Hugh Broders - Academia.edu (original) (raw)

Papers by Hugh Broders

PloS one, 2015

Migratory patterns of bats are not well understood and traditional methods to study this, like ca... more Migratory patterns of bats are not well understood and traditional methods to study this, like capture-mark-recapture, may not provide enough detail unless there are many records. Stable isotope profiles of many animal species have been used to make inferences about migration. Each year Myotis lucifugus and M. septentrionalis migrate from summering roosts to swarming caves and mines in the fall, but the pattern of movement between them is not well understood. In this study, fur δ13C and δ15N values of 305 M. lucifugus and 200 M. septentrionalis were analyzed to make inferences about migration patterns between summering areas and swarming sites in Nova Scotia, Canada. We expected that there would be greater variability in δ13C and δ15N among individuals at swarming sites because it was believed that these sites are used by individuals originating from many summering areas. There was extensive overlap in the standard ellipse area, corrected for small sample sizes (SEAc), of bats at sw...

Characterizing movement dynamics and spatial aspects of gene flow within a species permits infere... more Characterizing movement dynamics and spatial aspects of gene flow within a species permits inference on population structuring. As patterns of structuring are products of historical and current demographics and gene flow, assessment of structure through time can yield an understanding of evolutionary dynamics acting on populations that are necessary to inform management. Recent dramatic population declines in hibernating bats in eastern North America from white-nose syndrome have prompted the need for information on movement dynamics for multiple bat species. We characterized population genetic structure of the little brown bat, Myotis lucifugus, at swarming sites in southeastern Canada using 9 nuclear microsatellites and a 292-bp region of the mitochondrial genome. Analyses of F ST , Φ ST, and Bayesian clustering (STRUCTURE) found weak levels of genetic structure among swarming sites for the nuclear and mitochondrial genome (Global F ST = 0.001, P < 0.05, Global Φ ST = 0.045, P < 0.01, STRUCTURE K = 1) suggesting high contemporary gene flow. Hierarchical AMOVA also suggests little structuring at a regional (provincial) level. Metrics of nuclear genetic structure were not found to differ between males and females suggesting weak asymmetries in gene flow between the sexes. However, a greater degree of mitochondrial structuring does support male-biased dispersal long term. Demographic analyses were consistent with past population growth and suggest a population expansion occurred from approximately 1250 to 12,500 BP, following Pleistocene deglaciation in the region. Our study suggests high gene flow and thus a high degree of connectivity among bats that visit swarming sites whereby mainland areas of the region may be best considered as one large gene pool for management and conservation.

Fragmentation and loss of natural habitat are considered major threats to global biodiversity, wi... more Fragmentation and loss of natural habitat are considered major threats to global biodiversity, with the impact of forest harvesting of particular concern in many regions. A reduction in the size and connectivity of natural habitats as a result of forest harvesting practices has the potential to fragment and isolate populations of organisms. Evaluation of the effects of disturbance on ecological

Neuropeptides, 2008

Neonatal manipulation of oxytocin (OT) has long-term effects on behavior and physiology. The obje... more Neonatal manipulation of oxytocin (OT) has long-term effects on behavior and physiology. The objective of this research was to determine if neonatal exposure to OT can affect partner preferences and to characterize the mechanisms underlying social behavior such as neural activities of relevant brain regions in socially monogamous mandarin voles (Microtus mandarinus). After receiving a subcutaneous injection of isotonic saline (SAL) or OT within 24 h of birth, mandarin vole at 60 days of age was paired with an unfamiliar opposite sex for 24 h, followed immediately by an examination of their partner preference and 30 days later by the second examination of their partner preference and Fos expression in some brain regions. The results indicated that (1) while 24 h cohabitation was insufficient for both female and male SAL-treated mandarin voles to form partner preference, neonatal exposure to OT significantly facilitate female, but not male mandarin voles to form partner preference within 24 h of cohabitation; (2) the maintenance of partner preference in females was suppressed by neonatal OT treatment, while neonatal OT-treated males showed significant partner preference as neonatal SAL-treated males and females; in addition, the tendency of aggression to the strangers was impaired in both females and males, and neonatal OT-treated males showed significantly higher mounting behavior to the partner;

Molecular Ecology, 2013

Variation in prey resources influences the diet and behaviour of predators. When prey become limi... more Variation in prey resources influences the diet and behaviour of predators. When prey become limiting, predators may travel farther to find preferred food or adjust to existing local resources. When predators are habitat limited, local resource abundance impacts foraging success. We analysed the diet of Myotis lucifugus (little brown bats) from Nova Scotia (eastern Canada) to the Northwest Territories (north-western Canada). This distribution includes extremes of season length and temperature and encompasses colonies on rural monoculture farms, and in urban and unmodified areas. We recognized nearly 600 distinct species of prey, of which ≈30% could be identified using reference sequence libraries. We found a higher than expected use of lepidopterans, which comprised a range of dietary richness from ≈35% early in the summer to ≈55% by late summer. Diptera were the second largest prey group consumed, representing ≈45% of dietary diversity early in the summer. We observed extreme local dietary variability and variation among seasons and years. Based on the species of insects that were consumed, we observed that two locations support prey species with extremely low pollution and acidification tolerances, suggesting that these are areas without environmental contamination. We conclude that there is significant local population variability in little brown bat diet that is likely driven by seasonal and geographical changes in insect diversity, and that this prey may be a good indicator of environment quality.

