Reproductive Constraints Research Articles

Do reproductive constraints or experience drive age-dependent space use in two large herbivores?

Life histories are strongly age dependent, notably linked to the onset of reproductive maturity and subsequent senescence. Consequently, ageing is predicted to impact behaviour, through the expression of either mating tactics in males or neonatal antipredator tactics in females. However, the influence of ageing, and the associated reproductive activity, on spatial behaviour remains poorly investigated. In this regard, we quantified age- and sex-specific intra-annual variation in movement rates and space use of two large herbivores with contrasting life histories: the roe deer, Capreolus capreolus, an asocial species with a territorial male mating strategy and a hider neonatal tactic, and the Mediterranean mouflon, Ovis gmelini musimon × Ovis sp., a gregarious species with a roaming male mating strategy and a follower neonatal tactic. We expected age-related differences to be mostly related to (1) age-specific mating tactics during the rut for males and the presence/absence of offspring for females, and (2) experience and/or locomotory senescence otherwise. During the rutting period, older roe deer males travelled greater daily distances than younger males due to patrolling behaviours for territory defence, whereas older mouflon males travelled less than younger males, which often adopted coursing tactics to mate with females. During the birth period, reproductive females had smaller home ranges than nonreproductive females in roe deer, whereas no marked differences were observed in mouflon females. The most marked age-related variation in space use of mouflon occurred outside the reproductive periods; specifically, the oldest individuals travelled less far and had a smaller home range (females only) than younger individuals. Our findings illustrate how space use tactics vary within and between populations of large herbivores, providing strong evidence that age and reproductive activity are major determinants of their spatial behaviour.

First evidence of avian predation of threatened freshwater mussels (

Abstract Context Conservation efforts for New Zealand freshwater mussels (kākahi) are challenging because of their longevity and their complex life history, but also by the scarcity of research that has investigated causes of decline. Reproductive constraints may impair recruitment, but other key aspects that influence population structure, such as predation pressure, remain unknown. Predation is an emerging risk for kākahi because, although bivalve predation has been observed in New Zealand waterways, its prevalence and impacts remain unquantified. Aims The present study resolves trophic interactions with predator populations by identifying kākahi predators and examining characteristics of freshwater mussels (e.g. species or size) that may indicate vulnerability to predation. Methods Intensive monitoring was conducted over 6 weeks (January to March 2020) by using trail cameras to observe kākahi predators at the Orongo Stream, a western Waikato (New Zealand) site with high densities of Echyridella aucklandica (threat status: Vulnerable) and E. menziesii (Declining). Predated kākahi shell remains were analysed to (i) identify typical patterns of shell damage, and (ii) determine prey selectivity via size distribution. Key results Eight observations of an avian predator (pūkeko, Porphyrio porphyrio melanotus) interacting with both E. aucklandica and E. menziesii were recorded; however, E. menziesii comprised a significantly greater proportion of the shell remains that had direct evidence of predation. Both species of mussel displayed significantly more damage to the posterior end of the valves but size selectivity was detected only for E. menziesii. Conclusions Pūkeko actively search for mussels and frequently consume them as part of a wider diet when they are accessible during summer. Whereas healthy populations of freshwater mussels may withstand predation by native species, populations that face substantial pressure from other natural stressors and anthropogenic change may suffer. Predation impacts on kākahi populations should be a factor considered for the future management of New Zealand mussel species. Implications Identifying pūkeko as kākahi predators clarifies food webs for conservation managers and highlights the need to quantify their impact on mussel populations; particularly for E. menziesii, which may be more vulnerable to predation.

