Data from: Habitat geometry and limited perceptual range affect habitat choice of a trap-building predator

By considering various biotic and abiotic factors, organisms are expected to distinguish among suitable habitats of different quality and choose the one that offers them the highest fitness payoff. According to the ideal-free-distribution model, density drives organism choice and ultimately distribution among habitats. However, deviations from the basic model are common, as it does not take into account intrinsic and extrinsic constraints. Two important constraints are those of habitat geometry (e.g., habitat area, habitat shape), and perceptual range. We used a trap-building predator, the wormlion larva, to examine these constraints. We manipulated the geometry of the preferred shaded microhabitat and the distance of individuals from it, and assessed their effect on wormlion habitat choice, distribution patterns and performance. Habitat geometry affected wormlion microhabitat choice and distribution patterns, measured as distance from the habitat center and spatial pattern type, but had no effect on performance, expressed as the area of the pit-trap constructed. The interaction between habitat geometry and density was inconsistent regarding the distribution patterns, affecting distance from the center but not the spatial pattern type. Furthermore, we found that wormlions demonstrated a low perceptual range, which limited their ability to sense proximate shaded conditions. We highlight the importance of incorporating the interplay between habitat geometry, density and perceptual range when studying habitat choice and spatial patterns, and suggest that spatial patterns should be analyzed in more than a single way.综合考量各类生物与非生物因子后，生物体应可区分不同质量等级的适宜生境，并选择能为自身带来最高适合度收益的生境。根据理想自由分布模型（ideal-free-distribution model），种群密度决定了生物体的生境选择，并最终决定其在不同生境中的分布格局。然而，该基础模型的偏差现象十分普遍，因其未纳入内在与外在限制因素的考量。其中两类关键限制因素为：生境几何特征（habitat geometry，如生境面积、生境形状）以及感知范围（perceptual range）。本研究以一类筑阱捕食者——蚁狮幼虫（wormlion larva）作为实验对象，对上述限制因素展开探究。我们操控了实验对象偏好的遮阴微生境的几何特征，以及个体与该微生境之间的距离，并评估了这两个因素对蚁狮生境选择、分布格局及其适合度表现的影响。生境几何特征会影响蚁狮的微生境选择与分布格局（以距生境中心的距离和空间格局类型作为衡量指标），但对以所筑陷阱坑穴面积表征的适合度表现并无显著影响。生境几何特征与种群密度的交互作用对分布格局的影响并不一致：其会改变个体距生境中心的距离，但不会影响空间格局类型。此外，本研究发现蚁狮的感知范围较低，这限制了其感知周边遮阴环境的能力。本研究强调，在探究生境选择与空间格局时，应纳入生境几何特征、种群密度与感知范围三者间的交互作用，并提出应采用多种方法对空间格局展开分析。