Experimental Animals, 2011

Mood disorders are more frequent in women than men, however, the majority of research has focused... more Mood disorders are more frequent in women than men, however, the majority of research has focused on male rodents as animal models. We used a variety of common behavioral tests to look for differences in anxiety-like and social behaviors between and within C57BL/6J and BALB/cJ mice. Our results show that female C57BL/6J mice exhibited lower levels of anxiety-like behavior and higher levels of activity than female BALB/cJ during the open field and elevated plus maze tests. Principal component analysis generated more factors in the behavioral variables of males than females. In the open field, a sex difference was also found and factor 1 emerged as anxiety in males, and motor activity in females. While C57BL/6J mice were found to have higher levels of social exploration and social contacts, differences were found between the sexes (females were more social) in both strains for this measure and also for anxiety-like behaviors. When interacting with animals of the same sex, levels of sniffing body and huddling in both male and female C57BL/6J mice were higher than those in male and female BALB/cJ mice. However, in the between-sex interactions, male C57BL/6J mice sniffed the stimulus mouse less, and female C57BL/6J mice sniffed the stimulus more compared to BALB/cJ mice. This study provides important behavioral phenotypes and confirms the multidimensional behavioral structure of two widely used mice strains.

Behavioural Brain Research, 2010

Various hypotheses have been proposed to explain factors influencing male alloparental behavior i... more Various hypotheses have been proposed to explain factors influencing male alloparental behavior in cooperatively breeding species. Mandarin voles (Microtus mandarinus) are ideal animal models to investigate these factors because they are highly social rodents and display biparental care and spontaneous parental care when exposed to foster pups. Here we test the idea that the sexual and paternal experience of males influences alloparental behavior toward novel pups, and that these experiences alter the expression of neuropeptide oxytocin (OT) and estrogen receptor alpha (ER␣). Alloparental behavior and OT and ER␣ expression were compared between virgin males that had no prior sexual or reproductive experience, exposed males that with prior exposure to novel pups before the test, paired males that had been housed with a female, and new fathers having their first litter with a female. Our results show that prior exposure to novel pups and prior mating and paternal experience increased male alloparental behavior toward a novel pup. This experience also increased OT expression and affected the expression of ER␣. This study reveals important initiation factors for male alloparental behavior and suggests a relationship between alloparental behavior and central OT expression in males.

Early deprivation is popularly used in rodent models as an early life social stress to investigat... more Early deprivation is popularly used in rodent models as an early life social stress to investigate and determine the factors that affect the development of the brain and behavior. Ultrasonic calls made by pups play an important role in parental-pup interactions during the neonatal period. However, whether repeated early deprivation affects the properties of ultrasonic vocalizations (USVs) produced by mandarin vole (Microtus mandarinus) pups, and whether ontogenetic development is subsequently affected, remains unclear. Here we measured USVs and developmental parameters in mandarin vole pups deprived of their parents and littermates for 3h per day (ED, which is significantly different from 5 min isolation used to induce USVs) and another pup group developed under normal nest conditions (PC). Repeated measures analysis indicated that the number of USVs from ED pups was significantly lower than those from PC pups during the postnatal period (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The pulse durations of ED pups were longer than those of PC pups at two (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) and five days of age (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), but shorter at 14 days of age (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Compared with PC pups, the frequency range of the ED pups was wider at 18-45 kHZ, variable during the first week, smaller and narrower at 18-30 kHZ at eight and 11 days of age, and became stable similar to PC pups at 25 kHZ after 14 days of age. ED also reduced pup body weight significantly and resulted in earlier eye opening compared with PC pups (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). A positive relationship was also found between USV emissions and levels of parental care received by pups. It appears that pup USVs are an important age-dependent behavioral phenotype and an effective communicative method between parents and offspring. Prolonged parental and littermate deprivation (ED) may alter USVs emitted by pups and then ontogenetic development and parental care. Mandarin voles show USV properties similar to socially monogamous rodents and this add further support to the hypothesis that species with different social systems produce different patterns of ultrasonic vocalizations. USVs, ontogenetic development and parental care are closely associated.

