Evidence for the ‘Good Genes’ Model: Association of MHC Class II DRB Alleles with Ectoparasitism and Reproductive State in the Neotropical Lesser Bulldog Bat, Noctilio albiventris

Abstract

The adaptive immune system has a major impact on parasite resistance and life history strategies. Immunological defence is costly both in terms of immediate activation and long-term maintenance. The ‘good genes’ model predicts that males with genotypes that promote a good disease resistance have the ability to allocate more resources to reproductive effort which favours the transmission of good alleles into future generations. Our study shows a correlation between immune gene constitution (Major Histocompatibility Complex, MHC class II DRB), ectoparasite loads (ticks and bat flies) and the reproductive state in a neotropical bat, Noctilio albiventris. Infestation rates with ectoparasites were linked to specific Noal-DRB alleles, differed among roosts, increased with body size and co-varied with reproductive state particularly in males. Non-reproductive adult males were more infested with ectoparasites than reproductively active males, and they had more often an allele (Noal-DRB*02) associated with a higher tick infestation than reproductively active males or subadults. We conclude that the individual immune gene constitution affects ectoparasite susceptibility, and contributes to fitness relevant trade-offs in male N. albiventris as suggested by the ‘good genes’ model.

Prelude to a panzootic: Gene flow and immunogenetic variation in northern little brown myotis vulnerable to bat white-nose syndrome

“…The MHC has been studied in several bats, including a suite of Neotropical phyllostomid species (Schad et al 2012b;Real-Monroy et al 2014;Salmier et al 2016), the sac-winged bat (Saccopteryx bilineata; Mayer and Brunner 2007), and two North American Myotis species (M. velifer, M. velesi;Richman et al 2010). MHC variants are correlated with ectoparasite load in the lesser bulldog bat (Noctilio albiventris; Schad et al 2012a). Baseline MHC variation in North American bat populations and the role of MHC in the survival of bats with WNS are unknown.…”

Host–parasite network structure is associated with community-level immunogenetic diversity

“…At the individual host level, susceptibility to helminths can result from one of the two alleles or from a co-dominant effect of both, also depending on the parasite in question 13 . It is common in studies of MHC diversity to use only alleles/supertypes, rather than genotypes in statistical analyses 5,6,44 . However, owing to the lack of knowledge of the genetic mechanism, and because working with genotypes would create sparse networks, we used supertypes and validated our analyses with genotypes 13 .…”

Major histocompatibility complex alleles associated with parasite susceptibility in wild giant pandas

“…This was the first demonstration that MHC heterozygotes have an advantage against multi-parasite infections in a natural population (Oliver et al, 2009). 'Good' MHC genes were also evidenced by the association of MHC class II DRB alleles with ectoparasitism resistance in the neotropical lesser bulldog bat (Noctilio albiventris) (Schad et al, 2012). These studies showing the interaction between MHC and parasite infection, however, have been mostly limited in small or experimental animals.…”