Our results were recently highlighted in a news article in Science Magazine. Stevens, Department of Biological Sciences, UCSB Populations of organisms often exhibit a surprisingly heterogeneous spatial distribution. Spatial heterogeneity may result from recruitment variation, habitat variation, or post-recruitment processes such as competition, predation or disease. Furthermore, the parasites must recruit from one host to another to complete the life cycle, which may intensify or diminish spatial variability. Host behavior may also affect the distribution of parasites at the individual, population, or community level.
Digenetic trematodes have complex life cycles, which require at least two hosts.
In this study, the first intermediate host is the snail, Cerithidea californica. Second intermediate hosts include the crab, Hemigrapsus oregonesis, two fishes, Gillichthys mirabilis and Fundulus parvipinnus, and the clam, Tagelus californianus. The snail population of Carpinteria Salt Marsh harbors 13 different trematode species. Of these 13 species, two parasitize the crab, two parasitize the fishes and one parasitizes the clam. These studies confirm that there was significant spatial heterogeneity of trematode infections in the snail, crab, and clam populations, but not in the fishes.