Number Of Scent Marks Research Articles

Effects of food availability on proceptivity: A test of the reproduction at all costs and metabolic fuels hypotheses

Proceptive behaviours are used by animals to indicate interest in opposite-sex conspecifics. These behaviours can be affected by an individual's nutritional status. Two mutually exclusive hypotheses have been proposed to account for the effects of food availability on reproduction. These are the metabolic fuels hypothesis and the reproduction at all costs hypothesis. It is not known if food availability affects proceptive behaviours such as scent marking, over-marking, and self-grooming. In this study, we tested the hypothesis that food-deprived and nonfood-deprived meadow voles, Microtus pennsylvanicus, differ in the number of scent marks they deposit, the proportion of over-marks they deposit, and the amount of time they spend self-grooming when they encounter the scent marks of opposite-sex conspecifics. We tested this hypothesis by exposing meadow voles that either had continuous access to food or were food-deprived for either 6 hours or 24 hours to the scent marks of an opposite-sex conspecific. Due to differences in the natural history of male and female meadow voles, we predicted that female voles' behaviour will best be explained by the metabolic fuels hypothesis whereas males' behaviour will best be explained by the reproduction at all costs hypothesis. We found that both male and female voles deprived of food for either 6 hours or 24 hours spent less time self-grooming compared to nonfood-deprived voles. However, food availability did not affect the scent marking and over-marking behaviour of male and female voles. Differences in the effects of food availability on these proceptive behaviours are discussed within the context of the natural history of meadow voles.

Sex differences in scent-marking in sifaka: Mating conflict or male services?

Male and female interests can either be in conflict or serve as a basis for exchange. Communication is thus an important aspect of intersexual relationships. Verreaux's sifaka (Propithecus verreauxi verreauxi), like many prosimians, uses chemical signals as one form of communication. The goals of this study were to determine 1) if males and females exhibit sex differences in their scent-marking behavior, and 2) if scent-marking is an example of mating conflict or cooperation. All occurrences of scent-marks, scent-mark context, and scent-mark style were collected on 23 sifaka in the Kirindy Forest of western Madagascar for 7 months (September 2001-March 2002). Scent-mark rates were collected using continuous focal animal sampling from November 2000-March 2002. Home-range data were collected using monthly censuses and instantaneous focal sampling throughout those 17 months. The pressures of behavioral ecology seem to have shaped scent-marking in sifaka: the sexes exhibited significantly different scent-marking behavior. Results from this study are consistent with the hypotheses that 1) females scent-mark to advertise their presence and mark their resources, 2) clean-chested males use scent-marks as between-group communication to advertise their presence, and 3) stained-chested males use scent-marks as a form of olfactory mate-guarding. Scent-marking does not appear to be a "service" that males provide to females, because overmarking limits female communication rather than adding to the overall number of scent-marks. Scent-marking behavior is a crucial aspect of the mating conflict and for understanding intersexual relationships in sifaka.

Scent-marking in the Eurasian beaver (Castor fiber) as a means of territory defense

Beaver (Castor spp.) normally scent-mark by depositing castoreum and/or anal gland secretion on scent mounds close to the water's edge. The aim of this study was to investigate the hypothesis that the Eurasian beaver (C. fiber) scent-marks as a means of territory defense. Scent-marking behavior was studied during an entire year (April 1, 1995–March 31, 1996) in seven adjacent territories along 9.2 km of the BΦ River in Telemark County, Norway. The number and location of fresh scent marks were recorded biweekly. The main results showed that: (1) the number of scent marks in territories was significantly higher in spring, when dispersal of subadults normally occurs than during the rest of the year; (2) the number of scent marks was clumped near territorial borders; and (3) the number of scent marks was significantly greater upstream than downstream of the lodge.

Odor modulation of ventral scent gland marking in the Mongolian gerbil.

Gerbil odors were allowed to accumulate in individual home cages for several months in order to provide stable olfactory stimuli that might modulate the number of ventral scent gland marks produced by both male and female Mongolian gerbils. Male marking levels for most test conditions were 2-3 times larger than those in females. In general, the relative patterns of responsiveness to particular odors were similar in both sexes. The number of scent marks in home cages was significantly smaller than the number obtained in clean cages. This suppression was not strongly dependent on the odors emanating from an individual's own ventral gland sebum. Marking levels in the home cages of other gerbils were substantially higher than those seen in the test animal's own cage and were maximal in the home cages of other males. Behaviorally receptive females marked at significantly higher levels in home, clean, and conspecific cages than did nonreceptive females. Conspecific urine odors, especially those from females, increased marking levels significantly over those obtained in home cages. In males, home cage marking was significantly enhanced by the presence of a female. Females, on the other hand, marked at similar levels in home cages whether a potential mating partner was present or not. Both sexes showed significant reductions in marking levels in another's cage if the resident animal was present. These results suggest that when sufficient gerbil-related odors are available to a test animal, its rate of scent-marking is altered, depending on the particular odor environment. Some gerbil-related odors increase marking levels, whereas others decrease marking. Scent-marking then, like other olfactory guided behaviors and odor preferences, is context specific.

Changes in social behavior of the male golden hamster accompanying photoperiodic changes in reproduction

Testicular regression and decreased serum testosterone levels result when male hamsters are placed in a short-day photoperiod, and these changes are reversed after reexposure to long-days. The present study was undertaken to determine whether these physiological changes lead to modifications in social behavior in the male hamster. Animals in a nonstimulatory short-day (LD 6:18) or a stimulatory long-day (LD 14:10) photoperiod were observed every 3 weeks for 21 weeks. After 9 weeks, half of the LD 6:18 males were returned to LD 14:10 and showed rapid testicular recrudescence. The other half remained in LD 6:18 and showed a slower rate of testicular recrudescence. Assessment of aggression was accomplished by placing an intruder in the home cage of a test animal and recording latency to attack, decisive encounters, number of attacks, and number of aggressive postures. Dominance was evaluated in a neutral arena with opponents of different weights, using the same parameters. Scent-marking was recorded in response to both bedding from an intact male and bedding from an ovariectomized female in a clean cage. Short-day animals undergoing testicular regression showed heightened levels of aggression and an upward shift in their dominance status. Alteration of the photoperiod did not affect the pattern or number of scent marks. As animals underwent testicular recrudescence, there was a return to lower levels of aggression and to a lower dominance status. Males undergoing rapid testicular recrudescence also showed the most rapid decline in aggressive behaviors. These results suggest that levels of agonistic behavior in the male hamster are inversely related to serum testosterone levels. Scent-marking appears to be unreleated to androgen levels in the male hamster and its role in hamster social behavior remains unclear.