Adephaga
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Adephaga | |
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Cybister limbatus, a member of the family Dytiscidae (predaceous diving beetle) | |
Carabidae (ground beetles)
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Suborder: | Adephaga Schellenberg, 1806 |
Families | |
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The Adephaga (from
Anatomy
Adephagans have simple
Wings
The transverse fold of the hind wing is near the wing tip. The median nervure ends at this fold, where it is joined by a cross nervure.
Internal organs
Adephagans have four
Chemical glands
All families of adephagan have paired
Secretions pass from the secretory lobes, which are aggregations of secretory cells, through a tube to a reservoir lined with muscles. This reservoir then narrows to a tube leading to an opening valve. The secretory lobes differ structurally from one taxon to another; it may be elongated or oval, branched basally or apically, or unbranched.
Delivery of glandular compounds
Secretion can occur in multiple manners:
- Oozing: if the gland is not muscle-lined, the discharge is limited in amount.
- Spraying: if the gland is muscle-lined, which is typically the case of carabids, the substances are ejected more or less forcefully.
- Crepitation: boiling noxious chemical spray ejected with a popping sound. Crepitation is only associated with the Brachininae carabids and several related species. See bombardier beetle for a detailed description.
The secretions differ in the chemical constituents, according to the taxa.
The function of many compounds remain unknown, yet several hypotheses have been advanced:
- As predators; some compounds indirectly play this role by easing the penetration of the deterrent into the predator's integument.
- Antimicrobial and antifungal agents (especially in Hydradephaga)
- A means to increase wettability of the integument (especially in Hydradephaga)
- Alarm pheromones (especially in Gyrinidae)
- Propellant on water surfaces (especially in Gyrinidae)
- Conditioning plant tissues associated with oviposition
Distribution and habitat
Feeding
Most species are
carabids).Reproduction and larval stage
Some species are
The larvae are active, with well-chitinized cuticle, often with elongated cerci and five-segmented legs, the foot-segment carrying two claws. Larvae have a fused labrum and no mandibular molae.
Phylogeny
Adephagans diverged from their sister group in the
The adephagans were formerly grouped into the Geadephaga with the two terrestrial families Carabidae and Trachypachidae and the Hydradephaga, for the aquatic families. However this is no longer used as the Hydradephaga are not a monophyletic group. Modern analysis has supported the clade Dytiscoidea instead, which includes many aquatic adephagans, notably excluding Gyrinidae.
Cladogram of the relationships of living adephagan families after Vasilikopoulos et al. 2021[5] and Baca et al. 2021:[7]
Adephaga |
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See also
References
- Balke, M.; Ribera, I.; Beutel, R.; Viloria, A.; Garcia, M.; Vogler, A.P. (2008). "Systematic placement of the recently discovered beetle family Meruidae (Coleoptera: Dytiscoidea) based on molecular data". S2CID 86012007.
- "Adephaga". Integrated Taxonomic Information System.
- Adephaga Tree of Life