Meadow Voles (Microtus pennsylvanicus) and Prairie Voles (M. ochrogaster) Differ in Their Responses to Over-Marks from Opposite- and Same-Sex Conspecifics

Over‐marking occurs when one individual deposits its scent mark on the scent mark of a conspecific. Previous studies have shown that meadow voles (Microtus pennsylvanicus) and prairie voles (M. ochrogaster) that were exposed to an over‐mark of two same‐sex conspecifics, later responded similarly to the top‐scent mark but differed in their response to the bottom‐scent mark. In the present study, we examined the responses of meadow voles and prairie voles to same‐sex and mixed‐sex over‐marks to ascertain whether their responses reflect the different tactics which males and females in promiscuous (meadow voles) and monogamous (prairie voles) species use to attract opposite‐sex conspecifics and to compete with same‐sex conspecifics. Males and females of both species spent more time investigating the mark of the top‐scent donor than that of the bottom‐scent donor of an over‐mark. Meadow voles exposed to a mixed‐sex over‐mark spent more time investigating the mark of the opposite‐sex conspecific independently of whether it was from the top‐ or bottom‐scent donor. In contrast, prairie voles spent more time investigating the mark of the opposite‐sex donor if it was from the top‐scent donor. These results suggest that: (i) over‐marking serves a competitive function; (ii) the scent marks of individuals attract multiple mates in promiscuous species such as the meadow vole; and (iii) the scent marks of individuals establish and maintain pair bonds between familiar opposite‐sex conspecifics in monogamous species such as the prairie vole.     

Olfactory Experience Affects the Response of Meadow Voles to the Opposite‐Sex Scent Donor of Mixed‐Sex Over‐Marks

Scent marking and over‐marking are important forms of communication between the sexes for many terrestrial mammals. Over the course of three experiments, we determined whether the amount of time individuals investigate the scent marks of opposite‐sex conspecifics is affected by 4 d of olfactory experience with those conspecifics. In Experiment 1, female meadow voles, Microtus pennsylvanicus, spent more time investigating the scent mark of the novel male conspecific than that of the familiar male donor, whereas male voles spent similar amounts of time investigating the scent mark of the familiar female and a novel female conspecific. In Experiment 2, voles were exposed to a mixed‐sex over‐mark in which subjects did not have 4 d of olfactory experience with either the top‐scent donor or the bottom‐scent donor. During the test phase, male and female voles spent more time investigating the scent mark of the opposite‐sex conspecific that provided the top‐scent mark than that of a novel, opposite‐sex conspecific. Male and female voles spent similar amounts of time investigating the scent mark of the bottom‐scent donor and that of a novel opposite‐sex conspecific. In Experiment 3, voles were exposed to a mixed‐sex over‐mark that contained the scent mark of an opposite‐sex conspecific with which they had 4 d of olfactory experience. During the test phase, male voles spent more time investigating the mark of the familiar, top‐scent female than the scent mark of a novel female donor but spent similar amounts of time investigating the mark of the familiar, bottom‐scent female and that of a novel female donor. In contrast, female voles spent more time investigating the mark of a novel male donor than that of either the familiar, top‐scent male or that of the familiar, bottom‐scent male. The sex differences in the responses of voles to scent marks and mixed‐sex over‐marks are discussed in relation to the natural history and non‐monogamous mating system of meadow voles.     

Meadow Voles (Microtus pennsylvanicus, Arvicolidae) Over-mark and Adjacent-mark the Scent Marks of Same-sex Conspecifics

Scent over-marking occurs when an animal deposits its scent mark on top of the scent mark of a conspecific; adjacent-marking occurs when an animal deposits its scent mark next to the scent mark of a conspecific. Given that male rodents usually scent mark more than females and that animals spend more time investigating the odor of the top-scent donor of an over-mark, I tested the following three hypotheses. First, male meadow voles deposit more scent marks than female meadow voles. Second, male meadow voles will deposit more over-marks and adjacent-marks in response to the scent marks of a same-sex conspecific than females would. Third, meadow voles spend more time investigating the odor of the second vole placed in the arena than that of the first vole placed in the arena. To test these hypotheses, two age-matched, like-sex conspecifics (first vole and second vole) were placed successively into an arena in which they were allowed to freely explore and scent mark for 15 min. The first hypothesis was not supported. The first and second vole, independently of sex, deposited a similar number of scent marks. The second hypothesis was also not supported by the data: more conspecific scent marks were over-marked by the second female than by the second male. The third hypothesis was supported by the data. After investigating a scented arena, males and females spent more time investigating the odor of the second vole than that of the first vole. Sex differences in scent-marking behaviors of meadow voles are unlike those reported for other species of rodents.     

