Dimorphisme sexuel et régime alimentaire de l'hermine dans un agrosystème du Québec

1984 ◽  
Vol 62 (4) ◽  
pp. 594-600 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron ◽  
Yves Plante

Variations in the diet of the ermin (Mustela erminea) were studied from 1978 to 1980 in relation to the relative availability of meadow voles (Microtus pennsylvanicus), the dominant mammal of Southern Quebec agrosystems. The analysis of 328 ermine scat samples showed that the vole does constitute the main prey item, but that the masked shrew (Sorex cinereus), the short-tailed shrew (Blarina brevicauda), and various birds are also important food components. Male ermins have more flexible feeding habits than females, who eat mostly meadow voles whatever their relative abundance. Both males and females fail to make full use of the shrews and avoid prey that weigh more than 50 g. Overlap of their realized alimentary niches is thus considerable except when small mammals are scarce. In that case, males and females use different feeding strategies; however, the hypothesis suggested by J. H. Brown and R. C. Lasiewsky (1972. Ecology, 53: 939–943) does not seem to be confirmed. The evolution of size dimorphism in this small mustelid is discussed; our results confirm the intra-sexual selection hypothesis proposed independantly by S. Erlinge (1979. Oikos, 33: 233–245) and P. J. Moors (1980. Oikos, 34: 147–158).[Journal translation]

1986 ◽  
Vol 64 (9) ◽  
pp. 1973-1980 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron

Certain aspects of prey selection were studied in ermines (Mustela erminea) kept in an enclosed arena that simulated a temporary meadow. Four males and eight females were involved in the 12-h experiments. Four types of prey were used: (i) meadow voles (Microtus pennsylvanicus), (ii) deer mice (Peromyscus maniculatus), (iii) short-tailed shrews (Blarina brevicauda), and (iv) young albino rats (Rattus norvegicus). Males were more efficient at catching prey than females, both in number of individuals and number of species captured. Meadow voles and rats were the prey captured most regularly and rapidly by both males and females. Males were more efficient at catching deer mice, but shrews were rarely captured. There was a great similarity in the performance of the four males, but considerable variation was observed among the females. No food preference could be detected in these experiments. The results are discussed in relation to food preferences observed during studies of ermines in a natural environment.[Journal translation]


1976 ◽  
Vol 54 (9) ◽  
pp. 1565-1570 ◽  
Author(s):  
Jean-Marie Bergeron

One hundred and ninety-five meadow voles, Microtus pennsylvanicus (Ord.) were captured by means of 485 traps installed each month during the summer of 1974 in four types of culture. The analysis of minerals in their diet indicates low variation in potassium levels, whereas nitrogen, calcium, phosphorus, and magnesium levels appear to be much more environment-dependent. There are a few differences between the diets of males and females. Stomach contents of captured voles do not vary significantly from one type of culture to another, but the physiological reproductive condition of the animals accounts for significant differences in stomach contents.[Journal translation]


2006 ◽  
Vol 18 (7) ◽  
pp. 751 ◽  
Author(s):  
Javier delBarco-Trillo ◽  
Michael H. Ferkin

In many species of small mammals, females undergo post-partum oestrus soon after delivering a litter, becoming pregnant while suckling the previous litter. Females raising two concurrent litters need to allocate many more resources to reproduction than females raising only one litter. Consequently, there may be differences between litters raised concurrently or singly. We investigated this issue in the meadow vole, Microtus pennsylvanicus, a species in which most females in the wild reproduce during post-partum oestrus. Specifically, we tested the hypothesis that the development of pups in two concurrent litters differs from that of pups in a single litter. To test this hypothesis, we measured the following variables for concurrent and singly reared litters: gestation length; litter size; sex ratio; bodyweight of males and females at different ages; total litter weight at weaning; growth rates; and intra-litter variation in body mass. Except for bodyweight of males at 60 days of age, which was higher in the first of the concurrent litters, none of the variables differed among the litters. These results indicate that females are able to adjust to differing loads of maternal care to provide equivalent resources to concurrent litters and singly reared litters.


