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Genus Hydrophilus - Giant Water Scavenger Beetles

Large Water Beetle - Hydrophilus ovatus water nymph - Hydrophilus giant water beetle - Hydrophilus ovatus Giant Water Scavenger Beetle - Hydrophilus ovatus Giant Black Water Beetle? - Hydrophilus triangularis - male Hydrophilus ovatus Hydrophilidae ? - Hydrophilus ovatus 9050490 Hydro - Hydrophilus ovatus
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
No Taxon (Series Staphyliniformia)
Superfamily Hydrophiloidea (Water Scavenger and Clown Beetles)
Family Hydrophilidae (Water Scavenger Beetles)
Subfamily Hydrophilinae
Tribe Hydrophilini
Genus Hydrophilus (Giant Water Scavenger Beetles)
Explanation of Names
Hydrophilus Geoffroy 1762
Greek 'water-loving'
Numbers
4 spp. (in 2 subgenera) in our area(1); 3 subgenera total(2)
Subgenus Hydrophilus
H. ensifer: s. Florida; Caribbean and Mexico to Argentina
H. insularis: s. AZ, s. TX, FL; Mexico to Central America
H. triangularis: widespread in 48 states, southern Canada (BC-QC); Mexico
Subgenus Dibolocelus
H. ovatus: eastern US, se. Canada; (QC-FL-TX-IA); Mexico
Size
the largest members of the family, >30 mm (our spp. up to 40 mm, extralimital spp. up to ~50 mm)(2)(3)
Identification
key to spp. in Epler (2010)(2) and Short & McIntosh (2014)(4).
Range
widespread N. Amer. & Eurasia(1)(3)
Habitat
stagnant/slow waters; prefer deeper water (weedy ponds, deep drainage ditches)(2)
Life Cycle
Female deposits up to 140 yellow eggs in cocoon-like egg case with a "mast". Case is large, about 15 X 24 mm, and floats or is attached to an underwater object. Larvae aquatic, predatory? Pupation occurs in moist soil. Adults emerge in under two weeks and return to the water. There are one or two generations per year. Some adults overwinter on land, under leaf litter. Others may remain under ice of ponds and stay active all winter. Lifespan may exceed one year.
Remarks
The subgenus Dibolocelus in Mexico was recently revised, with five additional species (other than H. ovatus) recorded along the Gulf of Mexico coast in Mexico and one in Cuba. Further study could reveal the presence of these species in southern Texas or Florida. See Arce-Pérez et al. 2021.
Print References
Short, A. E. Z., and McIntosh, C. E. 2014. Review of the Giant Water Scavenger Beetle Genus Hydrophilus Geoffroy (Coleoptera: Hydrophilidae) of the United States and Canada. The Coleopterists Bulletin 68(2): 187–198. http://www.bioone.org/doi/full/10.1649/0010-065X-68.2.187
Internet References
Arce-Pérez, Roberto; Arriaga-Varela, Emmanuel; Novelo-Gutiérrez, Rodolfo; Navarrete-Heredia, Josè L. (2021). Giant water scavenger beetles Hydrophilus subgenus Dibolocelus (Coleoptera: Hydrophilidae) from Mexico with description of two new species. Zootaxa. 5027 (3): 387–407.
Works Cited
1.American Beetles, Volume I: Archostemata, Myxophaga, Adephaga, Polyphaga: Staphyliniformia
Arnett, R.H., Jr., and M. C. Thomas. (eds.). 2000. CRC Press LLC, Boca Raton, FL.
2.The Water Beetles of Florida
Epler J.H. 2010. Florida Department of Environmental Protection. Tallahassee. 414 pp.
3.Keys to the insects of the Far East of the USSR, Vol. 3. Coleoptera I
Lehr P.A., ed. 1989. Leningrad, Nauka Publishing House, 572 pp.
4.Review of the Giant Water Scavenger Beetle Genus Hydrophilus Geoffroy (Coleoptera: Hydrophilidae) of the US and Canada.
A. E. Z. Short and C. E. Mcintosh IV. 2014. The Coleopterists Bulletin 68(2): 187-198.