Parasite burden in decapod crustaceans from the central coast of Chile: is there any association with the relationship with definitive host abundances?

Abstract

Crustaceans play an important role in parasite life cycles, serving as second intermediate hosts. However, there are scarce parasitological studies in crustaceans from the rocky intertidal habitats, in Chile and around de world. In this study we aimed to record the parasites in decapod crustaceans, compare their parasitic loads between localities and relate them with the abundance of the definitive hosts (fishes and birds). Between July and September 2013, 409 crustacean specimens, corresponding to 16 species, were collected from the rocky intertidal zone of two localities of central Chile (33°S), Las Cruces and Montemar. Of out the sample, 65.5% was parasitized; counting 2,410 metacercariae and 18 nematodes. One group of these metacercariae belonged to the family Opecoelidae; while others corresponded to the family Microphallidae. Nematodes belonged to the family Cystidicolidae. The highest prevalence and abundance of opecoelids were in P. violaceus (96.9%, 13.59 ± 17.50 parasites/crustacean), microphallids were mostly recorded in the crab Petrolisthes tuberculosus (42.3%, 11.08 ± 4.8 parasites/crustacean), while cystidicolids were less prevalent and abundant than digenean at both localities. Parasite loads was affected by body size, locality and species of crustacean hosts. No association was found between parasite loads in these intermediate hosts and the abundance of definitive hosts. The low relationships between parasite loads and host abundances may be due to several reasons, such as a wide trophic spectrum and great capacity of movement, which would not contribute to the parasite transmission and the direct relationship with the definitive host abundances.