Evolutionary and Life History Insights into Masculinity and Warfare

In this paper I present, evaluate, and discuss evidence that evolutionary and life history theory can inform our understanding of violence and warfare as well as how these human challenges are influenced by the evolution of male life histories and our perceptions of masculinity. While other anthropological perspectives have interrogated the evolution of war from human and comparative contexts, few have addressed the influence of male life history variables such as age-specific mortality and reproductive constraints on the emergence and conduct of war. Other evolutionary factors worthy of consideration include sexual dimorphism, phenotypic plasticity, and paternity uncertainty. I initially present a contextual examination of the evolutionary science that underlies the engagement of human males with violence and warfare, casting particular attention on the opportunities and constraints of deploying evolutionary and life history theory. I later incorporate other variables including human variation, behavioral endocrinology, and comparative perspectives. In the latter half of this paper I suggest a novel perspective for understanding males, war, and violence by drawing on male-specific patterns of mortality, paternity uncertainty, and the evolution of male aging. While evolutionary and life history theory can provide an informative perspective to understand how males contribute to violence and warfare, there are limitations that set the stage for intellectual partnership opportunities with cultural anthropologists, psychologists, and other social scientists.

Drosophila melanogaster and worker honeybees (Apis mellifera) do not require olfaction to be susceptible to honeybee queen mandibular pheromone

Eusociality is characterised by the reproductive division of labour; a dominant female (queen) or females are responsible for the majority of reproduction, and subordinate females are reproductively constrained. Reproductive constraint can be due to behavioural aggression and/or chemical cues, so-called queen pheromones, produced by the dominant females. In the honeybee, Apis mellifera, this repressive queen pheromone is queen mandibular pheromone (QMP). The mechanism by which honeybee workers are susceptible to QMP is not yet completely understood, however it is thought to be through olfaction via the antennae and/or gustation via trophallaxis.We have investigated whether olfaction is key to sensing of QMP, using both Drosophila melanogaster- a tractable non-eusocial insect which is also reproductively repressed by QMP- and the target species, A. mellifera worker honeybees. D. melanogaster are still capable of sensing and responding to QMP without their antenna and maxillary palps, and therefore without olfactory receptors. When worker honeybees were exposed to QMP but unable to physically interact with it, therefore required to use olfaction, they were similarly not reproductively repressed. Combined, these findings support either a non-olfactory based mechanism for the repression of reproduction via QMP, or redundancy via non-olfactory mechanisms in both D. melanogaster and A. mellifera. This study furthers our understanding of how species are susceptible to QMP, and provides insight into the mechanisms governing QMP responsiveness in these diverse species.

Reproductive adaptations to high densities in social mammals

An overview of population density control in social mammals sets the framework for examining reproductive responses to increasing population densities. We begin by honoring John B. Calhoun who played a major role, starting about 70 years ago, in correcting the conventional wisdom of the time that population control was all about adjusting mortality rates. Reproduction was considered a constant, and emigration was viewed as a component of mortality. His research was mostly on domestic and feral populations of Rattus norvegicus and Mus musculus for which he built complex arenas that could house thousands of inhabitants. In addition, he constructed elaborate living quarters in the alleyways of Baltimore. For the captive populations, he would individually mark all the inhabitants so that he could identify them and observe their behavior. Eight examples of his research publications are described. He was able to document a list of reproduction related behaviors that are the main focus of this essay, and clearly demolish the simplistic notion that reproduction is a constant. A summary of some of the major issues that encompasses the science of population growth and regulation is provided. There follows a series of 19 examples of non-Calhoun publications that cover many more species of social mammals, including humans. A comprehensive list of the many negative adaptations involving reproductive processes are documented for the 27 publications reviewed confirming that in many species reproductive constraints are non-trivial. There follows a brief discussion that attempts to create a cohesive whole for this intellectual adventure.

Validation of advanced tools to evaluate sperm function in barramundi (Lates calcarifer).

