Spatial organization of the fat dormouse (Glis glis) in an oak-hornbeam forest during the mating and post-mating season

Home range (HR) size and overlap, movements, and nest site use of fat dormice Glis glis (Linnaeus, 1766) were studied by live-trapping and radiotracking in the Bialowieza Forest in north-eastern Poland. The study was conducted during a mast year of oak Quercus robur (2001) and hornbeam Carpinus betulus (2002). Average HR size measured by 100% minimum convex polygons varied from 3.6 to 7.0 ha in males and from 0.55 to 0.76 ha in females. HR size in males was significantly larger in the hornbeam mast year than in the oak mast year, which was probably due to the lower energy value of hornbeam mast. Males had significantly larger HRs and used more nest sites than females. In contrast to females, HRs of males overlapped extensively. In the mating season, core areas of males overlapped significantly more and they shared their core areas with more males than in the post-mating season. During the mating season, males were found to share nest sites with other males or with a single female. Additionally, groups of 2–3 males were observed aggregating around a female during the mating season. Our data suggest that fat dormice have a promiscuous mating system where the females are territorial, and the non-territorial males directly compete for access to receptive females during the mating season.     

Roost preferences and foraging ranges of the eastern forest bat Vespadelus pumilus under two disturbance histories in northern New South Wales,Australia

Little is known about the habitat requirements of Australian bats; however, this information is needed to make better‐informed decisions when systems are disturbed. This study contrasts the roosting and foraging ecology of the eastern forest bat Vespadelus pumilus (Vespertilionidae), one of Australia’s smallest bats, between two sites of differing disturbance history on the mid‐north coast of New South Wales. Lorne Flora Reserve (182 ha) is primarily old‐growth forest surrounded by regrowth forest and eucalypt plantations, while Swans Crossing is dominated by regrowth and eucalypt plantations established on part of an old dairy farm. A total of 38 bats were tracked during the maternity and mating seasons at the two sites. Roost preferences were determined by comparing trees used as roosts with those randomly available, while foraging bats were triangulated from fixed stations at night. Bats tracked at Lorne Flora Reserve typically roosted in hollows within large, mature trees and showed a strong preference for roosting and foraging (females only) within the Reserve. Lactating females at Swans Crossing roosted in hollows of remnant rainforest trees within a gully and dead eucalypts, while males often roosted in understorey trees (such as Acacia). Dead trees were frequently used as roosts at both sites. Under both disturbance histories, the mean distance of female maternity roosts from creeks was 20 m, indicating that riparian zones provide important roosting habitat for V. pumilus. However, roosts shifted to the mid‐slope prior to winter when bats mate. Retention of mature trees in a variety of topographic locations may allow behavioural adjustments with the seasons. Bats caught in the regrowth forest also foraged there, with foraging ranges averaging just 5.3 ha (n = 10), indicating that regrowth is used by this bat for both foraging and roosting.     

Effects of size and sex on the courting success and foraging behaviour of Embiotoca jacksoni

To test life-history theory that body size and sex should influence how animals allocate time to foraging versus reproductive activities, we measured the effects of size and sex on courting success and foraging behaviour of black surfperch Embiotoca jacksoni off Santa Catalina Island, southern California. Observations of focal fish were made while snorkelling, during which the length of each fish (estimated to the nearest cm), total duration of courting encounters and foraging rates were recorded. We made observations during and outside the mating season. Courtship occurred only between pairs and its duration increased with the size of both the male and female. Although males would court females that were smaller or larger than themselves, pairs that were closely matched in size had long courting sessions, whereas those that differed considerably in size courted only briefly. Small fish foraged more than larger fish, both during and outside the mating season. Males and females foraged at similar rates outside of the mating season, but during the mating season males reduced their foraging rates to less than half that seen outside of the mating season, whereas females continued to forage at the same rate. This decrease in foraging rate of males during the mating season was seen in all sizes of males but was proportionally greatest in the largest males. These observations indicate that males trade off time spent on foraging for time spent courting during the mating season, whereas females do not.     

