Data for: How does viewing angle affect the perceived accuracy of Batesian mimicry in hoverflies?

Despite Batesian mimicry often eliciting predator avoidance, many Batesian
mimics, such as some species of hoverfly (Syrphidae), are considered to
have an “imperfect” resemblance to their model. One possible explanation
for the persistence of apparently imperfect mimicry is that human
perceptions of mimicry are different from those of natural predators.
Natural predators of hoverflies have different visual and cognitive
systems from humans, and they may encounter mimics differently. For
example, whilst humans often encounter hoverflies at rest on vegetation,
or in photographs or textbooks, where they are typically viewed from
above, natural predators may approach hoverflies from the side or below.
To test how viewing angle affects the perception of mimicry, images of
mimetic hoverflies and their models (wasps and bees) were shown from
different angles in an online survey. Participants were asked to
distinguish between the images of models and mimics. The results show that
the viewing angle does affect perceived mimicry in some species, although
it does not provide a complete explanation for the persistence of
imperfect mimicry in nature. The effect is also highly species-specific.
This suggests that to better understand how selection has shaped mimetic
accuracy in hoverflies and other taxa, further study is required of the
viewing angles that predators utilize most commonly in nature.

尽管贝茨拟态（Batesian mimicry）通常可诱发捕食者的回避行为，但诸多贝茨拟态类群——例如部分食蚜蝇（Syrphidae）物种——被认为与其拟态模型之间存在“不完美”的相似性。针对这类看似不完美的拟态为何能够持续存续，一种可能的解释是：人类对拟态的感知与自然捕食者存在显著差异。食蚜蝇的自然捕食者拥有与人类迥异的视觉与认知系统，且二者遭遇拟态者的场景亦不相同。例如，人类通常在植被上静止的食蚜蝇个体、或是照片与教科书中见到它们，此时的观察视角多为俯视；而自然捕食者则往往从侧面或下方接近食蚜蝇。为探究视角如何影响拟态感知，本研究通过在线调查展示了拟态食蚜蝇及其模型（黄蜂与蜜蜂）的多视角图像，并要求参与者对模型与拟态者的图像进行区分。研究结果表明，尽管视角无法完全解释自然界中不完美拟态的持续存在，但它确实会对部分物种的拟态感知产生影响，且该效应具有极强的物种特异性。这提示，若要更深入地理解选择压力如何塑造食蚜蝇及其他类群的拟态精准度，未来还需进一步探究捕食者在自然界中最常采用的观察视角。