Host traits and competitive ability jointly structure disease dynamics and community assembly

Abstract

Parasitism and competition are both ubiquitous interactions in ecological communities. The ability of host species to interact directly via competition and indirectly through shared parasites suggests that host traits related to competition and parasitism are likely important in structuring communities and disease dynamics. Specifically, those host traits affecting competition and those mediating parasitism are often correlated either because of trade‐offs (in resource acquisition or resource allocation) or condition dependence, yet the consequences of these trait relationships for community and epidemiological dynamics are poorly understood. We conducted a literature review of parasite‐related host traits–competitive ability relationships. We found that transmission–competitive ability relationships were most often reported, and that superior competitors exhibited elevated transmission relative to their less‐competitive counterparts in nearly 80% of the cases. We also found a significant number of virulence–competitive ability and parasite shedding–competitive ability relationships. We investigated these links by altering the relationship between host competitive ability and three parasite‐related traits (transmission, virulence and parasite shedding rates) in a simple model, incorporating competitive asymmetries in a multi‐host community. We show that these relationships can lead to a range of different communities. For example, depending on the strength and direction of these distinct trait relationships, we observed communities with anywhere from high parasite prevalence to complete parasite extinction, and either one, two or the maximum of three host species coexisting. Our results suggest that parasite–competitive ability relationships may be common in nature, that further integration of these relationships can produce novel and unexpected community and disease dynamics, and that generalizations may allow for the prediction of how parasitism and competition jointly structure disease and diversity in natural communities.

The effect of host community functional traits on plant disease risk varies along an elevational gradient

“…The functional traits expressed by those species that are able to colonize and persist in a given location can, in turn, affect disease risk ( Halliday et al, 2019 ; Johnson et al, 2013 ; Kirk et al, 2019 ). Specifically, an infected host’s ability to transmit disease to uninfected hosts, a trait often referred to as host competence, is often related to fast-growing, poorly defended tissues and short lifespans ( Becker and Han, 2021 ; Cronin et al, 2014 ; Cronin et al, 2010 ; Huang et al, 2013 ; Johnson et al, 2012 ; Martin et al, 2019 ; Martin et al, 2016 ; Parker and Gilbert, 2018 ; Stewart Merrill and Johnson, 2020 ; Welsh et al, 2020 ).…”

Biodiversity loss underlies the dilution effect of biodiversity

“…While many studies focus on measuring the diversity of host species in the context of disease, the structure of host communities can also be measured in the context of disease using characteristics of host species or host functional traits (Johnson et al ., 2013; Halliday et al ., 2019; Kirk et al ., 2019), resulting in trait‐based measures of host community competence (Stewart Merrill and Johnson, 2020). This approach, which has rapidly gained traction in disease ecology, suggests that host species that are the best able to spread diseases (i.e., the most competent hosts), often share particular suites of physiological traits (Huang et al ., 2013; Martin et al ., 2019; Becker and Han, 2020).…”

Monitoring of diseases in wild plants and animals: a challenge to measure the success of environmental policies and management in Ecuador

“…Functional traits expressed by those species that can colonize and persist in a given location may, in turn, affect disease risk (Hallidayet al, 2019;Johnson et al, 2013;Kirk et al, 2019). Specifically, the ability of an infected host to transmit disease to uninfected hosts, a trait often referred to as host competence, is often associated with rapidly growing tissues and poor defense and short lifespans (Becker et In Ecuador, several environmental problems have been identified for several decades, but deforestation and changes in land use associated with oil exploitation, agriculture and livestock, and timber exploitation stand out, which cause ecosystem losses.…”