Barramundi (Lates calcarifer) is a tropical finfish species rapidly growing in popularity for aquaculture production. However, sperm quality tests have yet to be adapted to enable selection of highly fertile male broodstock in this species. Accordingly, in this study advanced tools were optimized to evaluate barramundi sperm function to facilitate the future study of male fertility and address some of the reproductive constraints currently observed in captive-bred broodstock. Sperm morphology data were used to calibrate and validate automated sperm counting and motility detection by computer-assisted sperm analysis (CASA; AndroVision, Minitube). Several parameters were examined to determine the optimum settings for accurate CASA sperm counting and were compared to manual haemocytometer methods including: sample dilution (1:1000, r = 0.87), minimum number of fields (n = 4, CV = 7.5%), and the effect of motile vs. immotile spermatozoa on automated counting (no effect, r = 0.99, P < .001). Assays for cell viability and DNA damage were also validated for barramundi spermatozoa using 70 °C heat-treated controls and a 5-point intact:damaged dilution curve (r = 0.98, P < .001), and DNase-treated sperm controls, respectively. Data from these optimized assessments indicated high variation between individuals for each parameter assessed and the presence of high rates of DNA and membrane damage in sperm samples tested. Further research building upon this preliminary sperm quality data, is required to identify the cause of DNA and membrane damage in barramundi spermatozoa and understand any potential relationships with paternal performance in commercial spawns.

Amerotyphlops brongersmianus (Vanzolini, 1976) (Typhlopidae, Serpentes) as a model for scolecophidian ontogenetic shifts of heart topography and relative size

Ontogenetic shifts in the snake heart topography are mostly associated with their life habits and physiological adaptations due to modifications of complex functional-adaptative and developmental constraints. However, such studies are incipient for scolecophidians, and the presence of shifts putatively related to physiological mechanisms are still unexplored for this group. We aimed to evaluate the presence of topological shifts in heart position and the allometry of heart/chambers total length in Amerotyphlops brongersmianus. Our results indicate that there is a craniad ontogenetic shift of the heart position related to total length increase. Heart total length and their chambers also grow isometrically in relation to head and total body length. We discuss the possible functional and evolutionary perspectives of our results with comparison to data available for alethinophidan snakes. We hypothesize the anterior displacement of organs possibly remains as an ancestral state to compensate reproductive constraints imposed by the ancestral scolecoid miniaturized body.

Seasonal grouping dynamics in a territorial vulture: ecological drivers and social consequences

Despite widespread occurrence of seasonal sociality among animals, little is still known about the social drivers and population-level social implications of seasonal grouping behaviours, especially in birds. Here, we studied the combined effects of ecological and social factors on seasonal grouping patterns in a sedentary population of Egyptian vultures living on the Eastern Canary Islands. We focussed on the social significance of large-scale gatherings taking place outside the breeding season at a highly preferred feeding station and a nearby temporary roost. Group sizes at this feeding patch followed a strong seasonal pattern characterized by distinct monthly changes in group composition, according to sex, age and territorial status. In between reproductive periods, vulture numbers at the feeding station may reach up 50% of the total population on a single day. GPS-tracking showed that this increase in vulture numbers was in part due to a shift in foraging range towards the centre of Fuerteventura by low-ranked territorial birds breeding in remote areas. During this period, vultures may spend on average 30% of their monthly time in a social gatherings context, depending on social status. We show that seasonal grouping patterns are shaped by the complex interplay between ecological factors (reproductive constraints, resource seasonality, food predictability), age-specific traits and social competitive processes, while social attraction may be an important additional component. We propose that for facultative social foragers living in highly despotic territorial systems, collective foraging may be of particular relevance regarding the development of hierarchical social relations and maintenance of population-level social cohesion. We show that seasonal grouping patterns in a sedentary island population of a territorial vulture are shaped by the complex interplay between ecological factors (reproductive constraints, resource seasonality, food predictability), age-specific traits and social competitive processes. We argue that vultures visit large gatherings also for social purposes. Group foraging events may be of special interest to vultures, given opportunities for rank maintenance/improvement, but also for conspecific evaluation and mate-seeking, and play an important role in the social structuring of populations. Vultures may serve as important model species to test the role of scavenging and fission–fusion social dynamics in driving the evolution of avian social cognition, or avian social complexity in general.

