Effect of Fruit Volatiles from Native Host Plants on the Sexual Performance of Anastrepha fraterculus sp. 1 Males.

Anastrepha fraterculus sp.1 males are sexually stimulated by the aroma of fruit of its native host Psidium guajava (guava). Other hosts, which are exotic to A. fraterculus, do not enhance male sexual behavior. Here we evaluate the effects of fruit volatile exposure on male A. fraterculus sp. 1 sexual performance using other native hosts, under the hypothesis that male improvement derives from a common evolutionary history between A. fraterculus sp. 1 and its native hosts. Four species were evaluated: Eugenia myrcianthes, Juglans australis, Psidium cattleianum, and Acca sellowiana. Guava was used as a positive control. Males were exposed to fruit from 12:00 pm to 4:00 pm, from day 8 to day 11 post-emergence. On day 12, we evaluated their calling behavior and mating success. Both guava and P. cattleianum enhanced calling behavior. Mating success was enhanced only by guava and a trend was found for P. cattleianum. Interestingly, the two hosts belong to the Psidium genus. A volatile analysis is planned to identify the compounds responsible for this phenomenon. The other native fruits did not improve the sexual behavior of males. Implications of our findings in the management of A. fraterculus sp. 1 are discussed.

On how to identify a seminal fluid protein: A response to Wigby et al.

The choice of criteria to delimit a group or class is a subjective matter, even though the reasoning, the objectives and the criteria themselves should always be clearly stated. This paper is part of a discussion about the criteria used to identify seminal fluid proteins (SFPs) in Drosophila species. SFPs are proteins that are transferred to females during copulation together with sperm. The only way to ascertain that a protein is an SFP is to prove that it is produced in a male reproductive organ and is found in the female reproductive tract after insemination. Nevertheless, the required methodology is labour-intensive and expensive, and therefore this kind of data is unlikely to be available for many species, precluding comparative and evolutionary studies on the subject. To conduct evolutionary analyses, in a previous study, we capitalized on the accumulated knowledge we have in the model species D. melanogaster to recommend a set of criteria for identifying candidate SFPs in other Drosophila species. Those criteria, based on transcriptomic evidence and in silico predictions from sequences, would allow a good balance between sensitivity (the inclusion of true SFPs) and specificity (the exclusion of false positives). In view of the criticism raised by another group, here we defend our criteria on one hand while accepting there is room for improvement on the other. The results are updated sets of criteria and SFPs that we believe can be useful in future evolutionary studies.

Research gaps and new insights in the evolution of Drosophila seminal fluid proteins.

While the striking effects of seminal fluid proteins (SFPs) on females are fairly conserved among Diptera, most SFPs lack detectable homologues among the SFP repertoires of phylogenetically distant species. How such a rapidly changing proteome conserves functions across taxa is a fascinating question. However, this and other pivotal aspects of SFPs' evolution remain elusive because discoveries on these proteins have been mainly restricted to the model Drosophila melanogaster. Here, we provide an overview of the current knowledge on the inter-specific divergence of the SFP repertoire in Drosophila and compile the increasing amount of relevant genomic information from multiple species. Capitalizing on the accumulated knowledge in D. melanogaster, we present novel sets of high-confidence SFP candidates and transcription factors presumptively involved in regulating the expression of SFPs. We also address open questions by performing comparative genomic analyses that failed to support the existence of many conserved SFPs shared by most dipterans and indicated that gene co-option is the most frequent mechanism accounting for the origin of Drosophila SFP-coding genes. We hope our update establishes a starting point to integrate further data and thus widen the understanding of the intricate evolution of these proteins.