Olsson Lab

Research Focus

Immunobiology and Host-Parasite Interactions

 

The immuno-competence-handicap (ICH) hypothesis suggests that increased levels of androgens are necessary for development of male sex traits, which may have costs through compromised immune function.

This may lead to increased susceptibility to pathogens, and in females, perhaps reduced efficiency of sperm-egg barriers at fertilization.

We have shown that lizards challenged with testosterone have reduced levels of erythrocytes infected with Haemoprotid parasites when they have a particular MHC haplotype (with the O-allele), than lizards that lack this fragment. Furthermore, corticosterone, which is known to have a depressing effect on immune function in reptiles, was elevated in males that lack the O-allele, particularly when they engage in male-male contests for females.

 

In terms of fitness, the importance of having the O-allele was validated by estimates of male reproductive success, which were higher in O-allele males. These observations suggest that particular loci that determine the function of the adaptive immune system are true ‘good genes’ and may be key targets of selection (e.g. through pre- or post-copulatory mate choice.