Defended (distasteful or toxic) prey are often characterized by conspicuous coloration and this phenomenon is called "aposematism". The main advantage of aposematism is that it promotes faster learning by predators to avoid the prey. Some defended prey species use a different strategy; they remain cryptic in the normal state, but display conspicuous aposematic signal (which is normally hidden) in response to a predator's approach/attack. This anti-predator strategy of a defended prey has not been well studied yet although it can theoretically give the benefits of both camouflage and aposematism. Here, we investigated the effectiveness of this ‘hidden-aposematic signal’ as a warning signal. Using wild tits (Parus minor) as predator and novel artificial prey models (which mimics wings of insects), we tested whether hidden conspicuous signal of a defended prey enhances the avoidance learning rate of predators and how does it compare with the typical conspicuous/non-conspicuous signal. We found that hidden conspicuous signal indeed enhances the avoidance learning rate of predators in comparison with the non-conspicuous signal. However the overall learning rate by predators to avoid the defended prey was slower than for the normal conspicuous signal. Our results suggest that the prey with hidden-aposematic signals could enjoy both the benefits camouflage and the benefits of aposematism that are however lower than benefits from a typical aposematic signal. We, for the first time, highlight the functional aspect of a unique, but yet largely ignored, defensive coloration of prey.

배추좀나방과 담배거세미나방 유충에 대한 30종 한방 식물체 메탄올 조추출몰의 살충활성 및 섭식 저해활성을 잎침지법을 이용하여 5,000ppm으로 검정하였다. 황련의 추출물은배추좀나방에 대해 살충작용을 보였다. 길경, 사삼, 세신, 오배자 및 자초의 추출물은 배추좀나방 유충에 대해, 목통 및 속새의 추출물은 담배거세미나방 유충에 대한 강한 섭식저해활성을 보였으나, 오배자와 황련의 추출물은 이들 나비목 유충 모두에 강한 섭식저해활성을 나타내었다.