Utopian Film Studies

304 SCIENCE FICTION STUDIES, VOLUME 47 (2020) makes a strong case that these and similar mechanics should be analyzed closely for the role they play in popular understandings of science and technology. Falling under “Inspiring Science,” Erika Lorraine Milam’s essay “Old Woman and the Sea: Evolution and the Feminine Aquatic” is also noteworthy. Like Willis’s analysis of sleep, Milam’s article compares works of sf literature with scientific discourses to understand better their interrelationships. But unlike Willis, Milam is interested in speculative science, mostly in the form of Elaine Morgan’s controversial Descent of Woman (1972), which “imbued agency in humanity’s female ancestors by adding a controversial aquatic phase to the narrative of human evolution” (199). Milam reads this revisionist take on evolution alongside two works of sf that imagine how oceans and aquatic life can transform evolutionary trajectories—specifically, Kurt Vonnegut’s Galapagos and Joan Slonczewski’s A Door into Ocean, both published in 1985. She finds that the novels share Morgan’s interest in imagining “in the aquatic a realm of conceptual possibility that potentially avoided the violence of terrestrial landscapes” (199-200). For Slonczewski in particular, this was part of a feminist conceptualization that freed women from the constraints of patriarchy, capitalism, and biological reproduction. Milam closes her article with the suggestion that envisioning aquatic pasts and futures could be highly relevant in the age of climate change and the Anthropocene, since these and similar efforts help us to “conceptualize ourselves as part of the natural world rather than independent of it” (215). By using sf as a tool to think beyond the conventional histories of science, the other articles in this volume of Osiris can be seen to do something quite similar, and this is important work. In fact, the current trajectory of devastating climate transformation, unfettered capitalism, and uncontainable viral outbreaks, all of which can be tied to a particular history of technoscience, makes it clear that new concepts and fictions are required to make sense of how we got here. We may very well live in desperate times, a reality that demands we take hold of even more desperate futures to orient ourselves and plot a path forward. Whether readers are interested in this broader humanist project, or more simply in the various and complex ways in which sf can contribute to the history of science, this is a vital collection that demands attention from sf researchers, historians of science, and especially those who travel freely across such disciplinary boundaries.—Chad Andrews, Independent Scholar Utopian Film Studies. Simon Spiegel. Bilder einer besseren Welt. Die Utopie im nichtfiktionalen Film [Images of a Better World: The Utopia in Nonfiction Film]. Marburg: Schüren, 2019. 432 pp. €48 pbk. Open online access at . There are tons of dystopian sf films, but utopian sf films seem to be nonexistent . Utopian studies scholars have tried repeatedly to find utopia in fictional films, but to no avail. Sf films narrate alternative technologies, times, places, and beings, and of course they can also narrate alternative social 305 BOOKS IN REVIEW orders. There is no logical reason why these should always be horrific. Better societies can certainly be imagined, as the genre of utopian literature shows, but while literary dystopias have often been adapted for film, utopias have been neglected by the film industry. Why is this? Utopian scholars have long known that fictional films need a narrative plot with conflict at its core and that utopias lack this core because they are discursive rather than narrative and address harmonious societies without conflict. So a fictional utopian film would be quite boring and nobody has bothered to shoot one yet. At this point the scholarly debate on utopian film is usually aborted. Simon Spiegel, on the contrary, uses this finding as a starting point for an extensive study of utopian film. His idea is that if fictional film is incapable of depicting utopias, one should start looking for nonfictional utopian films. He has analyzed documentaries and propaganda films and actually found a quite diverse set of filmic utopias, and now he shows them to us—literally. Spiegel has hyperlinks to many of them on his website (). In Bilder einer...

