Factors Influencing the Post-Release Movements of Translocated Fishers: Implications for Translocation Success

Long distance, post-release movements of translocated wildlife can be a key factor limiting translocation success. Yet, for many species, we have little or no understanding of factors that influence post-release movements. Translocations have been important for recovering fisher Pekania pennanti populations across the southern portion of their North American range. However, little is known about the post-release movements of translocated fishers and how these movements may be influenced by demographic or translocation-process factors. To restore fishers in Washington State, we moved 90 fishers from central British Columbia and released them at nine sites in the Olympic Fisher Recovery Area on the Olympic Peninsula of Washington from 2008 to 2010. We evaluated post-release movements of 48 fishers to determine both the distance and duration of movements prior to home range establishment. Fishers moved extensively following their release. Multi-model selection indicated a high level of support for the hypothesis that post-release movements differed by fisher sex and age; whereas, year of release had no apparent effect on movements, and release date had only a marginal influence on male movements. Mean distance (± 95% CI) from a release site to a home range was greater for adult males (62.0 ± 19.6 km) than for juvenile males (31.4 ± 16.0 km), adult females (30.9 ± 21.1 km), and juvenile females (29.0 ± 13.5 km). Mean number of days from release until home range establishment was similar for the sexes, however the variance in movement duration was greater for females. Twenty-six of 27 females established home ranges over an 11-month period (December-October), while 19 of 21 males did so within a 4-month period (April-July). Mean home range sizes differed between males (128.3 ± 21.1 km2) and females (63.5 ± 9.0 km2) and were among the largest reported for the species. A greater proportion of females (18 of 27; 67%) than males (8 of 21; 38%) established home ranges within or partially within the recovery area. Six females left a previously established home range during the breeding season, presumably to find breeding males. Given the large distances that fishers can move following release, translocation success could be furthered by releasing individuals at fewer sites in the interior of large reintroduction areas to facilitate greater exposure to a recovery area and greater opportunity to interact with conspecifics and potential mates.

Behavioural Competition in the Intertidal Shore Crab, Petrolisthes elongatus

<p>Competition is a well-documented ecological interaction that underpins community structures and much of population ecology. Physical characteristics such as size, age, sex and weaponry all have an important part to play in how an organism competes, and for many animals, competition is mediated by behavioural patterns. Outcomes of these competitive interactions are not only driven by these characteristics, but by the environmental conditions and external pressures that influence them. The focal species of my study is Petrolisthes elongatus (H. Milne Edwards, 1837), a porcellanid crab that aggregates in high densities among cobblestone beaches along the intertidal shores of New Zealand and Tasmania. They utilize rocks and crevices as shelter spaces to protect themselves from environmental and predation pressures, displaying variation in physical characteristics, such as sexual dimorphism and autotomy, as well as high levels of behavioural complexity. I used laboratory experiments with crabs collected from the field and placed them in shelter-limited tanks under the following comparisons; 1) adult and juvenile males, 2) males and females, 3) ovigerous and non-ovigerous females, and 4) autotomized and non-autotomized males. For each of these experiments I used three different environmental conditions; 1) a control high tide, 2) a low tide treatment (where water was drained from the experimental tank), and 3) with the presence of a predator, a juvenile spiny rock lobster (Jasus edwarsii). Each experiment was recorded for 8 hours, where time spent under shelter and shoving interactions among individuals were counted. In the adult vs. juvenile and male vs. female experiments, smaller individuals spent a significantly more time under shelter than larger conspecifics, but increasing size resulted in more time spent under shelter in the autotomized vs. non-autotomized experiment. In all experiments, smaller individuals initiated the least amount of competitive interactions, and each size class was more likely to displace a smaller individual from a shelter, than a larger one. There was no significant difference in the time spent under shelter between males and females, but ovigerous females and autotomized males spent significantly more time under shelter than their respective competitors. Males also engaged in more shoving interactions than females, with smaller classes of males displacing larger classes of females from shelter spaces. Ovigerous females also outcompeted non-ovigerous conspecifics in the large majority of competitive interactions, and autotomized individuals engaged in significantly more contests than non-autotomized conspecifics. In all experiments, the presence of a predator had no effect on the number of shoving interactions and only resulted in an increase in time spent under shelter for individuals in the male vs. female and ovigerous vs. non-ovigerous experiments. A field survey on body to cheliped size ratios, autotomy and claw punctures counts was also conducted in support of the shelter-competition experiments. Crabs were collected over a one-month period in November 2018, brought back to the lab to be sexed, measured (Carapace Width, BW; and Cheliped Length, CL) and then surveyed for autotomy and claw puncture wounds. Juveniles of both sex (BW =</p>

