Biology/Behavior. Most vespids are social insects that feed primarily on other arthropods. These wasps build paperlike nests by masticating wood fiber into pulp. In addition to the social wasps, many types of solitary wasps are capable of envenomization; but these wasps are easy to avoid since they are neither abundant nor aggressive. Female members of the dangerous wasp species will readily attack and inject their venom if someone disturbs or annoys them. Wasp stingers do not become detached, and a single wasp can sting a victim several times before retreating. Social wasps are particularly dangerous because a disturbance of their nest may result in attack by numerous wasps.
Avoidance/Control. Avoid garbage accumulation sites, which attract wasps. To avoid wasp stings, recognizing the nests of the dangerous species in the local area, is important. If possible, remove and destroy all nests found around inhabited areas. Wasps can be controlled by treating their nests with insecticide—preferably at night, when the wasps are least active. Treat nests found above the ground with a commercial wasp spray or other insecticide recommended by an entomologist. To treat wasp nests in the ground or in houses, a 5% carbaryl dust may be used.[38]
Envenomization Reaction/Treatment. (See [appendix].)
URTICATING/VESICATING ARTHROPODS
1. BLISTER BEETLES
(Order: Coleoptera; Family: Meloidae)
Identification. The Meloidae are narrow elongate beetles characterized by a “neck” (pronotum) which is distinctly narrower than its head or wings. Adult beetles range in body length from 1 to 2 cm (0.4-0.8 in) and vary considerably in their coloration.
Distribution. In general, blister beetles are found in greater numbers in the western half of the United States.[5]
Biology/Behavior. The immature stages of the blister beetle are usually predacious on other insects and are not harmful to man. Adult blister beetles release a clear amber fluid by rupture of thin membranes in the leg joints or other segmented areas of the body. The release of this fluid, which contains a vesicating agent called cantharidin, is triggered by pressure against the body of the beetle. Light pressure exerted by clothing or by brushing off a beetle is usually sufficient to cause the release of its vesicating fluid. The adult blister beetles are readily attracted to bright white light, and many cases of human exposure occur at night around such lights. Since the adults are plant feeders, some cases of human vesication occur as persons move through vegetation infested with blister beetles.
Avoidance/Control. In areas with an abundance of blister beetles, use yellow light bulbs for outdoor lighting. If a meloid beetle lands on the skin, blow it off, do not crush it. Since cantharidin is distributed throughout the beetle’s body, crushing the beetle against exposed skin would result in maximum cantharidin exposure. Dermatoses resulting from blister beetle contact are seasonal, with the greatest number of vesicating incidents in the United States occurring in July, August, and September. Chemical control usually is not recommended because of the mobility and wide distribution of blister beetles.