Fat Cycles, Breeding and Population-Changes in House Mice

The North American lesser scaup (Aythya affinis) population has declined since the mid-1980s. The acquisition of nutrient reserves during spring migration may play a role in explaining that trend. We studied nutrient-reserve dynamics of lesser scaup collected during spring at 3 major stopover sites and assessed whether reserves of birds on the lower Great Lakes (LGL) differed from those at other staging (or breeding) areas. At lakes Ontario and St. Clair, males had larger fat reserves than females, but no other substantial sex-related differences were observed in fat, protein, or mineral reserve levels of lesser scaup. Protein in males and mineral reserves of both sexes at lakes Erie and St. Clair did not change throughout spring. Male fat reserves remained constant at Lake Erie and increased at Lake St. Clair, whereas female fat and protein reserves increased at both stopover sites. Patterns of fat and protein dynamics in males partly may be due to energetic costs of courtship and pair-bond maintenance. However, maintenance and accumulation of fat reserves in both sexes while on the LGL is important for impending migration and subsequent reproduction. Female lesser scaup staging on the LGL had fat reserves comparable to, or slightly higher than, those reported in other studies of northern spring-staging and breeding birds. Fat reserves of LGL females, however, were much lower than those reported for birds at another midlatitude stopover site. These comparisons suggest that events occurring on Atlantic Flyway wintering areas or LGL staging areas are potential factors contributing to nutrient-reserve limitation and possibly to observed declines in scaup numbers in North America.

