Who Eats Whom in a Pool? A Comparative Study of Prey Selectivity by Predatory Aquatic Insects

Predatory aquatic insects are a diverse group comprising top predators in small fishless water bodies. Knowledge of their diet composition is fragmentary, which hinders the understanding of mechanisms maintaining their high local diversity and of their impacts on local food web structure and dynamics. We conducted multiple-choice predation experiments using nine common species of predatory aquatic insects, including adult and larval Coleoptera, adult Heteroptera and larval Odonata, and complemented them with literature survey of similar experiments. All predators in our experiments fed selectively on the seven prey species offered, and vulnerability to predation varied strongly between the prey. The predators most often preferred dipteran larvae; previous studies further reported preferences for cladocerans. Diet overlaps between all predator pairs and predator overlaps between all prey pairs were non-zero. Modularity analysis separated all primarily nectonic predator and prey species from two groups of large and small benthic predators and their prey. These results, together with limited evidence from the literature, suggest a highly interconnected food web with several modules, in which similarly sized predators from the same microhabitat are likely to compete strongly for resources in the field (observed Pianka’s diet overlap indices >0.85). Our experiments further imply that ontogenetic diet shifts are common in predatory aquatic insects, although we observed higher diet overlaps than previously reported. Hence, individuals may or may not shift between food web modules during ontogeny

A phylogenetic analysis of Sciomyzidae (Diptera) and some related genera

10.1111/cla.12002Cladistics294404-415CLAD

Descrição da larva de Cosmariomyia argyrosticta Kertész e do pupário de Dactylodeictes lopesi Lindner (Diptera, Stratiomyidae) Description of the larva of Cosmariomyia argyrosticta Kertesz and the puparium of Dactylodeictes lopesi Lindner (Diptera, Stratiomyidae)

<abstract language="eng">The larva of Cosmariomyia argyrosticta Kertész, 1914 and the puparium of Dactylodeictes lopesi Lindner, 1964 are described for the first time, based on four larvae and 10 puparia and one puparium respectively. Larvae were collected under the bark of fallen trees in an area near of tropical rain forest at Iguaba Grande (22º50'21"S, 42º13'44"W, 18 m) and Buzios (22º44'49"S, 41º52'54"W, 3 m), State of Rio de Janeiro, Brazil. Some biological notes are also presented. The larvae of Cosmariomyia argyrosticta and Dactylodeictes lopesi are compared with Chalcidomorphina aurata Enderlein, 1914 and Vittiger schnusei Kertész, 1909