This is a study of the effects of geographic transfer on the timing of seasonal breeding of free-... more This is a study of the effects of geographic transfer on the timing of seasonal breeding of free-living rhesus monkeys on Cayo Santiago and La Parguera islands in Puerto Rico. The results demonstrated a progressive shift in the breeding season of the transferred group. The full shift required a period of 2 years. Change from one environment to another produced shifts in onset of estrous. The explanation for this phenomenon proposes an interaction between the specific reproductive state of the female, which may or may not be sensitive to a particular environmental change, and the environmental variation which is correlated with onset of breeding.
We explored the relationship between reproductive success and parity in white-footed mice. Becaus... more We explored the relationship between reproductive success and parity in white-footed mice. Because these small mammals are short-lived and have low residual reproductive value in the field, we predicted, contrary to laboratory results, that litter size, weaning rates, and recruitment would not increase as a function of female age or parity. We used data from 3 years of mark-and-recapture trapping data and from nest boxes to estimate weaning and recruitment rates in a 2-ha woodlot in northwest Ohio. Of 401 mice from 82 litters born in nest boxes, 87 were recruited into the population as adults. We observed no increase in litter size, weaning rates, or recruitment with maternal age or parity, Season interacted with parity such that recruitment from spring-born litters produced by females having their first or second litters was four times higher than from all other litters. Litter size did not influence weaning rates and only affected recruitment when season and parity also were considered.
We explored the relationship between several aspects of the natal environment and dispersal dista... more We explored the relationship between several aspects of the natal environment and dispersal distances of white-footed mice, Perornyscus leucopus, in a 2-ha oak/hickory woodlot northeast of Bowling Green, Ohio, from 1991 to 1993. Litters of mice in nestboxes were marked at an early age. We evaluated litter size, the number of males and females in the litter, litter sex ratio, weanling survival to adulthood, and mother's parity as proximate factors that might affect dispersal. Dispersal was quantified as the straight-line distance between the mother's center of activity and that of her adult offspring. Of 401 mice from 82 litters, 78 (19.5%) were recaptured as adults. Males dispersed significantly farther than females. Females from small litters dispersed shorter distances than females from median or large litters. Females also dispersed farther with increasing numbers of male siblings. However, the proportion of males in the litter was not related to dispersal distance of either sex. Males with two or more sisters dispersed farther than did males with fewer than two sisters. Males from their mother's first litter dispersed farther than males from subsequent litters; however, the presence or absence of the mother at the time of dispersal was not related to male dispersal distance. Our results suggest that inbreeding avoidance between siblings may lead to male-biased dispersal, and that interactions between siblings may be more important than interactions with the mother in determining dispersal distances.
ABSTRACT Studies demonstrating paternal care in Peromyscus leucopus are conflicting; laboratory e... more ABSTRACT Studies demonstrating paternal care in Peromyscus leucopus are conflicting; laboratory evidence suggests that males care for young at an early age, whereas evidence from small enclosures suggests that paternal care does not exist. This study demonstrates the association of fathers with their weaned young in a wild population of P. leucopus. Live trapping, nest boxes, radio telemetry and DNA fingerprinting were used to determine if and when males associate with their own young. We frequently observed adult males alone with juveniles of either sex after they were weaned. Paternity was likely in most cases, and was confirmed by DNA fingerprinting in some cases. We observed an adult male forage with >two young on two occasions. We did not observe adult females in association with weaned juveniles but often observed them with juveniles before weaning. These findings contradict laboratory studies in small cages and studies in small enclosures which did not observe associations of adult males with young after weaning.
We determined if various trap and nestbox census methods used during a 22-year monthly study yiel... more We determined if various trap and nestbox census methods used during a 22-year monthly study yielded consistent density estimates of the white-footed mouse (Peromyscus Zeucopus) in an Ohio woodlot. Because trap and nestbox census methods were used concurrently for only 32 months during the 22-year study, we also compared census methods that had been used sequentially by first removing seasonality using density-dependent parameters. Nestbox estimates were lower than trap estimates in summer and higher in winter, and the three variations in trap census methods used over 22 years did not result in different density estimates. Twenty-five percent of individuals caught in nestboxes were never caught in traps, and nestboxes increased densities by 7% by increasing nest-sites during the 15 years they remained in the woodlot. Because the <minimum number alive' estimator could not overestimate the population in an isolated woodlot, trap censuses underestimated the population in winter, and nestbox censuses accurately estimated the popUlation in late autumn and winter.