Previous articleNext article No AccessNotes and CommentsSexual Selection in Mice. V. Reproductive Competition between +/+ and +/tw5 MalesLouis Levine, Robert F. Rockwell, and Joseph GrossfieldLouis Levine Search for more articles by this author , Robert F. Rockwell Search for more articles by this author , and Joseph Grossfield Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 116, Number 1Jul., 1980 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/283619 Views: 2Total views on this site Citations: 18Citations are reported from Crossref Copyright 1980 The University of ChicagoPDF download Crossref reports the following articles citing this article:Andreas Sutter, Anna K. Lindholm No evidence for female discrimination against male house mice carrying a selfish genetic element, Current Zoology 62, no.66 (Jun 2016): 675–685.https://doi.org/10.1093/cz/zow063ANN EILEEN MILLER BAKER Mendelian inheritance of t haplotypes in house mouse ( Mus musculus domesticus ) field populations, Genetics Research 90, no.44 (Oct 2008): 331–339.https://doi.org/10.1017/S0016672308009439Lara S. Carroll, Wayne K. Potts Functional Genomics Requires Ecology, (Jan 2006): 173–215.https://doi.org/10.1016/S0065-3454(06)36004-4Lara S. Carroll, Shawn Meagher, Linda Morrison, Dustin J. Penn, Wayne K. Potts FITNESS EFFECTS OF A SELFISH GENE (THE MUS T COMPLEX) ARE REVEALED IN AN ECOLOGICAL CONTEXT, Evolution 58, no.66 (Jan 2004): 1318.https://doi.org/10.1554/03-544T. Tregenza, N. Wedell Genetic compatibility, mate choice and patterns of parentage: Invited Review, Molecular Ecology 9, no.88 (Aug 2000): 1013–1027.https://doi.org/10.1046/j.1365-294x.2000.00964.xRobert C. Karn, Rosemary Russell The amino acid sequence of the alpha subunit of mouse salivary androgen-binding protein (ABP), with a comparison to the partial sequence of the beta subunit and to other ligand-binding proteins, Biochemical Genetics 31, no.7-87-8 (Aug 1993): 307–319.https://doi.org/10.1007/BF02401825Carol B. Coopersmith, Sarah Lenington Female Preferences Based on Male Quality in House Mice: Interaction between Male Dominance Rank and t-Complex Genotype, Ethology 90, no.11 (Apr 2010): 1–16.https://doi.org/10.1111/j.1439-0310.1992.tb00815.xSarah Lenington The t Complex: A Story of Genes, Behavior, and Populations, (Jan 1991): 51–86.https://doi.org/10.1016/S0065-3454(08)60319-8C.J. Barnard, J. Fitzsimons Kin recognition and mate choice in mice: the effects of kinship, familiarity and social interference on intersexual interaction, Animal Behaviour 36, no.44 (Aug 1988): 1078–1090.https://doi.org/10.1016/S0003-3472(88)80067-8R. J. Berry Where biology meets; or how science advances: Presidential Address to the Linnean Society delivered at the Anniversary Meeting, 24th May 1985, Biological Journal of the Linnean Society 30, no.33 (Jan 2008): 257–274.https://doi.org/10.1111/j.1095-8312.1987.tb00300.xSARAH LENINGTON Reproductive Behavior as a Phenotypic Correlate of T-Locus Genotype in Wild House Mice: Implications for Evolutionary Models, Annals of the New York Academy of Sciences 474, no.1 Reproduction1 Reproduction (Dec 1986): 141–147.https://doi.org/10.1111/j.1749-6632.1986.tb28006.xPatricia Franks, Sarah Lenington Dominance and reproductive behavior of wild house mice in a seminatural environment correlated with T-locus genotype, Behavioral Ecology and Sociobiology 18, no.66 (May 1986): 395–404.https://doi.org/10.1007/BF00300513R. J. Berry Genetical Processes in Wild Mouse Populations. Past Myth and Present Knowledge, (Jan 1986): 86–94.https://doi.org/10.1007/978-3-642-71304-0_10Raghavendra Gadagkar Kin recognition in social insects and other animals—A review of recent findings and a consideration of their relevance for the theory of kin selection, Proceedings: Animal Sciences 94, no.66 (Dec 1985): 587–621.https://doi.org/10.1007/BF03191863Louis Levine Sexual selection does not equal mate selection, Animal Behaviour 33, no.44 (Nov 1985): 1363–1364.https://doi.org/10.1016/S0003-3472(85)80200-1Kathleen Egid, Sarah Lenington Responses of male mice to odors of females: Effects of T- and H-2-locus genotype, Behavior Genetics 15, no.33 (May 1985): 287–295.https://doi.org/10.1007/BF01065983Sarah Lenington, Kathleen Egid Female discrimination of male odors correlated with male genotype at the T locus: A response to T-locus or H-2-locus variability?, Behavior Genetics 15, no.11 (Jan 1985): 53–67.https://doi.org/10.1007/BF01071932Sarah Lenington Social preferences for partners carrying ‘good genes’ in wild house mice, Animal Behaviour 31, no.22 (May 1983): 325–333.https://doi.org/10.1016/S0003-3472(83)80050-5

A SUBSTANTIAL ENERGETIC COST TO MALE REPRODUCTION IN A SEXUALLY DIMORPHIC UNGULATE

The house mouse, Mus musculus domesticus, shows extraordinary chromosomal diversity driven by fixation of Robertsonian (Rb) translocations. The high frequency of this rearrangement, which involves the centromeric regions, has been ascribed to the architecture of the satellite sequence (high quantity and homogeneity). This promotes centromere-related translocations through unequal recombination and gene conversion. A characteristic feature of Rb variation in this subspecies is the non-random contribution of different chromosomes to the translocation frequency, which, in turn, depends on the chromosome size. Here, the association between satellite quantity and Rb frequency was tested by PRINS of the minor satellite which is the sequence involved in the translocation breakpoints. Five chromosomes with different translocation frequencies were selected and analyzed among wild house mice from 8 European localities. Using a relative quantitative measurement per chromosome, the analysis detected a large variability in signal size most of which was observed between individuals and/or localities. The chromosomes differed significantly in the quantity of the minor satellite, but these differences were not correlated with their translocation frequency. However, the data uncovered a marginally significant correlation between the quantity of the minor satellite and chromosome size. The implications of these results on the evolution of the chromosomal architecture in the house mouse are discussed.

