Host Specificity and Ectoparasite Load of Bat Flies in Utila, Honduras
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University of New Orleans ScholarWorks@UNO Senior Honors Theses Undergraduate Showcase 8-2014 Host Specificity and ctE oparasite Load of Bat Flies in Utila, Honduras Courtney Miller University of New Orleans Follow this and additional works at: https://scholarworks.uno.edu/honors_theses Part of the Biology Commons, and the Entomology Commons Recommended Citation Miller, Courtney, "Host Specificity and ctE oparasite Load of Bat Flies in Utila, Honduras" (2014). Senior Honors Theses. 63. https://scholarworks.uno.edu/honors_theses/63 This Honors Thesis-Unrestricted is protected by copyright and/or related rights. It has been brought to you by ScholarWorks@UNO with permission from the rights-holder(s). You are free to use this Honors Thesis-Unrestricted in any way that is permitted by the copyright and related rights legislation that applies to your use. 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Host specificity and ectoparasite load of bat flies in Utila, Honduras An Honors Thesis Presented to the Department of Interdisciplinary Studies of the University of New Orleans In Partial Fulfillment of the Requirements for the Degree of Bachelors of Interdisciplinary Studies, with Honors by Courtney Miller May 2014 TABLE OF CONTENTS Acknowledgments...............................................................................................................ii List of Figures.....................................................................................................................iii Abstract...............................................................................................................................iv Chapters: 1. Introduction..............................................................................................................1 2. Materials, Methods, and Results..............................................................................6 3. Discussion............................................................................................................. 14 References......................................................................................................................... 19 ! i! ACKNOWLEDGEMENTS I would like to acknowledge my advisor, Dr. Phil DeVries for introducing me to the world of insects and providing me with the resources I needed to study them. I am also grateful for the valuable lessons in ecology, which played a huge part in this paper, from my second reader, Dr. Jerome Howard. I would also like to thank Kanahau Research and Conservation Facility in Utila. Specifically, I would like to acknowledge Steven Clayson for showing such enthusiasm for getting covered in bat guano on a daily basis and for helping me overcome any and every obstacle during field work. Also, Andrea Martinez for inspiring my interest in bats and for making it possible for this study to take place. ! ii! LIST OF FIGURES 1. Table I.............................................................................................................................9 2. Table II..........................................................................................................................11 3. Table III.........................................................................................................................12 4. Table IV.........................................................................................................................13 ! iii! ABSTRACT Bat flies (Streblidae) are obligate blood-feeding ectoparasites of bats that display varying degrees of host specificity. A total of 265 streblid bat flies were collected from 122 bats belonging to the families Phyllostomidae and Natalidae from Utila, the smallest bay island of Honduras. Out of four host-parasite associations, three were considered primary. Out of the three bat species analyzed, one had significantly lower parasite prevalence and another had significantly higher parasite load and intensity. Both male and female bats were equally likely to be infested and variables of parasite density did not differ amongst host sex for any species. However, one species of bat had a significantly larger number of male parasites than female parasites. No significant relationships were found between variables of parasite density and host body mass or bat health (indicated by the ratio of mass to forearm length). The roosting ecology of the two cave roosting species in the study was considered and despite no apparent lack of dispersal barriers, the bat flies exhibited consistent primary associations. Examination of similar host-parasite relationship has many implications in parasite-host relationships and coevolution. Keywords: Streblidae, ectoparasitic infestations, parasite-host associations, Chiroptera, bat health, roosting ecology ! iv! CHAPTER I INTRODUCTION Bat flies, Hippoboscoidea, are obligate ectoparasites of bats. They are highly specialized hematophageous true flies found in the fur or on the membranous areas of their hosts. The two families, Streblidae and Nycteribiidae, are both most diverse in the tropic regions with streblids having greater richness is the Western Hemisphere (Dick & Patterson 2006). Both bat fly and bat species can exhibit a wide variety of ecological, morphological, and behavioral differences. The nature of the associations between bat flies and their hosts provides many significant yet complicated avenues for exploration. Due to their odd lifecycle, the bat flies’ habitat expands far beyond the host environment. They are holometabolous insects that exhibit adenotrophic viviparity. The adult female bat fly leaves the host to find a suitable area on the roost substrate to deposit its offspring. A single 3rd instar larva immediately forms a puparium after being deposited, spends three to four weeks in a pupal stage, then emerges as an adult fly seeking a host (Dick & Patterson 2006). It is also notable that there have been cases where adult male bat flies were observed off the host, specifically amongst pupae (Dick & Patterson 2006). Considering that bat flies spend up to a third of their adult lifespans off of their hosts, one might suspect that this provides increased potential for associations with a variety of host species. In other words, bat flies may be obligate parasites of bats, but given their life cycle, they are not permanent parasites. While known life-histories are relatively similar, the morphological and behavioral characteristics of bat flies can vary significantly. Specifically, streblids may differ greatly in size, body shape, eye reduction, and wing development. Bat flies have ! 1! strong tarsal claws used for gripping host fur. Some also have a ctendium along the top posterior margin of their head, and various amounts and distributions of setae. Some species exhibit a host-site preference for either fur or membranous areas, such as the wings, which often correspond to certain morphological characteristics (Dick and Patterson 2006). In a study on the host and host-site specificity of 25 neotropical bat species and 32 bat fly species, functional wings were not associated with host-site preference, but only fur-specific species had ctenidia and long hind legs (ter Hofstede et al. 2004). Fly movement was also observed to be different in this study. Species with shorter legs were seen navigating through the fur while others, with longer legs were pushing to the surface and walking on top of the fur. Bat hosts also vary significantly in terms of physical and behavioral characteristics. Roosting ecology has shown to be an important factor in parasite and host associations. Some bats use more permanent roosts such as caves, tree cavities, or rock crevices, while others seek refuge in temporary roosts such as foliage or exfoliating bark. Bats also differ in their degree of roost fidelity, which is often related to the permanence of their roost and form of social organization (Kunz & Fenton 2005). A study conducted on 130 bat species with 116 bat flies species found that bats roosting in more permanent, enclosed structures had higher parasite densities, were infested with more parasite species, and were more likely to be infested (Patterson et al. 2007). Characteristics of both parasites and hosts may contribute to varying degrees of host specificity in parasites. Host specificity measures the tendency of a parasite to inhabit a single host species and results from the co-existence of parasite and host over evolutionary time (Dick & Patterson 2007). Host-parasite associations can be categorized as primary or ! 2! non-primary. More specifically, there are multiple degrees, or classifications, of host specificity. Monoxenous refers to a species of parasites that occur only on a single host species, oligoxenous refers to a parasite that occurs on two or more species of the same genus, and pleioxenous refers to the parasite occurring on two or more host genera in the same family (Seneviratne et al 2009). Furthermore, the smaller range of hosts, or the higher degree of specificity, a parasite has will be phylogenetically more similar or have shared behavioral and ecological attributes (Whitfield 1979). A recent study designed to eliminate cross-host contamination