The agonistic and spacing behaviour of white-footed mice, Peromyscus leucopus, was quantified in ... more The agonistic and spacing behaviour of white-footed mice, Peromyscus leucopus, was quantified in the field throughout an entire year to test the hypothesis that mice engage in interference competition for resources such as food, shelter and mates. Rates of aggression and displacement in paired arena tests increased markedly from winter to spring and summer, and declined in autumn, corresponding to the breeding season but not to population density, which remained low. Mice caught for the first time lost significantly more encounters than previously captured mice and the majority of the mice that lost encounters were transients. In spring, residents displaced transients, and mice paired within their home range usually won. Adults usually displaced juveniles, and aggression occurred more often between males than between females. The mean distance from non-pregnant females to the nearest male was negatively correlated with pregnancy rate, suggesting that non-pregnant females were receptive to males. When few receptive females were available, the distances between neighbouring males were low and displacement rates were high, suggesting that males competed for mates. These findings generally support the idea that interference competition is an important component of the lives of these small mammals.
American Journal of Physical Anthropology, Mar 1, 1973
The nocturnal distribution and behavior of individually marked Macaca mulatta were studied at the... more The nocturnal distribution and behavior of individually marked Macaca mulatta were studied at the La Parguera, Puerto Rico, colony of the Caribbean Primate Research Center. The new image intensifier was used successfully to identify 399 monkeys in 185 sleeping clusters. Monkeys moved into mangrove trees close to favorite feeding areas usually 35 minutes after sunset. The group condensed to less than one-half the daytime spread, vocalizations increased and grooming ceased. Movements and vocalizations ceased several hours after sunset, although bursts of activity occurred throughout the night. Activity resumed 40 minutes before sunrise. Activity was higher during full moon, when I observed feeding, play and sexual behavior. Fights at night were twice as frequent during the breeding season. Monkeys slept in clusters of one to four, 58% of which were of two. Sixty-three percent were composed of maternal relatives, 33% were mother-infant pairs. Mature males clustered with non-related males, slept alone or with females (in the breeding season). Yearlings slept with their mothers or with older siblings. Distribution of monkeys in a group at night reflects daytime associations.
In this paper we review and integrate key aspects of behavioral and life history traits, food sup... more In this paper we review and integrate key aspects of behavioral and life history traits, food supply and population dynamics of the white-footed mouse (Peromyscus leucopus), a species that is abundant and widely distributed across much of eastern North America. Results are based largely on a 33-year mark-and-recapture study in a forest fragment in northwest Ohio, USA. Behavioral plasticity in such reproductive traits as mating system and parental care allows this species to adjust quickly to changing environments. The species has a relatively "fast" life history, with rapid attainment of sexual maturity and high fecundity in the face of high mortality rates. Maximal reproductive effort early in life enables a rapid population response. Food supply, in the form of mast, determines the size of the reproducing population in early spring, which, in turn, influences the size of the late summer peak population. The peak population size is also affected by short-term weather events possibly acting via the food supply. The effects of weather and food on population growth are in part mediated through competition, including defense of space and suppression of reproduction. The inelasticity of female territories appears to set an upper limit to population density.
Most previous work in population ecology has modeled density-dependent eects in isolation. In thi... more Most previous work in population ecology has modeled density-dependent eects in isolation. In this paper, we concurrently modeled the eect of densitydependent and density-independent factors on the rate of population change (R t) in Peromyscus leucopus (white-footed mouse), using a Ricker equation expanded to include weather and seasonality. From 1973 to 1996, we live-trapped P. leucopus monthly in a 2-ha Ohio woodlot. Population peaks (July to August) varied from 27 to 181 individuals, while troughs (December to March) varied from 4 to 46 individuals. We used timedelayed densities to act as surrogates for unobserved density-dependent factors, and principal components to represent 12 highly collinear weather variables. We identi®ed time-delayed correlations by season between R t and the independent variables (i.e., previous densities and weather principal components) using transfer function analysis. In summer, when P. leucopus densities were above the seasonal mean for the month, R t was lower in the following 2 months; however, in winter, R t was greater in the ®rst but lower in the second succeeding month. R t also correlated positively in autumn with contemporaneous precipitation, and was negatively correlated with`extreme' weather in summer with 2-and 3-month lags and in winter with a 3-month lag. We hypothesize that precipitation aected juveniles by in¯uencing food resources and that`extreme' weather aected breeding. Our model explained 65% of the variability in R t , and density-dependent and density-independent factors explained an equal percentage of that variability. This model created good forecasts of population density up to 12 months in the future.
