School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
J Exp Biol. 2019 Dec 3;222(Pt 23):jeb203950. doi: 10.1242/jeb.203950.
Differences in wing morphology are predicted to reflect differences in bat foraging strategies. Experimental tests of this prediction typically assess the relationship between wing morphology and a measures of flight performance on an obstacle course. However, studies have lacked measures of obstacle avoidance ability true scores, which may confound interpretation of ability across the range of presented tasks. Here, we used Rasch analysis of performance in a collision-avoidance experiment to estimate the ability of bat species to fly through vegetative clutter. We refer to this latent trait as 'clutter negotiating ability' and determined the relationships between clutter negotiating ability and wing morphology in 15 forest insectivorous bat species that forage in the densely cluttered rainforests of Malaysia. The clutter negotiating ability scores were quantified based on individual responses of each species to 11 different obstacle arrangements (four banks of vertical strings 10-60 cm apart). The tasks employed for the collision-avoidance experiment were reliable and valid, although Rasch analysis suggested that the experiment was too easy to discriminate completely among the 15 species. We found significant negative correlations between clutter negotiating ability and body mass, wingspan, wing loading and wing area but a positive significant correlation with wingtip area ratio. However, in stepwise multiple regression analyses, only body mass and wing loading were significant predictors of clutter negotiating ability. Species fell into clusters of different clutter negotiating ability, suggesting a potential mechanism for resource partitioning within the forest interior insectivorous ensemble.
翅膀形态的差异预计反映了蝙蝠觅食策略的差异。对这一预测的实验测试通常评估了翅膀形态与在障碍物跑道上的飞行性能测量值之间的关系。然而，这些研究缺乏真正的回避障碍物能力的衡量标准，这可能会混淆对呈现的任务范围内的能力的解释。在这里，我们使用回避碰撞实验中的表现的 Rasch 分析来估计蝙蝠物种在穿过植被杂乱区域的飞行能力。我们将这个潜在特征称为“穿越杂乱能力”，并确定了在 15 种在马来西亚茂密丛林中觅食的森林食虫蝙蝠物种的穿越杂乱能力与翅膀形态之间的关系。穿越杂乱能力得分是基于每个物种对 11 种不同障碍物排列（每 10-60 厘米有 4 排垂直的线）的个体反应来量化的。尽管 Rasch 分析表明该实验太容易以至于无法完全区分 15 个物种，但回避碰撞实验所采用的任务是可靠和有效的。我们发现穿越杂乱能力与体重、翼展、翼载和翼面积呈显著负相关，但与翼尖面积比呈显著正相关。然而，在逐步多元回归分析中，只有体重和翼载是穿越杂乱能力的显著预测因子。物种分为不同穿越杂乱能力的聚类，这表明了在森林内部食虫动物群体中资源分区的潜在机制。
