Whirligig Beetles Are Skimmers That See Above and Below the Water Simultaneously
This is a close-up side view of a Whirligig Beetle.
What Are Whirligig Beetles?
You can find Whirligig Beetles on ponds, streams, canals, ditches, lakes, and slow-flowing rivers, pretty much any body of water you can think of. Although they generally avoid habitats with turbulent water or dense vegetation. There are well over 700 species worldwide, but as beetles go, they are unique. One thing that sets them apart from other beetles is their short, clubbed antennae. But the eyes of a whirligig beetle are the feature that makes them the most unique.
They have four eyes—two eyes (one on top of the other) on the left and two on the right (positioned in the same way). One of the eyes on each side allows them to see underwater, and one enables them to see above water.
The name of this family of beetles, Gyrinidae, is derived from the Latin word for circle. They have adapted well to life in the water, and their paddle-like legs have allowed them to become skilled swimmers. Like other beetles, Whirligig Beetles have membranous hindwings covered by forewings modified into very thick and heavy shields, although when their wings are closed, the shield-like forewings will form a straight line right down the back of the beetle.
The name "whirligig" comes from their habit of swimming wildly in circles when disturbed or threatened. They can be found throughout central Europe and Britain, where their presence is commonplace, although there are over 50 species in the United States and Canada.
New Species Identified in the United States
In 2015, a new species was identified by Grey Gustafson, a Ph.D. student at the University of New Mexico at that time. Gustafson found the new species, the first since 1991, in Alabama's Conecuh National Forest while hunting for similar Whirligig Beetles.
Gustafson named the new species Dineutus shorti after University of Kansas coleopterist Dr. Andrew E. Z. Short, whom he credited for much of his inspiration.
As the Whirligig Beetles are skimming across the water's surface, they are also cleaning the water, ridding it of dead and decaying matter, which makes them very beneficial insects.
Capable Flyers Who Prefer the Water
Metallic black with orange legs, Whirligig Beetles have wings like most other beetles and can fly. However, when flying, they usually search for water because they prefer aquatic life. Their outer layer is appropriately lubricated, and their hind legs are modified and paddle-like, which aids them in swimming.
Adult whirligigs can carry an air bubble with them at the tip of their abdomen, allowing them to breathe underwater and stay there for long periods. When they surface for air, the air bubble is replaced with a new one.
These particular beetles are active during the day and are very social creatures, often found in large numbers swimming around on the water's surface until disturbed. They begin their erratic behavior at that time and often dive to safety.
During Autumn nights, the adults fly in search of water. In July and August, the larvae go through pupation on land. A cocoon of plant matter protects them, and the adult beetles appear ten days later. The adults and the larvae are predatory, preying upon mosquitoes and other aquatic invertebrates.
Whirligigs as Predators and Prey
Whirligig Beetles and their larvae are carnivorous and predatory. While the adults feed on insects that happen to fall into the water, the larvae will eat other aquatic insects and invertebrates.
Adults are attracted to waves caused by a struggling insect, often crowding around it with each beetle grabbing a bite. Whirligig Beetles can locate drowning insects via their antennae that can sense waves. They can also detect prey using echolocation and the ripples their swimming motion produces. Plus, they are scavengers, often seen eating helpless or dead creatures.
Whirligigs' Defense System
Whirligig Beetles have a "chemical defense system," giving off an odor that smells slightly like sour apples. Some of their vertebrate predators don't like the scent, which often protects them from an attack. In addition, their dual vision, chemical defense, and swift swimming movements help them avoid predators above and below the water.
Whirligig Beetle Larvae
Larvae of the Whirligig Beetle
Larvae of the Whirligig Beetles are pale, elongated, and flattened, having three pairs of crawling legs and eight pairs of featherlike gills that protrude from the sides of the abdomen.
Eggs are laid on the surfaces of submerged water plants. The larvae are not seen as often as the adults, as they spend most of their time on the bottom surface of the water. When they are grown, they crawl out of the water to form pupas on plants that are close by. The adults will return to the water and overwinter in mud and debris, emerging in spring from hibernation to form hunting groups.
Classification of Whirligig Beetles
- Kingdom Animalia
- Phylum: Arthropoda
- Subphylum: Hexapoda (Hexapods)
- Class: Insecta
- Order: Coleoptera
- Suborder: Adephaga (Ground and Water Beetles)
- Family: Gyrinidae
- Genus: Gyrinus
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References
- http://www.arkive.org/whirligig-beetle/gyrinus-substriatus/ (Retrieved from website 7/08/2018)
- https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/whirligig-beetle (Retrieved from website 7/09/2018)
- https://nature.mdc.mo.gov/discover-nature/field-guide/whirligig-beetles (Retrieved from website 7/09/2018)
© 2018 Mike and Dorothy McKenney
Comments
Mike and Dorothy McKenney (author) from United States on July 09, 2018:
Me too! I didn't know what they were called back then, but they were fun to watch.
Alexander James Guckenberger from Maryland, United States of America on July 09, 2018:
I remember playing with these things in the stream as a kid. :)
