Spiny but Subitaneous Eggs: Egg Morphology and Hatching in AcartiaCopepods in the Tropics

摘要

Egg surface ornamentation, egg production rates, and hatching success of two calanoidcopepod species ( and cf. ) were examined in a tropical coral reef of Tioman Island,Malaysia, near the equator (2°N). All observed females of and cf. produced eggs with spines on thesurface, either short or long, which are common in resting eggs in temperate ecosystemsthat hatch when environmental conditions are favorable or after a certain refractoryperiod. However, all of these spiny eggs in the present study hatched within 48 hours whenexposed to ambient seawater temperature, suggesting that they were subitaneous eggs. Suchspine ornamentation has been thought to be an adaptive feature only for resting eggs tosurvive during egg dormancy, but the presence of spines on subitaneous eggs suggestsfurther possible functions of these spines such as reducing the risks of ingestion bypredators.