Epomis is a subgenus of ground beetle genus Chlaenius. The larvae of this subgenus are notable for being obligate role-reversal predators.[1] Amphibians such as frogs are normally predators of beetles; however, Epomis larvae feed exclusively on amphibians.[2][3]
| Epomis | |
|---|---|
| |
| Chlaenius dejeanii eating a southern banded newt, Ommatotriton vittatus | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Family: | Carabidae |
| Subfamily: | Harpalinae |
| Genus: | Chlaenius |
| Subgenus: | Epomis Bonelli, 1810 |
Description edit
Epomis beetles are often metallic blue- or green-colored, with a striking yellow-orange rim on the elytra and mostly yellow-colored legs and antennae.[4] They are 15–26 mm (0.59–1.02 in) in length.[5] Members of the Epomis subgenus can be distinguished from other species of Chlaenius by the short (less than three times as long as wide) and triangular labial palps.[4]
The larvae reach a body length up to 20 mm (0.79 in), they are white or yellow colored, with black and orange markings. Like many ground beetle larvae, they are elongated with two extensions (urogomphi) at the rear end. They have characteristic double-hooked mandibles. Larvae of the two European species can be distinguished by their color patterns.[6]
Feeding behavior edit
Epomis larvae hunt in a rare reversal of the usual predator-prey relationship between amphibians and insects. They lure their amphibian predators by making prey-like movements, then evade the predator's attack and disable the predator, often with a bite to the throat or underside.[1] After the attack, the larva stays attached to the amphibian while feeding on it, similarly to external parasites.[1][7][8] Adult Epomis beetles are generalist predators but can also feed on amphibians.[9][10] They sneak up behind their victims, and hold on firmly using their legs. To paralyze the victim, the beetle makes an incision in the pelvic region with its mandibles. The incision apparently cuts leg muscles.[11] The amphibian loses its ability to move and is eaten by the beetle. Scientists speculate that Epomis evolved this behavior as an aggressive evasion tactic in response to predation by amphibians and the success of this tactic led to Epomis becoming an obligate predator, itself.[1]
Taxonomic status edit
The subgenus Epomis belongs to the genus Chlaenius of the tribe Chlaeniini, subfamily Licininae, which consists of species associated with swamps, temporary ponds, and similar types of wetland habitats.[9] It contains about 30 species distributed in the Old World only, with the majority of species occurring in the Afrotropical region.[5][12] Epomis was formerly considered a genus of the tribe Chlaeniini rather than a subgenus of Chlaenius.[13]
Species edit
These 28 species belong to the subgenus Epomis:
- Chlaenius alluaudi Fairmaire, 1901 (Madagascar)
- Chlaenius amarae Andrewes, 1920 (Southwest Asia)
- Chlaenius barkeri Csiki, 1931
- Chlaenius bocandei (LaFerté-Sénectère, 1852) (Africa)
- Chlaenius circumscriptus (Duftschmid, 1812) (Europe, Africa, Asia)
- Chlaenius croesus (Fabricius, 1801) (Africa)
- Chlaenius croyi Kirschenhofer, 2003 (Africa)
- Chlaenius daressalaami Jedlicka, 1957 (Tanzania)
- Chlaenius dejeanii (Dejean, 1831) (Europe)
- Chlaenius deplanatus (LaFerté-Sénectère, 1851) (Africa)
- Chlaenius duvaucelii (Dejean, 1831) (India)
- Chlaenius elisabethanus Burgeon, 1935 (Africa)
- Chlaenius elongatus (Klug, 1833) (Madagascar)
- Chlaenius fimbriatus (Klug, 1833) (Madagascar)
- Chlaenius immunitus Murray, 1858 (Africa)
- Chlaenius jordani (Basilewsky, 1955) (Tanzania)
- Chlaenius kenyerii Kirschenhofer, 2003 (China)
- Chlaenius lastii Bates, 1886 (Africa)
- Chlaenius latreillei (LaFerté-Sénectère, 1852) (Africa)
- Chlaenius loveridgei (Basilewsky, 1951) (Tanzania)
- Chlaenius nigricans Wiedemann, 1821 (South and East Asia)
- Chlaenius nossibianus Facchini, 2011 (Madagascar)
- Chlaenius protensus Chaudoir, 1876 (Africa)
- Chlaenius rhodesianus Péringuey, 1898 (Africa)
- Chlaenius simba Alluaud, 1929 (Africa)
- Chlaenius tschitscherini Jedlicka, 1952
- Chlaenius vientianensis Kirschenhofer, 2009 (Laos)
- Chlaenius violaceipennis Chaudoir, 1876 (Africa)
References edit
- ^ a b c d Gil Wizen & Avital Gasith (2011). "An unprecedented role reversal: ground beetle larvae (Coleoptera: Carabidae) lure amphibians and prey upon them". PLoS ONE. 6 (9): e25161. doi:10.1371/journal.pone.0025161. PMC 3177849. PMID 21957480.
- ^ Lorenz, Wolfgang (2021). "Carabcat Database". doi:10.48580/dfqf-3dk. Retrieved 2023-03-04.
- ^ "Epomis Bonelli, 1810". Catalogue of Life. Retrieved 2023-03-23.
- ^ a b Trautner Jürgen, & Geigenmüller Katrin (1987). Tiger beetles, ground beetles. Illustrated key to the Cicindelidae and Carabidae of Europe. TRIOPS Verlag.
- ^ a b Basilewsky, P. (1955). Révision des epèces africaines du genre Epomis (Carabidae). Transactions of the Royal Entomological Society of London 107: 95-116.
- ^ Wizen, Gil; Gasith, Avital (2011). "Color variability and body size of larvae of two Epomis species (Coleoptera: Carabidae) in Israel". ZooKeys (119): 37–52. doi:10.3897/zookeys.119.1451. PMC 3192425. PMID 21998516.
- ^ Shiina, M., and Tachikawa, S. (1988). The life history of Epomis nigricans and its larval stage feeding on toads. Abstracts of the 48th Annual Meeting of the Entomological Society of Japan, p. 35. Nishibaru, Okinawa.
- ^ Tachikawa, S. (1994). Predation on anurans by Epomis nigricans larvae. Amazing Life of Insects, Atlas of the 48th Special Exhibition, Otaru Museum, Otaru.
- ^ a b Wizen, Gil; Gasith, Avital (2011). "Predation of amphibians by carabid beetles of the genus Epomis found in the central coastal plain of Israel". ZooKeys (100): 181–191. doi:10.3897/zookeys.100.1526. PMC 3131015. PMID 21738411.
- ^ Toshiaki, H. (2006). Predation by a carabid beetle (Epomis nigricans) on a juvenile frog (Rana nigromaculata). Bulletin of the Herpetological Society of Japan 2: 99-100.
- ^ "Absurd Creature of the Week: This Toad Isn't Eating a Bug. The Bug is Eating It". Wired.
- ^ Löbl Ivan, & Aleš Smetana (2010). Catalogue of Palaearctic Coleoptera, Vol.1: Archostemata, Myxophaga, Adephaga. Apollo Books, Stenstrup: 347-356.
- ^ Pietro Brandmayr, Teresa Bonacci, Tullia Zetto Brandmayr (2010): Larval morphology of epomis circumscriptus (Duftschmid 1812) and of first instar E. dejeani, Dejean, 1831 (Coleoptera, Carabidae, Chlaeniini), with morphofunctional remarks. Zootaxa 2388: 49-58.
