掠食者對獵物相似度的認知形塑擬態系統的動態

Abstract

擬態是一種反捕食策略，由擬態者擬態具防禦的被擬態者，以欺騙捕食者。儘管過去理論預測完美擬態，但在自然界中不完美的擬態（imperfect mimicry）仍普遍存在。本理論研究探討單一擬態系統和多擬態系統的族群動態與穩定性，並著重研究捕食者的認知能力以及獵物的防禦程度對系統動態的影響。本研究結合最佳覓食理論、信號檢測理論和族群動態模型，發現當擬態者與被擬態者的相似度為中等程度時系統動態最為穩定，且擬態者的族群量亦達到最高。我們發現當捕食者能根據擬態者和被擬態者的相對族群量而調整其認知能力時，上述不完美擬態的穩定效應仍然存在。另外，我們也發現即使被擬態者擁有更好的防禦，不完美擬態也仍然是有益的。當我們將系統擴展至同時包含貝氏和穆氏擬態的多擬態系統時，不完美擬態提供的效果仍然是有益的。貝氏擬態者和穆氏擬態者在不同相似程度下提供多擬態系統不同程度的保護，其中貝氏擬態僅在中等相似程度提供保護，而穆氏擬態則在中等相似度至高相似度時提供程度一致的保護。這些結果即使當被擬態者或穆氏擬態者具有更多防禦時仍然保持不變。整體來說，本研究顯示在各種捕食者的識別能力、被擬態者的防禦能力和多物種的擬態系統中，不完美擬態皆可使擬態者在自然系統中穩定存在。

Mimicry is a widespread anti-predator strategy where a prey species (the mimic) resembles an unprofitable species (the model) to deceive the predator. Despite past theoretical expectations for perfect mimicry, imperfect resemblances are common in nature. Here, we study the population dynamics and stability of both single- and multi-mimicry systems, with a particular focus on the influence of different predator recognition abilities and prey defenses. With a theoretical framework integrating optimal foraging theory, signal detection theory, and population dynamical systems, we demonstrate that intermediate mimic--model similarity stabilizes dynamics and promotes mimic abundance, thereby challenging past expectations for perfect mimicry. This stabilizing effect persists even when predators adjust recognition dynamically based on mimic and model abundance ratio; imperfect mimicry also remains beneficial even when the model is equipped with more defense. Furthermore, the beneficial effect of imperfect mimicry persisted when we extended the framework to consider a multi-mimicry system with both Batesian mimic and Müllerian mimic. Batesian and Müllerian mimics offer different levels of protection to the multi-mimicry system under different degrees of resemblance. Specifically, Batesian mimics provide protection under intermediate similarity, while Müllerian mimics offer equal strength of protection with under either intermediate or high similarity. All aforementioned patterns hold even when the model or Müllerian mimic possesses greater defense. Overall, our study offers novel insights into the prevalence of imperfect mimicry in nature --- it can be an ecologically stable anti-predator strategy across a wide range of predator recognition abilities, prey defenses, and mimicry systems.