Several studies have shown intraspecific geographical variation in the composition of sex pheromones. Pheromone lures from North America and Europe were not effective against the fall armyworm Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) in Brazil, so we examined the composition of the sex pheromone produced by females from Brazilian populations. Virgin female gland extracts contained (Z)-7-dodecenyl acetate (Z7-12:Ac), (E)-7-dodecenyl acetate (E7-12:Ac), dodecyl acetate, (Z)-9-dodecenyl acetate, (Z)-9-tetradecenyl acetate (Z9-14:Ac), (Z)-10-tetradecenyl acetate, tetradecyl acetate/(Z)-11-tetradecenyl acetate (Z11-16:Ac), and (Z)-11-hexadecenyl acetate. The relative proportions of each acetate were 0.8:1.2:0.6:traces:82.8:0.3:1.5:12.9, respectively. This is the first time that E7-12:Ac has been reported from the pheromone gland of S. frugiperda. Only three compounds, Z9-14:Ac, Z7-12:Ac, and E7-12:Ac, elicited antennal responses, and there were no differences in catch between traps baited with either Z7-12:Ac + Z9-14:Ac or Z7-12:Ac + Z9-14:Ac + Z11-16:Ac blends. However, the Z7-12:Ac + Z9-14:Ac + E7-12:Ac blend was significantly better than Z7-12:Ac + Z9-14:Ac, indicating that E7-12:Ac is an active component in the sex pheromone of the Brazilian populations of S. frugiperda.

Virgin female gland extracts of sugarcane moth Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), from three locations in Brazil, have been analyzed. By GC-MS analysis and comparison of the chromatographic retention time of the components of the pheromone gland with those retention times of synthetic standards, we observed the presence of (Z)- hexadec-11-enal (1), hexadecanal (2), (9E,11Z)-hexadecadienal (4), (9Z,11Z)-hexadecadienal (5) and (9E,11E)-hexadecadienal (6), as minor components besides the major constituent (9Z,11E)-hexadecadienal (3) already reported. We found no variations in the composition of the gland extracts deriving from the three Brazilian populations and only two compounds, (Z)-hexadec-11-enal (1) and (9Z,11E)-hexadecadienal (3), elicited antennal responses (GCEAD). In electroantennography (EAG), however, pure compounds 1 and 3, a binary mixture containing 1 and 3, and a mixture containing all of the six synthetic compounds 1-6 elicited a depolarization in male antennae of D. saccharalis, without any statistically different delay. The EAG responses to the other isomers of 9,11-hexadecadienal were small and not significantly different from the control, except for the (9Z,11Z)-isomer (5) which showed an relatively strong electroantennal activity.

The chemical composition of some volatile (2-heptanol) and nonvolatile constituents (a homologous 9-alkene/alkane series) of Mormolyca ringens flowers and Scaptotrigona sp. queen waxes (homologous 9-alkene/alkane series) and cephalic extracts (homologous series of 2-alkanols, including 2-heptanol) involved with the pseudocopulation or sexual mimicry in Orchidaceae pollination is compared. The similarity in chemical composition of flowers and insects is assigned to the chemically induced copulatory activity in Scaptotrigona males.

A lagarta-parda, Thyrinteina arnobia, causa grandes prejuízos à cultura do eucalipto, destacando-se como o principal lepidóptero desfolhador; portanto, medidas alternativas de controle são necessárias. Neste trabalho foi avaliada, pela técnica de eletroantenografia (EAG), a interação dos voláteis dos óleos essenciais de sete espécies de Eucalyptus, frente às antenas de fêmeas e de machos de T. arnobia. Foram também identificados 28 compostos voláteis bioativos contidos no óleo essencial de E. grandis, utilizando a detecção eletroantenográfica acoplada à cromatografia a gás (CG-EAD). Estes resultados indicam que CG-EAD é uma ferramenta muito útil na triagem de compostos bioativos presentes em extratos de plantas e sugerem que T. arnobia utiliza vários destes terpenos como sinais para encontrar seu hospedeiro.Eucalyptus is frequently attacked by the Brazilian eucalyptus brown looper, Thyrinteina arnobia. This caterpillar is regarded as the main lepidopterous pest of Eucalyptus and yet no practical and environmentally acceptable method of control currently exists. Electroantennographic techniques (EAG) have never before been used to detect semiochemicals that affect the behavior of T. arnobia. Thus, in this work, the ability of T. arnobia males and females to detect volatile essential oils of seven Eucalyptus species was investigated by EAG. We demonstrated that T. arnobia antennal olfactory system clearly showed differential sensitivity to several compounds, by coupled gas chromatography-electroantennographic detection (GC-EAD). Twenty-eight compounds were identified that elicited responses in T. arnobia, indicating that GC-EAD analysis may well be a useful means of screening active plant extracts for compounds that contribute to the observed behavior of this defoliator. The results also suggest that this species uses several volatile cues to find its host.Keywords: Thyrinteina arnobia, Eucalyptus brown looper, Eucalyptus spp., essential oil, electroantennography IntroductionThe genus Eucalyptus, native to Australia, is widely cultivated in Brazil, covering an area of more than three million hectares. This country is the world's leading producer of eucalyptus-based fiber and of the 6.3 million tons of cellulose produced here annually, the majority is extracted from this exotic species. Eucalyptus plantations also supply wood to the furniture industry and help to reduce the pressure on native forests. 1The Brazilian eucalyptus brown looper, Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae), is the most harmful of the Eucalyptus pests in Brazil, causing severe losses in wood production through defoliation. This moth attacks several genera of the Myrtaceae family, including six Psidium species, eight Campomanesia species, nine Eugenia species and twenty Eucalyptus species. Biological data on T. arnobia, reared on leaves of Eucalyptus spp, have been recorded by a number of groups. 2-6Several strategies have been tried and considerable effort spent on the development of methods to control this pest, yet no p...

The sand fly Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae: Phlebotominae) is the main vector of American visceral leishmaniasis. Adult males produce a terpenoid sex pheromone that in some cases also acts as male aggregation pheromone. We have analyzed the correlation between male pheromone production levels and pheromone gland cell morphogenesis after adult emergence from pupae. The abdominal tergites of L. longipalpis males were dissected and fixed in glutaraldehyde for transmission electron microscopy, or the pheromone was extracted in analytical grade hexane. Pheromone chemical analysis was carried out at 3- to 6-h intervals during the first 24 h after emergence and continued daily until the seventh day. All extracts were analyzed by gas chromatography. For the morphological analysis, we used insects collected at 0-6, 9-12, 12-14, and 96 h after emergence. Ultrastructural data from 0- to 6-h-old adult males revealed smaller pheromone gland cells with small microvilli at the end apparatus. Lipid droplets and peroxisomes were absent or very rare, but a large number of mitochondria could be seen. Lipid droplets started to appear in the gland cells cytoplasm approximately 9 h after adult emergence, and their number and size increased with age, together with the presence of several peroxisomes, suggesting a role for these organelles in pheromone biosynthesis. At 12-15 h after emergence, the lipid droplets were mainly distributed near the microvilli but were smaller than those in mature older males (4 d old). Pheromone biosynthesis started around 12 h after emergence and increased continuously during the first 3 d, stabilizing thereafter, coinciding with the period when males are more able to attract females.