Eusocial (truly social) animals are not very common. Only nine groups are known to be eusocial, eight of them live in terrestrial environments. The only known aquatic eusocial animals are snapping shrimps of the genus Synalpheus. But, since they live inside sponges-their shelter and food-little is known of their biology and colony organization.

STRI postdoctoral fellow Eva Toth doing research on Bocas del Toro, studies eusocial snapping shrimps, that have colonies with tens to hundreds of members with one reproductive female, a large queen carrying the embryos. These shrimp are smaller than their pair-living cousins, also sponge-dwelling animals.

These eusocial shrimps are equipped with an enlarged snapping claw that they use for communication and combat. By closing the fingers of their claws very rapidly, they send a water jet to their opponent, thereby indicating their strength. As a byproduct, an audible crackling sound is produced, hence their popular name. When conflict escalates they can grab and cut their opponents with their claws.

Eva focuses on how these small shrimps are able to successfully compete for their host sponges with their larger cousins. She also compares their colony structure and organization with terrestrial social animals.



Posted by: Kelly    Source