Reproductive behavior and sex pheromone identification of Pseudaletia sequax (Lepidoptera: Noctuidae) / Comportamento reprodutivo e identificação de feromônio sexual de Pseudaletia sequax (Lepidoptera: Noctuidae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The effects of pupal period and age on calling behavior of virgin females of Pseudaletia sequax were determined. Larvae were reared on artificial diet. Calling behavior of groups of females of similar age of pupation was observed every 10 minutes for six days at reversed photoperiod. Females were considered calling when they had assumed a characteristic position: wings and abdomen elevated, displaying the ovipositor, and presumably releasing pheromone. Calling behavior was discontinuous. Females that had emerged on the fifth day took more time to start calling those females with a longer pupal period. On the first day of calling, females took more time to initiate calling, on average during the seventh hour of the scotophase. On the second calling day, most females initiated calling during the fifth hour of the scotophase. On subsequent calling days, the average time to initiate calling changed to the fourth hour of the scotophase. Calling age had a significant effect on the onset of calling and mean time of calling per day. The first calling is influenced positively by pupal period, the calling length is influenced negatively mostly in groups of females the pupal period larger and mean number of calling bouts increased with calling age. Gas chromatographic and mass spectral analyses were conducted on pheromone gland extracts, volatiles collected from excised pheromone glands from females of P. sequax calling. Coupled Gas Chromatographic-electroantennographic Detection (CG-EAD) analysis of the female gland extract showed the presence of three EAD-active peaks, which were identified by CG-mass spectrometric (MS) analyses. The pheromone blend it is:(Z)-11-Hexadecenal (Z11-16: Al), (Z)- 11-Hexadecenyl acetate (Z-11-16: OAc) and (Z)-11- Hexadecen-1-ol (Z11-16: OH).The mean percentage of compounds identified from volatiles collected from calling females was 85.2% (Z)-11-Hexadecenal, 12.8% (Z)-11- Hexadecenyl acetate and 2% (Z)-11-Hexadecen-1-ol. The evaluation of antennal response of males to these pheromone components it was compared in laboratory by electroantennographic detection (CG-EAD) and the electroantennogram showed depolarization of antennae when in contact with these three compounds. Theses compounds is possible sex pheromone candidates of P. sequax. The behavioral response of P. sequax to synthetic sex pheromone was studied. Behavioral tests were carried out within a wind tunnel (3x1x1m) calibrated to 0.40m/s of wind speed. Virgin males were tested once during fifth and eighth hour of scotophase corresponding the female calling period. The males were placed at transparent glass cage and placed inside of tunnel on a wooden platform in v format (50 cm of height) during 2 minutes for acclimatization. A male was scored only once and then discarded. The rubber septa of pheromone it was located in (1,94m) the distance of platform of male. The treatments were: (blend) rubber septa of 100 g/l of the complete mixture (85.2 % Z11-16:Al, 12. 8% Z11-16:OAc, 2% Z11-16:OH), alcohol-free rubber septa 100 g/l (Z11-16:Al + Z11-16:OAc), acetate-free rubber septa 100 g/l (Z11-16Al + Z11-16:OH) and aldehyde alone rubber septa of 100 g/l (Z11-16:Al). Analyses of flight course indicted that Z 11-16:Al and Z11-16:OAc is an essential for inducing the upwind flight, landing and flight close and the minor component Z11-16:OH when added Z11-16:Al, Z11- 16:OAc significantly increase flight close response, although in all others behavioral responses this compound revealed to be unnecessary. Ours results confirmed that Z11-16: Al, Z11-16:OAc and Z11-16:OH are sex pheromone component of the P. sequax because of the high male attractiveness.

ASSUNTO(S)

feromônio sexual sex pheromone integrated pest management ecologia química entomologia agricola pseudaletia sequax manejo integrado de pragas mariposa do trigo chemical ecology

ACESSO AO ARTIGO

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