J. A. Coffelt

Isolation, identification, and synthesis of a female sex pheromone of the navel orangeworm,Amyelois transitella (Lepidoptera: Pyralidae)

A sex pheromone of the navel orangeworm,Amyelois transitella (Walker), was obtained from ether rinses of the sex pheromone gland of calling females. The pheromone was isolated by means of liquid and gas chromatography and was identified as one of four possible geometrical isomers of 11,13-hexadecadienal by means of spectroscopic and microchemical methods. Synthesis and laboratory bioassay of all four isomers revealed that only the (Z,Z) isomer was biologically active. (Z,Z)-11,13-hexadecadienal elicited quantitatively similar activation and attraction responses byA. transitella males as did the natural product.

Identification of sex pheromone produced by female sweetpotato weevil,Cylas formicarius elegantulus (Summers)

A sex pheromone of the sweetpotato weevil,Cylas formicarius elegantulus (Summers), was obtained from collections of volatiles from virgin females, and pheromone was isolated by means of liquid and gas chromatography. The purification procedure was monitored by quantitative laboratory and field bioassays and the compound was identified as (Z)-3-dodecen-1-ol (E)-2-butenoate by means of spectroscopic and microchemical methods. Synthesis, followed by laboratory and field bioassays, showed that the biological activity of the synthetic material was qualitatively and quantitatively indistinguishable from that of the purified natural product.

Models for dispersal of vapors in open and confined spaces: Applications to sex pheromone trapping in a warehouse

Methods are presented for mathematically determining dispersal of a vapor in still air, in turbulent air of zero average velocity, and in turbulent or laminar air currents of constant, nonzero average velocity. The methods are combined with several assumptions about insect behavior to derive an insect attraction model that predicts: (1) In a warehouse a searching insect is likely to be attracted to a calling insect if it comes within an attraction sphere, 0.4–2.5 m in radius. (2) The attraction spaces of typical sex pheromone-baited traps that emit pheromone at rates greater than 0.01 ng/sec extend beyond the boundaries of a 10 × 10 × 10-m warehouse. (3) The searching behavior of an attracted insect is likely to be altered from an extensive to an intensive pattern if it comes within an altered-behavior sphere, 6–60 cm from a calling insect or within 10 m of a trap emitting 0.76 ng/sec. (4) Pheromone does not sink unless it is emitted along with a large amount of a high-vapor pressure solvent. The model is used in support of several hypotheses, including: (1) The effect of an adsorptive surface on the vapor concentration after an extended period of emission is negligible except at positions near the surface. (2) Sex pheromone-baited traps with sources of small dimensions have greater trapping efficiency than otherwise identical traps with sources of large dimensions.

Recent Developments in the Use of Pheromones to Monitor Plodia Interpunctella and Ephestia Cautella

Stored commodities are particularly susceptible to insect infestation, in part, because food is rarely limited in storage facilities, and temperature and climatic conditions tend to be ideal for insect development. Furthermore, the handling involved in milling, processing, and transporting greatly increases the possibility of introducing insect pests into the commodity. These factors plus the very stringent requirements for absence of insects in processed commodities make sensitive insect monitoring tools necessary. Numerous entomologists have suggested that traps baited with sex pheromones may be ideally suited to this use.

Anemotactic response threshold of the Indian meal moth,Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), to its sex pheromone

The effect of different concentrations of the sex pheromone (Z,E)-9,12-tetradecadien-1-ol acetate on the upwind anemotactic behavior of the malePlodia interpunctella (Hübner) was measured at 23 ± 1 ° C and 34 ± 1 ° C. The stimulus-response regression lines were analyzed by a new procedure that accounts both for control responses in the absence of pheromone and also for peak responses below 100% in the presence of concentrations considerably above the normal physiological levels. From the regression line for each temperature, the upwind anemotactic thresholds were calculated to be 1.34 × 106 molecules/cm3 at 23 ° C and 1.65 × 104 molecules/cm3 at 34 ° C, similar to other thresholds reported in the literature. Since departures from the two lines occurred at the highest concentrations tested, near 108 molecules/cm3, the upwind anemotactic behavior may change qualitatively above an altered-behavior threshold that is about two orders of magnitude higher than the upwind anemotactic threshold. The lower response at 23 ° C suggests that cool temperatures inhibit flight in response to pheromonal stimulation.

Symposium: Use of Pheromones in Tropical Crops: Sex Pheromone Gland of the Navel Orangeworm, Amyelois Transitella (Lepidoptera: Pyralidae) Location, Bioassay and in Vitro Maintenance

Anatomical studies of the sex pheromone gland of the female navel orangeworm, Amyelois transitella (Walker), revealed the gland to be a broad, chevron-shaped structure located on the ventrolateral surface of the intersegmental membrane between abdominal segments VIII and IX. Support for this finding was obtained by bioassay and gas chromatographic analyses of extracts that were prepared from various portions of the terminal abdominal segments of female moths. Histological examination showed that the gland consists of a single layer of specialized columnar epidermal cells. Sex pheromone glands were obtained from surface-sterilized abdominal segments of 2 to 3-day-old virgin females and subsequently cultured for up to 7 days in either chemically defined or modified Graces medium. Bioassays of extracted medium in which sex pheromone glands had been maintained indicated that more pheromone was recovered from modified Graces medium than from the chemically defined growth substrate.

In vitro maintenance of the sex pheromone gland of the female Indian meal mothPlodia interpunctella (Hübner)

Sex pheromone glands ofPlodia interpunctella were isolated from surface-sterilized donors of different ages, freed of most of the attached gut, oviduct, and other tissues; rinsed in sterile medium; and cultured in 1 ml of culture medium. The sex pheromone gland cells that were cultured for 10 days in either chemically defined Graces medium or modified Graces medium appeared normal in histological examinations. Bioassays of extracted medium in which pheromone glands from mature females had been incubated showed that a greater percentage of the available pheromone was recovered from modified Graces medium than from chemically defined Graces medium.