Paederus
Paederus | |
---|---|
Paederus rove beetles, showing size | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Family: | Staphylinidae |
Tribe: | Paederini |
Subtribe: | Paederina |
Genus: | Paederus Fabricius, 1775[1] |
Type species | |
Paederus riparius | |
Species | |
Paederus alfierii |
Paederus is a genus of small
Distribution
Paederus species are widely distributed around the world.[5]
Description
Paederus species are much more brightly colored than most other rove beetles, with metallic blue- or green-colored elytra and many with bright orange or red on the
Biology
Although most adult rove beetles avoid daylight, Paederus species are active during the day and attracted to bright lights after nightfall.[3]
Paederus eggs are laid singly, in moist habitats. Larvae go through two instars before pupation. Both larvae and adults are predatory on other insects.[3] Because of their preference for moist soil, large numbers of Paederus beetles may be attracted to irrigated farmland, where they provide some benefit by eating herbivorous insects but can cause problems for people working in fields or grassy areas.[6]
Pederin
According to Medical and Veterinary Entomology (2009) "At least 20 of the more than 600 species of Paederus beetles have been associated with Paederus dermatitis",[6] even though Paederus beetles do not bite or sting.[7] This skin irritation results from contact with pederin, a vesicant toxin in the hemolymph of many but not all females in the genus Paederus.[8] The toxin is manufactured, not by the beetles themselves, but by endosymbiont bacteria, probably some species of Pseudomonas.[9]
Impact on human beings
Paederus dermatitis is caused when a pederin-containing beetle is crushed, even partially, against the skin.[6] This skin irritation is also called "dermatitis linearis" or "linear dermatitis" because one can inadvertently drag a beetle across the skin in a more-or-less straight line when trying to brush it away. The resulting inflammation will also be linear.[10] Because Paederus species are widely dispersed around the world, this syndrome has many different local nicknames including "whiplash dermatitis", "spider lick",[6] and "Nairobi fly dermatitis". In East Africa, conjunctivitis from getting pederin in the eye is called "Nairobi eye".[11]
Once pederin is on the skin from the initial beetle contact, it may also be spread elsewhere on the skin. "Kissing" or "mirror-image" lesions where two skin areas come in contact (for example, the elbow flexure) are often seen.[10] Washing the hands and skin with soap and water is strongly recommended if contact with a rove beetle has occurred.[7]
Initial skin contact with pederin shows no immediate result. Within 12–36 hours, however, a reddish rash (erythema) appears, which develops into blisters. Irritation, including crusting and scaling, may last from two to three weeks.[7]
Mass infestations
An article in The Lancet suggests that events like those described as the first two of the ten plagues of Egypt (anoxic die-off in the Nile, followed by many dead frogs) would have created ideal breeding conditions for P. alfierii. The authors suggest that the plague of "boils" could be the skin irritation, typically delayed by a day or more, resulting from contact with Paederus during the third or fourth plagues (lice or flies). They also note that Paederus infestations are often localized, so it would be quite possible for them to have invaded Pharaoh's palace but not the homes of the Jews.[4]
Many modern occurrences of localized but intense Paederus impact are documented in research papers with titles like "An outbreak of paederus dermatitis in a suburban hospital in Sri Lanka",[12] "An outbreak of 268 cases of Paederus dermatitis in a toy-building factory in central China",[13] "Outbreak of dermatitis linearis caused by Paederus ilsae and Paederus iliensis (Coleoptera: Staphylinidae) at a military base in Iraq",[14] and "Evacuation of an Aboriginal community in response to an outbreak of blistering dermatitis induced by a beetle (Paederus australis)".[15]
References
- ^ "Paederus Fabricius 1775". Fauna Europaea. Archived from the original on 30 September 2007. Retrieved 28 July 2011.
- ^ Frank, J.H. (1988). "Paederus, sensu lato (Coleoptera: Staphylinidae): An index and review of the taxa". Insecta Mundi. 2 (2): 97–159.
- ^ PMID 3295241.
- ^ S2CID 38364604.
- ^ Sharp, David (1887). Biologia Centrali-Americana. Insecta. Coleoptera Vol. 1 Part 2. Vol. 1. p. 609.
- ^ ISBN 978-0-12-372500-4. Retrieved 31 July 2011.
Pederin contacts human skin only when a beetle is brushed vigorously over the skin or crushed.
- ^ a b c "Just the facts…Paederus Beetles" (PDF). US Army Public Health Command. Archived from the original (PDF) on 16 March 2012. Retrieved 30 July 2011.
- S2CID 44776265.
This study investigates the effects of pederin, a hemolymph toxin that is accumulated in the eggs of most Paederus females
- PMID 12381784.
- ^ PMID 17314440.
- ISBN 978-1-4160-2999-1.
- S2CID 39540236.
- S2CID 12349799.
- PMID 20084733.
- S2CID 40346362.