TEMPERATURE MODIFICATION OF MALE SEX PHEROMONE RESPONSE AND FACTORS AFFECTING FEMALE CALLING IN HOLOMELINA IMMACULATA (LEPIDOPTERA: ARCTIIDAE)

In Holomelina immaculata (Reakirt) periodicity of male attraction to synthetic 2-methylheptadecane, the female-produced sex pheromone, is modified by temperature cues. In the field this response interval occurs from approximately sunset to about 4 h after sunset on a warm day and night (30° to 17 °C) and for the 2 h prior to sunset on a cool day and night (23° to 16 °C). In laboratory studies at 24 °C female H. immaculata placed in continual scotophase have an endogenous calling rhythm, but they are apparently inhibited from calling by constant photophase. In 16:8 or 12:12 light-dark cycles at 24 °C calling occurs from the 2nd to the 6th hour of scotophase, whereas at 15 °C calling takes place from the initiation to the 5th hour of scotophase. The critical cues governing initiation of calling behaviour are lights-off or a temperature decrease cue, and a temperature decrease signal overrides the apparent inhibitory effect of continual photophas

Individual Variation in Sex Pheromone Component Ratios in Two Populations of the Redbanded Leafroller Moth, Argyrotaenia velutinana

Gas chromatographic analyses of pheromone component ratios from 381 individual female tip extracts from field and laboratory populations of redbanded leafroller moths revealed that a narrow-variance signal (coefficient of variance = 9.7%) was used by both populations. Although all measured ratios of (E)-/(Z)-11-tetradecenyl acetates for both populations fell within 4-15% for the E-component, the untransformed means and standard deviations for the field and lab insects were 9.1±1.8 and 7.0±1.4%, respectively (difference significant at P<0.01). The field Insects contained an average of 139±81 ng of pheromone/female compared to 107±58 ng/female for the laboratory insects. No significant relationships were found between insect body weights, quantity of pheromone, or component ratio

Gypsy Moth Responses to Pheromone Enantiomers as Evaluated in a Sustained-Flight Tunnel

(−)-Disparlure reduced: (1) the durations of anemotactic flights of male gypsy moths, Lymantria dispar (L.), in plumes of (+)-disparlure; (2) the rate of moth flight with respect to a moving floor pattern; and (3) the percentage of moths initiating anemotactic flights. The effects of (−)-disparlure were much more apparent on in-flight than pre-flight behavio

Initiation and Termination of Oriental Fruit Moth Male Response to Pheromone Concentrations in the Field

The distance from the pheromone source at which Grapholitha molesta (Busck) males initiated walking, upwind flight, or wing fanning while walking varied directly with the pheromone emission rate. Roughly a 10-fold increase in emission rate resulted in a ca. 2-fold increase in mean maximum distance for initiation of these behaviors. Also, an apparent upper concentration threshold in males caused upwind flight to be terminated at increasing distances from the source with increasing emission rates. Thus, upper and lower thresholds apparently determine the boundaries of the "active distance” for upwind flight. There was much daily variation in mean maximum active distance, possibly due to temperature effects upon male threshold. The active distance estimates were used to design an optimal monitoring trap deployment strategy to minimize attraction of males from areas surrounding orchards. Using Bossert and Wilson's equation for active space, the average lower (initiation) threshold for upwind flight was 7.2 × 10−17 g/cm3 and the upper (termination) threshold was 2.1 × 10−13 g/cm3. Their model should be altered so that active space is defined as the space where pheromone concentration is within both lower and upper thresholds for a particular behavio

DIEL PERIODICITY OF MALE SEX PHEROMONE RESPONSE AND FEMALE ATTRACTIVENESS IN THE GYPSY MOTH (LEPIDOPTERA: LYMANTRIIDAE)

In field studies gypsy moth males were attracted to synthetic cis-7,8-epoxy-2-methyloctadecane (disparlure), the female sex pheromone, and virgin females from 0900 to 2000 (Eastern Standard Time). The greatest numbers of males were lured to the synthetic attractant or the calling female from 1100 to 1500. These periods of male response are longer than reported in previous (1896 and 1932) New England investigations and suggest the possible recent evolution of a new diel rhythm of male sex pheromone respons

Interference with the Mate-Finding Communication System of the Obliquebanded Leafroller (Lepidoptera: Tortricidae) Using Synthetic Sex Pheromones

Effect of atmospheric permeation with synthetic sex pheromone on the behavior and control of obliquebanded leafroller, Choristoneura rosaceana (Harris), was studied in small and large plots in commercial apple orchards. Synthetic sex pheromone significantly reduced the ability of male moths to locate pheromone-baited traps and tethered females; however, no differences were found among 3 pheromone rates. Location of pheromone dispensers within the tree canopy did not alter the number of males locating pheromone-baited traps and mating tethered females. Obliquebanded leafroller activity was greatest in the upper positions of the tree canopy and no edge effect was observed around perimeters of large disrupted blocks. The presence of gravid feral females, mated tethered females, high larval densities, and fruit damage within large pheromone disrupted blocks indicate obliqubanded leafrollers mate in orchards treated with synthetic sex pheromone. However, fruit damage caused by obliquebanded leafroller larvae was similar in pheromone, pheromone plus insecticide, and insecticide treatment

Theory of adsorbate induced surface reconstruction on W(100)

We report results of a theoretical study on an adsorbate induced surface reconstruction. Hydrogen adsorption on a W(100) surface causes a switching transition in the symmetry of the displacements of the W atoms within the ordered c(2x2) phase. This transition is modeled by an effective Hamiltonian, where the hydrogen degrees of freedom are integrated out. Based on extensive Monte Carlo renormalisation group calculations we show that the switching transition is of second order at high temperatures and of first order at low temperatures. This behavior is qualitatively explained in terms of an XY model where there is an interplay between four and eight fold anisotropy fields. We also compare the calculated phase diagrams with a simple mean field theory.Comment: CSC Preprint, 31 pages (plain TeX file, no figures