1982 ◽  
Vol 60 (11) ◽  
pp. 2787-2797 ◽  
Author(s):  
John O. Whitaker Jr ◽  
Thomas W. French

Ectoparasites and other associates were examined from seven species of insectivores and nine species of rodents from Mount Carleton Provincial Park, New Brunswick. The most abundant forms found were (at least 2.0 per host individual) the following: Orycteroxenus soricis and Amorphacarus hengererorum on Sorex cinereus and on Sorex (Microsorex) hoyi; A. hengererorum and O. soricis on Sorex fumeus; O. soricis, Miyatrombicula esoensis, and Ixodes angustus on Sorex gaspensis; O. soricis, I. angustus, Pygmephorus horridus, and Protomyobia americana on Blarina brevicauda; M. esoensis, Protomyobia claparedei, and Glycyphagus hypudaei on Sorex palustris; Orycteroxenus canadensis, O. soricis, P. horridus, G. hypudaei, Ctenophthalmus pseudagyrtes, and Haemogamasus ambulans on Condylura cristata. More abundant ectoparasites of the rodents were as follows: G. hypudaei, Listrophorus mexicanus, M. esoensis, Neotrombicula harperi, and Radfordia lemnina on Clethrionomys gapperi; G. hypudaei, L. mexicanus, M. esoensis, N. harperi, and Laelaps kochi on Microtus chrotorrhinus; L. mexicanus, G. hypudaei, Radfordia hylandi, Laelaps alaskensis, M. esoensis, Polyplax alaskensis, L. kochi, N. harperi, and Myocoptes j. japonensis on Microtus pennsylvanicus; Listrophorus synaptomys, Hoplopleura acanthopus, L. alaskensis, G. hypudaei, M. esoensis, I. angustus, R. hylandi, and N. harperi on Synaptomys cooperi; all of these except the last one on Synaptomys borealis; M. esoensis on Peromyscus maniculatus; Dermacarus newyorkensis on Zapus hudsonius; D. newyorkensis, N. harperi, Radfordia ewingi, and G. hypudaei on Napaeozapus insignis; Dermacarus hylandi, N. harperi, Megabothris acerbus, and M. esoensis on Tamias striatus.


1979 ◽  
Vol 57 (3) ◽  
pp. 504-520 ◽  
Author(s):  
D. A. Simms

A livetrapping program, augmented by enclosure experiments, was undertaken to study resource utilization by ermine (Mustela erminea) and long-tailed weasels (M. frenata) in southern Ontario. Data on food habits, habitat preferences, foraging strategies, and competitive interactions were collected. Based on this information, a theory was formulated to explain the distribution or North American weasels. Ermine fed primarily on meadow voles (Microtus pennsylvanicus) and had body diameters closely approximating those of meadow voles, enabling them to readily exploit these items in subnivean and subterranean environments. Long-tailed weasels were larger and their feeding habits were more general. Dietary overlap between the two species in areas of sympatry was 57.5%. Regarding habitat preferences, ermine selected successional communities, whereas long-tailed weasels showed no preferences. Overlap in areas of sympatry was 76.9%.Long-tailed weasels appear to be limited in their northward distribution by snow cover which restricts the size of foraging spaces, thereby conferring an advantage to the smaller weasels. Conversely, the southward distributions of ermine and least weasels (M. nivalis) appear to be limited by interference interactions with long-tailed weasels. Where ermine and least weasels are sympatric, size differences and general distributions suggest that they hunt different prey in different habitats.


1996 ◽  
Vol 199 (1) ◽  
pp. 195-200 ◽  
Author(s):  
L A Galea ◽  
M Kavaliers ◽  
K P Ossenkopp

