Effects of Polysispyrenia simulii (Microspora; Duboscqiidae) on development of the gonads of Simulium pertinax (Diptera; Simuliidae)

The effects of the infection caused by the microsporidium Polydispyrenia simulii in gonads of the simuliid Simulium pertinax were evaluated. This blackfly species is the main target of control programmes in southeastern Brazil. Infected and noninfected blackflies were reared from larval stage to adults using a laboratory rearing system. There was no significant difference between the oogenic development and dimensions of ovarian follicles of healthy females compared to those reared from infected larvae. Otherwise, there was a significant difference between the fecundity of healthy females and those reared from infected larvae. In males, there was an evident recuction of motility of spermatozoids of males reared from infected larvae. The results obtained suggest that the microsporidium P. simulii have an important effect on the natural population dynamics of S. pertinax.

Histopatología de kingiella chilenica (bivalvia, cyamiidae) parasitada por redias y cercarias de la familia gymnophallidae / Histopathology of kingiella chilenica (bivalvia, cyamiidae) parasitized by rediae and cercariae of the gymnophallidae family

Se hace un estudio histológico (gónada y hepatopáncreas) en especímenes del microbivalvo kingiella chilenica infectados con larvas de tremátodo digenea, con el fin de definir los órganos en los cuales se localizan las larvas de este parásito. Redias conteniendo cercarias de este tremátodo digenético, aparecen restringidas al tejido hepatopancreático del molusco (estando ausentes en gónadas u otros órganos contiguos) pudiendo mostrar infección masiva de dicho tejido. Por tanto, las gónadas presentan desarrollo gametogénico normal; esto último, unido al hallazgo de hembras parasitadas que igualmente incuban embriones, nos permiten concluir que la infección señalada no afecta, al menos directamente, la actividad reproductiva de este bivalvo