Coelostoma (Holocoelostoma) stultum, is a species of water scavenger beetle widely distributed in Palearctic and Oriental realms from West Pacific towards Indian Ocean, such as China, Taiwan, Andaman Islands, Myanmar, India, Indonesia, Japan, Korea, Malaysia, Mascarene Islands, Nicobar Islands, Oman, Philippines, Saudi Arabia, South Korea, Sri Lanka, Thailand, United Arab Emirates, Oman, and Vietnam.[1][2][3][4]

Coelostoma stultum
Scientific classification
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C. stultum
Binomial name
Coelostoma stultum
(Walker, 1858)
Synonyms
  • Hydrobius stultus Walker, 1858
  • Coelostoma sulcata Pu & Zhe-Long, 1963
  • Cyclonotum simplex Sharp, 1874

Description

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Body length is about 4.2 to 5.8 mm. Body oval. Labrum blackish with yellow edges. Front margin of the labrum is emarginate. Elytral surface densely punctate. Prosternum moderately convex medially. Fifth abdominal ventrite is feebly emarginate posteromesally, not carinate. It bears a row of stout setae apically. Prosternum is not dentate. Head, pronotum and elytra consists with similar punctation. Median lobe of the aedeagus of male is almost parallel with broadly rounded apex. Aedeagus is shorter than parameres. Parameres are not sharply pointed whereas mesofemora without pubescence, and glabrous. Pronotum coarsely punctate and sparsely covered by short setae.[5][6]

Biology

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The species has found commonly near the shore of paddy fields, ponds and rivers in Japan. Adult beetle has a breeding season once a year in early summer. Females build one egg cocoon enfolds several eggs after a single mating. It produces silk from the genitalia and then spins the lower part of the egg cocoon from it. Later, the female lays eggs and spins the lid of the egg cocoon to cover the eggs. Meanwhile, it has observed that female coats the lid with her feces for the protection against predators. During night time, the marsh slug, Deroceras laeve is known to prey on these eggs cocoons.[7]

References

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  1. ^ Sheth, Sayali D.; Ghate, Hemant V.; Fikáček, Martin (2020-07-24). "Review of Coelostoma of the Indian subcontinent (Coleoptera: Hydrophilidae) Part 1: Coelostoma s. str. and Holocoelostoma". European Journal of Taxonomy (690). doi:10.5852/ejt.2020.690. S2CID 225461174. Retrieved 2021-07-30.
  2. ^ "New record of Coelostoma stultum (Coleoptera, Hydrophilidae) from the Daitô Islands, far off Southwest Japan". Diversification and systematics of Hydrophilidae. Retrieved 2021-07-30.
  3. ^ "Coelostoma stultum (Walker, 1858)". www.gbif.org. Retrieved 2021-07-30.
  4. ^ "Review of the Chinese species of the genus Coelostoma". biotaxa.org. Retrieved 2021-07-30.
  5. ^ GHAHARI, HASSAN; SPRECHER-UEBERSAX, EVA; ZILIOLI, MICHELE (2014-11-25). "Review of the Chinese species of the genus Coelostoma Brullé, 1835 (Coleoptera: Hydrophilidae: Sphaeridiinae)". Zootaxa. 3887 (3): 354–376. doi:10.11646/zootaxa.3887.3.4. PMID 25543937. Retrieved 2021-07-30.
  6. ^ Liu, Hsing-Che; Hu, Fang-Shuo; Fikáček, Martin (2020-03-11). "Review of the genus Coelostoma of Taiwan with description of a new species (Coleoptera: Hydrophilidae)" (PDF). Acta Entomologica Musei Nationalis Pragae. 60 (1): 155–162. doi:10.37520/aemnp.2020.008. S2CID 216332820. Retrieved 2021-07-30.
  7. ^ Matsushima, Ryosuke; Haga, Takuma (2021-07-12). "Predation on the egg of Coelostoma stultum (Coleoptera: Hydrophilidae) by the alien species Deroceras laeve (Mollusca: Gastropoda: Agriolimacidae)". Molluscan Research. 41 (3): 254–261. doi:10.1080/13235818.2021.1946895. S2CID 237799718. Retrieved 2021-07-30.