Demography of a population of Peromyscus leucopus

1979 ◽  
Vol 57 (2) ◽  
pp. 323-328 ◽  
Author(s):  
Richard M. Harland ◽  
Peter J. Blancher ◽  
John S. Millar
Keyword(s):  
Peromyscus Leucopus ◽  
Adult Males ◽  
Adult Mice ◽  
Adult Females ◽  
Young Of The Year ◽  
Juvenile Males ◽  
Initial Capture

Livetrapping and removal trapping were used to monitor a population of Peromyscus leucopus. Breeding adult arid young of the year females averaged 2.0 and 1.1 litters per year, respectively. Nest mortality was 12–31%, while 58% of the juveniles disappeared within 2 weeks after weaning. The rate of disappearance of juvenile males (77%) was higher than that of juvenile females (44%); the greater loss of males was attributed to mortality. Loss of subadult and adult mice within 2 weeks after initial capture averaged 45 and 51%, respectively, and did not differ between the sexes. However, more males than females were recorded as entering the trapping grids, indicating that males tend to explore new areas more than females. Among resident mice, adult males had the highest rate of disappearance (0.31/week) while adult females had the lowest (0.05/week).

scholarly journals Microhabitat preferences of the freshwater prawn Macrobrachium jelskii (Decapoda: Palaemonidae)

2019 ◽  
Vol 109 ◽  
Author(s):  
Jersei N. Silva ◽  
Guilherme de Oliveira ◽  
Sérgio S. da Rocha
Keyword(s):  
Sex Ratio ◽  
Water Reservoir ◽  
Habitat Choice ◽  
Freshwater Prawn ◽  
Adult Males ◽  
Adult Females ◽  
Males And Females ◽  
Microhabitat Preferences ◽  
Lower Depth ◽  
Juvenile Males

ABSTRACT We analyzed the microhabitat preferences of Macrobrachium jelskii (Miers, 1877) males and females inhabiting an urban water reservoir in Cruz das Almas, Bahia, Brazil. Prawns were collected monthly, from March 2015 to February 2016, in three microhabitats, using a sieve. Each microhabitat was dominated by one macrophyte species: Eleocharis sp. (M1), Cabomba sp. (M2), and Nymphaea sp. (M3). The prawns were measured (carapace length), and categorized as juvenile males, adult males, juvenile females, non-ovigerous adult females and ovigerous adult females. An analysis of variance (ANOVA) was used to compare the number and size of individuals. The sex ratio and frequency of ovigerous females in the three microhabitats were also calculated. The sex ratio was biased towards females in M1 and did not deviate from 1:1 in M2 and M3. When prawns were separated into five categories we observed that non-ovigerous adult females were more abundant in M1, while adult males were the most abundant demographic category in M2 and M3. Juveniles of both sexes and ovigerous females showed no microhabitat preference, although M1 and M2 appeared to be more suitable for the latter. Adult females were the largest individuals in all microhabitats. Food availability, lower depth and lower predation pressure in M1 are the main factors that make M1 more suitable for M. jelskii, particularly non-ovigerous adult females and larger adult males. Intraspecific competition for shelter in M1 might also occur and adult females win this competition due to their larger body size. Therefore, adult males are found in higher abundance in M2 and M3 and the juvenile of both sexes spread evenly across all microhabitats. Our results help to understand the ecological role and the niche used by M. jelskii. Future studies on the habitat choice and predation under laboratory conditions should help to understand the behavior of this species.

Host demographic predicts ectoparasite dynamics for a colonial host during pre-hibernation mating

Parasitology ◽  
2015 ◽  
Vol 142 (10) ◽  
pp. 1260-1269 ◽  
Author(s):  
QUINN M. R. WEBBER ◽  
ZENON J. CZENZE ◽  
CRAIG K. R. WILLIS
Keyword(s):  
Seasonal Changes ◽  
Myotis Lucifugus ◽  
Adult Males ◽  
Male And Female ◽  
Adult Females ◽  
Future Reproduction ◽  
Energetic Constraints ◽  
Young Of The Year ◽  
Parasite Exposure ◽  
Parasite Dynamics

SUMMARYParasite dynamics can be mediated by host behaviours such as sociality, and seasonal changes in aggregation may influence risk of parasite exposure. We used little brown bats (Myotis lucifugus) captured during the autumn mating/swarming period to test the hypothesis that seasonal and demographic-based variation in sociality affect ectoparasitism. We predicted that ectoparasitism would: (1) be higher for adult females and young of the year (YOY) than adult males because of female coloniality; (2) increase for adult males throughout swarming because of increasing contact with females; (3) decrease for adult females and YOY throughout swarming because of reduced coloniality and transmission of individual ectoparasites to males; (4) be similar for male and female YOY because vertical transmission from adult females should be similar. Ectoparasitism was lowest for adult males and increased for males during swarming, but some effects of demographic were unexpected. Contrary to our prediction, ectoparasitism increased for adult females throughout swarming and YOY males also hosted fewer ectoparasites compared with adult and YOY females. Interestingly, females in the best body condition had the highest parasite loads. Our results suggest that host energetic constraints associated with future reproduction affect pre-hibernation parasite dynamics in bats.

