Dytiscus alaskanus

J. Balfour-Browne, 1944

boreal water beetle, Alaskan diving beetle

Dytiscus alaskanus is a large predaceous diving beetle inhabiting freshwater systems across northern North America. The exhibits a with peaking in late spring and declining through summer. It is strictly , with activity levels approximately fifty times higher during dark hours than daylight. Mating involves elaborate courtship , prolonged copulation lasting 2-5 hours, and postcopulatory mate guarding by males.

Pronunciation

How to pronounce Dytiscus alaskanus: /dɪˈtɪskəs æˈlæskənəs/

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Habitat

Freshwater lentic including eutrophic lakes and ponds. In lakes, prefers the interface between open water and emergent vegetation, particularly areas with cattail (Typha) and sedge shoreline vegetation.

Distribution

North America; recorded from Alaska, Alberta, and British Columbia.

Seasonality

peak in late spring and decline throughout summer; activity constrained by short growing season.

Host Associations

Eylais sp. - Aquatic mite larvae attach preferentially to the costal-subcostal region of the hindwing surface; rates highest in early spring, decline through summer, and rise again in fall

Life Cycle

; one per year.

Behavior

Strictly diel activity pattern with peak activity during dark hours. Males use antennal contact for mate recognition and possess adhesive setae on pro- and mesotarsi for grasping females. Females exhibit resistance including escape swimming and diving. Postcopulatory mate guarding occurs with males remaining attached to females for extended periods.

More Details

Parasite phenology

The parasitic phase of Eylais mites coincides with peak . Mite larvae overwinter on beetles, grow rapidly to maximum size by late June-July, then enter a non-parasitic life phase.