The relationship between food energy and work effort (foraging) is crucial to small mammals such as the house mouse (Mus domesticus). Energy allocation processes were studied by using a special caging system in which animals were required to work for 45 mg food pellets by running on an activity wheel. Two experimental themes were investigated: 1) When weaning female mice were forced to work harder for less food, their highest energy allocation priority was to maintain fat reserves; body growth was next in importance while achieving puberty had the lowest prority of all. The relative insensitivity of fat deposition to high foraging costs suggests a strategy for survival whereby dispersing animals maintain emergency fat reserves at the expense of growth and fertility. In male mice, however, reproductive development is independent from body growth. Both sexes employed fundamentally different energy allocation strategies during peripubertal development. Some of these sex differences were gonad-dependent, while others were not. The time spent foraging while exposed to cold ambient temperature is also critical during peripubertal development, and this relationship probably determines whether or not house mice will breed continuously or seasonally in feral habitats. 2) Deer mice (Pemmyscus maniculatus) and house mice were challenged to produce litters at increasingly greater work requirements. Deer mice supported heavier litters and produced more pups at weaning than house mice, mainly because deer mice were more efficient at food use. With regard to circadian organisation, deer mice accomplished almost all of their locomotor tasks during darkness while house mice exhibited day-to-day flexibility in locomotor activity, especially during lactation. Deer mice attempted to wean five or six pups, regardless of how severe the feeding conditions; however, pups became progressively stunted as females worked harder and obtained less food. In contrast, house mice had more pups at birth than deer mice, but females killed and cannibalized offspring throughout the first 12 days of lactation. Most surviving house mouse pups thus attained similar body weights at weaning. These divergent energy allocation patterns may reflect strategies arising from opportunism (house mice) versus seasonality (deer mice).

In a population of first-generation offspring from wild-caught house mice (Mus musculus domesticus), previous evidence suggested that male fitness is more strongly affected by an increase in body weight than female fitness. This paper shows that in these mice the young are weaned at heavier weights the smaller the litter and the better the maternal body condition. These effects persisted into adulthood and were less pronounced in female young. However, contrary to expectation from conventional sex ratio theory, maternal condition and litter size had no detectable effect on sex ratios. Also, litter size did not affect sex ratios in two populations of laboratory-kept, wild-caught western (M. m. domesticus) and eastern house mice (M. m. musculus). Wild house mice, therefore, appear not to adaptively manipulate the sex ratio of offspring. It is argued that this absence of sex ratio trends might not be maladaptive, but rather that models currently used to predict sex ratio trends in rodents may not be valid.