The longitudinal survivorship of a group of free-ranging male and female rhesus monkeys from La P... more The longitudinal survivorship of a group of free-ranging male and female rhesus monkeys from La Parguera, Puerto Rico, was analyzed. Males had lower age-specific survivorship than females. There were no differences in the survivorship of daughters of high-and low-ranking mothers and there was no correlation between total number of offspring born and maternal rank for females. However, the sons of low-ranking mothers had lower survivorship than the sons of high-ranking females. This sex-related difference in survivorship, in conjunction with other evidence, indicates that the average lifetime reproduction of sons of low-ranking females is lower than that of daughters and vice versa for offspring of high-ranking females.
The seasonal appearance of mating activities and births of rhesus monkeys in a free-ranging colon... more The seasonal appearance of mating activities and births of rhesus monkeys in a free-ranging colony on two small islands near La Parguera, Puerto Rico, were recorded from the founding of the colony in 1962 to August 1966. Mating activities began in late August or September, reached a peak during November and December, and ceased in March or April. Except for a wide spread early in the colony's history, births were confined to the period from March to July, with 74% occurring during May and June. Lactating females began mating activities later than non-lactating females. The onset of mating typically followed vegetation changes associated with a period of high rainfall in late summer. The correlation between rainfall and mating activities, perhaps resulting from vegetational changes, also appears to be present at Cayo Santiago, another island colony of monkeys, and in Northern India, the natural home of the rhesus monkey.
... METHODS Colony History In 1962 approximately 250 rhesus monkeys were released on LaCueva and ... more ... METHODS Colony History In 1962 approximately 250 rhesus monkeys were released on LaCueva and Guayacan, two provisioned (with commercial monkey chow and water) island Page 3. ... FIG. 1.-Proportion of males born in social groups on La Cueva from 1964-1978. ...
... Group Changing in Free-Ranging Male Rhesus Monkeys LEE C. DRICKAMER Williams College ... ABST... more ... Group Changing in Free-Ranging Male Rhesus Monkeys LEE C. DRICKAMER Williams College ... ABSTRACT. Group changing behavior of male Macaea mulatta was studied over a six-year period at the rhesus monkey colony on two coastal islands at La Parguera, Puerto Rico. ...
This is a study of the effects of geographic transfer on the timing of seasonal breeding of free-... more This is a study of the effects of geographic transfer on the timing of seasonal breeding of free-living rhesus monkeys on Cayo Santiago and La Parguera islands in Puerto Rico. The results demonstrated a progressive shift in the breeding season of the transferred group. The full shift required a period of 2 years. Change from one environment to another produced shifts in onset of estrous. The explanation for this phenomenon proposes an interaction between the specific reproductive state of the female, which may or may not be sensitive to a particular environmental change, and the environmental variation which is correlated with onset of breeding.
We explored the relationship between reproductive success and parity in white-footed mice. Becaus... more We explored the relationship between reproductive success and parity in white-footed mice. Because these small mammals are short-lived and have low residual reproductive value in the field, we predicted, contrary to laboratory results, that litter size, weaning rates, and recruitment would not increase as a function of female age or parity. We used data from 3 years of mark-and-recapture trapping data and from nest boxes to estimate weaning and recruitment rates in a 2-ha woodlot in northwest Ohio. Of 401 mice from 82 litters born in nest boxes, 87 were recruited into the population as adults. We observed no increase in litter size, weaning rates, or recruitment with maternal age or parity, Season interacted with parity such that recruitment from spring-born litters produced by females having their first or second litters was four times higher than from all other litters. Litter size did not influence weaning rates and only affected recruitment when season and parity also were considered.
We explored the relationship between several aspects of the natal environment and dispersal dista... more We explored the relationship between several aspects of the natal environment and dispersal distances of white-footed mice, Perornyscus leucopus, in a 2-ha oak/hickory woodlot northeast of Bowling Green, Ohio, from 1991 to 1993. Litters of mice in nestboxes were marked at an early age. We evaluated litter size, the number of males and females in the litter, litter sex ratio, weanling survival to adulthood, and mother's parity as proximate factors that might affect dispersal. Dispersal was quantified as the straight-line distance between the mother's center of activity and that of her adult offspring. Of 401 mice from 82 litters, 78 (19.5%) were recaptured as adults. Males dispersed significantly farther than females. Females from small litters dispersed shorter distances than females from median or large litters. Females also dispersed farther with increasing numbers of male siblings. However, the proportion of males in the litter was not related to dispersal distance of either sex. Males with two or more sisters dispersed farther than did males with fewer than two sisters. Males from their mother's first litter dispersed farther than males from subsequent litters; however, the presence or absence of the mother at the time of dispersal was not related to male dispersal distance. Our results suggest that inbreeding avoidance between siblings may lead to male-biased dispersal, and that interactions between siblings may be more important than interactions with the mother in determining dispersal distances.