A number of studies examining developmental, neural and hormonal aspects of sexually dimorphic spatial learning (Morris water-maze) in meadow voles (Microtus pennsylvanicus) and deer mice (Peromyscus maniculatus) are described. We found that, in adult deer mice, female spatial performance decreased during the breeding season relative to the non-breeding season, whereas the reverse pattern was observed in male performance. There was a sex difference favouring males in spatial learning during the breeding season, but not during the non-breeding season. In adult meadow voles, females with low levels of oestradiol and males performed better in the water-maze than females with high levels of oestradiol. Postweaning voles (20 and 25 days after birth) acquired the water-maze task more quickly than preweaning voles (day 10). No sex difference in water-maze performance was evident at any of these juvenile ages. When these same voles were tested again as adults to investigate retention and re-acquisition of the water-maze, both males and females from male-biased litters re-acquired the task better than males and females from female-biased litters. Together, the results of these studies indicate that sexually dimorphic spatial ability is dependent on the organization (in utero) and activational effects of gonadal hormones. These studies provide the first demonstration of the influence of natural changes in reproductive status on spatial learning of deer mice and meadow voles. The results also demonstrate that spatial performance of males and females is differentially affected by changes in reproductive status and that group differences in the laboratory are associated with group differences in space utilization in the wild. These findings help to clarify previous apparently contradictory findings about sex differences in spatial ability.


1964 ◽  
Vol 42 (2) ◽  
pp. 259-279 ◽  
Author(s):  
Charles H. Buckner

The metabolic rates of Sorex cinereus, Sorex arcticus, Microsorex hoyi, and Blarina brevicauda were calculated from oxygen consumption, carbon dioxide production, and urinary nitrogen excretion and found to be 6.1, 6.9, 67, and 9.7 Calories per animal per day respectively. The resting rate of oxygen consumption was lower for S. cinereus than values reported by previous authors and was probably close to the basal level. Respiratory quotients were higher than expected for carnivorous animals, averaging 0.83 for all species. Protein catabolism accounted for about half the daily caloric output. Metabolic rate increased with increasing population densities.The minimum numbers of larch sawfly eonymphs required to support the daily metabolic requirements, including fecal wastage, for S. cinereus, S. arcticus, M. hoyi, and B. brevicauda were 87, 123, 98, and 150 respectively. Because of digestive inefficiency and wasteful feeding habits the approximate numbers of eonymphs destroyed daily could be as high as 663, 570, 711, and 150, and if hoarding is considered, 833, 790, 891, and 410 respectively could be taken. Excepting B. brevicauda, the larch sawfly is a preferred food of the group and, when available in abundance, comprises over 70% of the diet. It was estimated that shrews have the capacity to consume numbers of cocoons in excess of naturally occurring populations, but the likelihood of complete destruction of populations is remote. Of the species studied, S. cinereus appeared to be the most likely to provide effective control of larch sawfly populations.


1979 ◽  
Vol 57 (10) ◽  
pp. 2028-2032 ◽  
Author(s):  
Jean-Marie Bergeron ◽  
Jacques Juillet

Stomach content analyses performed on 272 meadow voles (Microtus pennsylvanicus) revealed that the animal feeds on 35 of the 45 species of plant present in its habitat. Timothy is the most abundant and the most common plant in the vole's diet. The abundance of the plants sampled in the habitat is positively correlated with the abundance of the plants found in the stomach contents. However, some species, like meadow grass (Poa spp.), aredefinitely preferred by the voles since they appear more frequently in the stomach contents than in the habitat. Some feeding habits are also sex dependent.[Translated by the journal]


Author(s):  
M. Carrassón ◽  
J. Matallanas

The feeding habits of Polyacanthonotus rissoanus, the sixth most abundant species below 1000 m on the deep slope of the Catalan Sea (western Mediterranean), were studied in the Mediterranean Sea. Samples were obtained at depths between 1000 and 2250 m. Diet was analysed for two seasons (summer and autumn) and three different bathymetric strata. The most important food items found were small epibenthic and suprabenthic crustaceans and polychaetes, and occasionally other groups such as Priapulida, Gastropoda and Foraminifera. At 1000–1425 m, the mysids were preferential prey, while in summer at all depths analysed, isopods were a dominant prey. Polychaetes have certain incidence in the diet only at 1000–1425 m, being a dominant prey in autumn. Individuals at the 1000–1425 m depth ingest larger numbers of prey of higher average sizes than those at 1425–2250 m. The scarcity of resources below 1200–1400 m resulted in diversification of diet and encouraged preying on deposited foraminiferans, molluscs or moving copepods.


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