"This is not an apple"-yeast mutualism in codling moth.

The larva of codling moth Cydia pomonella (Tortricidae, Lepidoptera) is known as the worm in the apple, mining the fruit for food. We here show that codling moth larvae are closely associated with yeasts of the genus Metschnikowia. Yeast is an essential part of the larval diet and further promotes larval survival by reducing the incidence of fungal infestations in the apple. Larval feeding, on the other hand, enables yeast proliferation on unripe fruit. Chemical, physiological and behavioral analyses demonstrate that codling moth senses and responds to yeast aroma. Female moths are attracted to fermenting yeast and lay more eggs on yeast-inoculated than on yeast-free apples. An olfactory response to yeast volatiles strongly suggests a contributing role of yeast in host finding, in addition to plant volatiles. Codling moth is a widely studied insect of worldwide economic importance, and it is noteworthy that its association with yeasts has gone unnoticed. Tripartite relationships between moths, plants, and microorganisms may, accordingly, be more widespread than previously thought. It, therefore, is important to study the impact of microorganisms on host plant ecology and their contribution to the signals that mediate host plant finding and recognition. A better comprehension of host volatile signatures also will facilitate further development of semiochemicals for sustainable insect control.

Isophorone derivatives as a new structural motif of aggregation pheromones in Curculionidae.

The beetle Homalinotus depressus (Coleoptera: Curculionidae) is a major pest of coconuts in the Northern region of Brazil, for which environmentally friendly methods of control are desired. Behavioral responses of H. depressus to airborne volatile extracts from conspecifics suggested the presence of a male-produced aggregation pheromone. GC analyses of these extracts showed the presence of four male-specific compounds. Analytical data in combination with the synthesis of standards led to the identification of the male-released semiochemicals as epoxyisophorone (1), isophorone (2), homalinol (3), and 2-hydroxyisophorone (4), of which (3) was the major constituent. The configuration of homalinol was determined to be cis on the basis of retention times of synthetic cis and trans synthetic standards. Enantiomers of cis-homalinol were obtained in high enantiomeric excess by using biocatalysis. Their separation on a GC enantioselective column (ß-Dex325®), allowed us to unambiguously determine that the absolute configuration of natural homalinol was (1R,2R,6S). Field bioassays demonstrated that both the synthetic major compound per se and mixtures of all four male-specific compounds were attractive to H. depressus.

Synergism and redundancy in a plant volatile blend attracting grapevine moth females.

A flight tunnel study was done to decipher the behavioral effect of grape odor in grapevine moth Lobesia botrana. A blend of 10 volatile compounds, which all elicit a strong antennal response, attracts mated grapevine moth females from a distance, by upwind orientation flight. These 10 grape volatiles are in part behaviorally redundant, since attraction to a 3-component blend of beta-caryophyllene, (E)-beta-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene was not significantly different from the 10-component blend. Blending these three compounds had a strong synergistic effect on female attraction, and omission of any one compound from this 3-component blend almost abolished attraction. It was nonetheless possible to substitute the three compounds with the other grape volatiles which are perceived by the female antenna, to partly restore attraction. Several blends, of varying composition, elicited significant attraction. The observed behavioral plasticity in response to grape volatile blends probably reflects the variation of the natural plant signal, since females oviposit on different grape varieties, in different phenological stages.

Synthesis and field tests of sex pheromone components of the leafroller Argyrotaenia sphaleropa.

Female pheromone glands of the leafroller Argyrotaenia sphaleropa were analyzed. Two acetates were identified as (11Z,13)-tetradecadien-1-yl acetate and (11Z)-tetradecen-1-yl acetate by comparison with synthesized references. The (11Z,13)-tetradecadien-1-yl acetate and the aldehyde (11Z,13)-tetradecadienal were synthesized via a Wittig reaction. A field-trapping test showed that a lure consisting of a mixture of (11Z,13)-tetradecadienal and (11Z,13)-tetradecadien-1-yl acetate in a 10:1-ratio produced the highest trap catches.