ABSTRACT Studies demonstrating paternal care in Peromyscus leucopus are conflicting; laboratory e... more ABSTRACT Studies demonstrating paternal care in Peromyscus leucopus are conflicting; laboratory evidence suggests that males care for young at an early age, whereas evidence from small enclosures suggests that paternal care does not exist. This study demonstrates the association of fathers with their weaned young in a wild population of P. leucopus. Live trapping, nest boxes, radio telemetry and DNA fingerprinting were used to determine if and when males associate with their own young. We frequently observed adult males alone with juveniles of either sex after they were weaned. Paternity was likely in most cases, and was confirmed by DNA fingerprinting in some cases. We observed an adult male forage with &gt;two young on two occasions. We did not observe adult females in association with weaned juveniles but often observed them with juveniles before weaning. These findings contradict laboratory studies in small cages and studies in small enclosures which did not observe associations of adult males with young after weaning.
We determined if various trap and nestbox census methods used during a 22-year monthly study yiel... more We determined if various trap and nestbox census methods used during a 22-year monthly study yielded consistent density estimates of the white-footed mouse (Peromyscus Zeucopus) in an Ohio woodlot. Because trap and nestbox census methods were used concurrently for only 32 months during the 22-year study, we also compared census methods that had been used sequentially by first removing seasonality using density-dependent parameters. Nestbox estimates were lower than trap estimates in summer and higher in winter, and the three variations in trap census methods used over 22 years did not result in different density estimates. Twenty-five percent of individuals caught in nestboxes were never caught in traps, and nestboxes increased densities by 7% by increasing nest-sites during the 15 years they remained in the woodlot. Because the <minimum number alive' estimator could not overestimate the population in an isolated woodlot, trap censuses underestimated the population in winter, and nestbox censuses accurately estimated the popUlation in late autumn and winter.
The agonistic and spacing behaviour of white-footed mice, Peromyscus leucopus, was quantified in ... more The agonistic and spacing behaviour of white-footed mice, Peromyscus leucopus, was quantified in the field throughout an entire year to test the hypothesis that mice engage in interference competition for resources such as food, shelter and mates. Rates of aggression and displacement in paired arena tests increased markedly from winter to spring and summer, and declined in autumn, corresponding to the breeding season but not to population density, which remained low. Mice caught for the first time lost significantly more encounters than previously captured mice and the majority of the mice that lost encounters were transients. In spring, residents displaced transients, and mice paired within their home range usually won. Adults usually displaced juveniles, and aggression occurred more often between males than between females. The mean distance from non-pregnant females to the nearest male was negatively correlated with pregnancy rate, suggesting that non-pregnant females were receptive to males. When few receptive females were available, the distances between neighbouring males were low and displacement rates were high, suggesting that males competed for mates. These findings generally support the idea that interference competition is an important component of the lives of these small mammals.
American Journal of Physical Anthropology, Mar 1, 1973
The nocturnal distribution and behavior of individually marked Macaca mulatta were studied at the... more The nocturnal distribution and behavior of individually marked Macaca mulatta were studied at the La Parguera, Puerto Rico, colony of the Caribbean Primate Research Center. The new image intensifier was used successfully to identify 399 monkeys in 185 sleeping clusters. Monkeys moved into mangrove trees close to favorite feeding areas usually 35 minutes after sunset. The group condensed to less than one-half the daytime spread, vocalizations increased and grooming ceased. Movements and vocalizations ceased several hours after sunset, although bursts of activity occurred throughout the night. Activity resumed 40 minutes before sunrise. Activity was higher during full moon, when I observed feeding, play and sexual behavior. Fights at night were twice as frequent during the breeding season. Monkeys slept in clusters of one to four, 58% of which were of two. Sixty-three percent were composed of maternal relatives, 33% were mother-infant pairs. Mature males clustered with non-related males, slept alone or with females (in the breeding season). Yearlings slept with their mothers or with older siblings. Distribution of monkeys in a group at night reflects daytime associations.
