Paederus

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Superfamily: Staphylinoidea
Family: Staphylinidae
Subfamily: Paederinae
Tribe: Paederini
Subtribe: Paederina
Genus: Paederus

Pronunciation

How to pronounce Paederus: //ˈpiːdərəs//

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Summary

Paederus is a genus of small rove beetles known for their bright colors and the potential to cause skin irritation through contact with their toxin, pederin. They are predatory insects found in moist environments, with some species being beneficial for controlling pest populations but problematic for humans due to dermatitis issues.

Physical Characteristics

7-10 mm brightly colored (red/orange & black/blue) with metallic blue- or green-colored elytra and many with bright orange or red on the pronotum and basal segments of the abdomen.

Identification Tips

Brightly colored; attracted to light; distinct coloration may be an example of aposematism, warning potential predators.

Habitat

Moist habitats; commonly found in irrigated farmland where moisture is present.

Distribution

Widespread distribution worldwide, with 15 species in North America and several species reaching Canada.

Diet

Both larvae and adults are predatory on other insects.

Life Cycle

Eggs are laid singly on moist substances; larvae pass through two instars before reaching adulthood, typically developmental time is 3-19 days.

Reproduction

Eggs are laid in moist environments; development progresses through larval stages.

Ecosystem Role

Beneficial in controlling herbivorous insect populations but can cause human skin irritation.

Economic Impact

Large numbers can be beneficial in agriculture by controlling pests, but they also pose health risks for workers in fields or grassy areas.

Cultural Significance

Extracts of Paederus beetles have been used in traditional medicine since at least 739 AD in China for treating skin conditions.

Health Concerns

Some species contain a toxic chemical (pederin) in their hemolymph that can cause contact dermatitis when crushed against skin; various regional nicknames exist for the skin irritation it causes.

Misconceptions

The name 'Paederus dermatitis' is misleading as it is caused by only a few species and some species from closely related genera.