Wild-caught Mice Research Articles

Comparative arboreal behaviors of wild-caught and captive-born deer mice, Peromyscus maniculatus Wagner, from Isle Haute and mainland Nova Scotia

Locomotor, climbing, and nesting behaviors of wild-caught and captive-born deer mice (Peromyscus maniculatus Wagner) from mainland Nova Scotia and from an isolated predator- and competitor-free island were compared in a laboratory observation room. Locomotor activity did not differ consistently between populations, but wall-seeking was significantly greater in mainland mice. When exposed to an artificial tree, insular mice made more climbs than mainland mice, but mainland mice climbed for longer periods. Climbing behavior differed little between males and females in any group. In a choice experiment, mainland mice selected elevated nest sites significantly more often than ground-level nest sites, while insular mice exhibited no preference.

Culturing Borrelia burgdorferi from spleen and kidney tissues of wild-caught white-footed mice, Peromyscus leucopus

Borrelia burgdorferi was isolated most frequently from tissue of spleen (n = 13) and kidney (n = 10) and less often from blood (n = 5) of wild-caught Peromyscus leucopus. Prevalence of infection tended to be highest at sites where Lyme disease was most common (e.g., 5 of 6 mice were positive in East Haddam, Connecticut). Spirochetes were not isolated in Danbury or New Hartford, areas where this malady is rare. However, in Fairfield, where the disease is also uncommon, 4 of 9 mice were infected. Larval and nymphal I. dammini, containing borreliae, parasitized P. leucopus at all sites where B. burgdorferi was cultured from mice. Borreliae were also detected in D. variabilis feeding on hosts at two of the sites. P. leucopus appears to be an excellent animal to identify focal areas of B. burgdorferi.

Environmental monitoring for genotoxicity: in vivo sister chromatid exchange in the house mouse (Mus musculus).

Sister chromatid exchange (SCE) values were determined in bone marrow cells isolated from mouse (Mus musculus) femurs after injections of 5-bromo-2'-deoxyuridine (BrdU) and 5-fluorodeoxyuridine (FrdU). Male mice of C3H/J, C57BL/6J, and DBA/2 strains maintained in the laboratory gave mean SCE values of 3.42 +/- 0.07, 3.62 +/- 0.08, and 3.97 +/- 0.13, respectively. Males obtained from natural populations of southwestern Ontario had a higher mean SCE value (6.02 +/- 0.16), as did inbred males maintained in outdoor enclosures for at least 3 weeks (5.07 +/- 0.22). Wild mice housed in the laboratory for 9 months or longer had SCE values similar to laboratory bred mice (3.46 +/- 0.05). The SCE values in wild-caught mice were inversely proportional (r = -0.49) to the distance between the sites where these animals were collected and the nearest major industrial center. Based on these results, SCE analysis in mice is proposed as a possible first-line monitoring procedure for the detection of general changes in environmental genotoxicity.

Distribution of feeding and drinking by groups of captive house mice

Locations of feeding and drinking by social groups of commensal house mice (Mus domesticus), were monitored daily for 30 to 90 minutes for 1 to 3 months. Eighteen foodcups and 18 water bottles were distributed in a 2.4 × 5.1 m population cage. Social groups concentrated their feeding at a few of the foodcups which varied among replicates but drank from most of the water bottles. A mouse feeding at the same sites that are used by others implies that mice use social cues in choosing feeding sites. This is the first documentation of socially influenced choice of feeding sites by wild-caught commensal house mice. A mouse drinking at several sites without concentrating on any sites implies social cues are less important in choosing drinking sites.

Female discrimination of male odors correlated with male genotype at the T locus: a response to T-locus or H-2-locus variability?

Female house mice (Mus musculus), derived from several populations of wild-caught mice, were tested for their ability to discriminate between males whose genotype at the T locus was +/+ and those whose genotype was +/t, using odor cues alone. Females spent more time near the odors or +/+ males than near the odors of +/t males. This preference was independent of the T-locus genotype of the female and the particular type of t allele carried by either the male or the female. A female's preference, however, did appear to be related to the genotype of her parents. Females with one +/t parent were more likely to prefer +/t males than were females whose parents were both +/+. In a second experiment 18 females were tested with odors from soiled bedding of recombinant males whose genotype varied at the T locus but who were similar at the H-2 locus. As a control, these 18 females were also tested with bedding of wild-derived +/+ and +/tw semilethal males. Females tested with recombinant males preferred odors of males not carrying lethal t alleles over those of males carrying two lethal t alleles, indicating that T-locus variability, not H-2-locus variability, is responsible for odor differences between +/+ and +/t males. Female responses to odors of recombinanat males did not differ from those to odors of +/+ and +/tw semilethal males. Responses of mice to odor differences associated with T-locus variability may have evolved independently of responses to odor variability associated with the H-2 locus.

