Royal Society Open Science最新文献

Variation in reproductive success is a fundamental prerequisite for sexual selection to act upon a trait. Assessing such variation is crucial in understanding a species' mating system and offers insights into population growth. Parentage analyses in cetaceans are rare, and the underlying forces of sexual selection acting on their mating behaviours remain poorly understood. Here, we combined 25 years of photo-identification and genetic data to assess patterns of male reproductive success and reproductive autonomy of the New Caledonian (Oceania, South Pacific) humpback whale breeding population. Paternity analysis of 177 mother-offspring pairs and 936 males revealed low variation in male reproductive success (average 1.17 offspring per father) relative to other polygynous species. The observed skew in success was higher than expected under random mating and skewed overall towards males (93%) without evidence of paternity over the study period. Finally, an updated male gametic mark-recapture abundance estimate of 2084 (95% confidence interval = 1761-2407, 1995-2019) fell between previous census estimates of the New Caledonian population and the wider Oceanian metapopulation. Our results provide critical insights into the mating competition of male humpback whales and population dynamics across Oceanian populations, two important factors affecting the slow recovery from whaling across the South Pacific region.

Following previous reports that male deer mice, Peromyscus maniculatus, produce chemical signals that attract conspecific females, we analysed and field-tested sex-attractant semiochemicals (message-bearing chemicals) of male deer mice. Field traps baited with urine- and faeces-soiled bedding of male mice captured adult female, but not male, mice, indicating dissemination of sex-attractant semiochemicals from the males' excreta. Analysing excreta headspace volatiles of both males and females by gas chromatography-mass spectrometry revealed that 5-methyl-2-hexanone was male-specific, and that eight other ketones (3-methyl-2-pentanone, 2-hexanone, 4-heptanone, 2-heptanone, 6-methyl-2-heptanone, 3-octanone, 2-octanone, 2-nonanone) were 2.6-5.6 times more abundant in male, than in female, samples. In a field experiment with paired trap boxes, treatment boxes baited with the synthetic ketone lure captured 3.4 times more females (17 : 5) and 1.6 times fewer males (5 : 8) than corresponding unbaited boxes. In a follow-up paired-trap field experiment, treatment boxes baited with both the ketone lure and synthetic testosterone captured 8 times more mature females and 2.3 times more immature females, but 9 times fewer immature males, than control boxes baited only with the ketone lure, all indicating that testosterone is a synergistic sex-attractant semiochemical. As previously shown in house mice, Mus musculus, and brown rats, Rattus norvegicus, sex-attractant semiochemicals of male deer mice comprise both volatile and sex steroid components.

Central-place foragers face high predation risk when repeatedly using routes near their nest, as predators can learn to ambush them there. We investigated the factors influencing the likelihood of desert ant foragers falling into pitfall traps, simulating common predators such as antlions or spiders. We varied the spatial configuration of the pitfall traps, the presence of trapped nestmates and the availability of visual landmarks to study the workers' susceptibility to falling into pits and their foraging success. Our results showed that a zigzag configuration of pits led to the fewest workers reaching the food reward, compared with straight-line and right-angled-triangle configurations. Over successive runs, workers became more efficient, with fewer falls into pits and faster food discovery, suggesting they either learned the locations of the pits or became more cautious. In any case, the ants learned about important landscape features close to their nest and the best way of navigating around it. Additionally, we examined the impact of trapped nestmates and visual landmarks. We found that pits marked with visual landmarks resulted in fewer falls. However, pits containing trapped nestmates attracted more ants, impaired food discovery and increased falling rates into pits, thereby imposing a twofold cost on ant foragers.

Listening is understood to be a foundational element in practices that rely on effective conversations, but there is a gap in our understanding of what the effects of high-quality listening are on both the speaker and listener. This registered report addressed this gap by training one group of participants to listen well as speakers discuss their character strengths, allowing us to isolate the role relational listening plays in strengths-based conversations. Participants were paired and randomly assigned to a high-quality listening (experimental) or moderate-quality listening (comparison) condition manipulated through a validated video-based training. High-quality listening predicted a more constructive relational experience; specifically, positivity resonance. Intrapersonal experiences (perceived authenticity and state anxiety) were not affected. Those who engaged in high-quality listening expressed a behavioural intention to continue listening, but condition did not predict a behavioural intention for speakers to continue applying character strengths. This is the first evidence of positivity resonance as a shared outcome between both a speaker and listener when the listener conveys high-quality (as opposed to 'everyday') listening. These early findings merit further study with stronger listening manipulations to explore the potential role of listening within interpersonal communication, and inform the applied psychological sciences (counselling, psychotherapy, coaching, organizational, education).

Maintaining a pair bond year after year (perennial monogamy) often enhances reproductive success, but what familiar pairs are doing differently to improve success is unknown. We tested the hypothesis that endocrine changes mediate improvements in parental attendance in known-age Cassin's auklets Ptychoramphus aleuticus, for which we found limited evidence. Instead, we found sex-specific parental roles in familiar pairs. Males modulated their nest attendance depending on the attendance of their mate, but the direction depended on mate familiarity. We suggest his flexibility may be mediated by prolactin. In a historical dataset, females with a familiar mate laid larger eggs that hatched into more robust chicks, but larger eggs correlated with lower female body condition. In study birds, attendance by males and females in good condition predicted chick weight, but attendance by females in poor condition did not, suggesting female-specific energetic constraint. Our findings suggest that males and females contribute differently to their joint reproductive fortunes, and that improvements in their respective roles may result in the benefits of mate familiarity. Since improved reproductive success is presumed to be a main benefit of maintaining a long-term pair bond, these results suggest a new avenue of research in the evolution of monogamy.