Linear roadside remnants: Their influence on den‐use,home range and mating system in bobucks (Trichosurus cunninghami)

Abstract Forest clearance results in a marked change in the dispersion of resources such as food and shelter: from a relatively continuous distribution, to patches and strips of remnant habitat set in a more or less inhospitable matrix. Such changes in the patterns of resource dispersion have the potential to strongly influence the dynamics of social and mating systems of resident animal populations. We studied the den‐use patterns, home range characteristics and mating system of a population of bobucks, Trichosurus cunninghami (Marsupialia: Phalangeridae), permanently resident in linear roadside strips of vegetation in north‐eastern Victoria, Australia in order to gain a greater understanding of the impacts of occupying linear roadside habitats on the behavioural ecology of arboreal marsupials. We radio‐tracked 11 adult females and six adult males and collected 2126 diurnal fixes (mean 125/individual) and 1044 nocturnal fixes (mean 61/individual). Males used significantly more den‐trees (mean 16.5 ± 1.5 den‐trees/individual) than females (mean 7.4 ± 0.6 den‐trees/individual) and had home ranges more than twice the size of those of females (male mean 5.1 ± 0.8 ha, female mean 2.1 ± 0.3 ha). On average, each male's home range overlapped with those of three females; there was little intrasexual home range overlap in either sex. Genetic parentage analysis of all young sampled during the study (n = 22) established that only males that overlapped in home range with females had sired those females' young. All but one male in the study sired multiple young in each of the years they were recorded breeding. These behavioural and genetic data indicate that the roadside population was polygynous, in contrast to the socially monogamous bobuck population we studied in a neighbouring forest patch. These differences in behaviour may reflect patterns of resource distribution in the two habitats.     

Time and energy constraints and the evolution of sexual size dimorphism — to eat or to mate?

Summary We present an empirical test of the Ghiselin—Reiss small-male hypothesis for the evolution of sexual size dimorphism (SSD). In mating systems dominated by scramble competition, where male reproductive success is a function of encounter rate with females, small males may be favoured when food is limiting because they require lower absolute amounts of food. Given a trade-off between time and energy devoted to foraging and to mate acquisition, small males should be able to devote more time to the latter. If at the same time larger females are favoured, this mechanism will contribute to the evolution of SSD and may be the major determinant of the female-biased SSDs that characterize most animal taxa. We tested this hypothesis using the water strider,Aquarius remigis (Heteroptera: Gerridae), a scramble competitor which mates many times over a prolonged mating season and which shows female-biased SSD. Laboratory experiments demonstrated that foraging success and giving up times (GUTs) are lower for males than for females during the reproductive season and that male water striders flexibly alter their time budgets under conditions of energy limitation. Controlled feeding experiments showed that male and female longevity, female fecundity and male mating success are positively related to food availability. As predicted, male body size is negatively correlated with several indices of male fitness (longevity, number of mating attempts and mating success), while female body size is positively correlated with longevity. These results are consistent with the hypothesis that scramble competition for mates favours small males in this species and provides empirical support for the Ghiselin—Reiss small-male hypothesis.     

Sociality in river otters: cooperative foraging or reproductive strategies?

We evaluated factors influencing social organization in coastalriver otters (Lontra canadensis) to test two hypotheses: groupformation is an antipredation strategy, or, alternatively,group information is related to cooperative foraging. Dataon group size, group composition, and sociality were obtainedthrough radiotracking 55 otters in Prince William Sound, Alaska, USA, from 1996 through 1998. For males, larger groups occurredafter the mating season and concurrent with availability ofschooling pelagic fishes. Stable isotope analysis revealedthat otters social in >10% of their locations had dietssignificantly higher in rapidly swimming pelagic fishes thandid less social otters, regardless of gender. In addition, ottersthat were more social had significantly smaller home rangesthan did less social otters, an observation consistent withincreased foraging efficiency through cooperative foraging.Discounting associations of females with young of the year,approximately 47% of females and only 24% of males were asocial.Among social otters, males were social in 46% of their locationsand 63% of that time occurred in all-male groups. Females wereonly social in 26% of locations and were in mixed-sex groups78% of that time. We hypothesize that the time-consuming taskof raising offspring prevents females from joining foraginggroups. When not raising young, females may join males to cooperativelyforage for better-quality prey (pelagic fishes), which wouldbe more difficult to acquire as a solitary forager.     

Is Male Cohabitation Costly for Females of the Spider Stegodyphus lineatus (Eresidae)?

