Research Institute CIBIO (Centro Iberoamericano de la Bioaffiliationersidad) Science Park, University of Alicante, E-03690, Alicante, Spain.
J Chem Ecol. 2022 Oct;48(9-10):690-703. doi: 10.1007/s10886-022-01383-1. Epub 2022 Sep 9.
The detection of dung odors is a crucial step in the food-searching behavior of dung beetles (Coleoptera: Scarabaeoidea). Yet, whether certain compounds characteristic of a given dung type contribute to a 'choosy generalism' behavior proposed for this taxonomic group is unknown. To address this, we analyzed the chemical composition of three types of dung (cow, horse, and rabbit) and conducted behavioral and electroantennogram (EAG) bioassays on 15 species of dung beetles using 19 volatile organic compounds representing the three dung samples. Chemical analyses revealed substantial qualitative and quantitative differences among dung types. When offered these food options in an olfactometer, 14 species exhibited a feeding preference. Surprisingly, all 19 compounds used in the EAG assays elicited antennal responses, with species displaying different olfactory profiles. The relationship between behavioral preferences and electrophysiological profiles highlighted that species with different food preferences had differences in antennal responses. Moreover, a specific set of EAG-active compounds (nonanal, sabinene, acetophenone, ρ-cresol, 2-heptanone, 1H-indole, and 6-methyl-5-hepten-2-one) were the strongest drivers in the distinct sensory profiles of the trophic preference groups. Our results point to the importance of the whole bouquet of dung-emanating compounds in driving food-searching behavior, but specific volatiles could aid in determining highly marked trophic preferences in certain species.
粪便气味的检测是蜣螂（鞘翅目：金龟子总科）觅食行为中的关键步骤。然而，某些特定于给定粪便类型的化合物是否有助于该分类群所提出的“挑剔的广食性”行为尚不清楚。为了解决这个问题，我们分析了三种粪便（牛、马和兔）的化学成分，并使用代表三种粪便样本的 19 种挥发性有机化合物对 15 种蜣螂进行了行为和触角电位（EAG）生物测定。化学分析显示粪便类型之间存在显著的定性和定量差异。当在嗅觉计中提供这些食物选择时，14 种物种表现出摄食偏好。令人惊讶的是，EAG 测定中使用的 19 种化合物都引起了触角反应，不同物种表现出不同的嗅觉特征。行为偏好和电生理特征之间的关系表明，具有不同食物偏好的物种在触角反应上存在差异。此外，一组特定的 EAG 活性化合物（壬醛、柠檬烯、苯乙酮、对甲酚、2-庚酮、1H-吲哚和 6-甲基-5-庚烯-2-酮）是不同取食偏好群体感官特征的最强驱动因素。我们的研究结果表明，粪便散发的化合物整体气味在驱动觅食行为方面非常重要，但特定的挥发性化合物可能有助于确定某些物种高度明显的取食偏好。
