Numbers
15 species in North America (
nearctica.com)
more than 600 species worldwide
Size
length 7-10 mm; width about 1 mm
Identification
body color is an alternating black-red-black-red-black, corresponding to head-pronotum-elytra-anterior abdomen-posterior abdomen
Range
throughout North America
occurs on all continents except Antarctica
Habitat
moist habitats; adults may be attracted to artificial light
Season
adults most common in spring and early summer
Food
larvae and adults are general predators of small insects and other arthropods, including pests of crops
Life Cycle
eggs laid singly on moist substances and typically develop in 3-19 days; larvae pass through two instars before reaching adulthood
Remarks
Paederus species contain a toxic chemical (pederin) in their hemolymph which causes contact dermatitis in humans, usually as a result of slapping the beetle and crushing it against exposed skin. The affected area becomes red, swollen, and itchy, causing the skin to peel when scratched. Outbreaks of Paederus dermatitis have occurred in Africa, Asia, and South America.
Historically, extracts of Paederus beetles have been used by the Chinese since at least the year 739 in the medicinal treatment of boils, nasal polyps, and ringworm.
Internet References
live adult image of
P. riparius, a holarctic species (M. Kozlowski, Germany)
pinned adult image of
P. littorarius (Insects of Cedar Creek, Minnesota)
Beware of Beetle Juice! - an account of dermatitis caused by pederin, and photo of patient with "Nairobi eye" condition (Dept. National Defence, Canada)
pinned adult images of
P. riparius, a holarctic species (Malcolm Storey, BioImages Virtual Field Guide, UK)
overview of biology and dermatitis caused by pederin, with photos of adult beetle and damage to human skin (Dept. National Defence, Canada)
Contributed by
Robin McLeod on 23 June, 2005 - 2:50am
Last updated 23 June, 2005 - 4:02am
