Your infections are what you eat: How host ecology shapes the helminth parasite communities of lizards

Abstract

Understanding how parasite communities are assembled, and the factors that influence their richness, can improve our knowledge of parasite–host interactions and help to predict the spread of infectious diseases. Previous comparative analyses have found significant influences of host ecology and life history, but focused on a few select host taxa. Host diet and habitat use play key roles in the acquisition of parasitic helminths as many are trophically transmitted, making these attributes potentially key indicators of infection risk. Given the paucity of comparative studies with non‐piscine, non‐avian or non‐mammalian hosts, it is critical to examine the degree to which host ecology influences parasite communities in other host taxa in order to identify common drivers. We examined helminth diversity in over 350 species of lizards in relation to their body mass, ecology (diet and habitat use) and life history (clutch size, and ovo‐ or viviparity) using previously published data. Overall, lizard species with herbivorous diets harboured fewer types of helminths (especially larval stages), with similar results for traits that were ultimately strongly associated with diet (host mass and habitat use). Large hosts tended to be herbivores with few helminth types, whereas species utilizing arboreal habitats typically consumed some animal matter and hosted more helminths. Understanding how host ecology and life history are related to their parasite assemblages has significant implications for the risk of acquiring novel parasites. Our results indicate an overwhelming influence of host diet such that many helminths may be relatively easily acquired by hosts in new ranges, or through dietary shifts.

Strongylid infection varies with age, sex, movement and social factors in wild African elephants

“…Our study did not control for differences in diet. Varying diet was found to have a large effect on parasitic worm infections in many species of lizards (Leung and Koprivnikar, 2019). Although we did not explicitly quantify diet, previous work has shown that the ratio of grass to browse elephants eat changes predictably with NDVI (Cerling et al ., 2006; Wittemyer et al ., 2009).…”

“…Additionally, environmental factors influence the exposure of a host to infection (González-Hernández et al ., 2014). These factors include seasonality (Cizauskas et al ., 2015), the cleanliness of available water sources (Khan et al ., 2010), diet (Leung and Koprivnikar, 2019), and properties of soil such as particle size (Condy, 1974).…”

Functional traits shape small mammal-helminth network: patterns and processes in species interactions

“…The host's diet may be considered an important factor in increasing their exposure to parasite infection (Dallas et al ., 2019 ). Many helminths can be acquired by contact with infectious stages present in the environment or by the consumption of contaminated food (Leung and Koprivnikar, 2019 ). Host species that have an omnivorous diet can consume a variety of food items available in the environment, including fruits, vertebrates and many invertebrates, which may act as intermediate hosts.…”

Nematodes of Amphibians from the South American Chaco: Distribution, Host Specificity and Ecological Aspects

“…It has been often documented that the composition of the helminth community in herps is closely related to the foraging mode [153,154]. Specifically, sit-and-wait ambush predators capture generally few large prey individuals, and wide-ranging searching predators capture small, sedentary and locally abundant prey.…”

“…In terrestrial amphibians, the mean species richness of nematodes is greater than in aquatic, arboreal and semi-aquatic species [25,[153][154][155][156]. For example, A. hylambatis was the dominant species in the helminth community of the terrestrial L. bufonius, R. major and D. muelleri [42,52,80], and C. podicipinus was the dominant species in the terrestrial host R. dorbignyi (=R.…”