GASTROPOD PREDATION ON THE PANAMANIAN CARIBBEAN COAST

Dynamics of gastropod predation in the fossil record has been the subject of extensive studies and its patterns are well documented in the literature. Unfortunately, much less is known for recent molluscan communities especially from tropical shallow waters. Amongst these, drilling intensities in soft bottom communities are the ones less studied.

In general, the Caribbean region is considered a nutrient-poor, phototrophic ecosystem, product of the declining primary productivity and increased water temperatures consequence of oceanographic changes brought about by the rise of the Isthmus of Panama 3 million years ago. The Bocas del Toro region, located in the Caribbean coast of Panama, is considered a relatively high productivity zone due mainly to runoff from the mangrove area bordering the coastline.

Here we present data on predation by gastropods on a soft bottom tropical mollusk community. Analyzes of over 100 recent dredges collected in the Bocas region as part of the Panama Recent Biotic Survey show a relatively high incidence of predation on both gastropod and bivalve shells. Many gastropod shells also show signs of incomplete drilling representing failed attempts by the predator and successful escapes by the prey. These observations are important for the discussion concerning the so-called multiply bored prey and its implication for predator-prey interaction studies. In general, we didn’t find significant differences in drilling intensities amongst bivalve and gastropod shells. Both naticids and muricids seem to play an important role as predators in this region.

We were also interested in testing the hypothesis concerning lower rates of predation in the Caribbean as opposed to the eastern Pacific. For that we analyzed gastropod predation intensity in gastropods in a series of samples from the Gulf of Panama, eastern Pacific coast. Preliminary results show that drilling intensities in the Bocas del Toro samples are somewhat lower than in the Gulf of Panama.

More studies using bigger sample sizes are needed in order to better access differential predation in shallow tropical waters of Central America.