Predation of adult large diving beetles Dytiscus marginalis (Linnaeus, 1758), Dytiscus circumcinctus (Ahrens, 1811) and Cybister lateralimarginalis (De Geer, 1774) (Coleoptera: Dytiscidae) on fish fry

Abstract

The presented study describes the presence of fish fry in the diet of imagines of large Dytiscidae. The study was conducted between March and September in 2012 and 2013. A total of 163 large, aquatic, diving beetles were caught, which represented the following species: Dytiscus marginalis, Dytiscus circumcinctus, Cybister lateralimarginalis. Fish were identified by scales, bones, vertebrae, pharyngeal teeth. Insects were identified by epicrania, mandibles, hooks, limbs, body segments, eyes and wings. Crustaceans were identified by limbs and Oligochaeta by bristles. Seeds and eggs of invertebrates were found whole and intact. Fragments of fish fry were found in the digestive tracts of all three species collected in three studied ponds. The alimentary canals of the studied beetles contained also fragments of insects, detritus, plant tissue, Crustacea, Arachnida, other invertebrates, Oligochaeta, and Gastropoda.*

Field observation of predation on a horsehair worm (Gordioida: Chordodidae) by a diving beetle larva Cybister brevis Aubé (Coleoptera: Dytiscidae)

“…In freshwater environments, diving beetles (Coleoptera: Dytiscidae) are carnivorous during both the larval and adult stages; larvae are exclusively predatory, whereas adults also scavenge for food (Culler et al ). They are known to prey on zooplankton, insects, gastropods, fish, amphibians and reptiles (Drummond & Wolfe ; Ohba ,b; Cobbaert et al ; Rosa et al ; Frelik ; Hayashi & Ohba ). In addition, a previous report described finding larval horsehair worms in the gut of an adult diving beetle, Dytiscus marginalis , in a laboratory experiment, which was attributed to predation on larval Lepidoptera infested with larval horsehair worms (Blunck ).…”

Dine‐in or take‐away? Scavenging strategies in predaceous diving beetles at different water depths

“…Scientists have been investigating the diet preference and prey compositions of dytiscids through food choice experiments, and many studies have found that adults scavenge for animal carcasses even with preference over live prey (Velasco & Millan, 1998; Kehl & Dettner, 2003; Bofill & Yee, 2019). Examinations of gut contents in wild‐caught dytiscid adults indicated high diversity of their food sources, including zooplankton, invertebrates, and vertebrates (Frelik, 2014; Frelik & Pakulnicka, 2015), which potentially implies a less selective scavenger lifestyle. Most studies on foraging strategies of dytiscids so far have been focused on predation at their larval stage (e.g., Michel & Adams, 2009; Yee, 2010), leaving scavenging tactics of adults unclear.…”

Rearing of Bitterling (Rhodeus amarus) Larvae and Fry under Controlled Conditions for the Restitution of Endangered Populations

“…Larvae swim out of their incubators after 3–4 weeks (depending on the water temperature) band form shoals of several to several hundred larvae very soon thereafter [ 13 , 14 ]. They prefer shallow places, with dense vegetation, where they are not exposed to attacks of predators, i.e., other fish and aquatic insects, larvae and adults, such as great diving beetle Dytiscus marginalis , the beetle Cybister lateralimarginalis [ 15 ], or dragonfly larvae Anax sp. of the family Aeshnidae [ 16 ].…”