Reproductive Opportunities Research Articles

The Evolution of Mate Attachment.

AbstractWhether natural selection leads to attachment in monogamous pair bonds has seldom been addressed. Operationally defining attachment as a behavioral modifier that decreases divorce probability with pair duration, we develop a model for the evolution of attachment. If divorce (the ending of a pair bond when both individuals survive to the next breeding season) is more likely to occur out of poor-quality reproductive opportunities (i.e., poor territory or low-quality mate), individuals in experienced pairs are more likely to be found in high-quality opportunities. Consequently, when divorce decisions occur using imperfect information from reproductive success, pair duration provides individuals with information about the quality of their reproductive opportunity and attachment can evolve. We show that high survival rates, divorce propensities, and probabilities of nest failure favor the evolution of attachment. Attachment is also more likely to evolve when individuals can directly assess the quality of their reproductive opportunity (as opposed to relying on imperfect information from reproductive success), when the quality of the reproductive opportunity has adult survival ramifications, and when divorce coevolves with attachment. We show that our core conclusions are robust to a variety of assumptions using individual-based simulations. Our results clarify how attachment can be adaptive and suggest that studying pair bonds as dynamic entities is a promising avenue for future work.

A Framework to Enhance Flexible Blended Architectural Design Education

In the last few years, there have been lots of challenges facing the world from pandemics and wars that have raised a series of challenges facing architectural education, which create a challenge for both teachers and students and to which extent they can adapt to the post-digital adaptation period, as well as the future of architectural education in general. Architecture and design environments mainly require face-to-face learning and teaching techniques that depend on the interaction between the student and the teacher, where application and practical education take place. Furthermore, studio-designed spaces provide solidarity, positive energy, and motivation for students. Therefore, activating the distance learning process that affect the architectural education strategy and directed institutions and teachers to the necessity of flexibility and adaptation as a part of the structure of architectural education curricula. this study is a humble try to evaluate the role of blended learning experiences incorporating architectural design programmes that were first applied after the last pandemic. It focuses on the importance of flexible architectural education through the overlap between the traditional studio and the virtual studio to achieve a positive experience for students and staff members. This is done by observing a design studio procedure during a blended learning period and with the help of a questionnaire for a diverse number of students and faculty members on the subject of architectural design at one of the Egyptian universities that host the architecture department. It is conducted for the purpose of flexible handling through the integration of distance learning with architectural design education in relation to the era of pandemics, the digital age, and the like in the future. The research contributes to developing a future framework that enhances the flexibility of architectural design education, supports self-education, and turns the architectural design studio into an opportunity for reproduction and renewal.

Human-derived food shrinks home ranges and alters resource selection of mammals at the urban-wild interface

Protected lands are an important source of food, shelter, and reproductive opportunities for wildlife, especially in urban landscapes. When urban development abuts the edges of undisturbed ecosystems, synanthropic species can alter their foraging behaviors and movement to utilize human-supplemented resources throughout the urban-wild interface. Therefore, urban development on the edges of protected lands can have pronounced effects on animal movement and ecosystem functions. Iconic urban adaptive mesopredators such as northern raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana) often benefit from human-supplemented food sources such as unsecured garbage, pet food, and fresh water when available. To investigate how urban edges affect the movements of urban-adapted omnivores within conservation lands, we estimated home ranges and third-order resource selection of 27 raccoons and 12 opossums with GPS collars throughout the protected areas of northern Key Largo, FL, USA between April 2022–October 2023. The proportion of urban development in an individual's home range was the most influential factor associated with home range size, followed by species and sex. Individuals with greater proportions of residential neighborhoods and commercial areas in their home ranges exhibited smaller home ranges. Third-order resource selection functions identified both mesopredator species using residential and commercial land use areas more than they were available on the landscape. These results indicate that urban areas attract urban-adapted mesopredators from protected areas and result in smaller home ranges in the face of abundant human-derived food. Reduced home ranges on edges can support higher densities of animals, which may increase rates of disease transmission, especially when the urban borders support populations of feral domestic species. Shifting foraging behaviors from the protected areas to urban edges could have cascading downward effects if seed-dispersing roles are diluted. As urbanization increases and the distance between wild lands and human disturbance decreases, it is increasingly important to study the mechanisms of how urban development on the edges of protected areas affect the movement of wildlife.

