Rates of urine excretion by house mouse (Mus domesticus): Differences by age,sex, social status,and reproductive condition

A series of five experiments was used to test hypotheses about factors affecting excreted urine output per day in male and female house mice (Mus domesticus). Urine was collected in metabolism cages over a 24-hr period. Male house mice excrete urine at a rate 1.5–2.0 times that of females. Daily average urine output increases with age for both sexes and for mice of the same age; urine output per day is correlated with body mass. Females in estrus produce more urine than females in diestrus. Urine output per day increases during the latter two thirds of pregnancy and remains high throughout lactation. Density does not influence urine output per day for either sex over the range of densities tested. Castration reduces urine output per day in male mice, but ovariectomy in females does not alter rates of urine production. Dominant males produce more urine than subordinate males, but there are no similar effects for female mice. The findings have potential implications for our understanding of the functional and ecological uses of urine by house mice.     

Urinary chemosignals,reproduction, and population size for house mice (Mus domesticus) living in field enclosures

The effects of urinary chemosignals influencing reproduction and puberty were studied in free-living house mice maintained in six 0.1-ha outdoor enclosures. Two enclosures were provided with urine and soiled bedding from male mice, two with urine and soiled bedding from group-caged female mice, and two with water and clean bedding as a control. Reproduction, puberty, recruitment, and population size all were affected by the urine treatments. Overall, populations reached significantly greater numbers in the enclosures treated with male urine and soiled bedding, intermediate levels with the water and clean bedding treatment, and were lowest for enclosures treated with urine and soiled bedding from grouped females. The population differences resulted from urinary chemosignal effects on adult female reproduction and female puberty; in general, females were in higher states of reproductive condition, more pregnancies occurred, and young females attained puberty earlier in male-treated enclosures and later in female-treated enclosures than in control enclosures. Urinary chemosignals that affect endocrine physiology and related reproductive processes may be one mechanism by which various factors influence population size in house mice.     

Extraction,characterization, and binding analysis of two pheromonally active ligands associated with major urinary protein of house mouse (Mus musculus)

Mouse urine contains substantial quantities of a family of proteins (MUPs) that are members of the lipocalycin family of proteins and that are potentially capable of binding hydrophobic molecules. We have used gas chromatography-mass spectrometry (GC-MS) to characterize two ligands associated with the MUPs, a thiazole and a brevicomin derivative. Previous work has suggested a role for these two ligands as androgen-dependent pheromones. In urine, nearly all of these ligands are protein bound and fractionation of MUPs on Mono-Q anion exchange chromatography indicated some specificity of ligand binding by the MUP subclasses.     

Variations in mouse (Mus musculus) urinary volatiles during different periods of pregnancy and lactation

Mouse urine samples from different pregnancy and lactation periods were examined by capillary gas chromatography to assess variations in the volatile signals that may affect the endocrine function of other females. Statistically significant changes in the excretion of certain urinary volatiles were observed; from 26 readily quantifiable constituents, 14 appear to be under the endocrine control. These selected components, positively identified through mass spectrometry and retention data, and the synthetic standards are ketones, unsaturated alcohols, esters, and cyclic vinyl ethers.     

Avoidance of bird repellents by mice (Mus musculus)

It is believed that mammalian chemosensory irritants are not aversive to birds and vice versa. Nevertheless, few avian repellents have been tested against mammals. For that reason, we evaluated the efficacy of 1.0% w/v methyl anthranilate, orthoaminoacetophenone, 2-amino-4,5-methoxyacetophenone, 2-methoxyacetophenone, and veratryl amine as mouse repellents in 3-hr no-choice drinking tests. Relative to ingestion of plain water, all test substances significantly reduced (P < 0.05) intake. Orthoaminoaceto-phenone was the most effective repellent, with intake reduced to levels statistically indistinguishable from zero.     

Odor preferences of wild stock female house mice (Mus domesticus) tested at three ages using urine and other cues from conspecific males and females

Urinary chemosignals from conspecific males and females can influence the physiological processes of sexual development in female house mice. The experiments reported here involved testing the odor and whole animal preferences of female mice presented with stimuli from male mice and grouped female mice. Mice were tested at three different ages. Five types of tests were performed: an olfactometer test using whole animals as stimuli, a second olfactometer test using urine stimuli, a soiled bedding substrate preference test, an animal association test, and a stick-chewing test. The results from all tests indicate that prepubertal females avoided male odors and prefer odors associated with grouped females. By about the age of puberty, the females exhibited a preference for male cues and generally avoided cues from grouped females. As adults, the females strongly preferred cues associated with males and avoided cues from grouped females. Thus, female mice appear to be exhibiting some control over their own physiological development and their reproductive condition by the nature of the stimuli with which they associate. Their stimulus preferences may have consequences for their fitness.     

Use of odor baits in traps to test reactions to intra- and interspecific chemical cues in house mice living in outdoor enclosures

House mice (Mus musculus) living in outdoor enclosures were tested for urinary chemical cue preferences using odor-baited traps. In the first experiment, with only volatile cues available, odors from conspecific males and females of various age classes and reproductive conditions were tested; no preferences were exhibited. In the second experiment mice had both nonvolatile and volatile cues available from the same sources as in experiment I. All age and sex class and female reproductive condition groups exhibited odor cue preferences except juvenile females. There were no specific odor cue preferences exhibited by any of the responder types with regard to odors from juvenile females. In the third and fifth experiments, mice were presented with nonvolatile plus volatile or only volatile urine odor cues, respectively, from four genera,Mus, Peromyscus, Microtus, andHomo. Mice of all age classes and both sexes preferredMus musculus odor, were neutral towardMicrotus ochrogaster odor, and avoided odors fromPeromyscus leucopus andHomo sapiens; these patterns were the same regardless of whether only volatile or both volatile and nonvolatile cues were presented. The fourth and sixth experiments involved testing volatile cues only and volatile cues plus nonvolatile cues from human sweat or feces from dogs, cats, or shrews. Mice avoided the human sweat and feces from cats and shrews, but were neutral toward the odor of dog feces. There were effects on whether mice were trapped in the interior of the enclosure or on the perimeter for some odors tested in these six experiments. The findings provide insights regarding possible functions of odor cues in the behavioral ecology of house mice. Odor-baiting traps can be an effective tool with respect to testing some, but not all questions pertaining to olfactory cues and house mouse social biology.