Amsterdam Expeditions to the West Indian Islands, Report 28. Predation as a factor influencing the occurrence and distribution of small Crustacea in West Indian groundwaters

Hadziid Amphipoda are known from inland groundwaters of 14 West Indian islands, Thermosbaenacea from those of 9 islands. Only 4 islands show joint occurrence of both groups. Even in islands of joint occurrence, hadziids occur significantly more often alone in a given locality, than in combination with Thermosbaenacea or Copepoda Cyclopidae. The latter two groups do not show any significant avoidance of each other. Some possible causes for the non-random occurrence of small groundwater Crustacea are discussed; it seems most likely that hadziids predate on other Crustacea, such as Thermosbaenacea or Cyclopidae. This predation may have, or have had, influence on the actual distribution patterns of the groups under consideration.