Whirligig Beetle Larva In the larval stage the beetle resides in a shallow area of the pond because they are dependent on the oxygen only available in the shallower areas. Their life cycle includes four stages – egg, larva, pupa and adult. The water scavenger beetle has triangular yellow markings on the sides of the abdomen and usually swims near the bottom of shallow pools. Larvae lack wing pads, prolegs and outgrowing tracheal gills. Beetles of both families may occur in the same habitats, thus are often collected simultaneously. These voracious predators consume any kind of living organisms that they get caught with robust and serrated mandibles. This film functions as a gill in habitats with high concentrations of dissolved oxygen. Life cycle: In diversity, Coleoptera is the largest order of insects (containing more than 400 000 described species) and one of the largest groups of animals on Earth. As already mentioned, beetles undergo complete metamorphosis. Due to the Covid19 pandemic, our shipping time may take up to 48 hours to ship. Size: In order to breathe continuously, larvae often position themselves with the tip of abdomen in contact with the surface. Larvae have elongated body and can be distinguished by the presence of sclerotized head, distinct neck, three pairs of segmented legs and prominent mandibles. However, they are found often in Spring and Autumn. 1. The generic name “Water Beetle” refers to any beetle that, during its life cycle at any point, has adapted to living in the water. Even though most beetles are terrestrial, many of them have colonized freshwater habitats and spend at least one of their life stages as aquatic. Food Life Cycle What do they eat? In general, water scavenger beetles feed on decaying organic matter, but eat considerable amount of living invertebrates as well. Elongated, cylindrical larvae have tufts of gills on the last abdominal segment. Some live up to 2 – 3 years as adults. Nymph. When grown, the larvae crawl out of the water and form pupas on nearby plants. Riffle Beetle Larva. There is a cavity under the elytra, where the air is stored. Great diving beetle (Dytiscus marginalis), Great diving beetle (Dytiscus marginalis) larvae, Lesser diving beetle (Acilius sulcatus) larvae, Lesser diving beetle (Graphoderus cinereus), Lesser diving beetle (Graphoderus sp.) Most species deposit eggs in a silk case that they attach to an aquatic plant. This increase of air maintains buoyancy and enables the beetle to rise simply to the surface to get fresh air, rather than swim or crawl. Additional air supply is kept under the flattened coxal plates, which partially cover the first segment of hind legs. When the larval development is completed, they leave the water and dig a cellar in a damp soil to pupate. Head, thorax and bottom side of the abdomen are hardened (sclerotized) as well. Beetles entered aquatic environment after millions of years evolving on land, yet they can be found in almost any freshwater habitat. The life cycle of the aquatic beetle has four life stages during which it undergoes transformation to eggs, larvae, pupa and adult. Suborder: Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles), Superfamily: Hydrophiloidea (Water Scavenger and Clown Beetles), Family: Hydrophilidae (Water Scavenger Beetles), Genus: Hydrophilus (Giant Water Scavenger Beetles), Species: Triangularis (Giant Black Water Beetle). Eggs are deposited near places like the moist soil, the river substrate or on a host plant so that these can serve as a larval food supply. – Presence of thin layer of air on the bottom of the body. Species such as longhorn beetles, leaf beetles and weevils feed only a single plant and are thus very host-specific. Whirligig beetles are sensitive to water ripples, which reveal the location of potential prey. Scavenger beetles consume the dead and decaying organic material found in the water. Colorful and shiny adult beetles crawl out of the soil and their first flight often leads back into the water. Diving beetles may look very similar to their terrestrial relatives, but dytiscids have developed some modifications, which enable them to be so successful and diverse. Movement: The tail filaments are usually short. 1,000 secondarily terrestrial species derived from aquatic ancestors. Water Scavenger Beetle. Dytiscids use the tip of abdomen to break the water tension and replenish the air supply. Movement: Some species live up to 5 years. Adults are collectors, gatherers, or predators. Hydrophilids are water scavenger beetles and eat various dead organisms and live algae in fresh water. 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