Individuals colonizing new areas during range expansion encounter challenging and unfamiliar environments, suggesting that colonists should differ in behavioural traits from residents of source populations. The colonizer syndrome is supposed to be associated with boldness, exploration, activity and low sociability. We assessed spatial and temporal variation of the colonizer syndrome in an expanding population of midday gerbils (Meriones meridianus). Male-first colonists did not differ significantly from residents of the source population, whereas female-first colonists were bolder, faster and more explorative than females from the source population. These findings support a boldness/exploration syndrome as a typical colonizer trait, which appears to be restricted to females in midday gerbils. Males and females also differed in behavioural dynamics after colony establishment. In males, boldness/exploration/sociability peaked in newly founded colonies, then sharply decreased in subsequent generations consistently with decreasing environmental uncertainty in ageing colonies. In females, greater boldness/exploration did not diminish with time post-colonization, i.e. female colonists retained the bold/explorative phenotype in subsequent generations despite facing a less challenging environment. Thus, female colonists, unlike males, carry a specialized behavioural colonizer phenotype corresponding to a proactive behavioural coping strategy. We link sex differences in behavioural traits of colonists to sex-specific life-history strategies.

Male crickets sing to attract females for mating. Sound is produced by tegminal stridulation, where one wing bears a plectrum and the other a wing vein modified with cuticular teeth. The carrier frequency (f_c ) of the call is dictated by the wing resonance and the rate of tooth strikes. Therefore, the f_c varies across species due to the size of the vibrating membranes on the wings and/or the speed of tooth strikes. But how well is the resonant frequency (f_o ) conserved in dried preserved specimens? This project is designed to investigate the gradual change in cricket wing f_o over time and aims to produce equations that help to predict or recover the original natural frequency of wing vibration in dry-preserved crickets and allies. Using laser Doppler vibrometry, we scanned the wings of living specimens to determine their f_o . The specimens were then preserved, allowing us to continue measuring the wings f_o as they desiccate. We found that after the first week, f_o increases steeply, reaching a plateau and stabilizing for the following months. We go on to propose a model that can be used to recover the original f_c of the wings of preserved Ensifera that use pure tones for communication. Models were corroborated using preserved specimens previously recorded and mounted in dry collections for more than 10 years.

The retraction of an article is probably the most severe outcome of a scientific project. While great emphasis has been placed on articles retracted due to scientific misconduct, studies show many retractions are due to honest errors. Unfortunately, in most cases, retraction notices do not provide sufficient information to determine the specific types and causes of these errors. In our study, we explored the research data management (RDM) errors that led to retractions from the authors' perspectives. We collected responses from 97 researchers from a broad range of disciplines using a survey design. Our exploratory results suggest that just about any type of RDM error can lead to the retraction of a paper, and these errors can occur at any stage of the data management workflow. The most frequently occurring cause of an error was inattention. The retraction was an extremely stressful experience for the majority of our sample, and most surveyed researchers introduced changes to their data management workflow as a result. Based on our findings, we propose that researchers revise their data management workflows as a whole instead of focusing on certain aspects of the process, with particular emphasis on tasks vulnerable to human fallibility.

Teeth are a key vertebrate innovation; their evolution is generally associated with the origin of jawed vertebrates. However, tooth-like structures already occur in jawless stem-gnathostomes; heterostracans bear denticles and morphologically distinct tubercles on their oral plates. We analysed the histology of the heterostracan denticles and plates to elucidate their morphogenesis and test their homology to the gnathostome oral skeleton. We identified a general model of growth for heterostracan oral plates that exhibit proximal episodic addition of tubercle rows. The distal hook exhibits truncated lamellae compatible with resorption, but we observe growth layers to be continuous between denticles. The denticles show no evidence of patterns of apposition or replacement indicating tooth homology. The oral plates and dermal skeleton share the same histological layers. The denticles grew in a manner comparable to the oral plate tubercles and the rest of the dermal skeleton. Our test of phylogenetic congruence reveals that the distribution of internal odontodes is discontinuous, indicating that the capacity to form internal odontodes evolved independently several times among stem-gnathostomes. Our results support the 'outside-in' hypothesis and the origin of teeth through the spread of odontogenic competence from extra-oral to oral epithelia and the subsequent co-option to a tooth function in gnathostomes.

The physical and superconducting characteristics of SrPd₂P₂ and SrPd₂As₂ compounds with applied pressure were calculated using density functional theory. The pressure effect on the structural properties of these compounds was investigated. The results show that both lattice constants and volume decrease almost linearly with increasing pressure. The elastic constants (C _ij) for both compounds increase with increasing pressure and satisfy Born criteria for mechanical stability. The elastic parameters indicate the ductile behaviour and anisotropic nature of these compounds under applied pressure. The Debye temperature (ϴ _D) and melting temperature (T _m) increase with increasing pressure. The electronic band structure calculation of both compounds exhibits metallic characteristics at different pressures. The density of electronic states at the Fermi level, N(E _F), consistently decreases as pressure increases, which is also reflected in the repulsive Coulomb pseudopotential (µ*), and the electron-phonon coupling constant (λ). These optical features suggest that both compounds are suitable for optoelectronic device applications. Furthermore, the superconducting transition temperature, T _c, for both compounds is predicted to vary with applied pressure due to changes in ϴ _D , N(E _F), µ* and λ.