A live-trapping of Australian brush-tailed possums, Trichosurus vulpecula (Kerr), in the Orongorongo Valley, Wellington, New Zealand

1973 ◽  
Vol 21 (1) ◽  
pp. 75 ◽  
Author(s):  
MC Crawley
Keyword(s):  
New Zealand ◽  
Home Ranges ◽  
Trichosurus Vulpecula ◽  
Adult Males ◽  
Adult Females ◽  
Capture Site ◽  
Live Trapping ◽  
Indigenous Forest ◽  
Autumn And Winter ◽  
Initial Capture

A live-trapping study of a population of Australian brush-tailed possums, Trichosurus vulpecula (Kerr), in indigenous forest of the Orongorongo Valley, Wellington, N.Z., was carried out from March 1966 to November 1968. In 14 ha of podocarp-mixed broadleaf forest, 301 possums (150; 151) were individually marked and repeatedly captured in a series of trapping periods. The population comprised residents and transients of both sexes with sub- adults forming the bulk of the latter, particularly in spring. The estimated population density varied from 10.6 per ha in November 1966 to 6.4 per ha in August 1968. There was one well-defined season of births each autumn and a few births in winter. On average, 73% (67-92%) of mature females produced pouch young each year. Females resident throughout the study had the highest breeding success (79%). Achievement of sexual maturity was delayed; no females bred until they were 2 yr old, and some not even at 3 yr. Losses occurred at all stages of the life history and averaged 62% between the pouch young and subadult stages; thus only 28 subadults per 100 females were recruited. Adult losses averaged 26% per annum. Adult males (mean weight 2.46 kg) were heavier than adult females (2.33 kg). Weights varied seasonally, with males heaviest in summer and lightest in spring, and females heaviest in winter and lightest in summer. Possums of both sexes were rather sedentary, with males (95% of captures within 115 m of the initial capture site) being less so than females (95 % of captures within 90 m of the initial capture site). More than half of the captures (55% for males, 62% for females) were made within 30 m of the site of initial capture. Males moved farther in autumn and summer than in other seasons, while females did so in autumn and winter. Subadults were apparently more sedentary than adults. Home ranges of adult males (mean 0.81 ha) were significantly larger than those of adult females (0.46 ha). Considerable overlapping of the ranges of both sexes occurred, and territorial behaviour was not conspicuous. The dispersion of the population remained the same throughout the study although the component individuals changed. The results of the present study are compared with those of similar studies in New Zealand and Australia, and the dynamics of the Orongorongo Valley possum population are discussed with reference to variable rates of reproduction and mortality.

Predicted susceptability of Dasyurus geoffroii to canid baiting programmes: variation due to sex, season and bait type

1993 ◽  
Vol 20 (3) ◽  
pp. 287 ◽  
Author(s):  
TR Soderquist ◽  
M Serena
Keyword(s):  
Body Weight ◽  
Adult Males ◽  
Laboratory Assessment ◽  
Fresh Meat ◽  
Adult Females ◽  
Original Weight ◽  
Seasonal Factors ◽  
Lactating Females ◽  
Juvenile Males

A laboratory assessment of the susceptibility of Dasyurus geoffroii to baits used to control foxes and dingoes was conducted using five types of non-poisoned baits: polony, fresh meat, meat dried by 50% and 70% of the original weight, and compressed beef crackle. Trials were designed to simulate the initial encounter of a bait by hungry wild juveniles and adults of both sexes, including lactating females. In overnight trials, juveniles and lactating females ate significantly more fresh meat per body weight (mean consumption: 23.7% for juvenile males, 21.5% for juvenile females, 23.1% for lactating females) than non-lactating adult females and adult males (combined mean, 18.3%). Maximum overnight bait consumption was 43% of body weight. These values greatly exceed those previously reported for other species of Dasyurus. Moist baits were eaten more rapidly and in larger amounts than drier baits. Seasonal factors lead to the prediction that the period when canid baiting can be conducted with the least danger to Dasyurus geoffroii is January-March.

