Data from: An ambusher’s arsenal: chemical crypsis in the puff adder (Bitis arietans)

Ambush foragers use a hunting strategy that places them at risk of predation by both visual and olfaction-oriented predators. Resulting selective pressures have driven the evolution of impressive visual crypsis in many ambushing species, and may have led to the development of chemical crypsis. However, unlike visual crypsis, few studies have attempted to demonstrate chemical crypsis. Field observations of puff adders (Bitis arietans) going undetected by several scent-orientated predator and prey species lead us to investigate chemical crypsis in this ambushing species. We trained dogs (Canis familiaris) and meerkats (Suricata suricatta) to test whether a canid and a herpestid predator could detect B. arietans using olfaction. We also tested for chemical crypsis in five species of active foraging snakes, predicted to be easily detectable. Dogs and meerkats unambiguously indicated active foraging species, but failed to correctly indicate puff adder, confirming that B. arietans employs chemical crypsis. This is the first demonstration of chemical crypsis anti-predatory behavior, though the phenomenon may be widespread among ambushers, especially those that experience high mortality rates due to predation. Our study provides additional evidence for the existence of an ongoing chemically-mediated arms race between predator and prey species.

伏击觅食者所采用的狩猎策略，使其同时暴露于视觉导向与嗅觉导向捕食者的被捕食风险之下。由此产生的选择压力，推动诸多伏击物种演化出卓越的视觉隐蔽（visual crypsis）特征，亦可能促成了化学隐蔽（chemical crypsis）的演化。然而与视觉隐蔽不同，目前鲜有研究尝试证实化学隐蔽的存在。针对鼓腹咝蝰（Bitis arietans）在野外未被多种嗅觉导向的捕食者与猎物察觉的观测结果，我们着手对该伏击物种的化学隐蔽现象展开研究。我们通过训练家犬（Canis familiaris）与狐獴（Suricata suricatta），以检验犬科与獴科捕食者是否可通过嗅觉探测到鼓腹咝蝰。此外，我们还对5种主动觅食蛇类开展了化学隐蔽测试——这类蛇类被认为极易被感知察觉。实验结果显示，家犬与狐獴均能明确识别主动觅食的蛇类，却未能正确辨识鼓腹咝蝰，这证实了鼓腹咝蝰具备化学隐蔽能力。本研究首次证实了化学隐蔽这一反捕食行为，尽管该现象在伏击物种中或广泛存在，尤其针对那些因捕食面临较高死亡率的类群。本研究亦为捕食者与猎物间持续存在的化学介导军备竞赛提供了新的实证支撑。