PloS one, 2015

Migratory patterns of bats are not well understood and traditional methods to study this, like ca... more Migratory patterns of bats are not well understood and traditional methods to study this, like capture-mark-recapture, may not provide enough detail unless there are many records. Stable isotope profiles of many animal species have been used to make inferences about migration. Each year Myotis lucifugus and M. septentrionalis migrate from summering roosts to swarming caves and mines in the fall, but the pattern of movement between them is not well understood. In this study, fur δ13C and δ15N values of 305 M. lucifugus and 200 M. septentrionalis were analyzed to make inferences about migration patterns between summering areas and swarming sites in Nova Scotia, Canada. We expected that there would be greater variability in δ13C and δ15N among individuals at swarming sites because it was believed that these sites are used by individuals originating from many summering areas. There was extensive overlap in the standard ellipse area, corrected for small sample sizes (SEAc), of bats at sw...

Characterizing movement dynamics and spatial aspects of gene flow within a species permits infere... more Characterizing movement dynamics and spatial aspects of gene flow within a species permits inference on population structuring. As patterns of structuring are products of historical and current demographics and gene flow, assessment of structure through time can yield an understanding of evolutionary dynamics acting on populations that are necessary to inform management. Recent dramatic population declines in hibernating bats in eastern North America from white-nose syndrome have prompted the need for information on movement dynamics for multiple bat species. We characterized population genetic structure of the little brown bat, Myotis lucifugus, at swarming sites in southeastern Canada using 9 nuclear microsatellites and a 292-bp region of the mitochondrial genome. Analyses of F ST , Φ ST, and Bayesian clustering (STRUCTURE) found weak levels of genetic structure among swarming sites for the nuclear and mitochondrial genome (Global F ST = 0.001, P < 0.05, Global Φ ST = 0.045, P < 0.01, STRUCTURE K = 1) suggesting high contemporary gene flow. Hierarchical AMOVA also suggests little structuring at a regional (provincial) level. Metrics of nuclear genetic structure were not found to differ between males and females suggesting weak asymmetries in gene flow between the sexes. However, a greater degree of mitochondrial structuring does support male-biased dispersal long term. Demographic analyses were consistent with past population growth and suggest a population expansion occurred from approximately 1250 to 12,500 BP, following Pleistocene deglaciation in the region. Our study suggests high gene flow and thus a high degree of connectivity among bats that visit swarming sites whereby mainland areas of the region may be best considered as one large gene pool for management and conservation.

Fragmentation and loss of natural habitat are considered major threats to global biodiversity, wi... more Fragmentation and loss of natural habitat are considered major threats to global biodiversity, with the impact of forest harvesting of particular concern in many regions. A reduction in the size and connectivity of natural habitats as a result of forest harvesting practices has the potential to fragment and isolate populations of organisms. Evaluation of the effects of disturbance on ecological

Neuropeptides, 2008

Neonatal manipulation of oxytocin (OT) has long-term effects on behavior and physiology. The obje... more Neonatal manipulation of oxytocin (OT) has long-term effects on behavior and physiology. The objective of this research was to determine if neonatal exposure to OT can affect partner preferences and to characterize the mechanisms underlying social behavior such as neural activities of relevant brain regions in socially monogamous mandarin voles (Microtus mandarinus). After receiving a subcutaneous injection of isotonic saline (SAL) or OT within 24 h of birth, mandarin vole at 60 days of age was paired with an unfamiliar opposite sex for 24 h, followed immediately by an examination of their partner preference and 30 days later by the second examination of their partner preference and Fos expression in some brain regions. The results indicated that (1) while 24 h cohabitation was insufficient for both female and male SAL-treated mandarin voles to form partner preference, neonatal exposure to OT significantly facilitate female, but not male mandarin voles to form partner preference within 24 h of cohabitation; (2) the maintenance of partner preference in females was suppressed by neonatal OT treatment, while neonatal OT-treated males showed significant partner preference as neonatal SAL-treated males and females; in addition, the tendency of aggression to the strangers was impaired in both females and males, and neonatal OT-treated males showed significantly higher mounting behavior to the partner;

Molecular Ecology, 2013

Variation in prey resources influences the diet and behaviour of predators. When prey become limi... more Variation in prey resources influences the diet and behaviour of predators. When prey become limiting, predators may travel farther to find preferred food or adjust to existing local resources. When predators are habitat limited, local resource abundance impacts foraging success. We analysed the diet of Myotis lucifugus (little brown bats) from Nova Scotia (eastern Canada) to the Northwest Territories (north-western Canada). This distribution includes extremes of season length and temperature and encompasses colonies on rural monoculture farms, and in urban and unmodified areas. We recognized nearly 600 distinct species of prey, of which ≈30% could be identified using reference sequence libraries. We found a higher than expected use of lepidopterans, which comprised a range of dietary richness from ≈35% early in the summer to ≈55% by late summer. Diptera were the second largest prey group consumed, representing ≈45% of dietary diversity early in the summer. We observed extreme local dietary variability and variation among seasons and years. Based on the species of insects that were consumed, we observed that two locations support prey species with extremely low pollution and acidification tolerances, suggesting that these are areas without environmental contamination. We conclude that there is significant local population variability in little brown bat diet that is likely driven by seasonal and geographical changes in insect diversity, and that this prey may be a good indicator of environment quality.

