The olfactory system of male and female Spodoptera frugiperda (J. E. Smith) was studied by examining the morphology and distribution of antennal sensilla and determining the responses of both sexes to conspeciÞc female sex pheromone components and plant volatiles using electroantennography (EAG). Seven types of sensilla were observed on the ßagellum of the antennae: trichodea, chaetica, coeloconica, styloconica, auricilica, squamiformia, and basiconica. Only one type of trichodea sensilla was found on the antennae of both sexes, but these sensilla were more abundant on male than on female. EAG records of both sexes to 10-g stimulus loads of six pheromone components showed that (Z)-7-dodecenyl acetate (Z7Ð12: Ac) and (Z)-9-dodecenyl acetate (Z9 Ð12: Ac) elicited larger responses than those evoked by (Z)-11-hexadecenyl acetate (Z11Ð16: Ac), (Z, E)-9,11-tetradecadienyl acetate (Z9, E11Ð14: Ac), (Z, E)-9,12-tetradecadienyl acetate (Z9, E12Ð14: Ac), and hexane in female antennae. In the case of male antennae, (Z)-9-tetradecenyl acetate (Z9 Ð14: Ac) and Z9, E12Ð14: Ac evoked larger EAG responses than those elicited by Z7Ð12: Ac, Z11Ð16: Ac, Z9, E11Ð14: Ac, and hexane. The compounds that selectively evoked larger EAG responses from males than females were Z9, E12Ð14: Ac, and Z9 Ð14: Ac. Dose-response experiments showed that, at the lowest dose tested, Z9 Ð14: Ac and Z9, E12Ð14: Ac elicited larger EAG responses than Z9 Ð12: Ac and Z7Ð12: Ac in male antennae. At the highest doses tested, the diene elicited the largest EAG responses. In the case of female antennae, the dose, but not the pheromone component, had a signiÞcant effect. Male and female responses to 10-g stimulus loads of 16 plant volatiles showed that hexan-1-ol evoked larger EAG responses in comparison with those elicited by hexanal, (E)-3-hexenol, 2-carene, phellandrene, limonene, ␤-pinene, and hexane. The response of male antennae was signiÞcantly stronger than the female. Dose-response experiments showed that both sexes appeared to be most sensitive to alcohols, particularly at the highest dose tested.

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For the first time, antennal sensorial organs of Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae) are described through scanning electron microscopy. The antennae are formed by a scape, pedicel, and a flagellum that is composed of two flagellomeres and is the main bearer of sensorial organs. Five types of sensory structures were identified: Trichoid sensilla, basiconic sensilla, coeloconic sensilla, campaniform sensilla, and placoid sensilla. Trichoid sensilla were divided into five subtypes. The large striated trichoid sensilla have almost straight longitudinally striated cuticles and were present throughout the antenna. Flattened trichoid sensilla were variable-sized curved hairs distributed from the base ofthe scape to the distal end ofthe first flagellomere. Small striated trichoid sensilla were found mainly on the antenna distal flagellomeres. Smooth trichoid sensilla were located at the distal end of the scape and along the entire length of the pedicel, and are the least abundant type on the antenna. Small smooth trichoid sensilla were found precisely on the joints between the pedicel and scape. Based on size and shape, the basiconic sensilla were also divided into five subtypes (Bsl, Bs2, Bs3, Bs4, and Bs5). These all are rod-shaped. Coeloconic sensilla were found exclusively on the second flagellomere ofthe flagellum. Just one campaniform sensilla on each antenna was located on the second flagellomere ofthe flagellum. Finally, a group of 10 oval placoid organs were found at the scape base, in proximity to the joint connecting the antenna to the insect's head.

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The antennal sensilla of Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) adults were studied by means of scanning electron microscopy. Both sexes have the same form and number of antennal segments. The scape and the pedicel are covered entirely by microtrichia. In the distal part of both segments, a series of longitudinally striated hairs was observed, originating in a flexible socket and ending in a pointed tip. Six types of sensilla were observed in the funiculus: 1) thick-walled multiporous pitted sensilla subtype I and subtype II, 2) thin-walled multiporous pitted sensilla long subtype I and medium length subtype II, 3) basiconic sensilla, 4) multiporous grooved sensilla, 5) clavate sensilla, and 6) an olfactory pit with two small conical and striated sensilla inside. Furthermore, there is a large quantity of microtrichia surrounding the entire funiculus. In the proximal dorso-lateral region of the funiculus, there are trichoid aristae composed of two short segments and one large segment, which have fixed base bristles or tactile hairs without membranes.

The calling behavior of mass-reared and wild males of Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) was studied both in the laboratory and in field cage tests. In the laboratory, density (1, 5, and 10 males per container), age, and hour of day significantly affected calling behavior. Mass-reared males called independently of density, whereas wild males only called at densities of 5 and 10 individuals. Males of both strains started calling when they were 5-7 d old. The daily pattern of male calling was similar in both strains, starting at 0730 hours, and reaching a peak at 1330-1630 hours. Field cage tests showed that mass-reared males started calling when they were 5d old; the period of peak calling was when males were 8-9 d old. In contrast, wild males began calling when they were 10 d old, reaching peaks when males were 13, 15, and 18 d old. Wild males tended to form leks to call during each day of the experiment, whereas mass-reared males only formed leks during 2 d, both strains displaying very low levels. During field cage tests, males, independently of strain, displayed two calling peaks, one peak in the morning and one peak in the afternoon, whereas males observed in the laboratory only showed a single calling peak. The results are discussed in view of the effects of mass rearing A. serpentina males in relation to potential use of the sterile insect technique.

The leaf-footed bug Leptoglossus zonatus (Dallas) (Heteroptera: Coreidae) is an important pest in the Americas. However, no preference of colors, sexual behavior nor aggregation pheromone has been reported, which can be used for detection, monitoring, and control purposes. In the laboratory we tested the attractiveness of white, violet, blue, green, yellow, and orange color to nymphs and adults (mated and unmated) and found that most adults and nymphs were attracted to and remained longer on blue and green colored cards than the other colors tested. We found that couples may remain in copula ≈185 min and mate ≈20 times in a 60 d period with a similar number of matings during the scotophase and the photophase. Sexual behavior consists of six patterns: grooming, abdomen movement, antenna movement, antennation, mounting, and mating. In a Y-tube olfactometer, 80 and 62.5% of the adults tested were attracted to a hexane-extract of the volatiles released by 40 males and 40 females, respectively. This is the first report of the biological evidence of an aggregation pheromone in this bug.