--We studied body condition and feather growth rate in Great Tits (Parus major) in relation to dominance in two localities during late autumn and early winter. The two localities differed in elevation, ambient temperature, and arthropod availability. We supplemented the two study areas with food (husked peanuts) throughout he study period. The percentage of time tits spent at feeders was higher at E1 Ventorrillo (the locality that was colder and had lower natural food availability) and was associated with dominance only at this locality. The number of aggressive displacements per hour experienced by each individual was 150 times higher in the area with lower arthropod availability and lower temperatures. Protein reserves (measured as pectoralis muscle thickness) were higher at E1Ventorrillo and were positively and consistently related to dominance at both localities. Growth rate of induced feathers was slower at E1 Ventorrillo but was not directly related to dominance in either locality. Only dominant adult males at E1 Ventorrillo compensated for the environmental harshness at this locality by attaining a higher feather growth rate than the other sex/age classes. Feather-mass asymmetry of induced feathers during autumn was not associated with body condition, did not change between localities, and was inversely and consistently related to dominance at both localities. The covariation among variables describing bird size, access to supplemental food, body condition, feather growth rate, and asymmetry was different at the two localities. Larger, dominant Great Tits spent more time foraging at feeders, had a thicker pectoralis muscle (i.e. body condition), and grew induced feathers at a higher rate only at the locality with colder temperatures and lower food availability. Received 9 September 1997, accepted 2 February 1998. SOCIAL DOMINANCE, food availability, and environmental stress (e.g. declining temperatures and/or high snow cover) are thought to influence winter survival of small passerines through their effects on body condition and access to food (Gauthreaux 1978, Lundberg 1985, Piper and Wiley 1990). The role of these variables in food access has been studied extensively (Ekman and Askenmo 1984, Millikan et al. 1985, Theimer 1987, Enoksson 1988, Hogstad 1988, Caraco et al. 1989, Desrochers 1989). Body condition generally has been defined in a very broad sense to indicate the ability of an individual to cope with present and future physiological stress, and therefore, the ability to enhance fitness. Fat reserves are thought o play an important role as energy stores to overcome periods of food scarcity or increased energetic demands 3 E-mail: mcnc152@fresno.csic.es (Blem 1990, Bednekoff et al. 1994, Bednekoff and Houston 1994, Rogers 1995, Gosler 1996, Lilliendahl et al. 1996). However, fat reserves may have costs in terms of winter survival diminished maneuverability, and increased predation risk (e.g. Lima 1986, Witter and Cuthill 1993, Ekman and Lilliendahl 1993, Witter et al. 1994, Clark and Ekman 1995, Gosler et al. 1995, Metcalfe and Ure 1995). Therefore, fat storing may be subjected to selection pressures not directly related to body condition. The complex interaction between fat reserves and environmental conditions also is complicated by the possible inverse relationship between fat stores and dominance in winter (Ekman and Lilliendahl 1993, Witter and Swaddle 1995, Gosler 1996). Protein reserves are not viewed as short-term energy stores because they are not as easily mobilized as fat and are not maintained as special depots. Muscle proteins are used for energy

Understanding the genetic basis of environmental adaptation in natural populations is a central goal in evolutionary biology. The conditions at high elevation, particularly the low oxygen available in the ambient air, impose a significant and chronic environmental challenge to metabolically active animals with lowland ancestry. To understand the process of adaptation to these novel conditions and to assess the repeatability of evolution over short timescales, we examined the signature of selection from complete exome sequences of house mice (Mus musculus domesticus) sampled across two elevational transects in the Andes of South America. Using phylogenetic analysis, we show that house mice colonized high elevations independently in Ecuador and Bolivia. Overall, we found distinct responses to selection in each transect and largely nonoverlapping sets of candidate genes, consistent with the complex nature of traits that underlie adaptation to low oxygen availability (hypoxia) in other species. Nonetheless, we also identified a small subset of the genome that appears to be under parallel selection at the gene and SNP levels. In particular, three genes (Col22a1, Fgf14, and srGAP1) bore strong signatures of selection in both transects. Finally, we observed several patterns that were common to both transects, including an excess of derived alleles at high elevation, and a number of hypoxia-associated genes exhibiting a threshold effect, with a large allele frequency change only at the highest elevations. This threshold effect suggests that selection pressures may increase disproportionately at high elevations in mammals, consistent with observations of some high-elevation diseases in humans.

Endocrine profiles in the males of a twice-annually spawning strain of rainbow trout, Salmo gairdneri

The range used for calving and for the first month of lactation by the Rivière George Caribou Herd (RGH), which peaked at over 600 000 individuals in the mid-eighties, showed signs of overgrazing, in contrast to that used by the adjacent Rivière aux Feuilles Herd. Density of females in the tundra habitat below 600 m asl averaged 11.2 animals/km2 on the overgrazed range in 1988, in comparison with ≈0.5/km2 on the other range. Inadequate foraging conditions during the first month of lactation caused complete exhaustion of fat reserves in females on the poor range; milk production was seemingly insufficient, as calves were lighter and grew at a slower rate than calves born on the better summer range or born in captivity from dams fed ad libitum. Moreover, females on the poor range were shorter and lighter than their counterparts on the good range, illustrating that priority goes to reproduction rather than to growth under suboptimal foraging conditions. Accretion of body fat and protein in RGH females was rapid in autumn, but individuals with a calf at yield accumulated smaller fat reserves than nonreproductive adult females. Condition did not affect ovulation. However, interruption of gestation was suspected in females that were unable to accumulate enough body reserves in autumn or early winter, judging from the progressive decline in the pregnancy rate and in the autumn cow:calf ratio observed for the RGH since 1984, concomitant with the levelling off of the herd. Summer nutrition seemingly regulated the RGH through a combination of decreased fecundity and survival.

