The population structure of Probopyrus floridensis (Isopoda, Bopyridae), aparasite of Macrobrachium potiuna (Decapoda, Palaemonidae) from the Pereque River, Parangua Basin, Southern Brazil
S. Masunari et al., The population structure of Probopyrus floridensis (Isopoda, Bopyridae), aparasite of Macrobrachium potiuna (Decapoda, Palaemonidae) from the Pereque River, Parangua Basin, Southern Brazil, CRUSTACEANA, 73, 2000, pp. 1095-1108
The population structure of the bupyrid isopod Probopyrus floridensis infes
ting the freshwater shrimp Macrobrachium potiuna from the Pereque River was
monthly analysed from January 1996 to October 1996. The parasites, taken f
rom preserved shrimps, were measured and sexed. A total of 635 isopod paras
ites was obtained from 197 shrimps. The following developmental stages and
sexes were recognized within the parasite population: cryptoniscus, bopyrid
ium, immature males, immature females, mature males, mature females, and ov
igerous females. The parasitic density fluctuated between 1 (January and Ma
y) and 33 (June) parasites per host. The parasitic incidence varied from 1.
1% (April) to 97.6% (September). Ovigerous females were observed only in Oc
tober. The cryptoniscus infestation occurred mainly in June (early winter)
and continued for three months. By July (winter), the majority of the paras
ite population was still composed of juvenile or immature parasites, but fr
om August to October (spring), the adult stages predominated. Probopyrus fl
oridensis reproduces only once a year. Its life cycle is discussed in more
detail.