Size-based Food Selection Pattern Of The Fulvous Fruit Bat (Rousettus Leschenaulti) And Short-nosed Fruit Bat (Cynopterus Sphinx) And Their Foraging Behavioral Response To Predators’ Odor

The Fulvous fruit bat（Rousettus leschenaulti）and the Short-nosed fruit bat（Cynopterus sphinx）are both pteropodid species, widely distributing in subtropicaland tropical areas of South China. Lately, they have done great harm to fruit productionin South China, which has aroused extensive attention. In this research, we comparedthe morphological and geological difference of the bat samples collected respectivelyfrom the campus of Sun Yat-sen University in Guangzhou, Lianghua Swallow Rocks inHuizhou city of Guangdong Province, and Botanical Garden in Xishuangbanna city ofYunnan Province, and we specifically found dimorphism only in R. leschenaulti ofSwallow Rock(t-test: forearm length P=0.004, body weight P=0.001). The statisticalsignificant geographical difference of body weight in these bats exists commonly butbetween female R. leschenaulti in Swallow Rocks and Banna Botanical Garden(P=0.817), while the forearm length disparity exists between males in these twolocations (P=0.04). We concluded that dimorphism could possibly appear whenindividual recognition pressure was relatively high. We used these bat samples to carryout experiment about their size-based fruit selection in captivity for clarifying their fruitsize preference and foraging strategies. We found out that they tended to forage on themedium-size food(type II and III, LSD: both P<0.001), and to take the fruits away fromthe food site before eating, if not forced to forage on too heavy food. Accordingly, weconcluded that medium-size fruit might be the most profitable for the bats. In anotherexperiment, we introduced the odor of predators like snake or owl to test their responseto it based on foraging behaviour and foraging Strategies. The result revealed that bothof the two species reacted negatively with the presence of odor from non-avianpredators (e.g.snake)(t-test all P<0.05), and specifically they would stay and eat less inthe odored end, while they showed no obvious avoidance of the odor from the avianpredators (e.g.owl)(t-test: all P>0.05). We concluded that the odor from non-avianpredators might be more efficient than those from the avian predators. Obviously, thefurther research about the foraging behavior, geographic and gender difference of thetwo species fruit bats as well as the methodology and basic data origined from thispaper will contribute to dealing with this human-bats conflict.