The ecological phenomenon of arthropods with defensive hairs is widespread. These urticating hairs can be divided into three categories: true setae, which are detachable hairs in Lepidoptera and in New World tarantula spiders; modified setae, which are stiff hairs in lepidopteran larvae; and spines, which are complex and secretion-filled structures in lepidopteran larvae. This review focuses on the true setae because their high density on a large number of common arthropod species has great implications for human and animal health. Morphology and function, interactions with human tissues, epidemiology, and medical impact, including inflammation and allergy in relation to true setae, are addressed. Because data from epidemiological and other clinical studies are ambiguous with regard to frequencies of setae-caused allergic reactions, other mechanisms for setae-mediated disease are suggested. Finally, we briefly discuss current evidence for the adaptive and ecological significance of true setae.

Urticating Hairs in Arthropods: Their Nature and Medical Significance

Few entomological topics capture the attention and arouse the apprehen­ sion of scientists and the general public alike as do insect venoms. These highly active, often painful biological materials attract interest partly be­ cause they represent a direct assault on the human body, which rarely culminates in death, and partly because they possess a perplexing array of active biological constituents. Prior to the last 20 years, biochemical investi­ gations of insect venoms were severely hampered by a lack of simple, effective methodology for separating and investigating individual compo­ nents contained in these complex blends. In concert with methodological advances came major advances in the understanding and demystification of insect venom biochemistry. These achievements set the stage for even more provocative and enlightening studies. Reviews of insect toxinology-the study of natural toxins and venoms from insects-have been written by Phisalix (153), Pawlowsky (149), Kaiser & Michl (103), and Beard (12), to name a few. The morphology of insect venom apparatuses in general is reviewed by Maschwitz & Kloft (126). Detailed reviews concerning specific topics of insect toxinology or of venomous taxa are available in several comprehensive works (18, 29).

Biochemistry of Insect Venoms

Diseases Caused by Arthropods and Other Noxious Animals

Comparative enzymology of venoms from stinging Hymenoptera

Caterpillars are the larval forms of moths and butterflies and belong to the order Lepidoptera. Caterpillars, and occasionally moths, have evolved defense mechanisms, including irritating hairs, spines, venoms, and toxins that may cause human disease. The pathologic mechanisms underlying reactions to Lepidoptera are poorly understood. Lepidoptera are uncommonly recognized causes of localized stings, eczematous or papular dermatitis, and urticaria. Part I of this two-part series on caterpillars and moths reviews Lepidopteran life cycles, terminology, and the epidemiology of caterpillar and moth envenomation. It also reviews the known pathomechanisms of disease caused by Lepidopteran exposures and how they relate to diagnosis and management. Part II discusses the specific clinical patterns caused by Lepidopteran exposures, with particular emphasis on groups of caterpillars and moths that cause a similar pattern of disease. It also discusses current therapeutic options regarding each pattern of disease. Learning objectives After completing this learning activity, participants should be able to appropriately use current terminology of adverse reactions to caterpillars and moths, understand the epidemiology of these reactions, and use our current understanding of the pathologic mechanisms of these reaction patterns to guide treatment.

Caterpillars and moths: Part II. Dermatologic manifestations of encounters with Lepidoptera

This study attempts to evaluate the possible pathogenic role of phospholipase A2 and of proteolytic c.q. esterolytic enzyme(s) recently shown to be associated with the skin irritating nettling hairs ofEuproctis chrysorrhoea caterpillars.

Investigative studies of dermatitis caused by larva of brown-tail moth, euproctis-chrysorrhoea l (lepidoptera, lymantriidae) .3. chemical-analysis of skin reactive substances

Investigative studies of dermatitis caused by larva of brown-tail moth, euproctis-chrysorrhoea l (lepidoptera, lymantriidae) .4. further characterization of skin reactive substances

Two different aspects related to the dermatitis caused by the socalled nettling hairs of the larva of the brown-tail moth,Euproctis chrysorrhoea L., are documented. The first part describes the sequence of histopathologic changes associated with the inflammatory process in the human skin induced by epicutaneous application of untreated (UT-N) and heat treated (HT-N) nettling hairs.

Investigative studies of dermatitis caused by larva of brown-tail moth (euproctis chrysorrhoea linn) .2. histopathology of skin-lesions and scanning electron-microscopy of their causative setae

Mcjmd Jong

Papers

Investigative studies of dermatitis caused by larva of brown-tail moth, euproctis-chrysorrhoea l (lepidoptera, lymantriidae) .3. chemical-analysis of skin reactive substances

Investigative studies of dermatitis caused by larva of brown-tail moth, euproctis-chrysorrhoea l (lepidoptera, lymantriidae) .4. further characterization of skin reactive substances

Investigative studies of dermatitis caused by larva of brown-tail moth (euproctis chrysorrhoea linn) .2. histopathology of skin-lesions and scanning electron-microscopy of their causative setae