Cumulative and interannual effects of reproduction in eastern grey kangaroos.

Reproduction can reduce energy allocation to other life-history traits such as survival and growth. Resource constraints give rise to (co)variation in life-history traits and to heterogeneity in energy acquisition and allocation. At each reproductive opportunity, females face a choice between allocation to current reproduction or to maintenance. Many studies compare reproductive trade-offs between two consecutive years, but few account for the cumulative effects of reproduction over multiple years, a crucial factor in understanding life-history evolution in long-lived iteroparous species. We compared short- (interannual) and long-term (cumulative) reproductive trade-offs with a 14-year capture-mark-recapture study of eastern grey kangaroos, where females can have substantial skeletal growth for several years after maturation. We used a multivariate approach to compare how interannual and multi-annual cumulative reproduction affected growth (n = 378 measurements), mass change (n = 376 measurements) and subsequent reproduction (n = 388 measurements), and to quantify (co)variation between these traits among individuals (n = 107) and years (n = 14). Interannually, young females that reproduced experienced decreased skeletal growth compared to young females that did not reproduce. Reproductive females of all ages experienced reduced mass gain and weaning probability in the following year. The cumulative effects of multiple reproductions included decreased skeletal growth, mass gain and weaning probability in the following year. These effects increased with age and reproductive rate. We found positive trait correlations between mass change, leg growth and subsequent reproduction among individuals and years, though weaker at the cumulative than interannual level. Females experience dynamic interannual and cumulative trade-offs. Our analyses of cumulative costs of reproduction revealed long-term trade-offs as well as cumulative costs that were not apparent when estimating interannual costs. Trait correlations suggested heterogeneity in growth and reproduction among females. Years of increased growth were followed by years of increased reproduction, and years of poor growth were followed by years of poor reproduction. Our exploration of both interannual and cumulative costs of reproduction underscores the need to account for long-term reproductive histories to better understand reproductive trade-offs in long-lived iteroparous species.

Do risk-prone behaviours compromise reproduction and increase vulnerability of fish aggregations exposed to fishing?

Human disturbances can prompt natural anti-predator behaviours in animals, affecting how energy is traded off between immediate survival and reproduction. In our study of male squaretail groupers (Plectropomus areolatus) in India's Lakshadweep archipelago, we investigated the impact of fishing pressure on anti-predatory responses and reproductive behaviours by comparing a fished and unfished spawning aggregation site and tracking responses over time at the fished site. Using observational sampling and predator exposure experiments, we analysed fear responses (flight initiation distance, return time), as well as time spent in vigilance, courtship and territorial defence. Unpaired males at fished sites were twice as likely to flee from simulated predators and took longer to return to mating territories. In contrast, paired males at both sites took greater risks during courtship, fleeing later than unpaired males, but returned earlier at the unfished site compared with the fished site. Our findings suggest that high fishing pressure reduces reproductive opportunities by increasing vigilance and compromising territorial defence, potentially affecting mate selection cues. Altered behavioural trade-offs may mitigate short-term capture risk but endanger long-term population survival through altered reproductive investment. Human extractive practices targeting animal reproductive aggregations can have disruptive effects beyond direct removal, influencing animal behaviours crucial for population survival.

