A trait‐based understanding of the vulnerability of a Paleotropical moth community to predation by a sympatric bat with flexible foraging strategies

• Published in: Ecological entomology 2024-10, Vol.49 (5), p.635-646
• Main Authors: Dey, Pritha, Balakrishnan, Rohini
• Format: Article
• Language: English
• Subjects: Availability; Bats; Biodiversity hot spots; Body size; Butterflies & moths; Diet; Foraging behavior; Hepialidae; Megaderma spasma; megadermatid bats; morphological traits; Morphology; moths; Predation; Predators; Prey; prey–predator; Rainy season; Seasonal variations; Seasons; Sphingidae; Sympatric populations; Western Ghats
• ISSN: 0307-6946; 1365-2311
• DOI: 10.1111/een.13335

Prey vulnerability across seasons can be predicted by measuring their morphological traits and availability. Although conventional prey–predator dynamics focus on pairs of prey and predator species, the trait‐based approach allows us to draw inferences at the scale of the entire assemblage. Here, we coupled measurable prey traits with their availability in the study area, to identify the vulnerability of a diverse moth assemblage to predation by the lesser false vampire bat (Megaderma spasma) Chiroptera: Megadermatidae, Linneaus 1758, a bat with flexible foraging strategies, in the Western Ghats biodiversity hotspot of India. We analysed the discarded prey remains from several roosts, collected over 3 years, for seasonal patterns in the diet and selective hunting. Through light‐trapping, we collected moth specimens in different seasons and measured the morphological traits likely to affect their vulnerability to predation, such as body size and evasive flight capability. Our results showed that consumed moth prey diversity varies seasonally, with moths belonging to the Hepialidae family being preferred in the wet season. We found that the larger moth species with lower evasive capabilities are more vulnerable to predation. Sphingid and Hepialid moths, among the most abundant in the diet, have the lowest manoeuvrability and the maximum body size, respectively. By assessing vulnerability at the prey assemblage level, our study sets the stage for future research on moth–bat interactions from the diverse and less‐explored Paleotropical communities. In addition, the study reiterates the usefulness of trait‐based approaches to understanding prey–predator dynamics. In a diverse Paleotropical moth assemblage, from the Western Ghats of India, we found that the largest moths with the lowest evasive capabilities are the most vulnerable to predation by a flexibly foraging bat. Moths belonging to the Sphingidae family were the most abundant in the diet. They also were the lowest on manoeuvrability index. Hepialid moths, with the largest body size among all families, are preferred in the wet season. These moths only emerge during the wet season.