James E. Oliver

Benzoquinones from millipedes deter mosquitoes and elicit self-anointing in capuchin monkeys ( Cebus spp.)

Neotropical monkeys of the genus Cebus anoint themselves by rubbing arthropods and plants against their pelage. A recent study has shown that free-ranging wedge-capped capuchin monkeys (C. olivaceus) in Venezuela self-anoint with a benzoquinone-secreting millipede, an activity by which they are hypothesized to appropriate chemical deterrents of mosquitoes. To evaluate the plausibility of this hypothesis, female yellow fever mosquitoes (Aedes aegypti) were presented with two millipede secretory compounds, 2-methyl-1,4-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone, on nylon-reinforced silicone membranes placed over wells filled with human blood, a highly preferred food. Mosquitoes exhibited fewer landings, fed less frequently, and flew more frequently (a possible indication of repellency) in the presence of membranes treated with benzoquinones than with controls. These compounds also elicit self-anointing in captive male and female tufted (C. apella) and white-faced (C. capucinus) capuchin monkeys.

IDENTIFICATION OF MALE-SPECIFIC VOLATILES FROM NEARCTIC AND NEOTROPICAL STINK BUGS (HETEROPTERA: PENTATOMIDAE)

Males of the Central American stink bug species,Euschistus obscurus, produce an attractant pheromone composed of a blend of compounds characteristic of North AmericanEuschistus spp. and the South American soybean pest,E. heros. The range ofE. obscurus extends into the southern United States, the species is easy to rear, and males produce an exceptionally large quantity of pheromone (>0.5µg/day/male). These factors madeE. obscurus useful for characterizing the novel pheromone components ofE. heros without importing this pest species into the United States.Euschistus obscurus males produce methyl (2E,4Z)-decadienoate (61 %) in abundance, which is characteristic of North American species, and methyl 2,6,10-trimethyltridecanoate (27%), the main male-specific ester ofE. heros. The chirality ofEuschistus spp. methyl-branched esters, and field activity of synthetic formulations, remain to be determined.

Sex Attractant Pheromone from the Rice Stalk Stink Bug, Tibraca limbativentris Stal

The male-produced sex pheromone from the Brazilian rice stalk stink bug Tibraca limbativentris is reported. Olfactometer bioassays with sexually mature males and females showed that males attracted females, which suggests that males release a sex pheromone. Males were not attracted to either sex, nor were females attractive to conspecific females. Attraction of the females to males was highest at night. The headspace volatiles collected from male and female bugs were analyzed by gas chromatography (GC) and GC–mass spectrometry. Two male-specific compounds were identified as isomers of 1′S-zingiberenol, whereas a series of defensive compounds were identified in extracts from both sexes. Zingiberenol has three chiral centers, and the nonselective syntheses used produced two groups of isomers, zingiberenol I containing four isomers, namely (1RS,4RS,1′R)-4-(1′,5′-dimethylhex-4′-enyl)-1-methylcyclohex-2-en-1-ol, and zingiberenol II containing the other four isomers, namely (1RS,4RS,1′S)-4-(1′,5′-dimethylhex-4′-enyl)-1-methylcyclohex-2-en-1-ol. Both groups of stereoisomers were more attractive than hexane controls. The absolute configuration of the insect-produced pheromonal components remains to be elucidated, but the 1′S stereochemistry was established for at least one of the isomers.

Pheromone hydrolysis by cuticular and interior esterases of the antennae, legs, and wings of the cabbage looper moth,Trichoplusia ni (Hübner).

Examination was made of the hydrolytic activities of esterases obtained from the antennae, legs, and wings of 3-day-old cabbage looper moths,Trichoplusia ni (Hübner), by elution and by homogenation of those appendages. Pheromone hydrolysis in 1-min assays was monitored by use of tritium-labeled (Z)-7-dodecen-1-ol acetate and thin-layer chromatography to separate the reaction products. Listed according to the activities of the esterases obtained by homogenation, the organs were antennae > legs > wings. In contrast, the order according to the activities of the eluted esterases was wings > legs > antennae. Also, the eluted enzymes were less active than the esterases obtained by homogenization. The relatively high pheromone-hydrolyzing activity present in homogenized antennae suggests that the esterases originated inside the antennae and lends support to the hypothesis proposed in earlier investigations that pheromone-inactivating enzymes may play an important role in the olfactory process, possibly by clearing pheromone from the vicinity of the olfactory receptors. The esterases detected on the cuticle, on the other hand, may function by preventing surface accumulation of pheromone. The higher measured esterase activity in homogenates of prothoracic legs than of mesothoracic or metathoracic legs suggests that the prothoracic legs, which are used to clean the antennae of debris, may function by removing and degrading pheromone from the surface of antennae.