Food Deprivation Suppresses a Preference for the Top-Scent Mark of an Over-Mark in Meadow Voles (Microtus pennsylvanicus)

Food availability affects whether mammals communicate their interest in interacting with opposite‐sex conspecifics. This study examined the responses of voles to over‐marks, and factors that influence the formation and maintenance of a preference for the top‐scent in an over‐mark. Specifically, we investigated how food deprivation affected the amount of time male and female voles exposed to an over‐mark, later responded to the marks of the top‐ and bottom‐scent donors when subsequently presented with the two scents side by side. Males and females that were not food deprived and males that were food deprived 6 h before exposure to an over‐mark later maintained a preference for the donor of the top‐scent mark compared with the donor of the bottom‐scent mark of the over‐mark. Females that were food deprived for 6 h before or after exposure of the over‐mark and males food deprived 6 h after the exposure to the over‐mark showed no preference for the top‐scent mark donor. Re‐feeding females that were food deprived for 6 h before exposure to an over‐mark was sufficient to restore their preference for the mark of the top‐scent male over that of the bottom‐scent male. The different responses of food‐deprived male and female voles to over‐marks of opposite‐sex conspecifics may be associated with differences in their tactics for interacting with potential mates and the higher energetic costs of reproduction in female voles than in male voles.     

Sex differences in olfactory social recognition memory in meadow voles,Microtus pennsylvanicus

Terrestrial mammals, like rodents, use odors, and scent marks to indicate their presence in an area to conspecifics. These odors convey information about the scent donor's genotype, sex, condition, and age. The ability to discriminate among the scent marks of conspecifics and later recollect the identity of the donor is essential for choosing between familiar and unfamiliar mates. We tested the hypothesis that the promiscuous meadow vole (Microtus pennsylvanicus) can recollect the odor of a familiar, opposite-sex conspecific and distinguish it from that of an unfamiliar, opposite-sex conspecific. We also hypothesized that because reproductive success is highly skewed among male meadow voles and competition for mates is intense, males will be more likely than females to recollect the odor of a familiar, opposite-sex conspecific and distinguish it from that of an unfamiliar, opposite-sex conspecific, for a longer period of time. Using a habituation task, we first exposed the voles, 4 times successively, to the anogenital area scent of an opposite-sex conspecific. Then, 1 hr, 24 hrs, 72 hrs, or 96 hrs after the fourth exposure, voles were presented with the odor of the donor from the exposure phase (familiar donor) and that of an unfamiliar, opposite-sex conspecific. Female meadow voles spent similar amounts of time investigating the scent of the familiar male donor and that of an unfamiliar male donor after the 1-hr and 24-hr intervals. Male meadow voles, however, spent more time with the scent of an unfamiliar female donor than that of the familiar female donor after the 1-hr, 24-hr, and 72-hr intervals, suggesting that male voles could recollect the scent mark of a familiar female for at least three days. The implications of these sex differences in social memory may reflect the different strategies male and female meadow voles use in the recognition of previous and potential mates. Recognition of an individual's scents may enhance fitness by allowing animals to direct appropriate behaviors toward those individuals.     

Meadow voles and prairie voles differ in the percentage of conspecific marks they over-mark

Many terrestrial mammals scent mark in areas containing the scent marks of conspecifics, and thus, may deposit their own scent marks on top of those that were deposited previously by conspecifics. This phenomenon, known as over-marking appears to play a role in same-sex competition or mate attraction. The present study determines whether meadow and prairie voles avoid over-marking the scent marks of conspecifics, target the scent marks of conspecifics and over-mark them, or randomly over-mark the scent marks of conspecifics. The data show that meadow and prairie voles adjust the number and location of scent marks that they deposit in areas marked previously by particular conspecifics. Male and female meadow and prairie voles target the scent marks of opposite-sex conspecifics and over-mark them. Female meadow and prairie voles also target the scent marks of female conspecifics. In contrast, male meadow and prairie voles over-mark the scent marks of male conspecifics in a random manner. By differentially over-marking the scent marks of conspecifics, voles may be able to communicate particular information to a variety of conspecifics.     

