Moths behaving like butterflies. Evolutionary loss of long range attractant pheromones in castniid moths: a Paysandisia archon model.

BACKGROUND: In the course of evolution butterflies and moths developed two different reproductive behaviors. Whereas butterflies rely on visual stimuli for mate location, moths use the 'female calling plus male seduction' system, in which females release long-range sex pheromones to attract conspecific males. There are few exceptions from this pattern but in all cases known female moths possess sex pheromone glands which apparently have been lost in female butterflies. In the day-flying moth family Castniidae ("butterfly-moths"), which includes some important crop pests, no pheromones have been found so far. METHODOLOGY/PRINCIPAL FINDINGS: Using a multidisciplinary approach we described the steps involved in the courtship of P. archon, showing that visual cues are the only ones used for mate location; showed that the morphology and fine structure of the antennae of this moth are strikingly similar to those of butterflies, with male sensilla apparently not suited to detect female-released long range pheromones; showed that its females lack pheromone-producing glands, and identified three compounds as putative male sex pheromone (MSP) components of P. archon, released from the proximal halves of male forewings and hindwings. CONCLUSIONS/SIGNIFICANCE: This study provides evidence for the first time in Lepidoptera that females of a moth do not produce any pheromone to attract males, and that mate location is achieved only visually by patrolling males, which may release a pheromone at short distance, putatively a mixture of Z,E-farnesal, E,E-farnesal, and (E,Z)-2,13-octadecadienol. The outlined behavior, long thought to be unique to butterflies, is likely to be widespread in Castniidae implying a novel, unparalleled butterfly-like reproductive behavior in moths. This will also have practical implications in applied entomology since it signifies that the monitoring/control of castniid pests should not be based on the use of female-produced pheromones, as it is usually done in many moths.

Sex pheromone of the Spanish population of the beet armyworm Spodoptera exigua.

The pheromone composition of the Spanish population of the beet armyworm (BAW), Spodoptera exigua (Lepidoptera: Noctuidae), was identified. Analysis of female gland extracts showed the presence of compounds Z9,E12-14:Ac (1), Z9-14:Ac (2), Z11-16:Ac (3), Z9,E12-14:OH (4), Z9-14:OH (5), and Z11-16:OH (6) in a ratio of 26:11:1:22:31:9. The amount of compound per gland ranged from 2.08 ng for 5 to 0.09 ng for 3. However, analysis of female volatiles by SPME revealed only the presence of compounds, 1, 2, 3, and 5 in a 34:40:4:22 ratio. In electroantennogram assays, compound 1 elicited the highest response, and the C14 acetates evoked higher electrophysiological responses than the corresponding alcohols or C16 isomers. In a wind tunnel, no behavioral difference was observed between formulations based on the gland extracts and female volatiles. In both cases, males responded as when virgin females were used as the attractant source. Compound 1 alone elicited upwind flight by males, but required the presence of compound 5 in a 80:20 to 40:60 ratio for full activity. Ternary mixtures of 1, 5 and the minor components did not improve the performance of the 1+5 blend in a 60:40 ratio. In the field, the mixture 1+5+3 in a 56:37:7 ratio was the most attractive formulation, and is expected to be useful in future pest control strategies.

Improved resolution in the acidic and basic region of 2-DE of insect antennae proteins using hydroxyethyl disulfide.

Olfaction is essential for processing chemical signals in insects, but characterizing the proteins implicated in this process has proved challenging. We optimized 2-DE gel resolution of insect proteins by using a buffer containing two reducing agents, DTT and hydroxyethyl disulfide. This buffer clearly improved resolution and decreased spot streaking and spot trains of 2-DE in comparison to DTT alone. We described for the first time that the buffer with DTT and hydroxyethyl disulfide further to reducing streaking in the basic part of the gel eliminates false spots in the acidic gel regions that appeared when only DTT was used as reducing agent.

Expression of differential antennal proteins in males and females of an important crop pest, Sesamia nonagrioides.

Pest damage causes important decrease in crop yield every year all over the world, particularly by Lepidoptera. Characterization of the antennal proteins implicated in the reproduction of Lepidoptera will help to develop new methods for pest management and contribute to sustainable agriculture and biodiversity maintenance. We present herein the characterization of some antennal proteins of Sesamia nonagrioides by proteomic techniques such as two-dimensional electrophoresis, MALDI-TOF MS, and electrospray ionization tandem mass spectrometry (ESI-MS/MS). The antennal proteins expressed in both sexes were analyzed and more than 800 spots were detected, finding 16 proteins differentially expressed between males and females. Most of the identified proteins were involved in olfaction. High levels of pheromone binding proteins (PBP1 and PBP2) were found as expected in males, but also in female antennae, although females did not electrophysiologically respond to their own pheromone. General odorant binding proteins (GOBP1 and GOBP2) were preferentially expressed in females but high levels were also detected in males. The expression was remarkably high in both sexes along the complete photoperiod. A sensitive proteomic methodology was developed to identify antennal proteins.