Dispersion of adult male Peromyscus leucopus in relation to female reproductive status

1989 ◽  
Vol 67 (4) ◽  
pp. 1047-1052 ◽  
Author(s):  
Xuhua Xia ◽  
John S. Millar
Keyword(s):  
Mating System ◽  
Adult Male ◽  
Early Pregnancy ◽  
Peromyscus Leucopus ◽  
Natural Populations ◽  
Negative Relationship ◽  
Late Pregnancy ◽  
Adult Males ◽  
Adult Females ◽  
Female Reproductive Status

We studied dispersion of adult male Peromyscus leucopus in relation to the stage of pregnancy of adult females in natural populations monitored with Longworth live traps. Because postpartum mating is common in P. leucopus and days to parturition measures how far a female is from her next mating, we predicted that a female in early pregnancy (many days to parturition) would have fewer adult males in her neighbourhood than a female in late pregnancy (few days to parturition). Number of adult males caught within 30 m of each adult female was recorded and number of days to parturition for each female was obtained by bringing females back to the laboratory and allowing them to give birth. A negative relationship was found between number of adult males in a female's neighbourhood and days to parturition of the female (r = −0.419, p < 0.01), with the latter accounting for 8.8% of the variance in the former. These results support the hypothesis of a promiscuous mating system in P. leucopus.

Morphological variation in deer mice in relation to sex and habitat

1987 ◽  
Vol 65 (3) ◽  
pp. 527-533 ◽  
Author(s):  
Xuhua Xia ◽  
John S. Millar
Keyword(s):  
Body Length ◽  
Tail Length ◽  
Deer Mice ◽  
Body Measurements ◽  
Adult Males ◽  
Adult Females ◽  
Foot Length ◽  
Hind Foot ◽  
Similar Body ◽  
Juvenile Males

Peromyscus maniculatus borealis were collected in two habitats with contrasting physiognomic features in the Kananaskis Valley, Alberta, in the summer of 1983. We tested for differences between sexes and habitats using 4 body measurements (body length, tail length, hind foot length, and ear length) and 10 cranial (including mandibular) measurements of 222 and 192 adult P. m. borealis, respectively. Body measurements of 132 juveniles and five cranial (including mandibular) measurements from 124 juvenile skulls were analysed similarly. When differences in body length were controlled, adult males had significantly longer hind feet than adult females. The mandible was also significantly longer in adult males than in adult females. We interpreted the longer hind foot length in adult males as an adaptation to provide greater mobility, and the differences in mandibular morphology as a consequence of differential habitat use between the two sexes. No significant differences were found between juvenile males and females. Sexual dimorphism appeared to be age dependent rather than size dependent when adults and juveniles of similar body size were analysed.

Population dynamics of a thelastomatid nematode of cockroaches

Parasitology ◽  
1988 ◽  
Vol 96 (2) ◽  
pp. 353-368 ◽  
Author(s):  
S. Zervos
Keyword(s):  
Adult Female ◽  
Egg Production ◽  
Goodness Of Fit ◽  
Host Size ◽  
Infection Prevalence ◽  
Adult Males ◽  
Chi Square ◽  
Faecal Pellets ◽  
Adult Females ◽  
Juvenile Males

SummaryBlatticola monandros Zervos lives in the hind gut of the endemic New Zealand cockroach Parellipsidion pachycercum Johns. A field survey showed that infection prevalence was high (54 %) in small nymphs and increased further with cockroach size to a maximum (92 %) in penultimate nymphs. Variance to mean ratios and the Chi-square test for goodness of fit of a Poisson distribution provide strong evidence that the distribution of the nematode was not clumped (over-dispersed) or Poisson (random) but under-dispersed in most host size classes. The modal infrapopulation type consisted of 1 adult male and 1 adult female. Other infrapopulations were transitional to this type. Monogamous infrapopulations increased in prevalence with increased host size. Juvenile males were uncommon and probably develop faster into adults than juvenile females. Infrapopulations with 2 juvenile males were very rare and no cockroach contained 2 adult males, although some contained 2 adult females. Seasonal variations in prevalence and infrapopulation structure were slight over a 3 year period, except during one unusually dry summer. During the drought, prevalence of monogamous infrapopulations and of transitional infrapopulations were lowest, while prevalence of single-worm and single-sex infrapopulations were greatest. It is evident that competition between females reduces fecundity. When only 1 adult female nematode is present in an adult cockroach, more eggs are produced than the total produced if 2 adult females are present. Eggs were produced cyclically with short periods of high egg production interspersed with several days of very low or no egg production. Most eggs produced on any one day were attached to the outer surface of only 1 of the up-to-6 faecal pellets produced by the host/day. Mechanisms which may regulate infrapopulations and control reproductive competition and cyclical egg production are discussed. It is suggested that B. monandros regulates its own infrapopulation.

scholarly journals Chemical characterisation of potential pheromones from the shoulder gland of the Northern yellow-shouldered-bat, Sturnira parvidens (Phyllostomidae: Stenodermatinae)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7734
Author(s):  
Chris G. Faulkes ◽  
J. Stephen Elmore ◽  
David A. Baines ◽  
Brock Fenton ◽  
Nancy B. Simmons ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Solid Phase ◽  
Species Recognition ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Components ◽  
Volatile Components ◽  
Adult Males ◽  
Mature Adult ◽  
Adult Females ◽  
Juvenile Males

