Choosing a healthy mate: sexually attractive traits as reliable indicators of current disease status in house mice

Abstract

Social interactions are critical for reproduction in many animals. Since several pathogens are transmitted by social contact, females searching for mating partners should select males that can signal being healthy. Not all signals, however, may be reliable, since males from a number of species can overcome behavioural symptoms of infection when mating opportunities are available. Here, we manipulated sickness status of male house mice, Mus musculus domesticus, by administering an immune challenge (lipopolysaccharide, LPS) and studied the consequences of this manipulation for two signals that function in mate attraction in this species: ultrasonic vocalizations and darcin (a urinary protein). Additionally, we quantified female visits to immune-challenged and control males, and the males' plasma testosterone levels. LPS-injected males had lower darcin and lower regular ultrasonic syllable production than control-injected males, while producing a larger number of high-frequency ultrasonic syllables. We conclude that immune-challenged male mice presented with a receptive female cannot maintain the production of sexually attractive signals. Females might use some of these cues when making mating decisions, since they spent significantly less time near LPS-injected males. Testosterone was reduced in LPS-injected males and could be a unifying mechanism downregulating both of the traits quantified. ultrasonic syllable production than control-injected males, while producing a larger 37 number of high frequency ultrasonic syllables. We conclude that immune-challenged 38 male mice presented with a receptive female cannot maintain the production of 39 sexually attractive signals. Females might use some of these cues when making 40 mating decisions, since they spent significantly less time near LPS-injected males. 41

Molecular heterogeneity in major urinary proteins of Mus musculus subspecies: potential candidates involved in speciation

“…2d). This band recapitulated the electrophoretic behaviour of the male peripheral MUP pheromone, darcin, identified previously in male laboratory mice52 and in wild-derived domesticus from the UK3452, US5354 and Switzerland55. While a mass peak at 18893 Da, corresponding to the known mass of darcin, was evident in allopatric male domesticus samples (Fig.…”

Infection-induced behavioural changes reduce connectivity and the potential for disease spread in wild mice contact networks

“…We found that immune-challenged animals reduced their movement as quantified by the number of times they entered and exited nest boxes, which impacted the number of different nest boxes used over night. Despite being able to detect diseased and immune-challenged conspecifics2629, mice in this study did not reduce the number of visits paid to the immune-challenged mice. Several lines of evidence indicate that urinary cues aid in the detection of diseased conspecifics in mice29.…”

The role of social cognition in parasite and pathogen avoidance

“…Whether or not the responses to other infections similarly involve the VNO as well as the relative roles of other olfactory components and receptors remains to be clarified. A number of low-level infections in rodents have been shown to not only affect the quality and composition of the urine odour components, but also the quantity and extent of male scent marking [63,75]. For example, Zala et al [63] showed that wild-derived male mice infected with Salmonella enterica bacteria have both a reduced marking rate and their odours appear less attractive to females.…”

“…Under natural conditions, odour and other sensory cues (e.g. ultrasonic vocalizations [75]) may result in female mice being more likely to detect and locate healthy males. Biased mating can result if the initial sensory-based choices lead to rejection of a less preferred male.…”