Reproductive Strategies Research Articles

Effective coverage of antenatal care services in Ethiopia: a population-based cross-sectional study

BackgroundAntenatal care (ANC) is a principal component of safe motherhood and reproductive health strategies across the continuum of care. Although the coverage of antenatal care visits has increased in Ethiopia, there needs to be more evidence of effective coverage of antenatal care. The 'effective coverage' concept can pinpoint where action is required to improve high-quality coverage in Ethiopia. Effective coverage indicates a health system's performance by incorporating need, utilization, and quality into a single measurement. The concept includes the number of contacts, facility readiness, interventions received, and components of services received. This study aimed to measure effective antenatal care coverage in Ethiopia.MethodsA two-stage cluster sampling method was used and included 2714 women aged 15–49 years and 462 health facilities from six Ethiopian regions from October 2019 to January 2020. The effective coverage cascade was analyzed among the targeted women by computing the proportion who received four or more antenatal care visits where the necessary inputs were available, received iron-folate supplementation and two doses of tetanus vaccination according to process quality components of antenatal care services.ResultsOf all women, 40% (95%CI; 38, 43) had four or more visits, ranging from 3% in Afar to 74% in Addis Ababa. The overall mean health facility readiness score of the facilities serving these women was 70%, the vaccination and iron-folate supplementation coverage was 26%, and the ANC process quality was 64%. As reported by women, the least score was given to the quality component of discussing birth preparedness and complication readiness with providers. In the effective coverage cascade, the input-adjusted, intervention-adjusted, and quality-adjusted antenatal coverage estimates were 28%, 18%, and 12%, respectively.ConclusionThe overall effective ANC coverage was low, primarily due to a considerable drop in the proportion of women who completed four or more ANC visits. Improving quality of services is crucial to increase ANC up take and completion of the recommended visits along with interventions increasing women’s awareness.

Life history correlations and trade-offs resulting from selection for dispersal in Tribolium castaneum.

Dispersal is an important facet of the life history of many organisms and is, therefore, subject to selective pressure but does not evolve in isolation. Across nature, there are examples of dispersal syndromes and life history strategies in which suites of traits coevolve and covary with dispersal in combinations that serve to maximize fitness in a given ecological context. The red rust flour beetle, Tribolium castaneum, is a model organism and globally significant post-harvest pest that relies on dispersal to reach new patches of ephemeral habitat. Dispersal behaviour in Tribolium has a strong genetic basis. However, a robust understanding of the relationship between dispersal and other life-history components, which could elucidate evolutionary processes and allow pest managers to control their spread and reduce the impact of infestation, is currently lacking. Here, we use highly replicated lines of T. castaneum previously artificially selected for divergent small-scale dispersal propensity to robustly test several important life history components: reproductive strategy, development time, and longevity. As predicted, we find that a suite of important changes as a result of our selection on dispersal: high dispersal propensity is associated with a lower number of longer mating attempts by males, lower investment in early life reproduction by females, slower development of later-laid offspring, and longer female life span. These findings indicate that correlated intraspecific variation in dispersal and related traits may represent alternative life history strategies in T. castaneum. We therefore suggest that pest management efforts to mitigate the species' agro-economic impact should consider the eco-evolutionary dynamics within multiple life histories. The benefits of doing so could be felt both through improved targeting of efforts to reduce spread and also in forecasting how the selection pressures applied through pest management are likely to affect pest evolution.

Responses of belowground bud bank density of geophytes to environmental perturbations: a meta-analysis

Abstract A belowground bud bank is a collection of asexual propagules produced by the underground storage organs of geophytes. Renewal through belowground bud banks is the main reproductive strategy of geophytes. The belowground bud bank density reflects the potential renewal capacity of geophyte communities. However, the effects of different perturbation regimes and habitats on the belowground bud bank density of geophytes are not comprehensively understood. Moreover, whether different types of belowground bud banks respond differently to perturbations is still unclear. For this meta-analysis, relevant papers on the effects of environmental perturbations on the belowground bud bank density of geophytes were systematically collected. The cumulative effect size of different perturbation regimes and habitats on belowground bud banks among different bud types was analyzed. Overall, the effect of environmental perturbations on belowground bud bank density was small, which may result from opposite or fluctuating responses of bud banks to different perturbations. Drought negatively affected bud bank density. Environmental perturbations decreased rhizome bud density but increased tiller bud density. In wetlands, perturbations decreased belowground bud bank density. However, no significant effect was found for other habitat types. In general, belowground bud banks of geophytes are highly resistant and resilient. Changes in belowground bud bank density depend on the type of perturbations, the habitats in which plants are distributed and the type of bud banks.

