Intraspecific priority effects and disease interact to alter population growth

Abstract

Abstract. Intraspecific variation may shape colonization of new habitat patches through a variety of mechanisms. In particular, trait variation among colonizing individuals can produce intraspecific priority effects (IPEs), where early arrivers of a single species affect the establishment or growth of later conspecifics. While we have some evidence for the importance of IPEs, we lack a general understanding of factors affecting their presence or magnitude across a landscape. Specifically, IPEs should depend strongly on success of colonizers in the new habitat patch. This success hinges on interactions between colonizer traits and local selective pressures, but such context dependence remains unexplored experimentally. We addressed this gap by looking for the dynamical signature of IPEs in environments with and without a selective (parasite) pressure. We tested whether IPEs affected the population dynamics of a zooplankton host species (Daphnia dentifera) collected from two populations showing a tradeoff between growth rate and resistance to a fungal parasite (Metschnikowia bicuspidata). Differences in arrival order significantly altered population growth during a period of rapid resource depletion, driving large (up to 65%) differences in population abundance. Furthermore, the presence of IPEs was context dependent, as parasites reduced the impact of early arrivers on later arrivers. Such context-dependent IPEs, mediated by colonizer traits, colonization order, and selective pressures, may play an unanticipated role in the ecological and evolutionary dynamics of natural metapopulations. This mechanism highlights the overall importance of intraspecific variation for understanding ecological patterns.

A novel method for quantifying the rate of embryogenesis uncovers considerable genetic variation for the duration of embryonic development in Drosophila melanogaster

“…Priority effects describe the effect of a community initiating species on the later arriving ones, and are well known and studied in ecology literature (for a review see [ 63 ]), in particular for plant [ 65 – 67 ] and aquatic communities [ 68 , 69 ]. While most studies focus on interspecific interactions, the importance of intraspecific effects has been described as well [ 68 , 70 ]. The observed delayed/de-synchronized development is indicative of a strong competitive interaction, and can be seen as a form of intraspecific inhibitive priority effect [ 63 , 64 ].…”

Habitat‐mediated carry‐over effects lead to context‐dependent outcomes of species interactions

“…; Bolnick et al . ; Pruitt ; Dibble, Hall & Rudolf ), but how it affects community assembly and coexistence is poorly understood (Agrawal et al . ).…”

“…However, differences in coexistence could instead arise due to differences in the phenotype of colonizing individuals. Phenotypic variation within species is increasingly recognized as having the potential to alter population dynamics and species interactions (Prout & McChesney 1985;Miner et al 2005;Conrad et al 2011;Bolnick et al 2011;Pruitt 2012;Dibble, Hall & Rudolf 2014), but how it affects community assembly and coexistence is poorly understood (Agrawal et al 2007).…”

Effects of environmental warming during early life history on libellulid odonates

“…There is a growing body of research indicating that variation within species can affect important ecological dynamics (Bolnick et al 2011) such as the ability to colonize new habitats (Dibble et al 2014), community interactions (Duffy 2010), and population stability and persistence (Agashe 2009), especially with environmental perturbations (Oney et al 2013). For our intraspecific comparisons, we measured the degree to which responses to temperature varied both within and between clutches of the dot-tailed whiteface (Leucorrhinia intacta (Hagen, 1861)) dragonfly.…”