Does chronic malaria modify the odours of its male mouse host?

Abstract

Chemical signalling, considered the most important means of communication in rodents, is controlled by the immune and endocrine systems. Several parasitic diseases are associated with modifications of the odour cues deposited by infected male mice and these modifications, conspicuous to sexually receptive females, are supposed to play a role in a parasite-mediated mate choice process. The present study clearly demonstrates, with the use of three different two choice test procedures, that females can discriminate the chemical message from malaria-infected and healthy male mice (Mus musculus L., 1758). Females spent more time sniffing soiled beddings and preputial skin rubbings collected from parasitized males at 15 days post injection and at 15, 22, 29 days post injection, respectively. Also, females could discriminate the overall body odour of a parasitized male at 35 days post injection. The cause of these modifications is discussed with regard to the numerous pathologies previously described in the genital tract of infected males. And the present study, although it avoids drawing any conclusions on a parasite-mediated mate choice under wild conditions, stresses the potential benefit that the parasite may gain from the situation.