Helen A. Lloyd

Pentatomid natural products

In addition to the primarily defensive metathoracic glands, adult Pentatomoidea possess a pair of active exocrine glands that open between the III and IV abdominal tergites. In the southern green stink bug,Nezara viridula, and other phytophagous species examined, the glands are small (< 10 μg secretion/individual) and of approximately equal size in both sexes. In some, but not all, of the predaceous pentatomids (Asopinae), the III-IV dorsal abdominal glands are small in females (< 10 μg secretion/individual) and extremely large in males (>500 μg secretion/individual). Using a GC-MS system, the secretion from both males and females ofN. viridula (Pentatominae) was found to contain (E)-2-hexenal, hexanal, 1-hexanol, andn-tridecane. Females contained about three times moren-tridecane than males. The capacious glands ofPodisus maculiventris (Asopinae) males produce (E)-2-hexenal, benzyl alcohol, α-terpineol, linalool, terpinen-4-ol, andcis-piperitol. The composition of the previously unanalyzed secretions from the adult III-IV dorsal abdominal glands is compared and contrasted to that of secretions from the metathoricic gland, and the role of coexisting exocrine glands in adult Heteroptera is discussed.

Chemistry of the defensive secretion of the caddisflyPycnopsyche scabripennis (Trichoptera: Limnephilidae)

From a pair of exocrine glands located on the fifth abdominal sternite, the caddisflyPycnopsyche scabripennis secretes a defensive exudate which containsp-cresol, indole, and skatole. This secretion effectively repels invertebrate predators such as ants. The probable significance of this secretion in the biology of these caddisflies is discussed.

Brunfelsamidine: a novel convulsant from the medicinal plant brunfelsia grandiflora

Abstract A convulsant isolated from Brunfelsia grandiflora is identified as pyrrole-3-carbox-amidine.

Identification of new components from anal glands ofTapinoma simrothi pheonicium.

In addition to 2-methyl-4-heptanone, 6-methyl-5-hepten-2-one, and iridodials, the anal gland exudate of the dolichoderine ant,Tapinoma simrothi, contains 4-heptanone and 4-hydroxy-4-methyl-2-pentanone. The secretion functions as an alarm pheromone.

Optical resolution of the α-tocopherol spiro dimer and demonstration of its fluxional nature

A model compound (1b) for the oxidative dimer of α-tocopherol (vitamin E)(1a) has been shown to undergo fluxion by NMR spectroscopy through a magnetization transfer experiment. This compound has also been resolved at low temperature using an optically active HPLC column. Its rate of racemization parallels the fluxion process suggesting a biradical intermediate and free radicals are shown to be present in non-degassed solutions of (1b). Its crystalline form has been examined with solid-state NMR spectroscopy and X-ray crystallography.

Exocrine glands ofPolyrhachis simplex: Chemistry and function

The mandibular glands of the Israeli weaver ant,Polyrhachis simplex, contain a mixture of 4-heptanone, 6-methyl-5-hepten-2-one and 6-methyl-5-hepten-2-ol;its Dufours gland secretion consists mainly ofn-tridecane. The significance of these glandular secretions in the biology of the weaver ant is discussed.

Lasiol, a new acyclic monoterpenol in the mandibular gland secretion of lasius meridionalis

Abstract A new, biogenetically anomalous, acyclic monoterpenol has been found in the mandibular glands of the formicine ant Lasius meridionalis , and identified as erythro - 1 , 2,3,6-trimethyl-5-heptenol (lasiol) on the basis of spectroscopic evidence and total synthesis.

Δ′-Pyrroline: An intermediary metabolite in the conversion of putrescine to 2-pyrrolidone

Abstract Δ′-Pyrroline, an oxidative product of putrescine metabolism, was chemically synthesized and incubated with a rat liver homogenate. The incubation mixture was fractionated on an amino acid analyzer before and after acid hydrolysis. The hydrolyzed sample, in contrast to the unhydrolyzed sample, contained a ninhydrin positive compound that cochromatographed with γ-aminobutyric acid, the product of 2-pyrrolidone acid hydrolysis. Authentic 2-pyrrolidone had the same retention time as the Δ′-pyrroline metabolite when analyzed by high-pressure liquid chromatography. It is concluded that Δ′-pyrroline is an intermediary metabolite in the pathway from putrescine to 5-hydroxy-2-pyrrolidone.

Novel Chemistry of Abdominal Defensive Glands of Nymphalid Butterfly Agraulis vanillae

Abdominal defensive glands of both sexes of the Gulf fritillary butterfly, Agraulis vanillae (Linnaeus) (Nymphalidae:Heliconiinae)emit a pronounced odor when disturbed. We have identified 6-methyl-5-hepten-2-one; oleic, palmitic, and stearic esters of the corresponding alcohol 6-methyl-5-hepten-2-ol; hexadecyl acetate; 1,16-hexadecanediol diacetate; and 1,15-hexadecanediol diacetate in the glandular exudate. Since we have determined that free-flying birds or birds in a butterfly conservatory discriminate against A. vanillaeas prey, we suggest that the constituents in the glands may play a defensive role against potential avian predators.

Mandibular Gland Secretions as Alarm Pheromones in Two Species of the Desert Ant Cataglyphis

Abstract Mandibular gland secretion of two Cataglyphis species were chemically analyzed by combined gas chromatography mass spectrometry. The exudates produced by C. bombycina consisted of citronellol and geraniol while that of C. nigra contained only geraniol. The reaction of both species to the glandular secretions was alarm and recruitment. While the reaction of C. bombycina was strong, that of C. nigra was relatively mild.