In this paper we review and integrate key aspects of behavioral and life history traits, food sup... more In this paper we review and integrate key aspects of behavioral and life history traits, food supply and population dynamics of the white-footed mouse (Peromyscus leucopus), a species that is abundant and widely distributed across much of eastern North America. Results are based largely on a 33-year mark-and-recapture study in a forest fragment in northwest Ohio, USA. Behavioral plasticity in such reproductive traits as mating system and parental care allows this species to adjust quickly to changing environments. The species has a relatively "fast" life history, with rapid attainment of sexual maturity and high fecundity in the face of high mortality rates. Maximal reproductive effort early in life enables a rapid population response. Food supply, in the form of mast, determines the size of the reproducing population in early spring, which, in turn, influences the size of the late summer peak population. The peak population size is also affected by short-term weather events possibly acting via the food supply. The effects of weather and food on population growth are in part mediated through competition, including defense of space and suppression of reproduction. The inelasticity of female territories appears to set an upper limit to population density.
Most previous work in population ecology has modeled density-dependent eects in isolation. In thi... more Most previous work in population ecology has modeled density-dependent eects in isolation. In this paper, we concurrently modeled the eect of densitydependent and density-independent factors on the rate of population change (R t) in Peromyscus leucopus (white-footed mouse), using a Ricker equation expanded to include weather and seasonality. From 1973 to 1996, we live-trapped P. leucopus monthly in a 2-ha Ohio woodlot. Population peaks (July to August) varied from 27 to 181 individuals, while troughs (December to March) varied from 4 to 46 individuals. We used timedelayed densities to act as surrogates for unobserved density-dependent factors, and principal components to represent 12 highly collinear weather variables. We identi®ed time-delayed correlations by season between R t and the independent variables (i.e., previous densities and weather principal components) using transfer function analysis. In summer, when P. leucopus densities were above the seasonal mean for the month, R t was lower in the following 2 months; however, in winter, R t was greater in the ®rst but lower in the second succeeding month. R t also correlated positively in autumn with contemporaneous precipitation, and was negatively correlated with`extreme' weather in summer with 2-and 3-month lags and in winter with a 3-month lag. We hypothesize that precipitation aected juveniles by in¯uencing food resources and that`extreme' weather aected breeding. Our model explained 65% of the variability in R t , and density-dependent and density-independent factors explained an equal percentage of that variability. This model created good forecasts of population density up to 12 months in the future.
The longitudinal survivorship of a group of free-ranging male and female rhesus monkeys from La P... more The longitudinal survivorship of a group of free-ranging male and female rhesus monkeys from La Parguera, Puerto Rico, was analyzed. Males had lower age-specific survivorship than females. There were no differences in the survivorship of daughters of high-and low-ranking mothers and there was no correlation between total number of offspring born and maternal rank for females. However, the sons of low-ranking mothers had lower survivorship than the sons of high-ranking females. This sex-related difference in survivorship, in conjunction with other evidence, indicates that the average lifetime reproduction of sons of low-ranking females is lower than that of daughters and vice versa for offspring of high-ranking females.
The seasonal appearance of mating activities and births of rhesus monkeys in a free-ranging colon... more The seasonal appearance of mating activities and births of rhesus monkeys in a free-ranging colony on two small islands near La Parguera, Puerto Rico, were recorded from the founding of the colony in 1962 to August 1966. Mating activities began in late August or September, reached a peak during November and December, and ceased in March or April. Except for a wide spread early in the colony's history, births were confined to the period from March to July, with 74% occurring during May and June. Lactating females began mating activities later than non-lactating females. The onset of mating typically followed vegetation changes associated with a period of high rainfall in late summer. The correlation between rainfall and mating activities, perhaps resulting from vegetational changes, also appears to be present at Cayo Santiago, another island colony of monkeys, and in Northern India, the natural home of the rhesus monkey.
... METHODS Colony History In 1962 approximately 250 rhesus monkeys were released on LaCueva and ... more ... METHODS Colony History In 1962 approximately 250 rhesus monkeys were released on LaCueva and Guayacan, two provisioned (with commercial monkey chow and water) island Page 3. ... FIG. 1.-Proportion of males born in social groups on La Cueva from 1964-1978. ...
... Group Changing in Free-Ranging Male Rhesus Monkeys LEE C. DRICKAMER Williams College ... ABST... more ... Group Changing in Free-Ranging Male Rhesus Monkeys LEE C. DRICKAMER Williams College ... ABSTRACT. Group changing behavior of male Macaea mulatta was studied over a six-year period at the rhesus monkey colony on two coastal islands at La Parguera, Puerto Rico. ...
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Papers by Stephen Vessey