Experimental Animals, 2011

Mood disorders are more frequent in women than men, however, the majority of research has focused... more Mood disorders are more frequent in women than men, however, the majority of research has focused on male rodents as animal models. We used a variety of common behavioral tests to look for differences in anxiety-like and social behaviors between and within C57BL/6J and BALB/cJ mice. Our results show that female C57BL/6J mice exhibited lower levels of anxiety-like behavior and higher levels of activity than female BALB/cJ during the open field and elevated plus maze tests. Principal component analysis generated more factors in the behavioral variables of males than females. In the open field, a sex difference was also found and factor 1 emerged as anxiety in males, and motor activity in females. While C57BL/6J mice were found to have higher levels of social exploration and social contacts, differences were found between the sexes (females were more social) in both strains for this measure and also for anxiety-like behaviors. When interacting with animals of the same sex, levels of sniffing body and huddling in both male and female C57BL/6J mice were higher than those in male and female BALB/cJ mice. However, in the between-sex interactions, male C57BL/6J mice sniffed the stimulus mouse less, and female C57BL/6J mice sniffed the stimulus more compared to BALB/cJ mice. This study provides important behavioral phenotypes and confirms the multidimensional behavioral structure of two widely used mice strains.

Behavioural Brain Research, 2010

Various hypotheses have been proposed to explain factors influencing male alloparental behavior i... more Various hypotheses have been proposed to explain factors influencing male alloparental behavior in cooperatively breeding species. Mandarin voles (Microtus mandarinus) are ideal animal models to investigate these factors because they are highly social rodents and display biparental care and spontaneous parental care when exposed to foster pups. Here we test the idea that the sexual and paternal experience of males influences alloparental behavior toward novel pups, and that these experiences alter the expression of neuropeptide oxytocin (OT) and estrogen receptor alpha (ER␣). Alloparental behavior and OT and ER␣ expression were compared between virgin males that had no prior sexual or reproductive experience, exposed males that with prior exposure to novel pups before the test, paired males that had been housed with a female, and new fathers having their first litter with a female. Our results show that prior exposure to novel pups and prior mating and paternal experience increased male alloparental behavior toward a novel pup. This experience also increased OT expression and affected the expression of ER␣. This study reveals important initiation factors for male alloparental behavior and suggests a relationship between alloparental behavior and central OT expression in males.

Early deprivation is popularly used in rodent models as an early life social stress to investigat... more Early deprivation is popularly used in rodent models as an early life social stress to investigate and determine the factors that affect the development of the brain and behavior. Ultrasonic calls made by pups play an important role in parental-pup interactions during the neonatal period. However, whether repeated early deprivation affects the properties of ultrasonic vocalizations (USVs) produced by mandarin vole (Microtus mandarinus) pups, and whether ontogenetic development is subsequently affected, remains unclear. Here we measured USVs and developmental parameters in mandarin vole pups deprived of their parents and littermates for 3h per day (ED, which is significantly different from 5 min isolation used to induce USVs) and another pup group developed under normal nest conditions (PC). Repeated measures analysis indicated that the number of USVs from ED pups was significantly lower than those from PC pups during the postnatal period (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The pulse durations of ED pups were longer than those of PC pups at two (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) and five days of age (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), but shorter at 14 days of age (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Compared with PC pups, the frequency range of the ED pups was wider at 18-45 kHZ, variable during the first week, smaller and narrower at 18-30 kHZ at eight and 11 days of age, and became stable similar to PC pups at 25 kHZ after 14 days of age. ED also reduced pup body weight significantly and resulted in earlier eye opening compared with PC pups (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). A positive relationship was also found between USV emissions and levels of parental care received by pups. It appears that pup USVs are an important age-dependent behavioral phenotype and an effective communicative method between parents and offspring. Prolonged parental and littermate deprivation (ED) may alter USVs emitted by pups and then ontogenetic development and parental care. Mandarin voles show USV properties similar to socially monogamous rodents and this add further support to the hypothesis that species with different social systems produce different patterns of ultrasonic vocalizations. USVs, ontogenetic development and parental care are closely associated.