Active facilitation of helper dispersal by parents and siblings in the cooperatively breeding acorn woodpecker

Offspring that delay dispersal in cooperatively breeding species have been hypothesized to gain direct fitness benefits via parental facilitation—being passively tolerated on their natal territory by their parents—thereby enjoying enhanced survival and increased probability of acquiring a breeding position in the population. Here we describe active facilitation in the acorn woodpecker (Melanerpes formicivorus) by parents and siblings assisting the dispersal of helpers in their social group. Helpers in this species compete for reproductive opportunities in “power struggles” that take place when all breeders of one sex die or disappear, creating a reproductive vacancy. Individuals compete at power struggles in coalitions of relatives, in which larger coalitions are more likely to be victorious. Based on observations of banded birds, we found that an estimated 26% of individuals competing as part of a winning coalition at a power struggle returned to their home territory at its conclusion, suggesting that they were facilitating the dispersal of kin (generally parents or siblings) that stayed to become breeders on the new territory. In at least one group, sibling facilitation was reciprocated; that is, a bird that was helped at a power struggle by a sibling joined that same sibling as part of a coalition at a subsequent power struggle. Dispersal facilitation is a novel means by which parents can nepotistically enhance the direct fitness of offspring and siblings can enhance each other’s inclusive fitness in this highly social species.Significance statementParental facilitation—being passively tolerated on the natal territory—may provide significant direct fitness benefits to helpers in cooperatively breeding species. We describe active facilitation of helper dispersal in the acorn woodpecker, where helpers compete in coalitions for reproductive opportunities at “power struggles” following the death or disappearance of all breeders of one sex. About one-fourth of individuals—including both parents and siblings—competing at power struggles were apparently facilitators who assisted related helpers by participating in the power struggle but then returned to their home territory rather than stay to breed on the new territory. In at least one group, dispersal facilitation was reciprocated; that is, a bird that was helped at a power struggle by a relative later joined that same relative as part of a coalition at a subsequent power struggle. Active dispersal facilitation by parents and siblings is an important, previously unrecognized, form of nepotistic behavior in this highly social species.

P-470 How much do the general population know regarding the menstrual cycle and conception?

Abstract Study question How much do the general population know regarding the menstrual cycle and conception? Summary answer There is a lack of basic knowledge regarding key menstrual cycle and conception facts which could lead to missed reproductive opportunities. What is known already Although the human menstrual cycle is a “normal” biological process, stigma remains regarding open discussion of periods, and there is limited research surrounding the public understanding of the menstrual cycle and conception. Infertility rates are rising globally. With people commencing a family later in life, it is essential that the knowledge needed to make informed decisions regarding conception is prevalent. The primary aim of this study was to determine the general populations’ knowledge regarding the menstrual cycle and conception. Study design, size, duration A prospective, voluntary, anonymous, self-completed ethically approved questionnaire was distributed internationally online via various social media platforms over a period of 3 months. Participants/materials, setting, methods In total, 676 fully completed questionnaires were analysed. 84.9% of participants identified as female, 13.5% identified as male, and a small remainder of the participants identified as non-binary (1.6%). Most participants were white (87%), lived in the UK (92%) and had a university education (62.1%). 12% of the respondents were healthcare workers of any type and 31.7% had biological children. Main results and the role of chance Female participants selected correct answers at higher rates than both males and non-binary participants for 88.9% of the questions. No differences in correct answers were seen when people with and without children were compared and those with university education versus those without. Some questions received a high number of correct answers by all participants; ‘What is menopause?’ (98.8% correct), ‘What does PMS stand for?’ (86% correct), ‘How many days does the average menstrual cycle last?” (89.2% correct), ‘Is it possible to get pregnant on your period?’ (77.4% correct). Whereas other questions were answered poorly by most participants; ‘How many days per month, on average is it possible to get pregnant?’ (40.9% correct), ‘What counts as the first day of a new menstrual cycle?’ (54.71% correct), and ‘How many days does the average period last?’ (56% correct). Limitations, reasons for caution The majority of participants were white, lived in the UK and the questionnaire was accessed through an online medium. Responses from non-white participants, outside of the UK and from those without access to the internet may have captured further themes in relation to the menstrual cycle and conception knowledge. Wider implications of the findings Increased education is urgently needed to ensure knowledge is sufficient for people to access healthcare when required and understand the principles of conception and fertility to fulfill or prevent when coveted. This data will facilitate the understanding that there is a need for sexual and reproductive education among the public. Trial registration number NA