Response of Prairie Voles, Microtus ochrogaster (Rodentia, Arvicolidae), to Scent Over-marks of Two Same-sex Conspecifics: A Test of the Scent-masking Hypothesis

Previous work shows that after investigating a same-sex over-mark, two nonmonogamous species, meadow voles and golden hamsters, preferred the odor of the top-scent donor to that of the bottom-scent donor, and behaved as the odor of the bottom-scent donor was not familiar. This finding supported the scent-masking hypothesis; one of three hypotheses suggested previously to account for how an animal responds to the overlapping scent marks of two same-sex conspecifics. The present experiments tested whether one of these hypotheses, either scent-masking, scent-bulletin-board, or scent-blending, predicts how a monogamous species, the prairie vole, responds to such over-marks. Our data show that none of the three hypotheses adequately describes the way in which prairie voles respond to conspecific over-marks. Although prairie voles preferred the top scent to the bottom scent, they behaved as if the latter scent was familiar and less important than a novel scent (a scent not part of the over-mark). Overall, the data suggest that the manner in which males and females respond to same-sex over-marks reflects the different tactics they may use to attract and compete with conspecifics in monogamous and nonmonogamous species.     

Over-marking and Adjacent Marking are Influenced by Sibship in Male Prairie Voles,Microtus ochrogaster

Scent over-marking occurs when an animal deposits its scent mark on top of the scent mark of a conspecific. Over-marking may provide advantages in the transfer of information to the individual whose scent is on top but not to the individual whose scent is on the bottom. We tested the hypothesis that over-marking is a competitive form of olfactory communication and that male prairie voles would over-mark the scent marks of same-sex conspecifics more than those of same-sex siblings. Two age-matched male voles (first male and second male) were placed successively into an arena in which they were allowed to explore freely and scent mark for 15 min at age 12, 20, 28, 36, 44, and 52 d. The first male was placed into a clean arena, whereas the second male was placed into an arena containing either the scent marks of an age-matched male sibling or nonsibling. Age affected the total number of scent marks deposited by the voles; 12-20-d-old voles deposited fewer scent marks, over-marks and adjacent marks than did 28-52-d-old voles. Sibship did not affect the total number of scent marks deposited by the first and second voles but did affect the number of over-marks and adjacent marks deposited by the second vole. Siblings received significantly fewer over-marks and adjacent marks than did nonsiblings; this effect was most dramatic after the voles reached 28 d of age, a time coincident with the onset of puberty. Males separated from siblings and housed singly at 44-d-old and tested at 52-d-old, deposited significantly more over-marks and adjacent marks in arenas if the first vole was a nonsibling than if it was a sibling. This differential scent-marking supports the hypothesis that over-marking and adjacent marking are used as competitive forms of olfactory communication by male prairie voles.     

Female meadow voles,Microtus pennsylvanicus,do not alter their over-marking in response to female conspecifics that were food deprived

Many terrestrial mammals will deposit scent marks and over-marks, the latter being the overlapping scent marks of two conspecifics. Studies have shown that male rodents that are exposed to the overlapping scent marks of two female conspecifics later spend more time investigating the mark of the top-scent female than that of the bottom-scent female. This suggests that over-marking is a form of competition and that the top-scent female is more likely than the bottom-scent female to be chosen as a potential mate. Thus, females should over-mark the scents of neighboring females at a rate that will maximize their chances of attracting males. However, meadow voles live in areas that may contain patchy food availability and residents may differ in their nutritional status. Females in a better nutritional state may be more likely than those in poorer nutritional states to indicate their presence in an area, signal possession of a territory, and to attract mates. Thus, we tested the prediction that female meadow voles, Microtus pennsylvanicus, that were not food deprived would deposit more over-marks than female voles that were food deprived for 6 h. Food-deprived female voles and female voles that had continuous access to food deposited a similar number of scent marks and used a similar proportion of those marks as over-marks when they encountered the scent marks of female conspecifics. These findings suggest that the nutritional status of female voles does not affect their ability to signal their presence in an area marked by a female conspecific.     

