Multichemical defense of plant bugHotea gambiae (westwood) (Heteroptera: Scutelleridae) : Sesquiterpenoids from abdominal gland in larvae.

Chemical defense in larvae of the plant bugHotea gambiae has been investigated. Results of analyses (GC, GC-MS) on the secretions from the three dorsally situated larval abdominal defense (scent) glands are reported. The secretion from the first abdominal gland consists of a mixture of C10 and C15 isoprenoids: (C10) α-pinene, β-pinene, limonene, β-phellandrene; (C15) β-caryophyllene, caryophyllene oxide, α-humulene, and (the major component) humulene epoxide II. The secretions from the second and third abdominal glands are similar mixtures consisting of (E)-2-decenal, (E)-4-oxohex-2-enal, andn-tridecane together with lesser amounts of (E)-2-hexenal,n-dodecane, and other materials. Isoprenoid defense is now known from four species of plant bugs (Heteroptera) associated with Malvaceae.