Cyclic dynamics drive summer movement ecology of snowshoe hares (Lepus americanus)

Animals exhibit dynamic movement and activity in response to environmental variation including changes in reproductive opportunities, predation risk, or food availability. Yet, it remains unclear which factors are primary in affecting animal movement, and whether the relative importance of these factors are consistent through time. We tracked snowshoe hares (Lepus americanus) using GPS telemetry during eight summers spanning a hare population cycle (2015–2022) in southwestern Yukon, Canada, to determine associations between environmental variation and hare movement and home range size. Hare density varied 25-fold during the study and home range size increased markedly during low hare density, especially for males. Both sexes retained similar core space use and linearity of movements, but at low densities males had greater and more variable movement rates and time spent travelling. Trail cameras revealed that annual changes in hare movement were also correlated with relative abundance of lynx (Lynx canadensis) and coyotes (Canis latrans). However, hare detection rates within a season were not closely associated with seasonal variation in predator detection. Observed differences between male and female hares in some metrics highlighted that different life histories and reproductive behavior are likely the main drivers of hare movement dynamics. Therefore, fitness rewards associated with successful mate search and reproduction appear to outweigh risks associated with increased movement, even in highly variable environments where costs of prioritizing reproduction-related activities are notably high and variable.

Osmundastrum cinnamomeum population differences in three habitat types in South Korea

Most ferns occur in moist and shaded environments; their relatively narrow band of survival conditions increase their extinction risk under Anthropocene-linked climate change. Osmundastrum cinnamomeum (L.) C. Presl is a perennial fern that has a natural distribution primarily encompassing the East Asian mountains. In this study, we characterized the vegetation and environmental factors in low- and high-elevation mountain ranges and montane wetlands to elucidate the optimal habitat for O. cinnamomeum. We found that populations of O. cinnamomeum developed better in high-elevation mountains than in low-elevation mountains. However, the low light intensity in high mountain forests reduces opportunities for reproduction. The montane wetlands recorded the highest biomass among the three habitat types, and the investment in reproduction was also significantly higher. The montane wetlands also showed higher light intensity, substrate fertility, and water content. Overall, the montane wetlands were found to be the optimal habitat for O. cinnamomeum. At lower elevations, lower precipitation, higher temperatures, human disturbance, and low substrate water could be factors limiting the expansion of this fern's distribution. Our study points to the importance of conserving montane wetlands to prevent the extinction of ferns.

Seasonal migration directs and facilitates gene flow in the Broad-tailed and Lucifer Sheartail Hummingbirds

Gene flow, the movement of genes between populations, profoundly influences genetic and phenotypic homogeneity among populations. This study investigates gene flow patterns in two migratory hummingbird species, Selasphorus platycercus and Calothorax lucifer, shedding light on the intricate interplay between migration, resource availability, and genetic diversity. Using previously published information on microsatellites, we examine the genetic makeup and the movement of genes within populations. Selasphorus platycercus displays distinct genetic groups which can be associated with its migratory behaviour. Gene flow analysis suggests a higher level of connectivity among populations sharing winter ranges. In contrast, Calothorax lucifer populations exhibit genetic divergence despite overlapping winter ranges, possibly due to environmental niche adaptation and limited reproductive opportunities for dispersing individuals. While geographical distance does not explain genetic differentiation in these species, environmental niche similarities appear to facilitate gene flow. This study underscores the significance of migratory routes, resource availability, and niche adaptation in shaping gene flow dynamics in hummingbirds. Understanding these dynamics is crucial for the conservation and management of these unique avian populations.

Key roles of insulin receptor InR1 in initiating reproductive diapause in males of the cabbage beetle Colaphellus bowringi (Coleoptera: Chrysomelidae).