Chemical composition of essential oil from Myrcia oblongata DC and potencial antimicrobial, antioxidant and acaricidal activity against Dermanyssus gallinae (Degeer, 1778) / Composição química do óleo essencial de Myrcia oblongata DC e potencial antimicrobiano, antioxidante e acaricida contra Dermanyssus gallinae (DEGEER, 1778)

Essential oils have aroused interest in the industrial sector due to the multitude of potential applications, especially with respect their antimicrobial and antioxidant properties, among others. The objective of this study was to determine the chemical composition of the essential oil from the leaves of Myrcia oblongata DC by gas chromatography coupled to mass spectrometry (GC-MS). To evaluate the antioxidant potential of the oil by using the free radical capture method with 2,2-diphenyl-1-picryl hydrazyl (DPPH); to test the oil antimicrobial activity using the broth microdilution method; and to evaluate the repellency and fumigant potential of the oil on Dermanyssus gallinae (Degeer, 1778). The GC-MS analysis resulted in the identification of 30 oil constituents, with the bulk of the composition identified as caryophyllene oxide (22.03%) and trans-verbenol (11.94%). The oil presented moderate antioxidant activity compared to the synthetic antioxidant 2,6-di-tert-butyl-4-hydroxytoluene (BHT). Antimicrobial activity of the essential oil showed an inhibitory activity on Gram-positive bacteria, Enterococcus faecalis, Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermidis and for the yeast Candida albicans, and showed no activity against Gram-negative bacteria. All concentrations of the essential oil used in the fumigation test on D. gallinae resulted in mortality below 20%. For the repellency test, significant potential was observed for the concentration of 10%.

Os óleos essenciais tem despertado interesse no setor industrial por apresentarem multiplicidade de aplicações, destacando-se por suas propriedades antimicrobianas, antioxidantes dentre outras. Diante disto, o objetivo deste estudo foi determinar a composição química do óleo essencial das folhas de Myrcia oblongata DC pelo método de cromatografia gasosa acoplada à espectrometria de massas (CG-EM), avaliar o potencial antioxidante do óleo pelo método de captura do radical livre 2,2- difenil-1-picril hidrazil (DPPH), testar a atividade antimicrobiana pelo método de microdiluição em caldo, bem como avaliar a repelência e potencial fumigante deste óleo sobre Dermanyssus gallinae (Degeer, 1778). As análises de CG-EM resultaram na identificação de 30 constituintes, sendo majoritários o óxido de cariofileno (22.03%) e o trans-verbenol (11.94%). O óleo apresentou atividade antioxidante moderada quando comparada ao antioxidante sintético 2,6-di-tert-butil-4-hidroxitolueno (BHT). Em relação à atividade antimicrobiana, o óleo essencial demonstrou atividade inibitória para as bactérias Gram-positivas, Enterococcus faecalis, Staphylococcus aureus, Bacillus subtilis e Staphylococcus epidermidis, e para levedura Candida albicans e não apresentou atividade para bactérias Gram negativas. Todas as concentrações do óleo essencial testadas no teste de fumigação sobre D. gallinae apresentaram mortalidade inferior a 20%. Para o teste de repelência, observou-se um potencial significativo para a concentração de 10%.

Codling moth males do not discriminate between pheromone and a pheromone/antagonist blend during upwind flight.

Discrimination between conspecific and heterospecific signals is a key element in the evolution of pheromone-mediated communication in insects. Pheromone antagonists prevent heterospecific attraction. They are typically pheromone synergists in other species and enable specific communication in closely related species, using partly the same chemicals. In codling moth, Cydia pomonella, as in other moths, upwind flights to a pheromone/antagonist blend were slower and more convoluted than to pheromone. However, this deteriorated flight behaviour did not account for the strong decrease in male attraction. The pheromone/antagonist blend blocked instead the onset of upwind flight. This was corroborated by placing a separate source of pheromone close by, which restored male attraction. Males flying upwind did not discriminate between pheromone and the adjacent pheromone/antagonist blend, and landed on either source. This indicates differences in the neural regulation for initiating and maintaining a behavioural response to pheromone.