Weather Related Insect Events

This year, much of Eastern Australia has received record rainfall leading to flooding and other issues. Unusual weather can lead to unusual outbreaks of pest insects. Rove beetles of the genus Paederus are one group of pests that responds to heavy rains with large population increases. Paederus rove beetles contain the toxin, pederin, a blistering agent reputed to be 12 times more toxic than cobra venom when ingested.

The Paederus rove beetles are typically less than 1 cm long and are attracted to lights at night. During outbreaks, the beetles fly to the lights and enter buildings where they come in contact with people. The poison is contained within the beetle. Crushing the beetle on the skin will release the toxin and cause blistering. People are advised to blow the beetle off their skin rather than trying to hit it or smack it. The beetles may crawl into bedding and be accidentally smashed by people in their sleep. Lesions can take 12 to 72 hours to appear. This makes the cause of the blistering difficult to diagnose. In Malaysia, there have been outbreaks of rove beetles that have caused dermatitis outbreaks in apartments and dormitories.

When they are not causing dermatitis, the beetles are useful biological control agents that live in rice paddies and feed on pest insects. Rove beetles of the genus Paederus occur in North America, but fortunately, outbreaks have not been reported. Serious outbreaks have occurred in Africa, Asia and Australia. For more information on rove beetle dermatitis and pictures of lesions, I recommend, DocFiles.

Paederus fuscipes (aka Creechie Bug)

Paederus Dermatitis Resulting from Smashing a Rove Beetle on the Skin
Photo: DocFiles