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Inter‐ and intraspecific variation in the life histories of three sympatric isopods in a Hong Kong forest
Author(s) -
Ma H. H. T.,
Lam P. K. S.,
Dudgeon D.
Publication year - 1991
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1991.tb03795.x
Subject(s) - biology , intraspecific competition , brood , sympatric speciation , fecundity , ecology , semelparity and iteroparity , avian clutch size , zoology , interspecific competition , population , isopoda , reproduction , demography , crustacean , sociology
There is a paucity of data on the life‐history strategies of tropical animals. Accordingly, the inter and intraspecific life‐history variations of three sympatric isopods, Burmoniscus oceliutus (Philosciidae), Formosillo raffaelei and Orodillo maculatus (Armadillidae), were studied at two sites in a Hong Kong forest. All three isopods were iteroparous. Burmoniscus oceilutus had more frequent breeding bouts, and smaller broods than O. muculutus 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. These findings were consistent with the predictions of r ‐ and K‐theory. 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 ocellutus 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, and the possible adaptive significance of this pattern was discussed. The potential influence of phylogenetic constraints on the evolution of life‐history strategies was also considered.