Social Experience of Captive Livingstone's Fruit Bats (Pteropus livingstonii).

Charlotte Hosie,Christina R. Stanley,Dominic Wormell,Morgan J. Welch,Eluned Price,Tessa Smith

doi:10.3390/ani10081321

Abstract

Simple SummaryThe maintenance and stability of social experience is an especially important element of the captive welfare of zoo-housed species. The population of critically endangered Livingstone’s fruit bats (Pteropus livingstonii) resident at Jersey Zoo display a complex social structure of affiliative and aggressive interactions. Subgroups defined by individual characteristics contribute in different ways to this structure. Social information, illuminated through the use of social network analysis techniques, could be used in the future to promote social stability and safeguard individual welfare when making evidence-based husbandry decisions.Social network analysis has been highlighted as a powerful tool to enhance the evidence-based management of captive-housed species through its ability to quantify the social experience of individuals. We apply this technique to explore the social structure and social roles of 50 Livingstone’s fruit bats (Pteropus livingstonii) housed at Jersey Zoo, Channel Islands, through the observation of associative, affiliative, and aggressive interactions over two data collection periods. We implement binomial mixture modelling and characteristic-based assortment quantification to describe the complexity and organisation of social networks, as well as a multiple regression quadratic assignment procedural (MRQAP) test to analyse the relationship between network types. We examine the effects of individual characteristics (i.e., sex, age, and dominance rank) on social role by fitting models to explain the magnitude of node metrics. Additionally, we utilize a quadratic assignment procedural (QAP) test to assess the temporal stability of social roles over two seasons. Our results indicate that P. livingstonii display a non-random network structure. Observed social networks are positively assorted by age, as well as dominance rank. The frequency of association between individuals correlates with a higher frequency of behavioural interactions, both affiliative and aggressive. Individual social roles remain consistent over ten months. We recommend that, to improve welfare and captive breeding success, relationships between individuals of similar ages and dominance levels should be allowed to persist in this group where possible, and separating individuals that interact frequently in an affiliative context should be avoided.

Highlights

Many species have been shown to associate non-randomly (e.g., honeybees (Apis mellifera L.) [1], guppies (Poecilia reticulata) [2], Columbian ground squirrels (Urocitellus columbianus) [3], African elephantsAnimals 2020, 10, 1321; doi:10.3390/ani10081321 www.mdpi.com/journal/animals (Loxodonta africana) [4], bottlenose dolphins (Tursiops truncatus) [5], Japanese macaques (Macaca fuscata) [6], feral goats (Capra hircus) [7], and yellow baboons (Papio cynocephalus) [8]), leading to distinct patterns of association within larger collectives at the group or population level [9]
To identify the influence of class membership on social roles, we examined the relationship between sex, age, and dominance on three important node metrics; betweenness centrality, closeness centrality, and weighted degree
Though the relationship between descriptive factors and social role await further exploration, this study has demonstrated that individual social roles can remain temporally stable

Summary

Introduction

Many species have been shown to associate non-randomly (e.g., honeybees (Apis mellifera L.) [1], guppies (Poecilia reticulata) [2], Columbian ground squirrels (Urocitellus columbianus) [3], African elephantsAnimals 2020, 10, 1321; doi:10.3390/ani10081321 www.mdpi.com/journal/animals (Loxodonta africana) [4], bottlenose dolphins (Tursiops truncatus) [5], Japanese macaques (Macaca fuscata) [6], feral goats (Capra hircus) [7], and yellow baboons (Papio cynocephalus) [8]), leading to distinct patterns of association within larger collectives at the group or population level [9]. Changes in overall social structure or individual social role can be indicative of changes in individual health and welfare status [14]. Because of this link, many modern zoo-based animal management systems have recognized the importance of maintaining species-specific social structures when seeking to safeguard individual welfare in captivity [15]. Many modern zoo-based animal management systems have recognized the importance of maintaining species-specific social structures when seeking to safeguard individual welfare in captivity [15] To meet this aim, new tools for improving the subjective experience and affective states of captive animals continue to be developed [16]. Changes in social stability and individual social role can indicate fluctuations in complex affective states in an quantifiable way [16]

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