Lawrence J P, Rojas Bibiana, Blanchette Annelise, Saporito Ralph A, Mappes Johanna, Fouquet Antoine, Noonan Brice P
Department of Biology, University of Mississippi, University, MS, 38677, USA.
Lyman Briggs College, Michigan State University, East Lansing, MI, 48825, USA.
J Chem Ecol. 2023 Apr;49(3-4):195-204. doi: 10.1007/s10886-023-01412-7. Epub 2023 Mar 1.
Many chemically-defended/aposematic species rely on diet for sequestering the toxins with which they defend themselves. This dietary acquisition can lead to variable chemical defenses across space, as the community composition of chemical sources is likely to vary across the range of (an aposematic) species. We characterized the alkaloid content of two populations of the Dyeing Poison Frog (Dendrobates tinctorius) in northeastern French Guiana. Additionally, we conducted unpalatability experiments with naive predators, Blue Tits (Cyanistes caeruleus), using whole-skin secretion cocktails to assess how a model predator would respond to the defense of individuals from each population. While there was some overlap between the two D. tinctorius populations in terms of alkaloid content, our analysis revealed that these two populations are markedly distinct in terms of overall alkaloid profiles. Predator responses to skin secretions differed between the populations. We identified 15 candidate alkaloids (including three previously undescribed) in seven classes that are correlated with predator response in one frog population. We describe alkaloid profile differences between populations for D. tinctorius and provide a novel method for assessing unpalatability of skin secretions and identifying which toxins may contribute to the predator response. In one population, our results suggest 15 alkaloids that are implicated in predator aversive response. This method is the first step in identifying the causal link between alkaloids and behavioral responses of predators, and thus makes sense of how varying alkaloid combinations are capable of eliciting consistent behavioral responses, and eventually driving evolutionary change in aposematic characters (or characteristics).
许多具有化学防御/警戒色的物种依靠饮食来摄取用于自我防御的毒素。这种通过饮食获取毒素的方式可能导致不同空间的化学防御存在差异，因为化学源的群落组成在（具有警戒色的）物种分布范围内可能会有所不同。我们对法属圭亚那东北部的两个染色箭毒蛙（Dendrobates tinctorius）种群的生物碱含量进行了表征。此外，我们用蓝山雀（Cyanistes caeruleus）这种未接触过该物种的捕食者进行了适口性实验，使用全皮分泌混合物来评估典型捕食者对每个种群个体防御的反应。虽然两个染色箭毒蛙种群在生物碱含量方面存在一些重叠，但我们的分析表明，这两个种群在总体生物碱谱方面明显不同。不同种群的捕食者对皮肤分泌物的反应也不同。我们在七个类别中鉴定出15种候选生物碱（包括三种此前未描述的），它们与一个蛙种群中的捕食者反应相关。我们描述了染色箭毒蛙不同种群之间的生物碱谱差异，并提供了一种新方法来评估皮肤分泌物的适口性以及确定哪些毒素可能导致捕食者产生反应。在一个种群中，我们的结果表明有15种生物碱与捕食者的厌恶反应有关。这种方法是确定生物碱与捕食者行为反应之间因果关系的第一步，从而有助于理解不同的生物碱组合如何能够引发一致的行为反应，并最终推动警戒特征的进化变化。
