Cantharidin, a potent defensive chemical, is present in all ten life stages of the blister beetle Epicauta funebris. The first five larval stages accumulate cantharidin as they feed and grow in size. When disturbed, they exude cantharidin in a milky oral fluid, not in hemolymph which adult beetles reflexively discharge from leg joints. Two subsequent larval stages and the pupa do not feed, grow, regurgitate, or change in their defensive reserves (110 micrograms cantharidin/insect, regardless of sex). Adult beetles kept in isolation for 60-90 d exhibit a pronounced sexual dimorphism in cantharidin production: the male biosynthesizes about 17 mg of the toxin, representing 10% of his live weight, whereas the female actually loses most of her defensive reserves. But in the wild a female beetle repeatedly acquires cantharidin as copulatory gifts from her mates.

Larvae of the sawfly Neodiprion sertifer (Hymenoptera: Diprionidae), when disturbed, discharge an oily oral effluent essentially identical chemically to the terpenoid resin of its host plant (Pinus sylvestris). The resin is sequestered by the larva upon feeding, and stored in two compressible diverticular pouches of the foregut. The fluid is effectively deterrent to predators. The defensive use by an insect of a plant resin provides an instance of secondary utilization by a herbivore of the protective chemical weaponry of its host.

The larva of Cassida rubiginosa carries a tight packet of cast skins and feces on a fork held over its back. The packet is a maneuverable shield used by the larva to protect itself against attack. It is highly effective in blocking the bite of ants.

Cantharidin, the well-known terpenoid compound from the blood of blister beetles (and active principle of Spanish fly), is a feeding deterrent to insects, effective at a concentration of 10(-5) molar.

A television camtiera, like the eyes of some insects, is sensitive to ultraviolet light. When equipped with an appropriate ultraviolet-transmitting lens, such a camera can be used for the direct examtiination of ultraviolet reflectiont patterns (for example, on flowers, butterflies) that are invisible to us, but visible to inisects.