Dineutus nigrior
Roberts, 1895
whirligig beetle
A of whirligig beetle in the Gyrinidae, found across North America. are surface-dwelling aquatic beetles known for their distinctive circular swimming patterns and social on water. Males possess enlarged protarsal pads used during mating attempts, and accessory glands that show positive allometry associated with increased mating success. The species serves as to water mites, with levels linked to host body condition and sex.
Pronunciation
How to pronounce Dineutus nigrior: //dɪˈnjuːtəs ˈnɪɡri.ɔːr//
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Identification
Distinguished from other Dineutus primarily by coloration; males exhibit enlarged protarsal pads (adhesive structures on forelegs) used during mating. Distinguished from the smaller Gyrinus by larger body size and hidden scutellum. Specific identification from such as D. discolor requires examination of ventral characters.
Images
Habitat
Surface waters of rivers, streams, and lakes; aggregate in groups on open water surfaces, particularly in sheltered pools and lazy water sections.
Distribution
North America; recorded from Manitoba, New Brunswick, and Nova Scotia in Canada, with broader distribution across the continent.
Host Associations
- water mites - associated with body condition and sex; mites attach to beetles
Behavior
exhibit rapid, erratic, circular swimming motion on water surfaces. Form social or 'rafts' that may function in detection and avoidance. Males attempt to grasp females using protarsal pads during mating; males with larger accessory glands attempt copulation more frequently.
Ecological Role
Surface-dwelling aquatic insect that contributes to surface dynamics; may serve as prey items for fish despite noxious chemical defenses from pygidial glands.
Similar Taxa
- Dineutus discolorLarger and more widespread ; D. nigrior distinguished by coloration and protarsal pad
- Gyrinus spp.Smaller whirligig beetles with exposed scutellum and different body proportions
Sources and further reading
- BugGuide
- Wikipedia
- GBIF taxonomy match
- iNaturalist taxon
- NCBI Taxonomy
- Gyrinidae | Beetles In The Bush
- New Whirligig Beetle Showcases U.S. Biodiversity Hotspot
- June | 2010 | Beetles In The Bush | Page 2
- Ozark Trail | Beetles In The Bush
- Social Behavior of Adult Whirligig Beetles (Dineutus nigrior and D. discolor (Coleoptera: Gyrinidae)
- Sexual Selection on Accessory Glands, Genitalia and Protarsal Pads in the Whirligig Beetle Dineutus nigrior Roberts (Coleoptera: Gyrinidae)
- Water mite parasitism is associated with body condition and sex of the whirligig beetleDineutus nigrior(Coleoptera: Gyrinidae)