Reproductive interests of females and males can vary over a number of issues, including the number of matings and the occurrence and duration of mate guarding and cohabitation. The mating system of the spider Stegodyphus lineatus (Eresidae) is characterized by an exceptional sexual conflict where males induce females to remate by committing infanticide. Females experience high costs because of this male strategy, while males benefit. During the mating season, males tend to stay with females for several days. We examined whether this male strategy of cohabitation is also disadvantageous for females of S. lineatus. A field experiment revealed that male presence in a female's nest negatively affected her body condition, whereas cohabiting males gained weight because they fed on prey caught in webs of females. As a response, females did not renew their webs when males were present. Thus, females with a cohabiting male experienced the combined cost of prey loss and loss of time available for foraging. These costs are expected to increase with every additional cohabiting male. Mated females behaved more aggressively toward males than did virgin females. This behavior may be interpreted as an adaptive response to reduce mating costs.     

The Haremic Mating System and Mate Choice in the Wide-Eyed Flounder, Bothus podas

The social structure and reproductive behaviour of the wide-eyed flounder, Bothus podas, was studied in the coastal waters around the Azorean Islands. Both sexes are territorial throughout the year. Adult males defend large territories, which include several smaller female territories. Intraspecific agonistic behaviour was frequent and differed between sexes: males were more aggressive towards other males, while females were only aggressive towards each other and juveniles. During the reproductive season and only at dawn, territorial males court and mate successively with females in their territories, and females seem to show mating fidelity to their dominant male. Such territoriality and mating patterns indicate a haremic social system in the wide-eyed flounder. In order to identify potential factors influencing female mate choice acting on this haremic system, we examined male mating success and some of its potential correlates. We found no evidence for female preference for any of the males' physical or territory characteristics. However, courtship effort was strongly correlated with the total number of attempted and successful spawnings, indicating that females seem to mate preferentially with males that court them more vigorously. Thus, our data suggest that courtship plays an important role in determining male mating success in the wide-eyed flounder and, that it may possibly serve as an honest indicator of male `quality' for female choice.     

Mating Group Size in Dusky Dolphins (Lagenorhynchus obscurus): Costs and Benefits of Scramble Competition

In fission–fusion social systems with scramble competition between males, multiple males join mating groups while surrounding an oestrous female. If male decisions to join a mating group have been shaped by natural selection, then there should be an optimal group size resulting from the trade‐offs between the benefits of monopolizing a female in small groups and the energy lost in defending her from rivals in large groups. Male dusky dolphins (Lagenorhynchus obscurus) off Kaikoura, New Zealand, provide a unique opportunity to assess the optimum mating group size because they join transient mating groups not confounded by foraging or predator evasion. Within aggregations of up to 1000 individuals, males search for oestrous females, encountering choices of staying with a large mating group or leaving to find a smaller group. Mating groups typically involve multiple males mating with a single female. We conducted focal follows of mating groups (N = 44) by vessel from November 2011 through January 2012. We used video and a GPS to record group size, behaviour and movement. For each group, we measured potential costs (Swim Speed, Loss of Monopolization Potential) and benefits (Copulation Rate and Duration, Energy Savings). Only Loss of Monopolization Potential was positively correlated with group size, while Energy Savings was negatively correlated. Using these two factors as utility functions, we constructed an optimality model and predicted the optimal mating group size to be seven individuals with a range of 4–11 individuals due to variance. The observed modal mating group size was five dolphins, with a range of 2–15. We compare variation in mating group currencies and sizes to past studies. We discuss potential limitations of applying optimality models to predict mating group size for socially complex and behaviourally plastic species such as dolphins.     

Behavioural and Genetic Data Suggest that Bechstein's Bats Predominantly Mate Outside the Breeding Habitat

Investigating mating systems of species with a cryptic lifestyle often requires a combination of behavioural and genetic data. We used such a combined approach to investigate the mating system of the communal breeding Bechstein's bat (Myotis bechsteinii). Although females of this species are philopatric, gene flow among colonies is high. Gene flow occurs if dispersing males mate within the colony to which they moved. Males could gain local matings by defending resources or females in their breeding habitat. Alternatively, mating may take place at swarming sites, apart from the breeding habitat of the females, where males and females of several colonies meet. Whether or not males defend resources or females in the breeding habitat is of importance for understanding the mating system. Detailed observations of individual foraging and roosting behaviour over 4 yr suggest that males do not defend resources or females to gain matings. Moreover, paternity assignment based on microsatellite data of four complete juvenile cohorts showed that local males fathered less than 25% of the juveniles born in the colony where they settled. Even more striking, none of the males that had immigrated into our study area reproduced with the local females.     

