Genus Hydrophilus - Giant Water Scavenger Beetles

Hydrophilus Geoffroy 1762

Greek 'water-loving'

3 spp. in 2 subgenera in our area(1); additional species may be expected in so. FL; 3 subgenera total(2)

the largest members of the family, >30 mm (our spp. up to 40 mm, extralimital spp. up to ~50 mm)(2)(3)

key to spp. in(2)

widespread NA & Eurasia(1)(3)

stagnant/slow waters; prefer deeper water (weedy ponds, deep drainage ditches)(2)

Apr-Nov (H. triangularis in the Carolinas)(4)(5)

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. Adults may be found at lights in summer as they disperse.

Hydrochara, Dytiscus, Cybister