Abstract

The gordiids, freshwater representatives of the parasite phylum Nematomorpha, function as a link between aquatic and terrestrial ecosystems; but despite the Gordiida's ecologic relevance, further studies are still needed to elucidate different aspects of the biology of the class—and among those, the infective capacity, a parameter that can be evaluated by the infection index mean abundance (IIMA). A knowledge of the intrinsic variability in the infective capacity of Chordodes nobilii would warrant priority in order to establish the range of acceptable responses for normal or standard conditions in the laboratory and to compare the criteria among different assays. Therefore, the objective of this study was to establish a baseline value for the infective capacity for Aedes aegypti larvae of the gordiid C. nobilii under controlled laboratory conditions by employing the IIMA as the evaluation parameter. To that end, we analyzed the infective capacity of C. nobilii larvae that had hatched from different strings of eggs laid in the laboratory by a total of 12 females. Our results enabled the corroboration of an ample range of responses in the infective capacity of this species, which characteristic would be linked to the female of origin of the hatch. Because this relationship prevents the establishment of a baseline for making comparisons among assays with gordiids through the IIMA as a response parameter, we recommend expressing the IIMA values in each assay relative to their respective controls. These findings also provide evidence for the greater success in infections by certain members of the progeny over others. Finally, on the basis of the results obtained from this study, we stress the relevance of the use of the IIMA as a final/definitive point to consider in different studies on the biology of the Gordiida.
Keywords: Parasite, Nematomorpha, Infective capacity, Infection index mean abundance, Female