Maternal influence on the larval morphometry of the brush-clawed shore crab Hemigrapsus takanoi (Decapoda: Brachyura)

The morphology of larvae is a key factor influencing their behaviour, performance and ultimately their survival. There is evidence indicating a significant morphological variability among broods, and that this may be related to the size or conditions of the mother. However, this maternal influence is not consistent across decapod crustaceans. Using 35 broods from different mothers of the crab Hemigrapsus takanoi collected in the same locality of inner Tokyo Bay and at the same time, we tested the hypothesis that there is a positive relationship between the size of the mother and the progeny’s morphology. Our results indicate that different patterns in the length of the lateral, rostral and dorsal spines differentiated two distinct morphogroups of larvae. These morphogroups were linked to the size of the mother, showing that larger mothers produced bigger larvae with longer carapace spines. It is possible that larger size and longer spines can influence swimming performance and predator avoidance, respectively. These relationships should be tested in future experimental studies.