Termite females prefer hybrid mating to parthenogenesis when conspecific males are absent

Abstract Parthenogenesis and interspecific mating are alternative reproductive strategies that species have evolved alternative strategies when the opportunity of sexual reproduction is hindered by the natural environment. However, it is still unclear how to make a choice between parthenogenesis and interspecific mating when females are unable to reproduce sexually with males of the same species. This study mainly investigated the reproductive behaviour of female termites in the absence of male termites of the same species. Here, reproductive behaviours of females Reticulitermes aculabialis (Ra♀) were observed when they encountered a male R. flaviceps (Rf♂) with the absence of male R. aculabialis(Ra♂). The results showed that Ra♀‐Rf♂ tandems were more prevalent and stable compared to Ra♀‐Ra♀ tandems. When a tandem inadvertently broke apart, the female R. aculabialis displayed longer pauses while waiting for male R. flaviceps, but shorter pauses when another female R. aculabialis was involved. Furthermore, there were mating behaviour between female R. aculabialis and males R. flaviceps, resulting in offspring produced in paired Ra♀‐Rf♂ colonies were hybridization between female R. aculabialis and male R. flaviceps. These results suggest that interspecific mating and recombination is an important aspect for the choice of reproduction strategy, which will provide new insights into the trade‐off between gene contribution rate and genetic diversity.

Impacts of noise pollution from high-speed rail and road on bird diversity: a case study in a protected area of Italy

The disturbance of infrastructures may affect biological communities that are exposed to them. This study assesses the impact of high-speed (highway and railway) infrastructures in a protected study site, the Natural Reserve Fontanili di Corte Valle Re (Emilia–Romagna, Italy). We compared bird diversity with sound intensity and frequency in three sampling areas, increasingly distant from the infrastructures at the border with the reserve, during the last 4 years (2019–2022), monitoring sedentary, nesting, and migratory bird species. We hypothesize a decreasing diversity closer to the source of disturbance, which is mostly attributable to noise pollution. Our findings confirmed this trend, and we show that, in particular, disturbance seems to influence species richness more than the total abundance of birds. We also discovered that highway disturbance was much higher than railway in terms of frequency and duration. In light of these results, we suggest that some species, which have a behavioral ecology strongly based on singing to communicate with each other for their reproductive and defensive strategies, may suffer more from constant acoustic disturbance. The installation of effective noise barriers to shield the sound produced by the highways should be considered a mandatory request not only in proximity to houses but also in the vicinity of protected areas.

Early Ontogeny of Cichlids Using Selected Species as Examples.

The purpose of this study was to characterize in detail the reproductive strategy, course of embryogenesis, and development of larvae in three species of fishes of the genus Cichlasoma: the green terror (Andinoacara rivulatus), the red discus (Symphysodon discus), and the jaguar cichlid (Parachromis managuensis). Eggs for the study were obtained from five pairs of each species (300 eggs from each female) and incubated at 26 °C. The developing eggs were observed under a microscope (Carl Zeiss Stereo Discovery. V12 and Nikon 2000SE software (NIS-Elements F 4.30.01 64-bit) from fertilization to larval hatching until complete yolk-sac resorption. The largest average number of eggs per female was found in the jaguar cichlid (x¯ = 2991 eggs), a smaller average number of eggs was shown in the green terror (x¯ = 922 eggs), and the red discus showed the smallest average number of eggs (x¯ = 300 eggs). There were significant differences in the sizes of the eggs of the studied species: jaguar cichlid eggs were the smallest (1.060 ± 0.05 mm3), red discus eggs were larger (1.070 ± 0.07 mm3), and green terror eggs were the largest (1.365 ± 0.16 mm3). The embryogenesis time in the red discus was 2132 °H (82 Hpf), in the green terror it was 2158 °H (83 Hpf), and the longest in the jaguar cichlid was 2470 °H (87 Hpf). At the end of embryogenesis, the average size of the larvae after hatching was measured (red discus x¯ = 4.346 mm, green terror x¯ = 5.203 mm, and jaguar cichlid x¯ = 5.301 mm) and the time of yolk-sac resorption from the moment of hatching to the transition from endogenous to exogenous feeding was determined (jaguar cichlid 5 days, green terror 6 days, and red discus 3 days). The results of this study may contribute to the development of reproductive biotechnology for the studied fishes that could be used in aquaculture and, thus, help protect them in their natural habitats.

