Paralysing venoms of solitary wasps

Abstract

1. 1. The literature dealing with the anatomy of the venom organ, the stinging behaviour and a number of properties of the paralysing venoms of solitary wasps has been summarized. 2. 2. The Terebrantes studied sting their prey at random. Most of the Aculeata reviewed sting into or in the direction of the central nervous system (CNS). However, a few species of Aculeata sting at random or at least not in the direction of the CNS. 3. 3. The range of species specificity of the venom seems to vary widely between different species of wasps. 4. 4. Species belonging to both the Terebrantes and the Aculeata may produce venoms causing either a long-lasting or a relatively short paralysis. 5. 5. All venoms studied at present cause a paralysis of the locomotion but have very little if any effect on the heart beat and the movements of the intestines. 6. 6. A few paralysing venoms have been studied in more detail. The venom of Microbracon hebetor Say specifically blocks the neuromuscular transmission in the somatic muscles. It especially affects the frequency of the miniature excitatory postsynaptic potentials and therefore is assumed to act at a presynaptic site. 7. 7. The chemical composition of the venom of Sceliphron caementarium (Drury) has been studied. It contains a great many different compounds. Which of these compounds possesses the paralysing activity is as yet unknown. 8. 8. Although Philanthus triangulum (F.) stings in the direction of the CNS, the main action of its venom is on the neuromuscular junction, where it acts at a presynaptic site.