Self‐Grooming Response of Meadow Voles to the Odor of Opposite‐Sex Conspecifics in Relation to the Dietary Protein Content of Both Sexes

Many animals self‐groom when they encounter the scent marks of opposite‐sex conspecifics. Self‐grooming transmits odiferous substances that contain information about the groomer’s condition, which is affected by its nutritional state. We tested the hypothesis that the amount of time that individuals self‐groom to opposite‐sex conspecifics is affected by the amount of protein in their diet and that of the scent donor. We did so by feeding meadow voles (Microtus pennsylvanicus) a diet containing 9%, 13%, or 22% dietary protein for 30 d and observing their self‐grooming behavior when they were exposed to bedding scented by an opposite‐sex conspecific (odor donor) fed one of the three diets, or fresh cotton bedding (control). The hypothesis was partially supported. We found that the protein content of the diet of male and female groomers did not affect the amount of time they self‐groomed. However, the protein content of the diet of male odor donors affected the amount of time that female voles spent self‐grooming. Female voles self‐groomed more in response to male odor donors fed a 22% protein‐content diet than to those produced by male odor donors fed either a 9% or a 13% protein‐content diet. Interestingly, the amount of time males self‐groomed was not affected by the protein content of the diet of the female odor donor. These results may, in part, be explained by the natural history of free‐living meadow voles, sex differences in costs associated with mate attraction and reproduction, and the direct or indirect benefits that females receive from males fed a diet high in protein content.     

Dietary protein content affects the response of meadow voles, <Emphasis Type="Italic">Microtus pennsylvanicus</Emphasis>, to over-marks

The response to signals, including scent marks, from opposite-sex conspecifics can be affected by the nutritional state of both the sender and receiver of these signals. Protein content of the diet affects how meadow voles (Microtus pennsylvanicus) respond to single scent marks, but it is unknown how it affects an individual’s response to the overlapping scent marks of two donors (an over-mark). In experiment 1, we tested the hypothesis that protein content of the diet affects the amount of time voles spend investigating the marks of the top- and bottom-scent donors of an over-mark. Males and females fed a 22% protein diet spent more time investigating the scent mark of the top-scent donor than that of the bottom-scent donor; voles fed 9% and 13% protein diets spent similar amounts of time investigating the top- and bottom-scent donors. In experiment 2, we tested the hypothesis that protein content of the diet of the top- and bottom-scent donors affects the amount of time conspecifics spend investigating their scent marks. Female voles spent more time investigating the mark of the top-scent male than that of the bottom-scent male, independent of the differences in protein content of the diets of the top- and bottom-scent donors. Male voles, however, spent more time investigating the top-scent female when she was fed a diet higher in protein content than that of the bottom-scent female. Our results are discussed within the context of the natural history of voles.     

Scent marking by voles in response to predation risk: a field-laboratory validation

Predators use scent to locate their prey, and prey animals oftenalter their behavior in response to predation risk. I testedthe hypothesis that voles would decrease their frequency ofscent marking in response to predation risk. I conducted trialsin which prairie voles, Microtus ochrogaster, and woodland voles,M. pinetorum, were allowed to scent mark ceramic tiles placedin their runways in the field. The tiles were subjected to oneof three treatments: scented with odor from mink, Mustela vison(a rodent predator); rabbit, Oryctolagus cuniculus (a nonpredatormammal control); and no odor (control). No significant differenceswere found in the frequency of scent marking in response tothe three treatments for either species. To validate that volesdid not decrease their scent marking in response to predationrisk, I brought male prairie voles from the field site intothe laboratory and allowed them to scent mark white paper substratetreated with mink odor, rabbit odor, or no odor. No significantdifferences were found in the frequency of scent marks in responseto the three treatments. These results differ from what waspredicted based on laboratory studies with other species ofrodents that show avoidance, reproductive suppression, decreasedactivity, and reduced scent marking in response to odors ofpredators. Voles appear to scent mark different substrates andunder a wide variety of social and environmental situations,and this is not influenced by the presence of odor from a predator.     