Quantifying maternal investment in mammals using allometry.

Maternal investment influences the survival and reproduction of both mothers and their progeny and plays a crucial role in understanding individuals' life-history and population ecology. To reveal the complex mechanisms associated with reproduction and investment, it is necessary to examine variations in maternal investment across species. Comparisons across species call for a standardised method to quantify maternal investment, which remained to be developed. This paper addresses this limitation by introducing the maternal investment metric - MI -for mammalian species, established through the allometric scaling of the litter mass at weaning age by the adult mass and investment duration (i.e. gestation + lactation duration) of a species. Using a database encompassing hundreds of mammalian species, we show that the metric is not highly sensitive to the regression method used to fit the allometric relationship or to the proxy used for adult body mass. The comparison of the maternal investment metric between mammalian subclasses and orders reveals strong differences across taxa. For example, our metric confirms that Eutheria have a higher maternal investment than Metatheria. We discuss how further research could use the maternal investment metric as a valuable tool to understand variation in reproductive strategies.

Comparative electron microscopy study of spermatozoa in snakes (Lepidosauria, Squamata)

The ultrastructure of snake sperm has received substantial attention primarily because snakes exhibit considerable variability in reproductive characteristics between species, with a wide range of mating systems and reproductive behaviors. Variability of sperm morphology among snake species may be associated with the reproductive strategies of each taxon, such as competition or sperm storage. We provide a detailed description of the sperm ultrastructure of nine snake species (Anilius scytale, Tropidophis paucisquamis, Bothrops jararaca, Oxyrhopus guibei, Dipsas mikanii, Micrurus corallinus, Xenopholis scalaris, Acrochordus javanicus, and Cylindrophis ruffus) and compared this with sperm data from the literature for the following taxa: Liotyphlops beui, Amerotyphlops reticulatus, Trilepida koppesi, Anilios waitii, Anilios endoterus, Aspidites melanochephalus, Boa constrictor amarali, Corallus hortulana, Epicrates cenchria, Boa constrictor occidentalis, Eryx jayakari, Micrurus corallinus, Micrurus surinamensis, Micrurus frontalis, Micrurus altirostris, Oxyuranus microlepidotus, Bothrops alternatus, Bothrops diporus, Crotalus durissus, Agkistrodon contortrix, Vipera aspis, Boiga irregularis, Zamenis schrenckii, Zamenis scalaris, Stegonotus cuculatus, Nerodia sipedon, Liodytes pygaea, and Myrrophis chinensis. We found twelve polymorphic characters in the ultrastructure of sperm among the described snakes. Our work supports the importance of ultrastructural analysis of sperm morphology to understand snake reproduction, and provides sperm-derived morphological characters for phylogenetic analysis.

Цивілізаційний образ «Заходу» в історичних працях Михайла Максимовича.

The purpose of the article is to study the reception of the image of the West by Mykhailo Maksimovich in the context of his civilizational views and ideas. The methodological basis of the article is mental mapping as a strategy of cognitive reproduction of geographical objects in the imagination of scientists. The basic component of the used methodology is imagology as a method of studying one’s own/another person’s images. The scientific novelty of the article lies in the fact that it first clarified the attitude of this scientist to the West as an image of a civilized community; the role of this image in the civilizational self-identification of the historian is traced; an analysis of his ideas regarding the relationship between the historical images of Russia-Ukraine and the West in Maksymovich’s historical works is made. Conclusions. In Mykhailo Maksymovich’s civilizational identity the Slavic world was "his" civilizational community. The role of the main "foreign" and "enemy" civilizational community was performed by the West. The West was imagined by Maksymovich as a space populated by Germanic peoples, on which the Catholic faith prevails. The historian did not notice Romanic peoples or the Protestant faith in his historical texts. The Germanic West was interpreted by Maksymovich as an environment that has always carried out an aggressive expansion into the Slavic world with the aim of conquering and assimilating it. The scientist considered Catholicism, primarily the order of the Jesuits, to be the main characteristic of the West. For him, the ethnic representative of Western civilization was primarily the German people. Maksymovich interpreted the Germans as a people for whom the primordial, genetically determined "hostility" towards the Slavs is inherent. His historical image of Poland was also inscribed in Maksymovich’s reception of the West. This historian interpreted the Poles as the people who were the first to experience Western (German) expansion and were heavily influenced by it. As a result, the Poles were interpreted by scholars as bearers of "Western" traditions among the Slavs.

