Habitat-specific adaptation of immune responses of stickleback (Gasterosteus aculeatus) lake and river ecotypes

Abstract

Freshwater populations of three-spined sticklebacks (Gasterosteus aculeatus) in northern Germany are found as distinct lake and river ecotypes. Adaptation to habitat-specific parasites might influence immune capabilities of stickleback ecotypes. Here, naive laboratory-bred sticklebacks from lake and river populations were exposed reciprocally to parasite environments in a lake and a river habitat. Sticklebacks exposed to lake conditions were infected with higher numbers of parasite species when compared with the river. River sticklebacks in the lake had higher parasite loads than lake sticklebacks in the same habitat. Respiratory burst, granulocyte counts and lymphocyte proliferation of head kidney leucocytes were increased in river sticklebacks exposed to lake when compared with river conditions. Although river sticklebacks exposed to lake conditions showed elevated activation of their immune system, parasites could not be diminished as effectively as by lake sticklebacks in their native habitat. River sticklebacks seem to have reduced their immune-competence potential due to lower parasite diversity in rivers.

Adaptive phenotypic plasticity contributes to divergence between lake and river populations of an East African cichlid fish

“…However, because F1s tend to be heterotic, and outbreeding depression is often not expressed until the F2 or later generations, conclusions about the relative fitness of hybrids must be tentative (Lexer, Randell, & Rieseberg, 2009). River stickleback, whether migrants or residents, were found to generally grow faster than lake fish (Scharsack et al., 2007; Kaufmann et al., 2017), suggesting a river‐specific trait of faster growth in this species. It has also been suggested that selection on juvenile hybrid stickleback may be weaker than detected in adults (Hatfield & Schluter, 1999).…”

Who is in control of the stickleback immune system: interactions between Schistocephalus solidus and its specific vertebrate host

“…(d) Immune parameters For immunological assays, head kidney leucocytes (HKL) were isolated from sticklebacks and analysed for proliferation and respiratory burst activity as described by Scharsack et al (2007). Briefly, total cell numbers in individual HKL isolates were determined by means of flow cytometry with the standard cell dilution assay (Pechhold et al 1994) as modified by Scharsack et al (2004).…”

Introduction. Ecological immunology

“…In both cases, the different parasite 'types' are likely to attempt infection with distinct 'attack' mechanisms, thus requiring diversity and flexibility in host recognition, processing and effector mechanisms. One of the few systematic studies of parasite diversity and its immunogenetic consequences was performed in lake and river ecotypes of the three-spined sticklebacks Gasterosteus aculeatus in northern Germany, which contain approximately 15 different eukaryotic parasite species (Kalbe et al 2002;Scharsack et al 2007). Parasite species richness within a population affects relevant components of both the innate and adaptive immune systems (Scharsack et al 2007), such as the diversity of major histocompatibility complex (MHC) genes (Wegner et al 2003a,b).…”

“…One of the few systematic studies of parasite diversity and its immunogenetic consequences was performed in lake and river ecotypes of the three-spined sticklebacks Gasterosteus aculeatus in northern Germany, which contain approximately 15 different eukaryotic parasite species (Kalbe et al 2002;Scharsack et al 2007). Parasite species richness within a population affects relevant components of both the innate and adaptive immune systems (Scharsack et al 2007), such as the diversity of major histocompatibility complex (MHC) genes (Wegner et al 2003a,b). The general importance of interactions with multiple parasite species or strains on host evolution has been emphasized in several theoretical articles.…”