The Reproductive State of Female Voles Affects their Scent Marking Behavior and the Responses of Male Conspecifics to Such Marks

During the breeding season, the reproductive condition of female mammals changes. Females may or may not be sexually receptive. We conducted a series of experiments to determine whether reproductive condition of female meadow voles affects their scent marking behavior as well as the scent marking behavior of male conspecifics. In expt 1, females in postpartum estrus (PPE females) deposited more scent marks than females that were neither pregnant nor lactating (REF females) or ovariectomized females (OVX females). In expt 2, male voles scent marked more and deposited more over‐marks in areas marked by PPE females than by REF and OVX females. In expt 3, PPE females deposited more scent marks and over‐marks in areas marked by males than did females in the other reproductive states. The results of these experiments showed that male and female voles may vary in the number, type and location of scent marks they deposit in areas scented by particular conspecifics.     

Meadow Voles and Prairie Voles Differ in the Length of Time They Prefer the Top-Scent Donor of an Over-Mark

Scent over-marking occurs when one individual places its scent mark on top of one deposited by a conspecific. Studies have shown that animals investigating an over-mark later behave as if the top-scent mark is more important than the bottom-scent mark. Differences in response to over-marks may reflect differences in social and mating systems. Here, we ascertained the length of time that meadow voles ( Microtus pennsylvanicus ) and prairie voles ( Microtus ochrogaster ), exposed to an over-mark, maintain a preference for the mark of the top-scent donor compared with that of the bottom-scent donor. If voles had no previous sexual experience with their top-scent and bottom-scent donors, male and female meadow voles maintained a preference for their top-scent donor's mark over their bottom-scent donor's mark for 48 h. In contrast, male and female prairie voles maintained such preferences for 24 h and 12 h, respectively. If voles had prior sexual experience with either their top- or bottom-scent donor, such experience did not affect the length of time meadow voles and male prairie voles maintained a preference for their top-scent donor. Female prairie voles maintained a 12-h preference for the top-scent mark if it belonged to the mate. If the mate was the bottom-scent donor, female prairie voles showed no preference for it or the top-scent mark. These findings are discussed within the framework that an association may exist between the manner in which voles respond to over-marks and their social and mating systems.     

Perspectives on over-marking: is it good to be on top?

What we refer to as over-marking occurs when one individual places its scent mark on top of, touching, or adjacent to the scent mark of another individual, usually a conspecific. Over-marking frequently occurs among mammals that share common paths, trails, and runways. Despite its ubiquity among terrestrial mammals, we know little about how individuals respond to over-marks and the function(s) of over-marking. Studies on voles and golden hamsters indicate that after exploring an over-mark, individuals respond selectively to the mark of the top-scent donor relative to that of the bottom-scent donor. Thus, individuals may be able to focus their attention on a particular scent mark relevant at a particular time and in a particular context, neglecting other scent marks that are present. The function(s) of over-marking are examined within the framework of ten hypotheses. Several hypotheses are plausible. However, the bulk of the literature is consistent with hypotheses stating that over-marking serving a role in olfactory communication between opposite and same-sex conspecifics. Lastly, we postulate the costs and benefits that may be garnered by the top-scent donor of an over-mark.     

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 6hours or 24hours 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 6hours or 24hours 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.     

Meadow voles,Microtus pennsylvanicus,can discriminate between scents of individual house cats,Felis catus

Individual discrimination provides animals the opportunity to adjust their exposure and behavior when interacting with other animals, both conspecifics and heterospecifics. Meadow voles, Microtus pennsylvanicus, were exposed to scents of house cats, Felis catus. Our first experiment tested whether meadow voles could discriminate between caudal, interdigital, and facial scents produced by a cat with a habituation–dishabituation paradigm. Upon exposure to the familiar scent and a novel one, meadow voles did not investigate either scent more than the other. Our second experiment tested whether meadow voles discriminate between the facial scents of different cats. When exposed to a familiar scent of one cat and the unfamiliar scent of another cat, the meadow voles did discriminate and investigated the unfamiliar scent more than the familiar scent. The results suggest that meadow voles will discriminate between cats using any scent that the cat may inadvertently leave within the environment, thereby reducing the vole's risk of predation by that individual.     