Structural shifts in plant functional diversity during biogeomorphic succession: Moving beyond taxonomic investigations in an alpine glacier foreland

AbstractThe complex interrelation between plants and geomorphic processes is described in the concept of biogeomorphic succession. While ecological research on succession and community assembly has transitioned towards functional approaches, studies on functional diversity in biogeomorphic settings, particularly in glacier forelands, remain limited. In this study, we investigated abundance of vascular plant species and functional traits in an alpine glacier foreland using data from 199 plots. Our objective was to unravel the development of functional diversity during biogeomorphic succession. Specifically, the study determined whether structural shifts in functional diversity are associated with stability thresholds related to plant cover, geomorphic influence, and examined trait spectra for stages of biogeomorphic succession. Our findings revealed a nonlinear trajectory of functional diversity along the plant cover gradient, marked by two distinct structural shifts at 30% and 74% cover, corresponding to established stability thresholds. Along the gradient of geomorphic influence, we observed an increase in functional diversity until 54% of the plot area was affected, beyond which functional diversity declined below the initial level. The analysis of community‐weighted means of traits across four stages of biogeomorphic succession determined by plant cover and absence and presence of geomorphic influence revealed significant differences in trait values. In the transition to the biogeomorphic stage, associated with the identified initial structural shift, there is a shift from a prevalence of above‐ground adaptation and reproductive traits, such as leaf longevity, structure, growth form and mixed reproductive strategies, to an increased dominance of competitor species and traits related to below‐ground structures, including root type and structures, as well as vegetative reproduction. Our results contribute to understanding the relationship between vegetation succession and geomorphic influence by linking them to plant functional traits. This study advances beyond traditional taxonomic investigations by emphasizing functional approaches to biogeomorphic succession. Moreover, the functional trait data used in this study, easily downloadable from a public repository, can serve as a valuable template for future research in (bio)geomorphology, along with the employed methodologies.

Dynamic Bayesian network structure learning based on an improved bacterial foraging optimization algorithm

With the rapid development of artificial intelligence and data science, Dynamic Bayesian Network (DBN), as an effective probabilistic graphical model, has been widely used in many engineering fields. And swarm intelligence algorithm is an optimization algorithm based on natural selection with the characteristics of distributed, self-organization and robustness. By applying the high-performance swarm intelligence algorithm to DBN structure learning, we can fully utilize the algorithm's global search capability to effectively process time-based data, improve the efficiency of network generation and the accuracy of network structure. This study proposes an improved bacterial foraging optimization algorithm (IBFO-A) to solve the problems of random step size, limited group communication, and the inability to maintain a balance between global and local searching. The IBFO-A algorithm framework comprises four layers. First, population initialization is achieved using a logistics-sine chaotic mapping strategy as the basis for global optimization. Second, the activity strategy of a colony foraging trend is constructed by combining the exploration phase of the Osprey optimization algorithm. Subsequently, the strategy of bacterial colony propagation is improved using a "genetic" approach and the Multi-point crossover operator. Finally, the elimination-dispersal activity strategy is employed to escape the local optimal solution. To solve the problem of complex DBN learning structures due to the introduction of time information, a DBN structure learning method called IBFO-D, which is based on the IBFO-A algorithm framework, is proposed. IBFO-D determines the edge direction of the structure by combining the dynamic K2 scoring function, the designed V-structure orientation rule, and the trend activity strategy. Then, according to the improved reproductive activity strategy, the concept of "survival of the fittest" is applied to the network candidate solution while maintaining species diversity. Finally, the global optimal network structure with the highest score is obtained based on the elimination-dispersal activity strategy. Multiple tests and comparison experiments were conducted on 10 sets of benchmark test functions, two non-temporal and temporal data types, and six data samples of two benchmark 2T-BN networks to evaluate and analyze the optimization performance and structure learning ability of the proposed algorithm under various data types. The experimental results demonstrated that IBFO-A exhibits good convergence, stability, and accuracy, whereas IBFO-D is an effective approach for learning DBN structures from data and has practical value for engineering applications.

