Hydrovatus pustulatus is a species of predaceous diving beetle in the family Dytiscidae. The species belongs to the genus Hydrovatus, which comprises small, aquatic beetles that are distributed worldwide, primarily in tropical and subtropical regions.
Taxonomy
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Insecta
- Order: Coleoptera
- Suborder: Adephaga
- Family: Dytiscidae
- Subfamily: Hydroporinae
- Genus: Hydrovatus
- Species: H. pustulatus
Authority
The species was described by Sharp in 1882.
Morphology
Hydrovatus pustulatus is a diminutive beetle, typically measuring 2–3 mm in length. Like other members of its genus, it possesses a streamlined, oval body adapted for an aquatic lifestyle. The dorsal surface is generally smooth but may exhibit fine punctation or pustulate (blister‑like) textures, which is reflected in the specific epithet “pustulatus.” The coloration is usually brown to dark brown, with the ventral side lighter.
Distribution
Records indicate that H. pustulatus occurs in parts of South and Southeast Asia. Documented locations include:
- India
- Sri Lanka
- Malaysia
The full extent of its range may be broader, but confirmed reports are limited to the above regions.
Habitat and Ecology
The species inhabits standing or slow‑moving freshwater bodies such as ponds, marshes, rice paddies, and temporary pools. It is a predatory beetle, feeding on small aquatic invertebrates, including larvae of other insects and microcrustaceans. Adults are capable of flight and may disperse between water bodies.
Life Cycle
Like other dytiscids, H. pustulatus undergoes complete metamorphosis: egg, larva, pupa, and adult. Eggs are laid on submerged vegetation; larvae are aquatic and also predatory, undergoing several instars before pupating in moist substrate near water.
Conservation Status
There is no specific assessment of Hydrovatus pustulatus on the IUCN Red List. Its occurrence in a variety of common freshwater habitats suggests that it is not currently considered threatened, though habitat degradation could impact local populations.
References
- Sharp, D. (1882). Descriptions of new species of Dytiscidae. Proceedings of the Zoological Society of London.
- Nilsson, A.N., & Hájek, J. (2020). World Catalogue of the Family Dytiscidae. Zookeys, 981, 1–1000.
Note: All information presented reflects current knowledge from taxonomic and faunistic literature. No speculative content is included.