Reproductive diapause serves as a valuable strategy enabling insects to survive unfavorable seasonal conditions. However, forcing insects into diapause when the environment is conducive to their well-being can cause them to miss out on seasonal opportunities for reproduction. This outcome not only reduces insect populations but also minimizes crop losses caused by insect feeding. Therefore, altering the timing of diapause initiation presents a potential strategy for managing pests. In this study, we examined the possible role of the Insulin Receptor 1 (InR1) in controlling reproductive diapause entry in the male cabbage beetle, Colaphellus bowringi. Compared to short-day (SD) conditions, long-day (LD) conditions led to reproductive diapause of C. bowringi males, characterized by arrested gonad development, increased Triglyceride (TG) accumulation, and upregulated expression of diapause protein 1 and genes associated with lipogenesis and stress tolerance. Upon employing RNA interference to knock down InR1 under SD conditions, males destined for reproduction were compelled into diapause, evidenced by arrested gonadal development, accumulation of TG, and elevated expression of diapause-related genes. Intriguingly, despite the common association of the absence of juvenile hormone (JH) with reproductive diapause in females, the knockdown of InR1 in males did not significant affect the expression of JH biosynthesis and JH response gene. The study highlight InR1 is a key factor involved in regulating male reproductive diapause in C. bowringi. Consequently, targeting insulin signaling could be a viable approach to perturb diapause timing, offering a promising strategy for managing pests with reproductive diapause capabilities. © 2024 Society of Chemical Industry.

The effect of sex and mating opportunity on ecological immunity in Brood X cicadas

Seventeen-year periodical cicadas represent an extreme life history, with individuals spending 17 years as juveniles and less than 45 days as adults. The implications of this life history on investment in immunity are unknown. Using monofilament implants, we examined sex differences in melanization and encapsulation-based immunity in Brood X Magicicada septendecim and M. cassini periodical cicadas. In many insects, females devote more effort to immunity than males which allows females additional time to lay eggs before death. In 17-year cicadas, the functional difference in lifespan between males and females is trivial as compared to their total lifespan. However, we found that in both species, adult females had better immunity (encapsulation response) than males. In both species, male immunity (melanization and encapsulation) declined as they aged, as did female encapsulation. However, female immunity (melanization) either did not decline or improved with age. We conclude that although male immunosenescence resembles that of shorter-lived insects, for females, melanization-based immunity is preserved as they age, potentially due to their unique life history. We also examined whether being housed in mixed-sex versus single-sex enclosures affected immunity but did not find an effect of reproductive opportunity on either melanization or encapsulation in males or females of either species. This is the first study to assay melanization or encapsulation in a cicada, so our results provide a first look at sex- and age-based immunity in this group.

Decreasing body size is associated with reduced calving probability in critically endangered North Atlantic right whales.

Body size is key to many life-history processes, including reproduction. Across species, climate change and other stressors have caused reductions in the body size to which animals can grow, called asymptotic size, with consequences for demography. A reduction in mean asymptotic length was documented for critically endangered North Atlantic right whales, in parallel with declines in health and vital rates resulting from human activities and environmental changes. Here, we tested whether smaller body size was associated with lower reproductive output, using a state-space model for individual health, survival and reproduction that quantifies the mechanistic links between these processes. Body size (as represented by the cube of length) was strongly associated with a female's calving probability at each reproductive opportunity. This relationship explained 62% of the variation in calving among reproductive females, along with their decreasing health (20%). The effects of decreasing mean body size on reproductive performance are another concerning indication of the worsening prospects for this species and many others affected by environmental change, requiring a focus of conservation and management interventions on improving conditions that affect reproduction as well as reducing mortality.

Ripple effects in a communication network: anti-eavesdropper defence elicits elaborated sexual signals in rival males.

