Browsing by Author "Ramirez, Ismael"

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    Philornis Downsi Interactions With Its Host In The Introduced Range And Its Parasitoids In Its Native Range
    (2018-12) Ramirez, Ismael
    The study of ecological interactions is important for the management of invasive species. In the Galapagos Islands, an invasive parasitic fly, Philornis downsi Dodge & Aitken (Diptera: Muscidae), is causing high rates of mortality among endemic avifauna. Long-term management of this invasive fly is not yet available, and research is needed to further understand the interactions among its host and its natural enemies to further consider management strategies. My research examines the interactions of Philornis downsi with one of its hosts in the Galapagos Islands and with its natural parasitoid enemies in mainland Ecuador. I studied the interactions between the fly and one of its hosts, the Galapagos flycatcher (Myiarchus magnirostris) in the Galapagos Islands, as well as with the fly’s natural parasitoid enemies in mainland Ecuador. My studies in the Galapagos Islands showed that Philornis downsi is mainly vespertine (active at dusk) and that its activity was higher when adult birds were more active around nests. And, my studies in mainland Ecuador showed that almost all parasitoids that emerged from Philornis pupae encountered in mainland Ecuador did not emerge from experimentally deployed pupae of non-Philornis fly species. The results of my thesis will provide information on P. downsi interactions which could aid in its management. Additionally, understanding these interactions should simplify the efforts to mitigate the impact of the fly and avoid the possibility of future extinctions of endemic avifauna in the Galapagos Islands.
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    Wasps, vampires, and carrion flies: addressing the safety of the parasitoid Conura annulifera (Hymenoptera: Chalcididae), a promising biological control agent for the Galapagos Islands.
    (2023-12) Ramirez, Ismael
    The avian vampire fly, Philornis downsi (Diptera: Muscidae), is an invasive species in the Galapagos Islands that has caused significant mortality among endemic bird species. This thesis delves into the safety of the neotropical wasp Conura annulifera (Hymenoptera: Chalcididae) as a biological control agent against the avian vampire fly in the Galapagos Islands and encompasses four chapters addressing such safety. Chapter one scrutinizes the ecological specificity of pupal parasitoid species found in the native range of the avian vampire fly and other fly species in mainland Ecuador using food web analysis. Additionally, in Chapter two, I comprehensively characterized the composition of the carrion fly community in the Galapagos Islands, encompassing the abundance and distribution of both endemic and introduced species. Furthermore, I investigated the potential for competitive interactions between introduced and endemic carrion fly species and their implications for biological control. In Chapter Three, I examine the burrowing behavior of endemic and introduced carrion fly species in the Galapagos Islands and evaluate the ability of C. annulifera to locate and attack subterranean puparium as the soil is an effective barrier that provides refuge for non-target species that burrow. Finally, in Chapter Four, I assess the physical host preference of C. annulifera and its potential to parasitize non-target carrion fly species using no-choice trials in containment facilities of the Charles Darwin Research Station in the Galapagos Islands. The findings of this thesis provide informative insights into the intricate ecological interactions between the avian vampire fly, C. annulifera, and carrion fly species in the Galapagos Islands and Mainland Ecuador. Additionally, it sheds light on the safety of C. annulifera to serve as a biological control agent for the avian vampire fly. This knowledge is crucial information to decision-making officials regarding the potential introduction of C. annulifera to the Galapagos Islands to mitigate the detrimental effects of P. downsi on endemic bird populations and possible extinctions.