Life history of an evolutionary distinct aquatic caecilian amphibian (genus Potomotyphlus) in eastern Amazonia, Brazil

Abstract Basic ecological data for caecilians are relatively lacking. This study presents the first comprehensive ecological investigation of the Amazonian aquatic caecilian Potomotyphlus kaupii, utilizing a large sample size. We collected population data over a 14-month period, and also used data of museum specimens, both from Belém, State of Pará, Brazil. Our analysis focused on sex ratio, sexual size dimorphism (SSD), female fecundity, and ecological observations. No significant differences in adult sex ratio were found. SSD was found in some characters such as circumference at midbody and body mass with females being larger than males, while males had a wider and longer cloacal disc. We provide the first determination of the approximate size at which males diverge from females in the terminal portion of the body, demonstrating an allometric growth pattern of the cloacal region. Female size showed a positive correlation with the number of ovarian eggs, indicating an important reproductive strategy. Furthermore, a novel behaviour in P. kaupii was documented. We expand the understanding of Gymnophiona biology, in particular of a fully aquatic species, and provide support for future ecological and conservation research on caecilians.

The immunolocalization of adiponectin and its receptors in the testis of the frog Pelophylax bergeri

In all vertebrates, reproductive strategies are achieved by modulation of the neuroendocrine system in a similar manner and with minor variations among the different classes. Most of the available information on amphibian testicular cycles derive from anurans, and among these, water frogs have been extensively studied in terms of reproductive mechanisms and sex steroid correlation. Adiponectin (AdipoQ) and its receptors—AdipoR1 and AdipoR2—are essential for most of the normal testicular and sperm functions. In this study, the identification of AdipoQ and its two receptors was carried out by immunohistochemistry in the testis of adult males of Pelophylax bergeri. The AdipoQ system was observed in the frog spermatogenic cysts, in both germinal and Sertoli cells, as well as in the rete testis. AdipoQ and AdipoR1 were localized in germ-line cells, from spermatogonia to round spermatids, while AdipoR2 was detected in the elongated spermatids, spermatozoa, and Sertoli cells. AdipoR1 was also observed in the intratesticular canals of the rete testis. This preliminary study shows the AdipoQ system’s presence in the anurans’ testis. The results obtained could be a starting point for future functional studies aimed at defining the physiological role of the AdipoQ system in frog testicular functions.

Navigating Educational and Urban Landscapes: Middle-Class School Choice Strategies in Local Education Markets

ABSTRACT The middle-classes use school choice as a strategy of class reproduction and comparative advantage. In this article, we show how middle-class parental school choice strategies are spatially dependent and how schooling preferences and final choices are bounded by the social and educational characteristics of the local education market of their neighborhood of residence in the city of Barcelona. Our findings reveal interesting differences relating to the search process and final decisions, which are dependent on parental preferences and risk perception in the different local education markets. Reflections on some policy implications of the analysis are considered in the conclusions.

Nicotinamide mononucleotide maintains cytoskeletal stability and fortifies mitochondrial function to mitigate oocyte damage induced by Triocresyl phosphate

Triocresyl phosphate (TOCP) was commonly used as flame retardant, plasticizer, lubricant, and jet fuel additive. Studies have shown adverse effects of TOCP on the reproductive system. However, the potential harm brought by TOCP, especially to mammalian female reproductive cells, remains a mystery. In this study, we employed an in vitro model for the first time to investigate the effects of TOCP on the maturation process of mouse oocytes. TOCP exposure hampered the meiotic division process, as evidenced by a reduction in the extrusion of the first polar body from oocytes. Subsequent research revealed the disruption of the oocyte cell cytoskeleton induced by TOCP, resulting in abnormalities in spindle organization, chromosome alignment, and actin filament distribution. This disturbance further extended to the rearrangement of organelles within oocytes, particularly affecting the mitochondria. Importantly, after TOCP treatment, mitochondrial function in oocytes was impaired, leading to oxidative stress, DNA damage, cell apoptosis, and subsequent changes of epigenetic modifications. Supplementation with nicotinamide mononucleotide (NMN) alleviated the harmful effects of TOCP. NMN exerted its mitigating effects through two fundamental mechanisms. On one hand, NMN conferred stability to the cell cytoskeleton, thereby supporting nuclear maturation. On the other hand, NMN enhanced mitochondrial function within oocytes, reducing the excess reactive oxygen species (ROS), restoring meiotic division abnormalities caused by TOCP, preventing oocyte DNA damage, and suppressing epigenetic changes. These findings not only enhance our understanding of the molecular basis of TOCP induced oocyte damage but also offer a promising avenue for the potential application of NMN in optimizing reproductive treatment strategies.

