Efeito do parasitismo de cimotóides escavadores em loricarídeos.

Abstract

Cymotroids belong to the order Isopoda and are ectoparasites of fishes. Among the parasitism strategies of cymotroids, it stands out the strategy of penetrating, burrowing and lodging in the abdominal cavity of the hosts. Due to this complex parasitism strategy, they are considered to be highly host-specific parasites. Therefore, we investigated the effects of parasitism of the burrowing cimothyoid Artystone sp. on the loricarids Hisonotus chromodontus and Curculionichthys luteofrenatus in the Selma stream, a tributary of the Teles Pires River - MT. The hypothesis under study is that parasitism causes negative effects on feeding, reproduction and length-weight relationship of the hosts. The presence of alternative hosts was also investigated. The parasitic interaction of Artystone sp. with C. luteofrenatus and H. chromodontus was monitored for one year with standardized monthly collections. We conclude that the burrowing cymotoid Artystone sp. has a high affinity for the hosts C. luteofrenatus and H. chromodontus due to their life history characteristics as a primary cause and then their abundance in the studied environment, and other hosts were not recorded. Parasitic castration caused by Artystone sp. occurred in C. luteofrenatus and H. chromodontus hosts and there was a higher prevalence of infestation in female hosts. The weight-length relationship was lower in parasitized H. chromodontus hosts, indicating a negative effect on somatic increment, even though all hosts had fully replete stomachs and gastrointetinal tracts. The highest standard length values for both species were observed in parasitized and castrated hosts, and this added to the number of hosts with undifferentiated sex, and immature males and females suggests that the parasitic interaction of Artystone sp. with C. luteofrenatus and H. chromodontus starts with very young individuals.