Red Imported Fire Ants in the Brown Food Web: Ecological, Behavioral, and Nutritional Mechanisms Underlying the Recruitment of Solenopsis invicta to Vertebrate Carrion
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Date
2023-12-13
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Abstract
This dissertation highlights the overlooked involvement of ants in vertebrate carrion decomposition. Insects such as flies and beetles have long been recognized as significant players in vertebrate carrion decomposition due to their roles as prolific primary colonizers and voracious biomass consumers. Ants, on the other hand, while being commonly recognized as opportunistic scavengers, have never been systematically studied in the context of decomposition ecology.
We therefore propose an interdisciplinary investigation articulated around three questions: What is the prevalence of vertebrate carrion consumption by ants? What in carrion is attractive to ants? What are the benefits associated with the recruitment to vertebrate carrion?
We conducted an extensive literature review, uncovering records of 154 ant species engaging with vertebrate carrion across various habitats and continents. We found that ants’ impact vertebrate carrion decomposition through both direct and indirect mechanisms. The direct effects encompass necrophagy and carcass laceration, while indirect effects entail predation on carrion-feeding invertebrates and microhabitat alterations through nesting activities. Our empirical research focused on the red imported fire ant (Solenopsis invicta) as a model species. Through a combination of field and laboratory experiments, our data confirmed that fire ants readily recruit to vertebrate carrion, but when consumed, it proved to be detrimental to colony performance. We hypothesize that while being attracted to vertebrate carrion, the main nutritional resource for the ants is not the carcass, but the dipteran larvae feeding on it. We also identified dimethyl disulfide (DMDS), a volatile organic compound (VOCs) emitted during vertebrate carrion decomposition, as a key attractant to vertebrate carrion, both in controlled laboratory settings and in the field. Then, we compared the nutritional benefits of a vertebrate carrion diet compared to a vertebrate carrion-feeding maggot diet and revealed the importance of fatty acid intake regulation in ants.
By its interdisciplinary approach, this dissertation paves the way for future research aiming to elucidate the complex relationships between green and brown food webs and offers valuable insights for the fields of ecology and forensics, ultimately contributing to a more holistic understanding of vertebrate carrion decomposition.
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Formicidae, vertebrate carrion decomposition, food webs, decomposition ecology, insect nutrition