Differences in expression of male aggression between wild bonobos and chimpanzees

Researchers investigating the evolution of human aggression look to our closest living relatives, bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), as valuable sources of comparative data.1,2 Males in the two species exhibit contrasting patterns: male chimpanzees sexually coerce females3,4,5,6,7,8 and sometimes kill conspecifics,9,10,11,12 whereas male bonobos exhibit less sexual coercion13,14 and no reported killing.13 Among the various attempts to explain these species differences, the self-domestication hypothesis proposes negative fitness consequences of male aggression in bonobos.2,15,16 Nonetheless, the extent to which these species differ in overall rates of aggression remains unclear due to insufficiently comparable observation methods.17,18,19,20,21,22,23 We used 14 community-years of focal follow data-the gold standard for observational studies24-to compare rates of male aggression in 3 bonobo communities at the Kokolopori Bonobo Reserve, Democratic Republic of Congo, and 2 chimpanzee communities at Gombe National Park, Tanzania. As expected, given that females commonly outrank males, we found that bonobos exhibited lower rates of male-female aggression and higher rates of female-male aggression than chimpanzees. Surprisingly, we found higher rates of male-male aggression among bonobos than chimpanzees even when limiting analyses to contact aggression. In both species, more aggressive males obtained higher mating success. Although our findings indicate that the frequency of male-male aggression does not parallel species difference in its intensity, they support the view that contrary to male chimpanzees, whose reproductive success depends on strong coalitions, male bonobos have more individualistic reproductive strategies.25.

Contradistinctive floral attributes, pollination guilds and their consequence on the outcrossing rate in two elevational morphs of Rhododendron arboreum Sm.

Infraspecific floral trait variations may appear in response to elevational differences in alpine plant species. There is enormous information on the selection of such morphs mediated by biotic and/or abiotic variables. Whether such differences contribute to differences in reproductive strategy and mating outcomes is rarely investigated. We investigated these aspects in two distinct elevational floral morphs (Red and Pink) of Rhododendron arboreum Sm. in Western Himalaya. The red morphs occupy the lower elevations while pink morphs the higher elevations. The two morphs differ in floral traits like phenology, dimension, display, quality of floral rewards, and pollinators that happen to influence interaction with available pollinator pool at each elevation. The pink morph exhibits entomophily, while the red ones show ornithophily. Although experimental pollinations established that both the morphs are self-compatible, selfing results in significantly lower fruit-set than either cross- or open-pollinations. The outcrossing rate in the red morph, as determined by using simple sequence repeat (SSR) markers, was higher (tm=0.82) than that in the pink morph (tm=0.76), with a tendency of the latter to be shifting towards mixed-mating strategy. However, the extent of biparental inbreeding was comparable among the two morphs. It is inferred that the differences in the mating outcomes among the morphs in the tree species are linked to those emerging from floral traits and the pollination by different functional groups of floral visitors.

Advances and prerequisites for strontium isotope analyses through laser ablation in an aquatic context – Targeting Mid-Neolithic Baltic Sea harp seal (Pagophilus groenlandicus) mobility and breeding grounds