Behavioural Competition in the Intertidal Shore Crab, Petrolisthes elongatus

<p>Competition is a well-documented ecological interaction that underpins community structures and much of population ecology. Physical characteristics such as size, age, sex and weaponry all have an important part to play in how an organism competes, and for many animals, competition is mediated by behavioural patterns. Outcomes of these competitive interactions are not only driven by these characteristics, but by the environmental conditions and external pressures that influence them. The focal species of my study is Petrolisthes elongatus (H. Milne Edwards, 1837), a porcellanid crab that aggregates in high densities among cobblestone beaches along the intertidal shores of New Zealand and Tasmania. They utilize rocks and crevices as shelter spaces to protect themselves from environmental and predation pressures, displaying variation in physical characteristics, such as sexual dimorphism and autotomy, as well as high levels of behavioural complexity. I used laboratory experiments with crabs collected from the field and placed them in shelter-limited tanks under the following comparisons; 1) adult and juvenile males, 2) males and females, 3) ovigerous and non-ovigerous females, and 4) autotomized and non-autotomized males. For each of these experiments I used three different environmental conditions; 1) a control high tide, 2) a low tide treatment (where water was drained from the experimental tank), and 3) with the presence of a predator, a juvenile spiny rock lobster (Jasus edwarsii). Each experiment was recorded for 8 hours, where time spent under shelter and shoving interactions among individuals were counted. In the adult vs. juvenile and male vs. female experiments, smaller individuals spent a significantly more time under shelter than larger conspecifics, but increasing size resulted in more time spent under shelter in the autotomized vs. non-autotomized experiment. In all experiments, smaller individuals initiated the least amount of competitive interactions, and each size class was more likely to displace a smaller individual from a shelter, than a larger one. There was no significant difference in the time spent under shelter between males and females, but ovigerous females and autotomized males spent significantly more time under shelter than their respective competitors. Males also engaged in more shoving interactions than females, with smaller classes of males displacing larger classes of females from shelter spaces. Ovigerous females also outcompeted non-ovigerous conspecifics in the large majority of competitive interactions, and autotomized individuals engaged in significantly more contests than non-autotomized conspecifics. In all experiments, the presence of a predator had no effect on the number of shoving interactions and only resulted in an increase in time spent under shelter for individuals in the male vs. female and ovigerous vs. non-ovigerous experiments. A field survey on body to cheliped size ratios, autotomy and claw punctures counts was also conducted in support of the shelter-competition experiments. Crabs were collected over a one-month period in November 2018, brought back to the lab to be sexed, measured (Carapace Width, BW; and Cheliped Length, CL) and then surveyed for autotomy and claw puncture wounds. Juveniles of both sex (BW =</p>

Hepatic global DNA Hypomethylation Phenotype in Rainbow Trout Fed Diets Varying in Carbohydrate to Protein Ratio

Background A high carbohydrate-low protein diet can induce hepatic global DNA hypomethylation in trout. The mechanisms remain unclear. Objective We aimed to investigate whether increase in dietary carbohydrates (dHC) or decrease in dietary proteins (dLP) can cause hepatic global DNA hypomethylation, and to explore the underlying mechanisms in trout. Methods Two feeding trials were conducted on juvenile males, both of which involved a 4-day fasting and 4-day refeeding protocol. In Trial 1, trout were fed either a high protein-no carbohydrate (HP-NC, protein 60% dry matter (DM), carbohydrates 0% DM) or a moderate protein-high carbohydrate (MP-HC, protein 40% DM, carbohydrates 30% DM) diet. In Trial 2, fish were fed either a moderate protein-no carbohydrate (MP-NC, protein 40% DM, carbohydrates 0% DM), a MP-HC (protein 40% DM, carbohydrates 30% DM), or a low protein-no carbohydrate (LP-NC, protein 20% DM, carbohydrates 0% DM) diet to separate the effects of dHC and dLP on the hepatic methylome. Global CmCGG methylation, DNA demethylation derivative levels, and mRNA expression of DNA (de)methylation-related genes were measured. Differences were tested by one-way ANOVA when data were normally distributed or by Kruskal-Wallis non-parametric test if not. Results In both trails, global CmCGG methylation levels remained unaffected, but the hepatic 5-mdC content decreased after refeeding (1–3%). The MP-HC group had 3.4-fold higher hepatic 5-hmdC and a similar 5-mdC level compared to the HP-NC group in Trial 1. Both MP-HC and LP-NC diets lowered the hepatic 5-mdC content (1–2%), but only the LP-NC group had a significantly lower 5-hmdC level (P &lt; 0.01) compared with MP-NC group in Trail 2. Conclusions dHC and dLP independently induced hepatic global DNA demethylation in trout. The alterations in other methylation derivatives levels indicated the demethylation process was achieved through an active demethylation pathway and probably occurred at non-CmCGG sites.