The predation risks of interspecific eavesdropping: weasel–vole interactions

Competing species benefit from eavesdropping on each other's signals by learning about shared resources or predators. But conspicuous signals are also open to exploitation by eavesdropping predators and should also pose a threat to other sympatric prey species. In western Finland, sibling voles Microtus rossiameridionalis and field voles M. agrestis compete for food and space, and both species rely upon scent marks for intraspecific communication. Both vole species are prey to a range of terrestrial scent hunting predators such as least weasels, however, the competitively superior sibling voles are taken preferentially. We tested in large out‐door enclosures whether field voles eavesdrop on the signals of its competitor, and whether they behave as though this eavesdropping carries a risk of predation. We presented field voles with scent marks from unknown conspecifics and sibling voles and measured their visitation, activity and scent marking behaviours at these scents under high (weasel present) and low (weasel absent) predation risk. Field voles readily visited both field and sibling vole scents under both high and low predation risk; however their activity at sibling vole scent marks declined significantly under increased predation risk. In contrast, predation risk did not affect field voles’ activity at conspecific scents. Thus, field voles were compelled to maintain eavesdropping on heterospecific scents under an increased risk of predation, however they compensated for this additional risk by reducing their activity at these risky scents. Scent marking rates declined significantly under high predation risk. Our results therefore reveal a hidden complexity in the use of social signals within multi‐species assemblages that is clearly sensitive to the potential for increased predation risk. The predation risks of interspecific eavesdropping demonstrated here represents a significant generalisation of the concept of associational susceptibility.     

Predator‐Naïve Brown Trout (Salmo trutta) Show Antipredator Behaviours to Scent from an Introduced Piscivorous Mammalian Predator Fed Conspecifics

Introduced mammalian predators may pose a high risk for native and naïve prey populations, but little is known about how native fish species may recognize and respond to scents from introduced mammalian predators. We investigated the role of diet‐released chemical cues in facilitating predator recognition, hypothesizing that native brown trout (Salmo trutta) would exhibit antipredator behaviours to faeces scents from the introduced American mink (Neovision vison) fed conspecifics, but not to non‐trout diets. In treatments‐control and replicate stream tank experiments, brown trout showed significant antipredator responses to faeces scent from mink fed conspecifics, but not to faeces scent from mink fed a non‐trout diet (chicken), or the non‐predator food control, Eurasian beaver (Castor fiber). We conclude that native and naïve brown trout show relevant antipredator behaviours to an introduced mammalian predator, presumably based on diet‐released conspecific alarm cues and thereby estimate the predation risk.     

Re‐Feeding Food‐Deprived Male Meadow Voles Affects the Sperm Allocation of Their Rival Males

An individual's nutritional status affects the manner in which same‐ and opposite‐sex conspecifics respond to that individual, which may affect their fitness. Male meadow voles, Microtus pennsylvanicus, increase their sperm allocation if they encounter the scent mark of an unfamiliar male that is not nutritionally challenged. If, however, the scent mark comes from a male that has been food deprived for 24 h, stud male voles do not increase their sperm allocation. Food‐deprived males may be viewed as being lower quality and a reduced risk of sperm competition by rival males. We hypothesized that stud males in promiscuous mating systems tailor their sperm allocations depending on whether rival males have been food deprived and then re‐fed. We predicted that newly re‐fed males will be considered a strong risk of sperm competition because of the potentially high fitness and survival costs associated with food deprivation in males, and that they will cause stud males to increase their sperm allocation. Our results, however, showed that the recovery period from 24 h of food deprivation was a relatively slow process. It took between 96 and 336 h of re‐feeding male scent donors that were food deprived for 24 h to induce stud males to increase their sperm allocation to levels comparable to when scent donors were not food deprived. Stud male voles may be conserving the amount of sperm allocated until the male scent donors have recovered from food deprivation and subsequent re‐feeding.