Harp seals (Phoca groenlandicus), once present in the Baltic Sea, now stand extinct. During the Middle Neolithic period, they held significant dietary importance for the Pitted Ware Culture hunter-fisher-gatherers in Scandinavia. Because they are no longer available for ecological studies, little is known about their specific behavioural intricacies, such as diet, mobility, and reproductive strategies. Because of the seal's pivotal role in these human societies and because they provide an interesting ecological case study on post-isolation ecological adaptation to new environmental conditions, a comprehensive investigation into Baltic Sea harp seal behaviour is warranted.In this pursuit, we employ sequential analysis of strontium isotope ratios (87Sr/86Sr) in harp seal teeth sourced from archaeological contexts across three study regions. This data is harmonized with osteometric analyses from fifteen archaeological sites from the Baltic Sea area, establishing a methodological framework for comprehending the Sr isotopic pathway in a brackish water inland sea. By adopting this approach, we unveil breeding and mobility patterns of the long-extinct Baltic Sea harp seals, approximate specific breeding areas connected to each group of seals and delve into the ontogenic temporal frame governing these observed patterns. This endeavour culminates in an enriched understanding of the adaptive behaviours exhibited by Baltic Sea harp seals and equips us with the insights necessary to decipher the lifestyle of the human societies intricately intertwined with them.

Transcriptome analysis of the bipotential gonads of hermaphroditic bivalve species Tridacna crocea unravels the potential genes responsible for spermatogenesis

Sex is an integral part of the evolution of species and often takes the form of intersex and sexual change in mollusks. As a major member of the deep-sea coral reef ecosystem, Tridacna crocea has complex gonadal development mechanisms and reproductive strategies, and the regulation model of spermatogenesis needs to be further explored. In this study, gonadal transcripts of T. crocea in resting, spermatogonia and sperm stage were evaluated. According to the statistics of bioinformatics analysis, a total of 10,260 DEGs were identified, including 3021 genes shared by three developmental stages. Through dynamic expression analysis, we identified the expression patterns and functional classification of genes that regulate spermatogenesis. These candidate genes were involved in regulatory mechanisms such as nucleotide binding, cell cycle, sexual reproduction and DNA replication. Subsequently, based on functional screening, PPI analysis was performed on the target gene cluster to learn the network relationships among candidate genes and other genes closely related to candidate genes. The results showed that in addition to candidate genes (zmcm6, gins2, mcm9, blm, mcm4, psmc3ip, haus, ccnb3, spice, rad1, rad17, ncapg, bub1b, lin9, tipin, and cks), several genes that have been shown to be associated with gonadal development were present in the network (such as fanci, aurka, kif20a and nek2), suggesting the reliability of the results. Finally, the expression levels of candidate genes between individuals at different developmental stages were compared with transcriptional expression profiles, which further proved that these candidate genes were related to T. crocea gonad development traits. These results make up for the lack of research on T. crocea gametogenesis, spermatogenesis and gonad development, and provide a reference for the research on Tridacna reproductive mechanism.

Mallard brood movements and survival in an urbanized landscape

AbstractWhen selecting a nest site, mallards (Anas platyrhynchos) balance differing habitat requirements for the nesting and brood‐rearing periods, such that the juxtaposition of these habitats in the landscape may influence the female's reproductive strategy and reproductive success. Mallard populations in the northeastern United States have declined since the mid‐1990s, and increasing urban development in this region may pose risks to broods and cause high duckling mortality. We assessed mallard brood and duckling survival in the urbanized landscapes of Connecticut, USA, and evaluated whether differences in brood movements, home ranges, and habitat use in urbanized areas influence brood survival. We monitored 32 mallard broods from females with global positioning system (GPS) transmitters in Connecticut in 2021 and 2022. Apparent brood survival to 30 days (0.48, n = 29 broods) was comparable to previous estimates in the Northeast (range = 0.21–0.72), but individual duckling survival (0.18, n = 257 ducklings) was lower than many previous estimates for this region (range = 0.14–0.44), suggesting this parameter warrants continued evaluation because it may be contributing to population declines in Connecticut and the greater Northeast region. Mallard females demonstrated different reproductive strategies and seemed to prioritize either high‐quality nesting habitat or proximity to high‐quality brood‐rearing habitat. High‐quality nesting habitat is not necessarily near high‐quality brood‐rearing habitat, and 61% (17/28) of females moved their ducklings an average of 1.1 ± 0.9 km (SD) shortly after hatch to a brood‐rearing site, often traveling along small streams. A similar proportion of successful (9/12) and failed (7/13) broods moved. We provide evidence of limited availability of brood‐rearing habitat, as females moved long distances to brood‐rearing wetlands and only 1 brood made additional inter‐wetland moves. Management actions that create or modify nesting and brood‐rearing habitat should consider connectivity between these sites; females may choose to nest away from wetlands to minimize exposure to predators but may depend on small streams for travel to brood‐rearing wetlands.