Foraging for mates in the hyperparasitic wasp, Dendrocerus carpenteri: impact of unfavourable weather conditions and parasitoid age

Males of the aphid hyperparasitoid Dendrocerus carpenteri (Curtis) were attracted by a sex pheromone released by conspecific females. The intensity of this cue, and thus female attractiveness, depended both on the female's mating status and her age. Only virgin females younger than 2 h were consistently recognized as mates by foraging males. Male age did not influence foraging and mating success. Empty mummies, from which females had emerged within the previous 10 min were attractive to males and examined intensively. Rain reduced the searching success of males, although the host plant Vicia faba provided sheltered places. Wind did not reduce mating success but prevented both sexes from leaving the host plant. Since the time of female attractiveness seems to be very limited, wind may have an enormous effect on the mating success of D. carpenteri in the field and thus on the population dynamics of this species. Received: 5 October 1998 / Accepted: 16 December 1998     

Alternative mating tactics in the yellow dung fly: resolving mechanisms of small-male advantage off pasture

Recent work suggests that the yellow dung fly mating system may include alternative patroller–competitor mating tactics in which large males compete for gravid females on dung, whereas small, non-competitive males search for females at foraging sites. Small males obtain most matings off pasture, yet the behavioural mechanism(s) giving rise to this pattern are unknown. We investigated the male and female behaviours that determine mating success in this environment by conducting field mating experiments and found small males to benefit from several attributes specific to the off-pasture mating environment. First, small males from foraging sites exhibited higher mating propensity, indicating that large males away from dung may be depleted of energy and/or sperm. Second, small males were more discriminating, being significantly less likely to attempt with non-gravid females, which are absent on dung but common off pasture. Third, non-gravid females were generally more likely to actively struggle and reject mating attempts; however, such behaviours occurred disproportionately more often with large males. Female Scathophaga stercoraria thus appear to preferentially mate with small males when off pasture. These findings challenge assumptions about male–female interactions in systems with alternative mating tactics and reveal hidden processes that may influence selection patterns in the field.     

The reproductive ecology of resident manta rays (Manta alfredi) off Maui, Hawaii, with an emphasis on body size

In resident manta rays (Manta alfredi) off Maui, sexual maturity appears delayed until growth exceeds 90% of maximum size, an indicator that large body size provides a reproductive advantage at the expense of a shorter reproductive time period. In this study, 286 surveys were conducted between 2005 and 2010 using photo-identification and photogrammetry to study the reproductive ecology of a resident population of manta rays off Maui, Hawaii, and investigate the reproductive benefits of large body size in each sex. Although reproductive activities occurred year-round, mating trains and late-term pregnant females were significantly more likely to be observed during the winter months. Some females were pursued by males during both winter and summer of the same year, suggesting multiple ovulations may be possible in a single year. Males likely detect a female’s reproductive state by positioning directly behind her, or passing through her bodily excretions. The mean pregnancy rate was estimated at 0.56 pregnancies/adult female/year with larger females pregnant more often, and more likely in consecutive years. The operational sex ratio was heavily skewed with 2.68 adult males per reproductively available female. Although males appear to compete with one another for females within a mating train, no direct physical competition was ever observed between males. Evidence of highly dynamic mating trains lasting more than one day suggests endurance rivalry may be the primary mating strategy among males, during which larger males may benefit from greater energy reserves. The study area appears to be an important staging area for mating individuals in this population.     

Life History Dependent Behavioural Variation in Water Striders,Aquarius remigis

We investigated behavioural consequences of life history states in Aquarius (Gerris) remigis, a hemipteran surface predator and scavenger of small North American streams. A repeated-measures field study comparing reproductive and non-reproductive first summer generation females and males during the same time in summer showed that non-reproductive males and females, which were foraging to survive the winter, behaved essentially alike, often being territorial. In contrast, reproductives of both sexes were more mobile than non-reproductives, reproductive males being much more mobile than reproductive females, always in search of and attacking potential mates. This resulted in reproductive males showing litde territoriality and having lower foraging success than all other categories, while reproductive females had higher foraging success than non-reproductive females or males, thus likely increasing their fecundity. Many behavioural variables did not change with time. Exceptions were a decrease in the mating activity of reproductives of both sexes, the number of mating attempts, mobility, and the stride rate of reproductive males, and an increase in overall foraging activity of all individuals. This indicates that the behaviour of reproductive males converged towards that of non-reproductive males as the season progressed. Individuals were assigned to either state post-hoc according to whether they had been seen mating at least once during the study period (July and August). Females were further tested to ascertain if they laid eggs. These results support the hypothesis that diapause and reproductive state to some degree predetermine behaviour, thus constraining behavioural flexibility. Attributing behavioural variation to various proximate causes can be central to the interpretation of alternative strategies and tactics.     

