , NAVARETTE et al 1999. The first egg volume data for freshwater crabs is presented here (Tab.…”

Population biology of the ghost shrimps, Trypaea australiensis and Biffarius arenosus (Decapoda: Thalassinidea), in Western Port, Victoria

“…This supports by greater than 5º in latitude which is similar to the degree of separation between the sites sampled by Rotherham and West (2009) and the sites sampled in the current study. Kubo et al (2006) also found a latitudinal gradient in the size of ghost shrimps (Nihonotrypaea japonica and N. harmandi) embryos, again with the smaller embryos at higher latitude. summarised literature that showed that food availability may be a driving factor of latitudinal differences in embryo size.…”

“…summarised literature that showed that food availability may be a driving factor of latitudinal differences in embryo size. In contrast, Kubo et al (2006) attributed latitudinal differences in embryo size to differences in temperature. For example, the higher the latitude the cooler the water and therefore the larger the embryo size [as seen for N. japonica (cooler waters) and N. harmandi (warmer waters)] (Kubo et al, 2006).…”

“…Ovigerous females of B. arenosus and T. australiensis were selected with stage 1 embryos only (as described by Rodrigues (1976) (cited in Kubo et al 2006)). Stage 1 embryos are tightly packed and round with a uniformly distributed yolk and no eye spots.…”

“…In contrast, a number of studies (e.g. Kubo et al (2006)) attributed latitudinal differences in thalassinidean embryo size amongst individuals of the same species to variations in water temperature. Differences in the size of individuals of Upogebia africana were related to variation in food availability and salinity of the water column (Hanekom and Erasmus, 1988).…”