Predation on endangered Gomphid dragonfly larvae by nonnative channel catfish

Abstract

Larvae of endangered gomphid dragonflies were found in the stomach contents of channel catfish Ictalurus punctatus, an invasive alien species, collected in the lower Yodo River, Osaka Prefecture, Japan in 2020–2023. The following dragonfly species were identified: Stylurus annulatus (25 individuals), S. oculatus (6 individuals), Melligomphus viridicostus (2 individuals), Shaogomphus postocularis, Nihonogomphus viridis, and Sieboldius albardae (1 individual each). One of the channel catfish collected in April 2022 fed on 20 larvae of S. annulatus, which is listed as Vulnerable (VU) in the Red List of Japan. Predation pressure from channel catfish may cause a decline in the population of S. annulatus. Ongoing accumulation of information on the feeding habits of channel catfish will reveal its impact on native aquatic organisms, including threatened insect species.