Mating for variety increases foraging activity in the harvester ant, Pogonomyrmex occidentalis

Multiple mating by females characterizes most insect species, but is relatively uncommon in social insects. Females may mate with multiple mates because they experience the direct benefits of increased survival or fecundity, to acquire high quality mates, or to lower the risk of reduced fecundity by mating with incompatible males. We used the extensive natural variation in mating frequency in the western harvester ant, Pogonomyrmex occidentalis , to test the hypothesis that increased mating by the queen leads to an increase in colony performance. Colonies with greater genetic diversity began to forage earlier in the day and foraged for longer time periods. The workers which initiated foraging were a nonrandom subset of the genotypes present in the colony. We used a statistical approach to correctly predict the direction and magnitude of the correlation between genetic diversity and colony foraging activity.     

Size and overlap of home range inCalomys musculinus (Muridae: Sigmodontinae)

Home range size and overlap ofCalomys musculinus (Thomas, 1913) was examined in relation to sex and breeding periods. The study was carried out in four 0.25 ha enclosures, in a natural pasture, between October 2002 and July 2003. The four enclosures functioned as independent populations and each was considered a replicate. The capture, mark and recapture method was used. Home range size and overlap inC. musculinus depended on sex and period. Home range size of males was always larger than that of females. Females showed a small degree of intra-sexual home range overlap during the breeding period. In general, male home ranges overlapped with females. We conclude that differences in home range size inC. musculinus is determined by sex and breeding period. Moreover, the degree of inter- and intra-sexual home range overlap during the breeding period suggests that both males and females ofC. musculinus use space differently. Females did not share their home range with other females, while males fully shared it with both sexes, and male spacing is influenced by the distribution of females. A promiscuous-polygynous mating system is suggested forC. musculinus.     

Vibratory signals enhance mate-guarding in a water strider (Hemiptera: Gerridae)

Mating males of the water strider Gerris remigisproduce vibratory signals when-single males grasp mating pairs. When played through live females with dead males on their backs, these signals repelled mating attempts by single males. A previous study showed that male mate-guarding enhances female foraging effectiveness in this species. Thus male mate-guarding signals also enhance female foraging effectiveness.     

To Feed or Not to Feed? Testing Different Hypotheses on Rut‐Induced Hypophagia in a Mountain Ungulate

In many ruminant species, males dramatically reduce forage intake during the rut. To date, different hypotheses have been suggested to explain this rut‐induced hypophagia. To assess the predictions of the main hypotheses, we analysed Alpine ibex (Capra ibex) activity budget and compared the behaviour of males and females before, during, and after the rut. Only males spent significantly less time foraging during the rut than outside of it, whereas females allocated a similar proportion of time to foraging before, during, and after the rut. Our results showed that during the rut males also reduced lying time, while the ratio of time spent feeding to time spent lying did not change for males among periods. In conclusion, during the breeding season males maximized energy intake when not actively engaged in mating activities and rut‐induced hypophagia appeared to result from time budget constraints generated by mating‐related activities. Accordingly, the foraging constraint hypothesis seems appropriate to explain this phenomenon in Alpine ibex males.     

The time budget of a group of wild woolly monkeys (Lagothrix lagotricha)

I studied a group of woolly monkeys (Lagothrix lagotricha)for 1800 hr from early 1985 until September 1987 near the lower Apaporis river of the Vaupés Department in the eastern Colombian Amazon. The group had an activity budget of 29.9% rest, 38.8% move, 25.8% forage, and 5.5% other activities during 720 hr of observations evenly spaced throughout this year. The only significant change in these activities during the study period was social activity, which increased as a function of increased food supply. Average diurnal activities of resting and moving are negatively correlated, and each activity show significant changes during the day, while foraging show no significant change. The activity budgets of the adult males and females are not significantly different, but the activities of the juveniles and infants showed much more social activity than the adults. High moving scores may be correlated with the comparative infertility of the soils of the Caparú forest, which require increased effort to maintain the energy levels necessary for maintenance and reproduction in Lagothrix.