Emitting conspicuous signals into the environment to attract mates comes with the increased risk of interception by eavesdropping enemies. As a defence, a commonly described strategy is for signallers to group together in leks, diluting each individual's risk. Lekking systems are often highly social settings in which competing males dynamically alter their signalling behaviour to attract mates. Thus, signalling at the lek requires navigating fluctuations in risk, competition and reproductive opportunities. Here, we investigate how behavioural defence strategies directed at an eavesdropping enemy have cascading effects across the communication network. We investigated these behaviours in the túngara frog (Engystomops pustulosus), examining how a calling male's swatting defence directed at frog-biting midges indirectly affects the calling behaviour of his rival. We found that the rival responds to swat-induced water ripples by increasing his call rate and complexity. Then, performing phonotaxis experiments, we found that eavesdropping fringe-lipped bats (Trachops cirrhosus) do not exhibit a preference for a swatting male compared to his rival, but females strongly prefer the rival male. Defences to minimize attacks from eavesdroppers thus shift the mate competition landscape in favour of rival males. By modulating the attractiveness of signalling prey to female receivers, we posit that eavesdropping micropredators likely have an unappreciated impact on the ecology and evolution of sexual communication systems.

Identification of hybrids between the Japanese giant salamander (Andrias japonicus) and Chinese giant salamander (Andrias cf. davidianus) using deep learning and smartphone images.

Human-mediated hybridization between native and non-native species is causing biodiversity loss worldwide. Hybridization has contributed to the extinction of many species through direct and indirect processes such as loss of reproductive opportunity and genetic introgression. Therefore, it is essential to manage hybrids to conserve biodiversity. However, specialized knowledge is required to identify the target species based on visual characteristics when two species have similar features. Although image recognition technology can be a powerful tool for identifying hybrids, studies have yet to utilize deep learning approaches. Hence, this study aimed to identify hybrids between the native Japanese giant salamander (Andrias japonicus) and the non-native Chinese giant salamander (Andrias cf. davidianus) using EfficientNetV2 and smartphone images. We used smartphone images of 11 individuals of native A. japonicus (five training and six test images) and 20 individuals of hybrids between A. japonicus and A. cf. davidianus (five training and 15 test images). In our experimental environment, an AI model constructed with EfficientNetV2 exhibited 100% accuracy in identifying hybrids. In addition, gradient-weighted class activation mapping revealed that the AI model was able to classify A. japonicus and hybrids between A. japonicus and A. cf. davidianus on the basis of the dorsal head spot patterning. Our approach thus enables the identification of hybrids against A. japonicus, which was previously considered difficult by non-experts. Furthermore, since this study achieved reliable identification using smartphone images, it is expected to be applied to a wide range of citizen science projects.

Evidence of the active participation of women in the intergroup conflict based on the use of aggression and cooperation

Intergroup conflict has been a persistent aspect of human societies since the emergence of our species. Various researchers have proposed that competition between groups has acted as a key selective force throughout human evolutionary history. Such intergroup competition for limited resources exacerbated the expression of intergroup aggression and intragroup cooperation. Furthermore, it would have a sexual dimorphism, with men demonstrating increased sensitivity to conflict threats—in order to maximize reproductive opportunities—, while women generally reject from active engagement in intergroup conflict. In the present study, we conducted behavioral experiments under controlled laboratory conditions to measure cooperation and aggression from using virtual games, specifically the Public Good Games and the Point Subtraction Aggression Paradigm, in a sample of 541 participants. We created control and experimental intergroup competition scenarios, where aggression and cooperation were necessary to increase monetary rewards. Our results shows that men modulate aggression and cooperation in the presence of intergroup conflict. In addition, our data also reveals that women cooperate more than men and display heightened levels of cooperation and aggression when confronted with intergroup conflict. These findings prompt a reevaluation of current functional theoretical models concerning the role of women in intergroup conflict and suggest that the dynamics of human aggression and cooperation may be more nuanced than previously believed.

