2026-03-20 カリフォルニア工科大学（Caltech）
＜関連情報＞
- https://www.caltech.edu/about/news/courting-the-competition-some-male-fruit-flies-serenade-each-other-rather-than-fight
- https://www.cell.com/current-biology/fulltext/S0960-9822(26)00233-2
ショウジョウバエにおける複数のフェロモンスイッチによる雄の同性間性行動の進化的基盤 Evolutionary basis of male same-sex sexual behavior by multiple pheromone switches in Drosophila
Youcef Ouadah ∙ Thomas H. Naragon ∙ Hayley Smihula ∙ … ∙ David L. Stern ∙ Joseph Parker ∙ David J. Anderson
Current Biology Published:March 20, 2026
DOI:https://doi.org/10.1016/j.cub.2026.02.046
Graphical abstract
Highlights
- Male-directed courtship is common in D. santomea despite working sex recognition
- D. santomea males produce unusually low levels of the anti-aphrodisiac pheromone cVA
- D. santomea females show sexual aversion to cVA likely to avoid interspecies hybridization
- Similar social and pheromonal evolution has occurred convergently in D. persimilis
Summary
Male same-sex sexual behavior (SSB) is widespread among animal species, but its proximate (mechanistic) and ultimate (evolutionary) explanations remain unclear. A prevailing view is that SSB reflects impaired sex recognition, especially in insects. By unbiased behavioral screening, we identified a Drosophila species, D. santomea, in which males seldom attack and spontaneously court males vigorously, in addition to females. Behavioral, chemical, and optogenetic neuronal manipulations indicate that D. santomea males can distinguish conspecific sex and retain functional aggression circuitry. Instead, male SSB reflects three evolved pheromonal changes affecting two separate signaling systems, resulting in both reduced pheromone production and behavioral valence reversal. One of these occurs unexpectedly in females and may have evolved to prevent hybridization with an interfertile, geographically overlapping sibling species. Remarkably, male SSB and similar pheromonal changes also selectively co-occur in D. persimilis, a geographically and phylogenetically distant species and member of another sympatric sibling pair, implying evolutionary convergence in the two young taxa. The results identify a pheromonal mechanism for rapid social evolution in Drosophila and suggest a plausible evolutionary origin for male SSB as arising in concert with female adaptations that ensure reproductive isolation during speciation.
