MEPS 442:123-132 (2011)  -  DOI: https://doi.org/10.3354/meps09402

ABSTRACT: In many species, size and age can be strong determinants of the reproductive success for both sexes. We examined age- and size-dependent reproductive performance (egg and sperm production, mating success) in a pelagic copepod, Temora longicornis. Compared with smaller males, larger males produced larger spermatophores containing more spermatozoa and fertilized a larger fraction of available females. Females mating with large males produced more offspring than those mating with small males. Similarly, large females had higher egg production rates as well as a higher lifetime egg production than did small females. Ageing effects were evident in this species: mortality rate increased and fertility decreased rapidly with age. The average adult longevity under optimal laboratory conditions was 30 d in both males and females, but females produced eggs for only 18 d, and males could fertilize females for only about 8 d after they matured. The strong size- and age-dependent fertility observed in this species is conducive to the development of sexual selection via mate choice for young and large partners, as has been shown in another copepod species.

KEY WORDS: Spermatophore · Spermatozoa · Egg production · Ageing · Mortality rate · DAPI · Temora longicornis