Universidade Federal de Pernambuco, Centro de Ciências Biológicas, Departamento de Zoologia, Av. Prof. Moraes Rego, 1235, Cidade Universitária, 50670-901 Recife, PE, Brazil.
Universidade Federal da Paraíba, Departmento de Sistemática e Ecologia, Cidade Universitária (Castelo Branco), 58051-900 João Pessoa, PB, Brazil.
An Acad Bras Cienc. 2022 Apr 11;94(1):e20200694. doi: 10.1590/0001-3765202220200694. eCollection 2022.
Night-foraging cyclocephaline scarab beetles rely on floral structures of specific plant hosts for food and shelter, as well as mating sites. Although the role of floral fragrances as long-range attractants in these interactions has been elucidated, the mechanisms that mediate close-range mate discrimination in aggregations are still unclear. We recorded the mating-oriented behavior of male Cyclocephala distincta, focusing on the influence of contact signaling and movement over mate selection in a series of controlled bioassays. Roughly half of the males chose a conspecific female over another male, readily engaging in copulation upon initial contact. The remainder males required more experience, acquired through successive mounts on both females and males. Eventually, all focal males invested in copulation with females. When faced with the choice for a live or an inert conspecific female, male C. distincta preferred the former in 76% of cases, although we also recorded sexual investment on inert females (10% of cases). In paired experiments with an inert female or a male, nonetheless, focal males significantly opted for the opposite sex, and that included mating with the inert females. Innate characteristics of the females of C. distincta are evaluated by males synergistically, and not separately, in discriminating potential sexual partners.
夜行性尖胸叩头甲（Cyclocephala distincta）依靠特定植物宿主的花结构来获取食物和庇护所，以及交配场所。虽然已经阐明了花的气味作为这些相互作用中的远程引诱物的作用，但在聚集时介导近距离交配识别的机制仍不清楚。我们记录了雄性尖胸叩头甲的交配导向行为，重点关注接触信号和运动对一系列受控生物测定中交配选择的影响。大约一半的雄性选择同种的雌性而不是另一只雄性，一旦接触就很容易进行交配。其余的雄性需要更多的经验，通过对雌性和雄性的连续交配来获得。最终，所有的雄性都投入到与雌性的交配中。当面临选择一个活的或一个无生命的同种雌性时，雄性尖胸叩头甲有 76%的情况下更喜欢前者，尽管我们也记录了对无生命雌性的性投资（10%的情况）。然而，在与无生命雌性或雄性的配对实验中，雄性焦点显著选择了异性，包括与无生命雌性的交配。在区分潜在性伴侣时，雄性尖胸叩头甲的雌性的固有特征是协同评估的，而不是单独评估的。
