Low Incidence of Miscarriage Induced by the Scent of Male Littermates of Original Mates: Male Kinship Reduces the Bruce Effect in Female Mice, Mus musculus

Yuting Wang,Dingzhen Liu,Johan J Bolhuis

doi:10.1371/journal.pone.0068673

Abstract

The scent of a novel male can elicit pregnancy block in recently mated female mice (Mus musculus), a phenomenon known as the Bruce effect. Despite abundant literature on the Bruce effect in rodents, it remains unclear whether males related to a female’s original mate can induce the Bruce effect in out-bred, communally living mice. We investigated this question using Kunming (KM) male mice of varying genetic relatedness. Recently mated females were subjected to three treatments: exposure to the urine of the mate, urine of the mate’s male littermate, and urine of a male unrelated to the mate. It was found that the urine of male littermates of the females’ mates did not elicit more pregnancy block than that of the females’ mates. However, the urine of novel males caused a higher rate of female miscarriage than that of the females’ mates. By using a habituation-dishabituation paradigm, we found that unmated females could discriminate the urine scents of two male littermates from those of a novel male unrelated to the littermates. To understand how females use urinary cues to discriminate between males with different genetic relationships, we used gas chromatography coupled with mass spectrometry (GC-MS) to examine the volatile composition of urine from males with varying relatedness. It was found that KM male littermates shared similar volatile compositions in their urine. Our results suggest that male kinship reduces the Bruce effect in female KM mice, and provide additional evidence for mate choice being partly mediated by the Bruce effect in KM mice.

Highlights

Pregnancy in female mice (Mus musculus) may be terminated after the female is exposed to an unfamiliar male (Bruce effect) [1]
The aims of our study are: 1) to test whether unmated female mice can discriminate between the scents of two male littermates and a novel male that is genetically unrelated to the littermates; 2) to test whether exposure of mated females to the urine scent from the male littermate of the females’ mate can lead to pregnancy block as predicted by the Bruce effect; 3) to test whether there are similarities in the chemical composition of urine scents from male littermate mice
The Cochran-Armitage trend test showed that male familiarity/similarity was significantly and negatively associated with pregnancy block (p = 0.0089): females exposed to urine scents from novel males are more likely to experience pregnancy block

Summary

Introduction

Pregnancy in female mice (Mus musculus) may be terminated after the female is exposed to an unfamiliar male (Bruce effect) [1]. Mated female mice exposed to odors from the stud male and a syngeneic male show pregnancy block significantly less frequently than females exposed to odors from a novel male differing from the stud male in one gene (H-2K) [12]. This means that female mice can discriminate between chemosensory cues from the three groups of males and recognize the novel male’s odor. Are the chemical compositions in the chemosensory cues of the urine of male littermates similar or dissimilar?

Objectives

Methods

Results

Conclusion