Song Woncheol, Lee Sang-Im, Jablonski Piotr G
Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea.
School of Undergraduate Studies, Daegu-Gyeongbuk Institute of Science and Technology, Daegu, South Korea.
PeerJ. 2020 Apr 10;8:e8915. doi: 10.7717/peerj.8915. eCollection 2020.
Some defended prey animals can switch on their normally hidden aposematic signals. This switching may occur in reaction to predators' approach (pre-attack signals) or attack (post-attack signals). Switchable aposematism has been relatively poorly studied, but we can expect that it might bring a variety of benefits to an aposmetic organism. First, the switching could startle the predators (deimatism). Second, it could facilitate aversive learning. Third, it could minimize exposure or energetic expense, as the signal can be switched off. These potential benefits might offset costs of developing, maintaining and utilizing the switchable traits. Here we focused on the third benefit of switchability, the cost-saving aspect, and developed an individual-based computer simulation of predators and prey. In 88,128 model runs, we observed evolution of permanent, pre-attack, or post-attack aposematic signals of varying strength. We found that, in general, the pre-attack switchable aposematism may require moderate predator learning speed, high basal detectability, and moderate to high signal cost. On the other hand, the post-attack signals may arise under slow predator learning, low basal detectability and high signal cost. When predator population turnover is fast, it may lead to evolution of post-attack aposematic signals that are not conforming to the above tendency. We also suggest that a high switching cost may exert different selection pressure on the pre-attack than the post-attack switchable strategies. To our knowledge, these are the first theoretical attempts to systematically explore the evolution of switchable aposematism relative to permanent aposematism in defended prey. Our simulation model is capable of addressing additional questions beyond the scope of this article, and we open the simulation software, program manual and source code for free public use.
一些具有防御能力的猎物能够开启它们通常隐藏的警戒信号。这种信号切换可能是对捕食者接近（攻击前信号）或攻击（攻击后信号）的反应。可切换警戒色的研究相对较少，但我们可以预期它可能会给具有警戒色的生物体带来各种益处。首先，信号切换可能会惊吓捕食者（威吓作用）。其次，它可能有助于厌恶性学习。第三，由于信号可以关闭，它可以将暴露或能量消耗降至最低。这些潜在益处可能会抵消发展、维持和利用可切换特征的成本。在这里，我们关注可切换性的第三个益处，即节省成本方面，并开发了一个基于个体的捕食者与猎物计算机模拟模型。在88128次模型运行中，我们观察到了不同强度的永久性、攻击前或攻击后警戒信号的进化。我们发现，一般来说，攻击前可切换警戒色可能需要适度的捕食者学习速度、较高的基础可探测性以及中等至高的信号成本。另一方面，攻击后信号可能在捕食者学习速度较慢、基础可探测性较低和信号成本较高的情况下出现。当捕食者种群更替速度较快时，可能会导致不符合上述趋势的攻击后警戒信号的进化。我们还表明，高切换成本可能会对攻击前和攻击后可切换策略施加不同的选择压力。据我们所知，这些是首次系统探索相对于具有防御能力的猎物中的永久性警戒色而言可切换警戒色进化的理论尝试。我们的模拟模型能够解决本文范围之外的其他问题，并且我们免费开放模拟软件、程序手册和源代码供公众使用。