Incidence of inherited enzyme activity variants in feral mouse populations.

We have screened 173 wild caught mice (Mus musculus) from multiple sites in Europe for variation in the activity of 14 enzymes and found 8 different mutants with low enzyme activity; an incidence of 3.69/1000. This compares with the incidence of 3.26/1000 found for low enzyme activity variants in man (Mohrenweiser, 1981).

Physiological variation of mouse haemoglobins.

Polymorphism at Hbb (haemoglobin beta-chain) is widespread in natural populations of the house mouse, Mus musculus, and appears to be maintained by natural selection. This report is an attempt to correlate genotypic fluctuations at Hbb with a most important physiological attribute of haemoglobin, its oxygen carrying capacity. Oxygen affinity has been studied and P50 values have been measured in 12 inbred strains as well as wild-caught mice from Skokholm island. The mean P50 of each inbred strain is a constant characteristic, although there is high within-strain variation and the oxygen affinity of the blood of an individual can fluctuate considerably from week to week. The causes of this variation remain obscure but neither within-strain nor between-strain differences are correlated with known modulators of oxygen binding. In general, the blood of mice of inbred strains as well as wild-caught mice that are homozygous for Hbbd tends to have a higher oxygen affinity than that from comparable animals homozygous for Hbbs, but it seems likely that the oxygen dissociation properties of haemoglobin are not the only ones important in determining differential survival of a particular Hbb type under varying environmental stress.

Genetic variation for morphological and behavioral traits in wild house mice.

Twenty-two wild-caught male house mice were test crossed to females from the CBA inbred line, and their progeny were measured for 7 morphological and 10 behavioral traits. Significant genetic variance among the wild-caught sires was detected for snout-vent length, tail length, footpad bristle number, and fertility, while significant effects of the maternal CBA environment were detected for tail length, hindfoot length, and open-field defecation. On average over all 7 morphological traits, 62% of the total variance among the progeny was estimated to be due to genetic variation, while 15% was attributed to differences in maternal environment. Over the 10 behavioral traits, the corresponding figures were 22% due to genetic variation and 24% due to the maternal environment.

Insect disturbance stridulation: Its Defensive role

1. Many insects stridulate when they are handled or attacked. It has been suggested that this disturbance stridulation acts to deter predators. This hypothesis was investigated in a series of experiments. Predators were given insects which had been silenced by disruption of their sound-producing mechanism or else had been sham operated but retained their normal ability to stridulate. 2. Three types of insects (mutillid wasps, Dasymutilla spp.; water scavenger beetles, Tropisternus spp.; and round sand beetles, Omophron labiatus) were given to wolf spiders (Lycosa ceratiola and Geolycosa ornatipes) at night in the field under natural conditions. When attacking silenced insects, spiders displayed greater persistence than when attacking phonic insects (Table 1). In addition, mortality was greater among silenced insects. 3. Spiders (L. ceratiola) were also given an artificial ‘insect’—a vibrating probe whose vibration mimicked that of the cuticle of a stridulating insect. As with real insects, spiders persisted longer in their attack on the probe when it was silent than when it was ‘stridulating”. 4. Female mutillid wasps were given to wild-caught mice (Peromyscus floridanus) in the laboratory. Unsilenced mutillids survived the encounter more often than their silenced counterparts. In another experiment, the stings of mutillid wasps were removed before testing. Mice killed nearly all these ‘unprotected’ mutillids. However, it took mice significantly longer to attack unsilenced mutillids and longer to kill them after initiating the assault (Table 2). 5. These results support the view that insect disturbance stridulation deters predators. Two modes of action by which these sounds may have their effect are discussed: they may serve to startle the attacker or they may alert it to the potential harmfulness of the insect and as such may qualify as an example of acoustic aposematism.

Effects of climate and social pressure on the adrenal response of lemmings, voles and mice.

ABSTRACT In vitro incubations of adrenals from wild-caught lemmings, voles and mice reveal secretory activity which reflects the adrenal status of populations. Secretory rates were higher in animals from natural »high density« and laboratory »crowded« groups. All species examined showed higher secretory rates in the winter than in the summer.

Prenatal Mortality in Wild-Caught House Mice

Prenatal Mortality in Wild-Caught House Mice