Utopian Film Studies

304 SCIENCE FICTION STUDIES, VOLUME 47 (2020) makes a strong case that these and similar mechanics should be analyzed closely for the role they play in popular understandings of science and technology. Falling under “Inspiring Science,” Erika Lorraine Milam’s essay “Old Woman and the Sea: Evolution and the Feminine Aquatic” is also noteworthy. Like Willis’s analysis of sleep, Milam’s article compares works of sf literature with scientific discourses to understand better their interrelationships. But unlike Willis, Milam is interested in speculative science, mostly in the form of Elaine Morgan’s controversial Descent of Woman (1972), which “imbued agency in humanity’s female ancestors by adding a controversial aquatic phase to the narrative of human evolution” (199). Milam reads this revisionist take on evolution alongside two works of sf that imagine how oceans and aquatic life can transform evolutionary trajectories—specifically, Kurt Vonnegut’s Galapagos and Joan Slonczewski’s A Door into Ocean, both published in 1985. She finds that the novels share Morgan’s interest in imagining “in the aquatic a realm of conceptual possibility that potentially avoided the violence of terrestrial landscapes” (199-200). For Slonczewski in particular, this was part of a feminist conceptualization that freed women from the constraints of patriarchy, capitalism, and biological reproduction. Milam closes her article with the suggestion that envisioning aquatic pasts and futures could be highly relevant in the age of climate change and the Anthropocene, since these and similar efforts help us to “conceptualize ourselves as part of the natural world rather than independent of it” (215). By using sf as a tool to think beyond the conventional histories of science, the other articles in this volume of Osiris can be seen to do something quite similar, and this is important work. In fact, the current trajectory of devastating climate transformation, unfettered capitalism, and uncontainable viral outbreaks, all of which can be tied to a particular history of technoscience, makes it clear that new concepts and fictions are required to make sense of how we got here. We may very well live in desperate times, a reality that demands we take hold of even more desperate futures to orient ourselves and plot a path forward. Whether readers are interested in this broader humanist project, or more simply in the various and complex ways in which sf can contribute to the history of science, this is a vital collection that demands attention from sf researchers, historians of science, and especially those who travel freely across such disciplinary boundaries.—Chad Andrews, Independent Scholar Utopian Film Studies. Simon Spiegel. Bilder einer besseren Welt. Die Utopie im nichtfiktionalen Film [Images of a Better World: The Utopia in Nonfiction Film]. Marburg: Schüren, 2019. 432 pp. €48 pbk. Open online access at . There are tons of dystopian sf films, but utopian sf films seem to be nonexistent . Utopian studies scholars have tried repeatedly to find utopia in fictional films, but to no avail. Sf films narrate alternative technologies, times, places, and beings, and of course they can also narrate alternative social 305 BOOKS IN REVIEW orders. There is no logical reason why these should always be horrific. Better societies can certainly be imagined, as the genre of utopian literature shows, but while literary dystopias have often been adapted for film, utopias have been neglected by the film industry. Why is this? Utopian scholars have long known that fictional films need a narrative plot with conflict at its core and that utopias lack this core because they are discursive rather than narrative and address harmonious societies without conflict. So a fictional utopian film would be quite boring and nobody has bothered to shoot one yet. At this point the scholarly debate on utopian film is usually aborted. Simon Spiegel, on the contrary, uses this finding as a starting point for an extensive study of utopian film. His idea is that if fictional film is incapable of depicting utopias, one should start looking for nonfictional utopian films. He has analyzed documentaries and propaganda films and actually found a quite diverse set of filmic utopias, and now he shows them to us—literally. Spiegel has hyperlinks to many of them on his website (). In Bilder einer...

Mating status and the evolution of eusociality: Oogenesis is independent of mating status in the solitary bee Osmia bicornis

The fundamental trait underlying eusociality is the reproductive division of labour. In honeybees (Apis mellifera), queens lay eggs while workers forage, defend and care for brood. The division of labour is maintained by pheromones including queen mandibular pheromone (QMP) produced by the queen. QMP constrains reproduction in adult honeybee workers, but in the absence of their queen workers can activate their ovaries and, although they cannot mate, they lay haploid male eggs. The reproductive ground plan hypothesis suggests that reproductive constraint may have evolved by co-opting mechanisms of reproductive control in solitary ancestors. In many insects mating is required to activate or accelerate oogenesis. Here, we use the solitary bee Osmia bicornis (Megachilidae) to test whether reproductive constraint evolved from ancestral control of reproduction by mating status. We present a structural study of the O. bicornis ovary, and compare key stages of oogenesis with honeybee workers. Importantly, we show that mating does not affect any aspect of the reproductive physiology of O. bicornis. We therefore conclude that mechanisms governing reproductive constraint in honeybees were unlikely to have been co-opted from mechanisms pertaining to mating status.

