Inter- and intraspecific variation in the life histories of three sympatric isopods in a Hong Kong forest

Abstract

Burmoniscus ocellatus (Philosciidae), Formosillo raffaelei and Orodillo maculatus (Armadillidae) were all iteroparous. Burmoniscus ocellatus had more frequent breeding bouts, and smaller broods than O. maculatus and F. raffaelei. Although the three isopods had different life spans, brood numbers and life-time fecundities, their rates of offspring production (number of eggs per month) were similar. The Hong Kong isopods had longer breeding periods, a greater number of broods per life time, and lower reproductive allocation per brood than their temperate counterparts. Intraspecific, between-site differences in fecundity and brood dry weight of F. raffaelei could probably be explained by the variations in the size of gravid females. Burmoniscus ocellatus produced heavier eggs at the site with a higher population density, suggesting that conditions at the site with a higher isopod density may be more K-selecting. Female-biased sex ratios, possibly resulting from differential sex-specific mortality, were common among the isopod samples. -from Authors