"Wolf-in-Sheep's-Clothing" Strategy of a Predaceous Insect Larva

The larva of the green lacewing Chrysopa slossonae lives in colonies of the wooly alder aphid Prociphilus tesselatus upon which it feeds. It disguises itself as its prey by plucking some of the waxy "wool" from the bodies of the aphids and applying this material to its own back. The investiture protects it from assault by the ants that ordinarily "shepherd" the aphids. Larvae artifically denuded are seized by the ants and removed from the aphid colonies. A larva requires on the average less than 20 minutes to coat itself with wax. A hungry denuded larva gives the coating procedure about the same behavioral priority as feeding.

Stink of Stinkpot Turtle Identified: ohgr-Phenylalkanoic Acids

The exocrine secretion of the "stinkpot turtle," Sternotherus odoratus, discharged by the animals in response to disturbance, contains four omega-phenylalkanoic acids (phenylacetic, 3-phenylpropionic, 5-phenylpentanoic, and 7-phenylheptanoic). The last two of these are new natural products. The first two are powerfully malodorous and responsible for the stench of the fluid. Lesser components, including several aliphatic acids, are also present. Only a few milligrams of secretion are discharged by a turtle at any one time. Although bioassays with fish suggest that the secretion has the potential to serve as a feeding deterrent to predators, it is argued that Sternotherus does not ordinarily discharge enough fluid to effect this action and may employ its secretion only as an aposematic signal that warns predators of its more generalized undesirability.

New methylcyclopentanoid terpenes from the larval defensive secretion of a chrysomelid beetle (Plagiodera versicolora)

The defensive secretion of larvae of the chrysomelid beetle Plagiodera versicolora contains two unstable, volatile methylcyclopentanoid terpenes: a dialdehyde (chrysomelidial) isomeric with dolichodial and anisomorphal, and a closely related enol lactone (plagiolactone). Chrysomelidial and plagiolactone are shown to have structures III and IV on the basis of a detailed analysis of their spectra, coupled with chemical transformations to products of known structure.

Characterization and synthesis of volatile compounds from the defensive secretions of some "daddy longlets" (Arachnida: Opiliones: Leiobunum spp.)

Analyses of the chief volatile constituents of the defensive secretions of three oplionids were carried out. Leiobunum nigripalpi produces three closely related C7 compounds: E-4-methyl-4-hexen-3-one(I), 4-methylhexan-3-one(II), and 4-methylhexan-3-ol(III), along with E-4-methyl-4-hepten-3-one(IV), E,E-2,4-dimethylhexa-2,4-dienal(IX), and a minor, unidentified component. L. leiopenis secretion contains E-4-methyl-4-hepten-3-one(IV), 4-methylheptan-3-one(V), E,E-2,4-dimethylhexa-2,4-dien-1-ol(VII), and E,E-2,4-dimethylhepta-2,4-dien-1-ol(VIII). L. calcar yields chiefly E-4,6-dimethyl-6-octen-3-one(VI) and E,E-2,4-dimethylhexa-2,4-dien-1-ol(VII). Six of these compounds are new natural products. The structures of these compounds, which can be regarded either as polyketide-derived or as modified isoprenoids, raise interesting biosynthetic questions.

Polyzonimine: A novel terpenoid insect repellent produced by a milliped

A nitrogen-containing terpene 6,6-dimethyl-2-azaspiro[4.4]non-1-ene (polyzonimine) was isolated from the defensive secretion of the milliped Polyzonium rosalbum. Polyzonimine, which is repellent to such natural enemies of the milliped as ants, acts as a topical irritant to insects (10-4 M induces scratching in cockroaches). Its structure was confirmed by a five-step synthesis starting from 2,2-dimethyl-7-oxabicyclo[4.1.0]heptane.