Which birds participate in mass concentrations of Bramblings Fringilla montifringilla?—Ring recoveries, biometry, age and sex composition

The Brambling Fringilla montifringilla combines several special features of migration and wintering: differential migration according to age and sex groups, large differences in winter densities as a response to food availability, and flocking behaviour as a response to local mass fructification of the beech Fagus sp. resulting in roosts of several million birds. This study examines (a) whether Bramblings participating in mass concentrations originate from different, or additional, breeding grounds compared with birds present in normal winters, and (b) how differential migration according to age and sex groups combines with irruptive migration and with congregations in mass roosts, i.e., whether the benefits from mass concentrations differ between age and sex groups. Wing biometry (wing length, lengths of outer primaries, and wing pointedness) did not vary geographically, as shown by museum skins, and was therefore not helpful to reveal differences in origin between birds of mass concentrations and normal winters. The extent of the post-juvenile moult was smaller in mass concentration birds and suggests that slightly later-born juveniles, i.e., born further east or north, participate in mass concentrations. Ringing recoveries could not demonstrate a difference in breeding range origin of Bramblings which participate in mass concentrations versus Bramblings in normal winters in Switzerland. However, this may be due to insufficient recoveries of ringed birds. A rough estimate suggests that the number of Bramblings migrating SW on a broad front across Europe could be sufficient to form mass concentrations of up to 10 million birds which are halted by a large area of beech mast. Across Europe, the proportion of juvenile males decreased towards south (i.e., with increasing migration distance) in autumn migrants and wintering birds, while adult females showed the opposite pattern, and adult males and juvenile females were intermediate. Mass concentrations in Switzerland were composed of significantly more adults, especially adult males, and fewer juveniles, particularly juvenile females, while the sex–age composition outside mass concentrations was similar to normal winters. Adults and females likely benefit from wintering further south where snow is less likely to cover food of this ground-feeding finch. On the other hand, the costs of migration are probably substantial in terms of direct costs or indirectly in terms of reaching the breeding grounds, so that juvenile males prefer to winter closer to the breeding area than adults. Feeding in large flocks in beech mast areas incurs the high risk of being cut off from this food by snowfall. Adult males are apparently best adapted to this risk, and hence predominate in mass concentrations.

Is Play Sexually Dimorphic in the Polygamous Squirrel Monkey?

Play behavior is widespread in juvenile mammals and may be a mechanism for practicing skills needed in adulthood. In mammals characterized by strong adult male competition over females, juvenile males perform more social play than do females, and such play may assist in later mating competition. This study examined whether social play behavior is sexually dimorphic in a polygamous neotropical primate, the squirrel monkey (Saimiri collinsi), through a six-week field study of two groups of wild monkeys in Eastern Amazonia, Brazil. We hypothesized that males would conduct more rough-and-tumble play than females and that any sex-based play differences would be more evident in older juveniles. We video recorded juvenile play bouts and scored: age category (younger or older juvenile) and sex of players (male or female); and rough-and-tumble play behaviors (i.e., bite, grab, and wrestle). Juvenile males initiated more play bouts than did females. Most players were older juvenile males, while older juvenile females were the least represented. Older juvenile play bouts occurred mostly among males, while younger juvenile bouts consisted of a more even sex distribution. While younger juveniles did not significantly affect the number of rough-and-tumble behaviors in bouts, the number of behaviors was significantly affected by the sex of older individuals. These results indicate that social play is sexually dimorphic in juvenile S. collinsi; specifically, males play more than females and sex differences are more pronounced in older cohorts. KEYWORDS: Squirrel Monkeys; Mating System; Sexual Dimorphism; Juvenile Period; Development; Play Behavior; Social Behavior; Ethology

Insulin-Like Growth Factor I and Prolactin Levels in Chimpanzees (Pan troglodyte) Across the Lifespan