Bats of the genus Sturnira (Family Phyllostomidae) are characterised by shoulder glands that are more developed in reproductively mature adult males. The glands produce a waxy secretion that accumulates on the fur around the gland, dyeing the fur a dark colour and giving off a pungent odour. These shoulder glands are thought to play a role in their reproductive behaviour. Using gas chromatography–mass spectrometry, we analysed solvent extracts of fur surrounding the shoulder gland in the northern-shouldered bat, Sturnira parvidens to (i) characterise the chemical composition of shoulder gland secretions for the first time, and (ii) look for differences in chemical composition among and between adult males, sub-adult/juvenile males and adult females. Fur solvent extracts were analysed as liquids and also further extracted using headspace solid-phase microextraction to identify volatile components in the odour itself. Odour fingerprint analysis using non-metric multidimensional scaling plots and multivariate analysis revealed clear and significant differences (P < 0.001) between adult males vs both juvenile males and adult females. The chemical components of the shoulder gland secretion included terpenes and phenolics, together with alcohols and esters, most likely derived from the frugivorous diet of the bat. Many of the compounds identified were found exclusively or in elevated quantities among adult (reproductive) males compared with adult females and non-reproductive (juvenile) males. This strongly suggests a specific role in male–female attraction although a function in male–male competition and/or species recognition is also possible.

scholarly journals Comparison of the population biology of Epialtus bituberculatus from two rocky shores with distinct hydrodynamic patterns

2012 ◽  
Vol 93 (3) ◽  
pp. 693-702 ◽  
Author(s):  
Samara de Paiva Barros-Alves ◽  
Douglas Fernandes Rodrigues Alves ◽  
Valter José Cobo
Keyword(s):  
Normal Distribution ◽  
Population Biology ◽  
Carapace Width ◽  
Wave Exposure ◽  
Rocky Shores ◽  
Adult Males ◽  
Adult Females ◽  
Size At Sexual Maturity ◽  
Sargassum Cymosum ◽  
Juvenile Males

The population biology of Epialtus bituberculatus was compared between two different intertidal localities with differing levels of wave exposure. Sampling was conducted monthly between January and December, 2001 on seaweed banks of Sargassum cymosum in the intertidal zone of the rocky shores Grande (GR) (23°23′S–45°03′W) and Domingas Dias (DD) (23°29′S–45°08′W). Four hundred and twenty-eight crabs were captured at the GR site: 111 juvenile males, 106 adult males, 57 juvenile females, 17 adult females and 137 ovigerous females; while 455 specimens were obtained at the DD site: 76 juvenile males, 113 adult males, 37 juvenile females, 40 adult females and 189 ovigerous females. The population from GR showed a non-normal distribution and from DD a normal distribution. The sex-ratio (female/male) was 1:0.97 at GR (χ2 = 0.77, P = 0.084), whereas it was 1:1.41 at DD (χ2 = 13.03, P < 0.001). The largest individuals occurred at DD (U = 78249.0, P < 0.001). The estimated size at sexual maturity was 6.3 and 5.0 mm carapace width (CW) for males, and 5.4 and 5.2 mm CW for females, from GR and DD, respectively. The observed differences in E. bituberculatus between the studied localities might be explained by the different degrees of wave exposure between sites. However, other factors that might also explain the observed differences (e.g. temperature, salinity and food availability) cannot be discarded as relevant in influencing the population structure between sites herein studied.

scholarly journals Experimenting usage of Camera-traps for Population Dynamics Study of the Asian Elephant Elephas Maximus in Southern India

2007 ◽  
Vol 6 (1) ◽  
pp. 81-95
Author(s):  
Surendra Varma ◽  
André Pittet ◽  
H. S. Jamadagni
Keyword(s):  
Population Dynamics ◽  
Cost Effective ◽  
Camera Trap ◽  
Camera Traps ◽  
Asian Elephant ◽  
Adult Males ◽  
Adult Females ◽  
Juvenile Males ◽  
Long Term Studies

To evaluate the application of camera-trap technology in population dynamics studies of the Asian elephant, indigenously designed, cost-effective, infrared-triggered camera-traps were used.Usability of pictures was defined based on quality, clarity and positioning of the subject.With 99 pictures of 330 elephants, 20 sequences were obtained and 44 distinct individuals were identified.It was found that 38.6% were adult females, 4.5% adult males, 13.6% sub-adult females, 6.8% sub-adult males, 20.4% juvenile females,while juvenile males were poorly represented(2%), and 13.6% were calves.These results were surprising identical with those of other systematic and long-term studies.

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