“…After the spring litter, the second (summer) litter may be born in June, gestation starting in May [24]. Females seem to be territorial, living in separate on average 7 ha home ranges, but males live in overlapping on average 60 ha home ranges encompassing several males and females [25]. Fig.…”
BackgroundOne way to cope with irregularly occurring resources is to adjust reproduction according to the anticipated future resource availability. In support of this hypothesis, few rodent species have been observed to produce, after the first litter born in spring, summer litters in anticipation of autumn’s seed mast. This kind of behaviour could eliminate or decrease the lag in population density normally present in consumer dynamics. We focus on possible anticipation of future food availability in Siberian flying squirrels, Pteromys volans. We utilise long-term data set on flying squirrel reproduction spanning over 20 years with individuals living in nest-boxes in two study areas located in western Finland. In winter and early spring, flying squirrels depend on catkin mast of deciduous trees. Thus, the temporal availability of food resource for Siberian flying squirrels is similar to other mast-dependent rodent species in which anticipatory reproduction has been observed.ResultsWe show that production of summer litters was not related to food levels in the following autumn and winter. Instead, food levels before reproduction, in the preceding winter and spring, were related to production of summer litters. In addition, the amount of precipitation in the preceding winter was found to be related to the production of summer litters.ConclusionsOur results support the conclusion that Siberian flying squirrels do not anticipate the mast. Instead, increased reproductive effort in female flying squirrels is an opportunistic event, seized if the resource situation allows.
“…After the spring litter, the second (summer) litter may be born in June, gestation starting in May [24]. Females seem to be territorial, living in separate on average 7 ha home ranges, but males live in overlapping on average 60 ha home ranges encompassing several males and females [25]. Fig.…”
BackgroundOne way to cope with irregularly occurring resources is to adjust reproduction according to the anticipated future resource availability. In support of this hypothesis, few rodent species have been observed to produce, after the first litter born in spring, summer litters in anticipation of autumn’s seed mast. This kind of behaviour could eliminate or decrease the lag in population density normally present in consumer dynamics. We focus on possible anticipation of future food availability in Siberian flying squirrels, Pteromys volans. We utilise long-term data set on flying squirrel reproduction spanning over 20 years with individuals living in nest-boxes in two study areas located in western Finland. In winter and early spring, flying squirrels depend on catkin mast of deciduous trees. Thus, the temporal availability of food resource for Siberian flying squirrels is similar to other mast-dependent rodent species in which anticipatory reproduction has been observed.ResultsWe show that production of summer litters was not related to food levels in the following autumn and winter. Instead, food levels before reproduction, in the preceding winter and spring, were related to production of summer litters. In addition, the amount of precipitation in the preceding winter was found to be related to the production of summer litters.ConclusionsOur results support the conclusion that Siberian flying squirrels do not anticipate the mast. Instead, increased reproductive effort in female flying squirrels is an opportunistic event, seized if the resource situation allows.
“…In Hokkaido, females enter estrus from the end of February to July and have a 10-day estrus cycle [21]. After copulation of the female with a few males, the gestation period lasts 40 days [22]. Females produce an average of three neonates per litter [21,22], and the pups are weaned at 60 days old [3].…”
Section: --64mentioning
confidence: 99%
“…After copulation of the female with a few males, the gestation period lasts 40 days [22]. Females produce an average of three neonates per litter [21,22], and the pups are weaned at 60 days old [3]. After the first reproduction up to 30% of females produce second litters [3].…”
The Siberian flying squirrel (Pteromys volans) spends almost all of its life on trees and thus depends extremely highly on forests. Forest fragmentation has been reducing its habitat. To conserve the squirrel's populations in fragmented landscapes we need information on not only its ecology but also its physiology, because stress and poor body condition resulting from clear-cutting could negatively influence its reproductive physiology. However, there is a paucity of information on the Siberian flying squirrel's basic reproductive physiology, and there is no established method for studying it. Our goal was to validate fecal progesterone analysis in this animal using a commercial enzyme immunoassay (EIA) kit for endocrine profiles in Siberian flying squirrels. First, we tested parallelism between serially diluted fecal progesterone and a standard curve to validate the EIA. Comparison of the slopes of the two regression lines to test for parallelism revealed no significant difference. Therefore, progesterone concentrations in the fecal samples of the Siberian flying squirrels were exactly measured. Second, we compared progesterone concentrations among four groups-pregnant females, adult females in the non-breeding season, juvenile females, and adult males-to determine whether fecal progesterone analysis was useful for evaluating reproductive status using GLMM. Fecal progesterone concentrations were significantly higher in pregnant females than in other groups. These results indicated that fecal progesterone analysis in Siberian flying squirrels was valid for predicting pregnancy.
“…In general, social factors and territory availability are important determinants of dispersal in arboreal squirrels (Boutin, Tooze, & Price, ; Wauters et al., ). Territory availability may affect breeding movements of females, but males may need to move longer distances when mate availability decreases (Selonen, Painter, Rantala, & Hanski, ). The flying squirrel is a forest specialist, and cavities or nest boxes are key elements in flying squirrel territories (Selonen & Hanski, ).…”
Section: Introductionmentioning
confidence: 99%
“…For females, we hypothesized that low breeding success in the previous year would increase their likelihood to abandon the nest site. Keeping in mind that female flying squirrels seem to be territorial (Selonen et al., ), if competition between females determines breeding movements, we hypothesized that changes in nest site are related to colonization of another female. Finally, we sought evidence for bequeathal of territories for offspring, that is, cases where a mother has moved to another site and her offspring have remained philopatric within their natal territory.…”
The lifetime movements of an individual determine the gene flow and invasion potential of the species. However, sex dependence of dispersal and selective pressures driving dispersal have gained much more attention than dispersal at different life and age stages. Natal dispersal is more common than dispersal between breeding attempts, but breeding dispersal may be promoted by resource availability and competition. Here, we utilize mark–recapture data on the nest‐box population of Siberian flying squirrels to analyze lifetime dispersal patterns. Natal dispersal means the distance between the natal nest and the nest used the following year, whereas breeding movements refer to the nest site changes between breeding attempts. The movement distances observed here were comparable to distances reported earlier from radio‐telemetry studies. Breeding movements did not contribute to lifetime dispersal distance and were not related to variation in food abundance or habitat patch size. Breeding movements of males were negatively, albeit not strongly, related to male population size. In females, breeding movement activity was low and was not related to previous breeding success or to competition between females for territories. Natal philopatry was linked to apparent death of a mother; that is, we did not find evidence for mothers bequeathing territories for offspring, like observed in some other rodent species. Our results give an example of a species in which breeding movements are not driven by environmental variability or nest site quality. Different evolutionary forces often operate in natal and breeding movements, and our study supports the view that juveniles are responsible for redistributing individuals within and between populations. This emphasizes the importance of knowledge on natal dispersal, if we want to understand consequences of movement ecology of the species at the population level.
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