Psephenidae (taxonomic family)
Flowing, unpolluted water
Mostly North America and India
No listed status
This species is
to the Truckee Meadows.
Water penny beetles are aquatic insects in the family Phsephenidae. The larvae of these species are more often seen than the adults, usually observed clinging to the undersides of rocks. Larvae are flat and brown with segmented bodies and legs on their undersides. As their name suggests, water penny beetle larvae often resemble pennies. Adults are small, black or brown beetles with flattened bodies.
Water penny beetles are a sign of a healthy river as they cannot live with high amounts of pollution, sediment, fungi, or algae growth.
Water penny beetles will use their legs to scrape algae off of rocks for food.
While they are very short-lived as adults, water penny beetles may spend up to a year as larvae.
Unlike most beetle larvae, which are grub-like, water penny beetle larvae are round, hence their name.
Missouri Department of Conservation, Water Penny Beetle Larvae, 2021, https://nature.mdc.mo.gov/discover-nature/field-guide/water-penny-beetle-larvae
Encyclopædia Britannica, Water-penny beetle, 2021, https://www.britannica.com/animal/water-penny-beetle
Image: TheAlphaWolf, https://commons.wikimedia.org/wiki/File:Water_penny_larva.JPG, license https://creativecommons.org/licenses/by-sa/3.0/deed.en, cropped from original.
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