Bruchins—Mitogenic 3-(Hydroxypropanoyl) Esters of Long Chain Diols from Weevils of the Bruchidae

Abstract Mono- and bis 3-(hydroxypropanoyl) esters of long chain, unsaturated diols have been isolated and identified from two genera of the family Bruchidae, and have been shown to be responsible for the mitogenic activity observed on pea pods resulting from oviposition by the pea weevil, Bruchus pisorum . The mitogenic compounds have been characterized and synthesized.

Lipid composition of the extracellular matrix of Botrytis cinerea germlings

Six simple lipid classes (mono-, di- and tri-acylglycerols, free fatty acids, free fatty alcohols and wax esters) were identified by TLC in the extracellular matrix of Botrytis cinerea germlings and the molecular components of each class were characterized using GC-MS. The relative amounts of fatty acids and fatty alcohols within each lipid class were determined by GC-FID. Over all the lipid classes, the most abundant saturated fatty acids were palmitic (ca. 30%) and stearic acid (ca. 22%). Palmitoleic and oleic acids made up ca. 21% and 24% (respectively) of the free fatty acids, while erucic (ca. 4.1%) and linoleic (ca. 3.6%) acids were the most abundant unsaturated fatty acids in the acylglycerides. The acylglycerides also contained almost 35% long chain fatty acids (C20:0 to C28:0). Six fatty acids were identified which had odd-numbered carbon chain lengths (C15:0, C17:0, C19:0, C21:0, C23:0 and C25:0). Of these, pentacosanoic acid made up almost 14% of the fatty acids in the acylglycerides. Three methyl-branched chain fatty acids, namely isopalmitic, isoheptadecanoic and anteisopalmitic, were identified in the ECM, all in small amounts. Of the fatty alcohols identified, only palmityl and stearyl alcohols were found in the free form (ca. 57% and 43%, respectively) but arachidyl alcohol (ca. 47%) and 1-octacosanol (ca. 30%) were the most abundant fatty alcohols found in the wax ester fraction.

Semiochemical Investigations of the Insidious Flower Bug, Orius insidiosus (Say)

Females of the insidious flower bug, Orius insidiosus (Say) (Hemiptera: Heteroptera: Anthocoridae), produce a volatile sex pheromone and a non-volatile trail pheromone. The sex pheromone consists of the female-specific compound, (E)-2,7-octadienal, and a compound emitted by both sexes, (E)-2-octenal. A synthetic blend of octadienal and octenal weakly, but significantly, attracted O. insidiosus males to sticky traps in the field. The trail pheromone is somehow deposited by O. insidiosus females on the substrate as they walk, and, once contacted, stimulates conspecific adults to search in the vicinity. O. insidiosus males most likely respond to the trail pheromone as the ultimate means to locate potential mates, whereas the benefit of females responding to the trail pheromone may be that this signal acts as a cue indicating the likelihood of finding nearby prey. The O. insidiosus trail pheromone compounds were not identified. The volatile and non-volatile pheromones of O. insidiosus, along with prior research demonstrating that Orius and other anthocorids frequently exploit prey-associated odors as kairomones that guide their foraging, highlight the extent to which the minute pirate bugs use chemical communication. The semiochemistry of the Anthocoridae, particularly their reliance on non-volatile pheromones and kairomones, reinforces the emerging realization that other terrestrial heteropterans also substantially communicate via contact chemoreception, although this communicative channel has not been thoroughly investigated.

Exocrine Secretions of Scentless Plant Bugs;Jadera,Boisea; Niesthrea species (Hemiptera:Heteroptera: Rhopalidae)

Abstract The so-called scentless plant bugs are actually exceptionally redolent insects. Twenty-two volatile exocrine compounds were identified from eight rhopalid species, including monoterpene hydrocarbons and alcohols, alkenals and ketoalkenals, 2-phenylethanol and (4S,5S)-(+)-5-hydroxy-4-decanolide. The lack of species-specificity for the exocrine blends from eastern and western boxelder bugs ( Boisea trivittatus and B. rubrolineatus , respectively) cast doubt on their validity as separate species. The biological roles for the array of exocrines released by rhopalids are largely unknown, but potentially important because boxelder bugs are an increasing urban nuisance and species such as Niesthrea Iouisianica may be useful weed control agents.

Enantioselective synthesis of 2-fluoro carboxylic acids from Trichloromethyl carbinols: an efficient approach to chiral fluorine introduction into insect sex pheromones

Abstract Chiral syntheses of 2-fluoro carboxylic acids were achieved (ee ≥ 92%, yield 50–60%) by stereoselective conversion (with inversion of configuration) of optically active trichloromethyl carbinols to fluoroacids with tetrabutylammonium fluoride. Fluorinated pheromone analogs of the European corn borer, Ostrinia nubilalis , and of the beet armyworm, Spodoptera exigua , were synthesized.

A male-produced pheromone of the spined citrus bug

An unusual hemiacetal, cis-3,4-bis[(E)-1-butenyl]tetrahydrofuran-2-ol, the major component of the dorsal abdominal glands of the title insect, was identified by spectral and chemical means, and the structure confirmed by synthesis.