Local distribution of blackfly (Diptera, Simuliidae) larvae in two adjacent streams: the role of water current velocity in the diversity of blackfly larvae

This study aimed to evaluate the influence of water velocity speed on the local distribution and taxocenosis structure of blackfly larvae. The larvae were collected from two adjacent streams located in the municipality of Angra dos Reis (RJ): Caputera River and one of its tributaries. Riffle litter patches were sampled randomly using a 30 x 30 cm quadrat. Four blackfly species were found: Simulium incrustatum s. l. Lutz, 1910; Simulium (Inaequalium) sp. ; Simulium pertinax s. l. Kollar, 1832 and Simulium subpallidum s. l. Lutz, 1909. Among these species, Simulium pertinax s. l. was clearly associated with higher water current speeds, while Simulium subpallidum s. l. showed association with lower water velocities, and Simulium (Inaequalium) sp. had a relatively constant distribution along the water current gradient.

Within tree distribution of a gall-inducing Eurytoma (Hymenoptera, Eurytomidae) on Caryocar brasiliense (Caryocaraceae)

For the first time, we identified the insect herbivore that induces one of the most conspicuous galls on the leaves of Caryocar brasiliense Camb. (Caryocaraceae), a widespread, typical cerrado woody plant of large economic importance. The gall inducing organism is a new and undescribed species of Eurytoma sp. (Hymenoptera, Eurytomidae). Furthermore, we recorded its spatial distribution within C. brasiliense trees. More Eurytoma galls were found on the eastern tree slope, followed the southern and northern slopes. More galls were found in the interior of the tree crown, i.e., on the proximal portion of the stems compared to the terminal portion. At the leaf level, more galls were found on the median region compared to the distal or proximal, perhaps due to the lower trichome density found in there. Leaf colonization by Eurytoma sp. may initiate at the leaf margin but after colonization reaches 50% the central portion starts to be colonized.