The parasiticwasps in the order Hymenoptera defend themselves, attack preys, and regulate hosts using toxins that are effective in small quantities. Advances in the research of parasitic hymenopteran toxins are summarized in terms of the production, categories, components, properties, ecological functions and mechanisms.
The glands that produce venom are derived from ectoderm tissue and evolved from the accessory glands of reproductive system. Venoms are excreted by the poison gland or acid gland of mature female wasps and stored in reservoir. The components of insect toxins are very complicated, and hymenopteran venoms contain alkanes, alcohols, aldehydes, ketones, organic acids, esters, lactones, proteins, polypeptides, enzymes, amines, and other compounds.
Toxins of parasitic hymenoptera play an important adaptive role. They can increase the probability of successful oviposition by paralyzing the host, enhance offspring survival by inhibiting host development and immunoreaction, and improve the nutrition available for their progeny by disturbing the host physiological response. Venoms of the ectoparasitoids often lead to arrested development, permanent paralysis and even death of host. These toxins are usually broad-spectrum and act on the central nervous system or at the neuro-muscular junction. While most endoparasitoids are koinobionts, these parasitoids can regulate host physiology and development, but no longer paralyze the host permanently. And they usually kill host in the concealed but safe position after host cocooned or built its pupal cell. Venoms of koinobiont parasitoids can contain polydnaviruses (PDV) that regulate host growth and development by inhibiting the immune system and influencing host metamorphosis. Thus, the PDVs are commensal and mutualistic, but non-pathogenic, with parasitoids at molecular level.
Promising prospects for the utilization of insect toxins, especially as medicines or specific bioinsecticides, are discussed. Because insect toxins are mixtures of complex ingredients and are usually produced in small quantities, isolation and purifications of all the ingredients with bioactivity is needed for biochemical and toxicological research and for practical application.