As human and chimpanzee genomes show high homology for IGF1 and PRL, we analyzed sera of 367 healthy chimpanzees obtained during routine physical examinations in a single colony and measured chimpanzee insulin-like growth factor (IGF)-I and prolactin (PRL) levels across the lifespan using standard human immunoassays. Assuming chimpanzee IGF-I levels peak during puberty as in humans, we randomly defined puberty as the age at which most IGF-I levels were equal to or above the 90 th percentile for each sex (males, ages ≥7.00 but &lt;9.20 years; females, ≥5.00 but &lt;8.00 years). IGF-I levels steadily increased at a similar rate in juvenile males and females and peaked in puberty, strongly correlating with age, then slowly decreased faster in adult males than in adult females. As a group, males had higher mean IGF-I level than did females, but comparison by age category showed similar mean IGF-I levels in males and females. PRL levels increased with age in females more than males and levels were twice as high in females than in males. One pubertal male reported to have short stature had lower IGF-I and weight compared with other males in the age group, confirming suspected GH deficiency; a second male of normal height but low IGF-I may have had delayed puberty. Overall, results show differences in IGF-I levels over the lifespan in this cohort of chimpanzees largely mimic those seen in humans, while patterns of PRL changes are less similar.

Sex-Specific Variation of Social Play in Wild Immature Tibetan Macaques, Macaca thibetana

Theories proposed to explain social play have centered on its function in establishing social relationships critical for adulthood, its function in developing motor skills needed to survive, and promoting cognitive development and social learning. In this study, we compared variations in social play among infant and juvenile male and female Macaca thibetana. Given that this species is characterized by female philopatry and male dispersal, we hypothesized that immature females use social play as a mechanism to develop bonds that persist through adulthood whereas immature males use play to develop social skills needed to successfully enter new groups. The results indicated that social play steadily increased during the infant period and peaked at approximately 12 months of age. There were no significant differences in the frequency or types of social play exhibited between infant males and infant females. During the juvenile period, however, social play was found to decrease with age, with males engaging in social play more frequently than juvenile females. Moreover, whereas juvenile males engaged in more aggressive forms of play, juvenile females engaged in more affiliative forms of play. In addition, juvenile females engaged in higher rates of grooming than juvenile males. These results provide evidence of sex-specific differences and imply the functional variation of social play in Tibetan macaques, with immature males using social play to develop skills needed to enter and enhanced their dominance rank in a new social group and immature females using social play to develop long-term same-sex social bonds in their natal group.

Sighting heterogeneity of right whales in the western North Atlantic: 1980-1992

The population of western North Atlantic right whales (Eubalaena glacialis) is distributed primarily between Florida, USA and NovaScotia, Canada, aggregating seasonally in five geographically distinct, high-use areas. To test the effectiveness of monitoring alldemographic classes (juvenile and adult males and females) of the population in these five habitat areas, an evaluation was carried out ofthe identification records of catalogued right whales collected between 1980 and 1992, for which the age, sex and reproductive status (foradult females) were known. The mean annual identification frequency of adult females was significantly lower than that of adult males,juvenile females and juvenile males. Among adult females, reproductively active females were seen significantly more often than expectedwhen lactating (with a calf) than during their pregnancy or resting years. These data suggest that, while research efforts in the five high-usehabitat areas have had relatively equal success at monitoring juvenile males and females and adult males, many adult females are segregatedat times from the rest of the population. Lower variability in annual identification frequencies of adult females indicates that they may bemore site specific in their distribution than males, particularly during the years when they are pregnant or resting from a previous pregnancy.Re-running these analyses using sighting records updated through 2000 will help determine if the trends continue to be documentedregardless of changes in survey effort and patterns of habitat use of some animals.

Sex-dimorphic role of prefrontal oxytocin receptors in social-induced facilitation of extinction in juvenile rats

We previously reported that in the adult animal extinction in pairs resulted in enhanced extinction, showing that social presence can reduce previously acquired fear responses. Based on our findings that juvenile and adult animals differ in the mechanisms of extinction, here we address whether the social presence of a conspecific affects extinction in juvenile animals similarly to adults. We further address whether such presence has a different impact on juvenile males and females. To that end, we examined in our established experimental setting whether conditioned male and female animals extinguish contextual fear memory better while in pairs. Taking advantage of the role of oxytocin (OT) in the mediation of extinction memory and social interaction, we also study the effect of antagonizing the OT receptors (OTR) either systemically or in the prefrontal cortex on social interaction-induced effects of fear extinction. The results show that social presence accelerates extinction in males and females as compared to the single condition. Yet, we show differential and opposing effects of an OTR antagonist in both sexes. Whereas in females, the systemic application of an OTR antagonist is associated with impaired extinction, it is associated with enhanced extinction in males. In contrast, prefrontal OT is not engaged in extinction in juvenile males, while is it is critical in females. Previously reported differences in the levels of prefrontal OT between males and females might explain the differences in OT action. These results suggest that even during the juvenile period, critical mechanisms are differently involved in the regulation of fear in males and females.