The leaf-footed bug, Leptoglossus zonatus (Heteroptera: Coreidae), is mainly found in maize fields in Brazil. In this work, we elucidated and quantified the volatile compounds from nymphs and adults of L. zonatus. The defensive compounds produced by nymphs are aldehydes and oxo-alkenals, with some compounds showing different proportions between instars. For the first time, 5-ethyl-2(5H)-furanone has been identified as a defensive compound for a species of this family. In adults, the alarm pheromone includes hexanal, 1-hexanol, hexanoic acid, hexyl acetate, and octyl acetate. Males and females produce the same compounds, however, hexanal showed a significant difference between sexes. Gas chromatography (GC) analysis of adult aeration extracts revealed male specific compounds, which attactiveness to females was confirmed through olfactometer bioassays. By using a GC-electroantennographic detector (EAD), it was shown that female antenna presented electrophysiological responses to five components ((Z)-β-ocimene, (Z, Z)-allo-ocimene, decanal, α-trans-bergamotene, and (E)-β-farnesene) from male aeration extracts. In this way, we propose that males are responsible for emission of a sex pheromone in this species.

The profile of volatiles emitted by Ilex paraguariensis, leaves of which are used to produce a popular South American tea, were identified and compared among treatments. Headspace collections were performed for 24-72 hours for control, mechanical damage (MD), herbivory by larvae of Thelosia camina (TC), and by adults of Hedypathes betulinus (HB). Based on gas chromatography-mass spectrometry (GC-MS) and gas chromatography-Fourier transform infrared (GC-FTIR) analyses, 20 compounds were identified, totaling about 7, 5, 20, and 25 µg/plant/treatment (control, MD, TC and HB, respectively). Statistical analyses revealed that control and MD treatments are different from TC and HB herbivory treatments. Furthermore, HB herbivory was distinctive from the other treatments at 24 h in that HB feeding induced a distinctive pattern of emission of terpenes. Major compounds per treatments were decanal for control and DM, 4,8-dimethylnona-1,3,7-triene (DMNT) and 2-undecanone for TC, and DMNT and (E)-β-ocimene for HB.

The identification and manipulation of chemical compounds involved in vital activities of arthropods have the potential for developing less aggressive pest control strategies. Herbivory induces the emission of volatile organic compounds involved in the recruitment of natural enemies, plant-plant interactions and repellency of other herbivores. In this report, we review the main chemical groups of volatile organic compounds and their ecological functions, provide an overview of the signal transduction pathways activated upon herbivory, and review the current state of knowledge for practical applications in pest management. We conclude by proposing perspectives for future research.

Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae) é uma espécie asiática, polífaga e reconhecida como agente de controle biológico de afídeos pelo mundo, provavelmente introduzida acidentalmente no Brasil, coletada pela primeira vez em 2002. É um importante predador intraguilda, pois compete por alimento com as espécies nativas de coccinelídeos. Foram estudadas as fontes alimentares de H. axyridis e suas plantas hospedeiras, sua abundância em relação às espécies nativas e estabelecidas, a influência dos fatores abióticos e as estações do ano sobre sua abundância durante um ano e discutidos os mecanismos que influenciam no deslocamento das espécies nativas de Coccinellidae. Além disso, foi testada a influência dos fatores abióticos e as estações do ano sobre sua abundância durante um ano. Harmonia axyridis foi encontrada em 38 espécies de plantas, sendo 20 delas novos registros, alimentando-se de 20 espécies de afídeos, oito novos registros alimentares. Entre os anos de 2006/2007, oito espécies de Coccinellidae foram coletadas e H. axyridis foi a mais abundante (91,23%). O pico de abundância de H. axyridis ocorreu em agosto e setembro de 2007, provavelmente influenciado pela temperatura e disponibilidade de alimento. Entre 1999 e 2007, foram observadas a redução e variação na diversidade de espécies de Coccinellidae coletadas, com a predominância de H. axyridis, o que pode indicar o desalojamento destas espécies.

Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae) is a polyphagous Asian species, well-known as a classical biological control agent of aphids around the world, introduced probably accidentally in Brazil, sampled for the first time in 2002. It is an important intraguild predator, competing for food with native coccinellids. It was studied H. axyridis alimentary sources and host plants, its abundance compared with native and established species, the influence of abiotic factors and the seasons over the abundance of H. axyridis throughout one year, and discussed the mechanisms which influence the displacement of species. Harmonia axyridis was found in 38 plant species, among them 20 were new records, feeding on 20 aphid species, eight of them new alimentary records. Between 2006/2007, eight Coccinellidae species were collected and H. axyridis was the most abundant (91.23%). Harmonia axyridis peak of abundance occurred in August and September 2007, probably influenced by the temperature and food availability. From 1999 to 2007 a reduction and variation in the diversity of collected species of Coccinellidae were observed with the predominance of H. axyridis, which may indicate their displacement.