Endocrine data from wild populations provide important insight into social systems. However, obtaining samples for traditional methods involves capture and restraint of animals, and/or pain, which can influence the animal’s stress level, and thereby undesirable release of hormones. Here, we measured corticosterone, testosterone and progesterone in the hair of 482 wild-derived house mice that experienced sexual competition while living under semi-natural conditions. We tested whether sex, age, weight and indicators of sexual maturity, reproduction and social conflicts predict hormone concentrations measured in hair (sampling at endpoint). We show that body weight, sex and age significantly predict cumulative testosterone and progesterone levels, allowing the differentiation between subadults and adults in both sexes. Corticosterone was only slightly elevated in older males compared to older females and increased with the level of visible injuries or scars. Testosterone in males positively correlated with body weight, age, testes size, and sperm number. Progesterone in females significantly increased with age, body weight, and the number of embryos implanted throughout life, but not with the number of litters when controlled for age and weight. Our results highlight the biological validity of hair steroid measurements and provide important insight into reproductive competition in wild house mice.

A major goal of evolutionary genetics is to understand the genetic and molecular mechanisms underlying adaptation. Previous work has established that changes in gene regulation may contribute to adaptive evolution, but most studies have focused on mRNA abundance and only a few studies have investigated the role of post-transcriptional processing. Here, we use a combination of exome sequences and short-read RNA-Seq data from wild house mice (Mus musculus domesticus) collected along a latitudinal transect in eastern North America to identify candidate genes for local adaptation through alternative splicing. First, we identified alternatively spliced transcripts that differ in frequency between mice from the northern-most and southern-most populations in this transect. We then identified the subset of these transcripts that exhibit clinal patterns of variation among all populations in the transect. Finally, we conducted association studies to identify cis-acting splicing quantitative trait loci (cis-sQTL), and we identified cis-sQTL that overlapped with previously ascertained targets of selection from genome scans. Together, these analyses identified a small set of alternatively spliced transcripts that may underlie environmental adaptation in house mice. Many of these genes have known phenotypes associated with body size, a trait that varies clinally in these populations. We observed no overlap between these genes and genes previously identified by changes in mRNA abundance, indicating that alternative splicing and changes in mRNA abundance may provide separate molecular mechanisms of adaptation.

Impact of male presence on female sociality and stress endocrinology in wild house mice (Mus musculus domesticus)

Steroid hormones in hair and fresh wounds reveal sex specific costs of reproductive engagement and reproductive success in wild house mice (Mus musculus domesticus)

The composition of the mammalian gut microbiota can be influenced by a multitude of environmental variables such as diet and infections. Studies investigating the effect of these variables on gut microbiota composition often sample across multiple separate populations and habitat types. In this study we explore how variation in the gut microbiota of the house mouse (Mus musculus domesticus) on the Isle of May, a small island off the east coast of Scotland, is associated with environmental and biological factors. Our study focuses on the effects of environmental variables, specifically trapping location and surrounding vegetation, as well as the host variables sex, age, body weight and endoparasite infection, on the gut microbiota composition across a fine spatial scale in a freely interbreeding population. We found that differences in gut microbiota composition were significantly associated with the trapping location of the host, even across this small spatial scale. Sex of the host showed a weak association with microbiota composition. Whilst sex and location could be identified as playing an important role in the compositional variation of the gut microbiota, 75% of the variation remains unexplained. Whereas other rodent studies have found associations between gut microbiota composition and age of the host or parasite infections, the present study could not clearly establish these associations. We conclude that fine spatial scales are important when considering gut microbiota composition and investigating differences among individuals.