Exploration during early life: distribution, habitat and orientation preferences in juvenile king penguins

BackgroundThe early life of marine apex predators is poorly known, particularly for diving species. The orientation and foraging skills are presumably less developed in juveniles than in adults, especially during their first year at sea when juveniles might disperse further than adults.MethodsOver two years of monitoring, we tracked the movements of 17 juvenile king penguins (Aptenodytes patagonicus, ~ 1 year old) using satellite relay tags from Crozet Archipelago (Southern Indian Ocean), starting when birds left their natal colony for the first time. For comparison we also tagged 6 non-breeding adults, which at that stage, similar to juveniles, are unhampered by reproductive constraints and might roam further than breeders. We used a combination of cluster analysis and habitat modelling to investigate and compare the movement patterns and habitat use of experienced (non-breeding adults) and non-experienced (juveniles) individuals.ResultsWhile juvenile penguins and non-breeding adults followed similar routes, the movements by adults started later in the season and ranged over a considerably smaller area than juveniles. Net squared displacement analysis revealed that both groups did not move to a specific wintering area. Changes in direction of juveniles in respect to their departure island were similar and synchronous for both years. Habitat models revealed that foraging behaviour was affected by environmental variables such as wind or current speeds, sea surface temperature, or oceanic productivity, for both stages. Analysis of tracks revealed that birds moved predominately perpendicular or against the main direction of the Antarctic Circumpolar Current and the prevailing wind during austral summer (juveniles only) and autumn (juveniles and non-breeding adults). However, both juveniles and adults were more likely to move against the prevailing winds if productivity increased along their trajectories.ConclusionsThe exceptional duration of our tracking study provided unprecedented insights into the distribution, habitat preferences and orientation of two poorly known life history stages of an expert avian diver. Our study suggests that juveniles might use both innate and learnt skills to reach profitable foraging areas during their first year at sea, which is critical in long-lived species.

Sex solves Haldane’s dilemma

The cumulative reproductive cost of multi-locus selection has been considered to be a potentially limiting factor on the rate of adaptive evolution. In this paper, we show that Haldane's arguments for the accumulation of reproductive costs over multiple loci are valid only for a clonally reproducing population of asexual genotypes. We show that a sexually reproducing population avoids this accumulation of costs. Thus, sex removes a perceived reproductive constraint on the rate of adaptive evolution. The significance of our results is twofold. First, the results demonstrate that adaptation based on multiple genes-such as selection acting on the standing genetic variation-does not entail a huge reproductive cost as suggested by Haldane, provided of course that the population is reproducing sexually. Second, this reduction in the cost of natural selection provides a simple biological explanation for the advantage of sex. Specifically, Haldane's calculations illustrate the evolutionary disadvantage of asexuality; sexual reproduction frees the population from this disadvantage.

How to walk carryinga huge egg? Trade-offs between locomotion and reproduction explain the special pelvis and leg anatomy in kiwi (Aves; Apteryx spp.).

