COLLABORATIVE RESEARCH: Multimodal Signaling in Rhinoceros Beetles

这项研究试图通过关注动物武器和求偶表演来了解生物多样性，这些特征往往比其他特征变化得更快。雄性犀牛在头上挥舞着一个巨大的干草叉形角，它们在雄性犀牛为争夺雌性犀牛到访的觅食领土而进行的战斗中使用这个角。号角最长的男性获胜，部分原因是号角的长度准确地反映了男性的体型和战斗力--这是男性素质的真实信号。然而，调查人员之前的工作表明，赢得战斗是不够的。即使在为保住地盘而战之后，雄性仍然必须每晚花几个小时用翼盖上的新奇文件夹摩擦腹部的盘子，向雌性歌唱，它们在蜡质的外层角质层产生混合的气味，似乎是在传达雄性的身体尺寸和营养状态。这项研究将探索雄性状态与歌声和气味信号之间的联系，研究雌性对这些信号的偏好，并描述这套求爱信号在整个物种范围内的多样性。女性是如何区分男性的，为什么她们忽视了男性素质的明显信号(号角)？调查人员还将与Gonzaga舞蹈系合作，设计以动物行为为灵感的表演，为米苏拉昆虫馆开发昆虫歌曲互动展览，并通过丹佛大学为K-16年级的学生设计互动在线课程，与公众分享甲虫信息。之前对日本犀牛甲虫Trypoxylus dichotomus的研究让调查人员怀疑，这些甲虫表现出了挑逗行为的元素。Trypoxylus dichotomus是一种装备精良的物种，其特征是教科书上的资源防御交配系统。雌性不愿与守卫觅食区域的常驻雄性交配，尽管这些雄性一直是种群中最大、角最长的个体之一。利用实验室操作实验、野外观察和扰动相结合的方法，这项研究将严格表征犀牛甲虫的鸣声和角质烃(CHC)剖面信号(目标1)，并评估它们对雌性配偶选择(目标2)和比赛中男性竞争对手评估(目标3)的重要性。此外，这项研究将比较该物种范围内的歌曲方言和CHC谱(目标4)，以对比竞争和配偶选择信号的相对进化速度。最后，他们将对相邻的、遗传相似但表型不同的群体进行数量性状基因座定位研究，将得到的连锁图谱与重新测序的参考基因组以及先前PoolSeq对相同群体进行的FST“异常值”研究结果相结合，以深入研究这套多峰信号序列的遗传结构。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This study seeks to understand biodiversity by focusing on animal weapons and courtship displays, which often diversify more rapidly than other traits. Male rhinoceros beetles wield a giant, pitchfork-shaped horn on their head that they use in battles between rival males over feeding territories visited by females. Males with the longest horns win, in part because horn length accurately reflects body size and fighting ability of males - it is an honest signal of male quality. Prior work by the investigators revealed that winning fights is not enough, however. Even after battling to hold a territory, males must still spend hours each night "singing" to females using a novel file on their wing covers that they rub against a plate on their abdomen, and they produce blends of scents in their waxy outer cuticle that appear to communicate male body size and nutritional state. This study will explore the link between male condition and both song and scent signals, examine female preferences for these signals, and characterize the diversification of this suite of courtship signals across the range of the species. How do females discriminate among males, and why do they ignore the obvious signal of male quality (the horn)? The investigators will also work with the Gonzaga department of dance to design performances inspired by animal behavior, develop an interactive exhibit on insect songs for the Missoula Insectarium, and design interactive online curricula for K-16 students through the University of Denver to share information about beetles with the public. Prior work on the Japanese rhinoceros beetle, Trypoxylus dichotomus, a heavily weaponed species characterized by a textbook resource defense mating system, led the investigators to suspect that these beetles show elements of lekking behavior. Females are reluctant to mate with resident males guarding feeding territories despite those males consistently being among the largest, longest-horned individuals in the population. Using a combination of laboratory manipulation experiments and field observation and perturbations, this study will rigorously characterize stridulatory song and cuticular hydrocarbon (CHC) profile signals in rhinoceros beetles (Aim 1), and evaluate their importance to female mate choice (Aim 2) and male rival assessment during contests (Aim 3). In addition, this study will compare song dialects and CHC profiles across the range of this species (Aim 4), to contrast the relative rates of evolution of agonistic and mate-choice signals. Finally, they will perform a quantitative trait locus mapping study of adjacent, genetically similar but phenotypically divergent populations, combining the resulting linkage maps with a re-sequenced reference genome, and FST 'outlier' results from a prior PoolSeq study of the same populations, to delve into the genetic architecture of this suite of multimodal signal traits.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.