![]() ![]() The diseases caused by these infectious agents can have profound fitness effects on individual hosts, resulting in selection for anti-parasite behaviors, immune defenses, and changes in life-history features such as birth weight. These parasites are also diverse in terms of their transmission modes (e.g., sexual, vertical, vector-borne, airborne, and fecal-oral) and life cycles (e.g., direct or via one or more intermediate hosts). Mammals are infected by a wide variety of parasites, ranging from microscopic viruses and bacteria to macroscopic tapeworms, flukes and biting arthropods. Identifying the host characteristics that support multiple parasites is therefore critically important for human health and the conservation of biodiversity. Additionally, we share approximately 60% of our infectious diseases with animals and many recent human pandemics originated in wildlife, including HIV and SARS. For example, infectious diseases are threatening various species (e.g., amphibians and Tasmanian devils, ), while biodiversity itself may influence the prevalence of parasites in ecological communities. Understanding parasite infections in wild animals is of great importance. Thus, shorter-lived ungulates may be more vulnerable to disease outbreaks, which has implications for ungulate conservation, and may be applicable to other short-lived mammals. Our results suggest that greater parasite burden is linked to higher host mortality in ungulates. We also found no evidence for a relationship between immune investment and host longevity in any of our three groups. ![]() We found a significant negative relationship between longevity and parasite species richness for ungulates, but no significant associations in carnivores or primates. Our analyses revealed weak relationships between parasite species richness and longevity. We also tested whether increased host longevity is associated with increased immunity, using white blood cell counts as a proxy for immune investment. We tested these two opposing predictions in carnivores, primates and terrestrial ungulates using phylogenetic comparative methods and controlling for the potentially confounding effects of sampling effort and body mass. Alternatively, if long-lived species represent a more stable environment for parasite establishment, host longevity and parasite species richness may show a positive association. If parasite burden causes increased mortality, we expect a negative association between host longevity and parasite species richness. Thus, parasites may influence host life-history characteristics, such as longevity, and simultaneously host life-history may influence parasite diversity. Hosts and parasites co-evolve, with each lineage exerting selective pressures on the other. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2022
Categories |