Kiwi (Aves; genus Apteryx) are famous for laying an enormous egg in comparison with their relatively small body size. Considering the peculiar gait of this flightless bird, we suspected the existence of morpho-functional trade-offs between reproduction and locomotion. To understand how structural constraints, imposed by a large egg size, might influence the terrestrial locomotion of Apteryx, we analysed the anatomy of the limb osteomuscular system in two species of kiwi (Apteryx mantelli and Apteryx owenii). We performed detailed dissections and brought to light specific anatomical features of kiwi, in comparison with other ratites and neognathous birds. Our osteological study revealed a strongly curved pelvis, a rigid tail, and enlarged ribs. Our myology study showed an unusual location of the caudofemoralis muscle origin and insertion. The insertion of the pars pelvica along the entire caudal face of the femur, contrasts with the proximal insertion usually seen in other birds. Additionally, the pars caudalis originates along the entire tail, whereas it only inserts on the uropygium in the other birds. To interpret these specificities from a functional point of view, we built three-dimensional osteomuscular models based on computed tomography scans, radiographies and our dissections. We chose three postures associated with reproductive constraints: the standing position of a gravid compared with a non-gravid bird, as well as the brooding position. The 3D model of the brooding position suggested that the enlarged ribs could support the bodyweight when leaning on the huge egg in both males and females. Moreover, we found that in gravid females, the unusual shape of the pelvis and tail allowed the huge egg to sit ventrally below the pelvis, whereas it is held closer to the rachis in other birds. The specific conformation of the limb and the insertions of the two parses of the caudofemoralis help to maintain the tail flexed, and to keep the legs adducted when carrying the egg. The caudal location of the hip and its flexed position explains the long stance phase during the strange gait of kiwi, revealing the functional trade-off between reproduction and locomotion in this emblematic New Zealand bird.

Trillium – toward Sustainable Utilization of a Biologically Distinct Genus Valued for Traditional Medicine

Trillium has fascinated the botanical world with its peculiar biology and high medicinal value. The genus appears in North America and Asia, and is widely used for traditional medicine on both continents. Medicinal value has been validated recently through the isolation and ex situ testing of constituent compounds. This study reviews biology, medicinal value, ecological threats and knowledge gaps, and offers suggestions for conservation and sustainable utilization. Findings indicate that the biology of the genus is well explored and the reproductive constraints are well recognized. Steroidal compounds and pharmaceutical potential of the genus are reported, but controlled clinical trials on humans are yet to be conducted. High medicinal value and the peculiar biology have made the genus susceptible to several threats.

Investigations Into the Reproductive Biology of the Southern Appalachian Endemic Piratebush (Buckleya distichophylla): Pollination Biology, Fruit Development, and Seed Germination

Endemic to the mountains of Tennessee, North Carolina and Virginia, piratebush (Buckleya distichophylla, Santalaceae) is a rare, dioecious, hemi-parasitic shrub with a scattered and isolated distribution. Vegetative reproduction and few visible seedlings within the densest population of piratebush on Poor Mountain in southwest Virginia emphasize the need for research into this species' reproductive biology to inform conservation strategies. Pollination data showed no evidence for wind pollination; instead multiple diurnal floral visitors to staminate flowers were observed. Fluorescence microscopy of stigma and styles on initiated fruits revealed almost 95% with pollen deposition. Most initiated fruits (52%) had tube growth continue to the base of the style, indicating potential fertilization. Pollination experiments showed outcrossing was necessary for fruit set. Non-pollinated flowers in bags had 0% fruit development, whereas fruit development in both open pollinated (86%) (p< 0.0001) and hand pollinated (65%) treatments (p<0.0001) were significantly greater. Embryo viability analysis indicated 73% of seeds had healthy embryos. Germination trials indicated that seeds must undergo stratification for successful germination. Germination for control (70.9%) and 10 min bleach (72.6%) treatments were significantly higher than mechanically scarified fruits/seeds (27.2%), suggesting a potentially negative impact that rodent gnawing would have on seed germination. Further, evidence of heavy seed predation was observed. These results suggest that there may be sufficient pollinators, successful outcrossing and seed development, and that embryos are viable and have the potential to germinate, but imply that seed predation may be a key reproductive constraint for piratebush.

