Temporal niche segregation is a way to reduce competition over shared resources. Species with overlapping spatial niches often show plasticity and can use different activity times to minimize competition with and disturbance by other species. In many granivores, especially those living in their food resources, there is low competition over food, but other selective forces can drive distinct temporal activity times. Reproductive interference, that is, the interaction between individuals of different species during mate acquisition, can be such a driving force. Reproductive interference is a strong driving force for niche segregation between the co-occurring flour beetles Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae). Nevertheless, most studies on Tribolium spp. evaluated other selective forces, such as resource competition, which are potentially weaker. Here, we aimed to characterize the species’ peak activity time and its plasticity when exposed to a possible reproductive interference cue. We used a synthetic aggregative pheromone, shared by both species, as a cue for potential reproductive interference. We compared temporal niche plasticity between the sexes because reproductive interference is known mainly to reduce the female’s fitness. We found that both species’ activity times were hard-wired to an endogenous clock and that the sexes differed in their peak activity time and activity level. However, once exposed to the aggregation pheromone, only females shifted their activity time to match that of conspecific males, hence expressing more plasticity than the males to reduce Reproductive interference. These findings suggest an important role of the aggregation pheromone in the process of niche segregation.

中文翻译：

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种间和种内雌性行为可塑性驱动两种谷盗物种的时间生态位隔离

时间利基隔离是减少共享资源竞争的一种方法。空间生态位重叠的物种通常表现出可塑性，可以利用不同的活动时间来尽量减少与其他物种的竞争和干扰。在许多食谷动物中，尤其是那些生活在食物资源中的动物，对食物的竞争程度较低，但其他选择性力量可以驱动不同的时间活动时间。生殖干扰，即不同物种个体在求偶过程中的相互作用，可以成为这样的驱动力。生殖干扰是共存的面粉甲虫赤拟谷盗和混淆谷盗（鞘翅目：拟步甲科）之间生态位隔离的强大驱动力。尽管如此，大多数关于谷盗的研究。评估了其他可能较弱的选择性力量，例如资源竞争。在这里，我们的目的是描述该物种在暴露于可能的生殖干扰线索时的峰值活动时间及其可塑性。我们使用两个物种共有的合成聚合信息素作为潜在生殖干扰的线索。我们比较了两性之间的时间生态位可塑性，因为已知生殖干扰主要会降低雌性的适应性。我们发现，这两个物种的活动时间都与内源时钟紧密相关，并且性别的峰值活动时间和活动水平有所不同。然而，一旦暴露于聚集信息素，只有雌性会改变其活动时间以匹配同种雄性，因此表现出比雄性更多的可塑性，以减少生殖干扰。这些发现表明聚集信息素在生态位分离过程中发挥着重要作用。