Spatial segregation between immatures and adults in a pelagic seabird suggests age‐related competition

Individual competitiveness conditions access to resources when they are limited. Immature individuals that are less skilled than adults have to adapt their foraging strategies to survive. Among strategies to reduce competition, spatial segregation has been widely demonstrated. However, the use of spatial segregation by immatures to limit intra‐specific competition with adults has rarely been tested.In this study, we investigated and compared habitat preferences and distributions of free‐ranging immature and breeding adult northern gannets Morus bassanus in order to determine whether they compete for similar habitats during the year, and if this results in a spatial segregation between birds of different age groups.Based on &gt; 66 000 km of aerial surveys conducted in the North‐East Atlantic Ocean during winter and summer 2012, habitats selected by immatures and adult birds were modelled independently, linking gannet density to a set of oceanographic and physiographic predictors. Their large‐scale seasonal distribution was then predicted.We found that gannets displayed a strong season‐dependent competition between immatures and adults, as a consequence of immatures and adults using similar habitats in both summer and winter. During summer, when adults are constrained by reproduction, both groups were spatially highly segregated despite similar habitat preferences (thermal fronts), with youngest individuals selecting habitats out of range of central‐place foragers, highlighting intra‐specific competition. Contrastingly during winter, when reproductive constraints disappear, immature and adult distributions largely overlapped.Our study provides new insights into the role played by age, foraging experience and reproductive constraints on the distribution of marine predators. More specifically, these results highlight in seabirds how the youngest fraction mitigates, through spatial segregation, the competition with experienced adults, and suggest a progressive strategy along the maturation process.

Indigenous Chicken Production Environments, Reproductive and Productive Performances and Constraints in Kaffa Zone, South Western Ethiopia

Indigenous Chicken Production Environments, Reproductive and Productive Performances and Constraints in Kaffa Zone, South Western Ethiopia

Reproductive constraints in frugivorous phyllostomid bats: seasonal and elevational variation in reproductive rates in the Brazilian Atlantic Forest

Reproductive rates in bats are higher when there is a greater availability of food, and when temperatures and rainfall are higher. Along elevational gradients, variation in these factors occurs over a small area, making them ideal natural laboratories for studies that aim to describe reproductive patterns and to identify possible vertical migrations for reproduction. We characterized the seasonal and elevational variation in reproductive rates of female and male Artibeus spp., Carollia perspicillata, and Sturnira lilium in the Brazilian Atlantic Forest. We sampled bats with mist nets at 13 sites in southeastern Brazil, between 23° and 24° of latitude, at elevations between 60 and 1,800 m a.s.l. The reproductive patterns of Artibeus spp. and S. lilium were seasonal, with higher reproductive rates in the period with higher rainfall, temperatures, and, consequently, greater availability of food. Moreover, elevation influenced reproductive activity in all study species. Reproductive rates for females of Artibeus spp. were higher at intermediate elevations (between 501 and 1,000 m a.s.l.), and for females of S. lilium at high elevations (above 1,000 m a.s.l.) with a less evident peak at intermediate elevations. Similarly, the proportions of reproductively active male Artibeus spp. and S. lilium were greater at intermediate and high elevations, respectively. In the dry season, reproductive rates of all females increased with local abundance of all females. Differences in reproductive rates along elevational gradients could influence population dynamics, and therefore entire elevational ranges should be protected to ensure conservation of the best reproductive habitats for a variety of bat species. Public policies are needed to ensure effective conservation of biodiversity, biological processes, and the ecosystem services provided by local fauna from the lower lands to the mountain peaks.

Threshold temperature constraints on reproduction of the banded killifish (Fundulus diaphanus)

Banded killifish (Fundulus diaphanus) are a small, freshwater fish that have a wide distribution in eastern North America and are considered a species-at-risk on the island of Newfoundland. We posit that because Newfoundland’s summer climate is much cooler than other locations at similar latitudes, there may be different constraints on banded killifish reproduction. We measured embryonic development under four temperatures (10, 16, 22, and 28 °C) and two conductivities (0.6 and 1.2 mS/cm). Warmer temperatures led to more developed embryos prior to death in embryos that ultimately did not hatch, higher hatch success, faster hatch time, and fewer thermal units to hatch. Conductivity and temperature interacted to affect hatch size. Therefore, banded killifish are likely challenged by the low temperature and conductivity conditions in Newfoundland which may result in reproductive constraints, and perhaps complete cohort failures in relatively cool summers.