Theoretical and Methodological Approaches to the Analysis of the Spatial Distribution of Endemic Diseases of Geochemical Nature

—Throughout millions of years of geological history (in the Phanerozoic), the coevolution of all living organisms took place in a fierce competition for resources and opportunities for the maximum reproduction. Due to the geochemical heterogeneity of the primary (pre-Quaternary) biosphere, this resulted in a self-regulating system of ecological niches, within which all local biocenoses and their animal and plant species were maximally adapted to the parameters of the habitat. However, with the emergence of reason, the situation changed fundamentally. Human beings became the dominant species and began the conscious development of new territories, including geochemically unfavorable ones, which led to the formation of zones of stable endemic diseases. Based on this premise, for all existing species, there should be areas with physiologically optimal habitat conditions, i.e., those under which the species has evolved to its present state. It follows that, by being able to record the geochemical parameters of the undisturbed biosphere, it is possible to obtain characteristics that are ecologically ideal for local animal and plant species. In theoretical terms, this allowed us to put forward the hypothesis that by fixing the difference between observed and ideal geochemical conditions, it is possible to build maps of risk of diseases of geochemical nature, including in areas subjected to anthropogenic pollution. The paper outlines the methodology and gives examples of construction of such maps. The obtained results can have an important practical value in organizing the system of sanitary–epidemiological service, in solving the problems of liquidation of the consequences of anthropogenic pollution, and in carrying out preventive measures to minimize the risk of diseases of geochemical nature.

Theoretical and Methodological Approaches to the Analysis of Peculiarities of Spatial Distribution of Endemic Diseases of a Geochemical Nature

Over millions of years of geological history (Phanerozoic), the co-evolution of all living organisms took place in condtions of fierce competition for resources and opportunities for maximum reproduction, which, given the geochemical heterogeneity of the primary (pre-Quaternary) biosphere, resulted in a self-regulating ecological niche system, within which all local biocenoses and their animal and plant species were adapted to the parameters of the habitat to the maximum extent. However, with the development of the brain and the emergence of reason, the situation changed radically. Humans became the dominant species and began to develop new territories, including geochemically unfavourable ones, which caused the formation of zones of persistent endemic diseases. Based on this premise, for all existing species, there must be territories with physiologically optimal habitat conditions, i.e. those in which the species was formed in its present form. This implies that by being able to determine the geochemical parameters of the undisturbed biosphere, it is possible to obtain characteristics corresponding to the ecologically ideal ones for local animal and plant species. In theoretical terms it has allowed to put forward the hypothesis that by fixing the difference between the observed and ideal geochemical conditions it is possible to build maps of risk of diseases of geochemical nature, including those caused by technogenic pollution. The article presents a methodology and examples of such mapping. The results obtained may have an important practical value in improving the system of sanitary and epidemiological services, in solving problems of carrying out preventive measures to minimize endemic morbidity eliminating endemic diseases.

Aggregation pheromone interrupts death feigning in the red flour beetle Tribolium castaneum

AbstractDeath feigning is a behavior in which a prey is rendered motionless due to stimulation or threat by a predator. This anti-predator defense mechanism has been observed across a wide range of animal taxa and is considered adaptive. However, long durations of death feigning can decrease opportunities for feeding and reproduction, and therefore is a fitness cost as compared to environments without predators. Because death feigning is thought to be affected by the balance between survival and other fitness costs, selection pressure may drive individuals who are capable of plastic changes in the intensity of death feigning. Pheromones, which are important semiochemicals that affect foraging and reproductive success, may be one of the factors influencing the intensity of death-feigning behavior. In this study, we investigated the effect of an aggregation pheromone on the death-feigning behavior of the red flour beetle Tribolium castaneum. We found that beetles exposed to the pheromone showed a significantly shorter duration of death feigning than beetles that were not exposed to the pheromone. Therefore, our results suggest that an aggregation pheromone can plasticly alter the death-feigning behavior in T. castaneum.

Exploring the males' terminal investment strategy: Impact of the dose of stress and the time lapse between stress and mating

Abstract In the terminal investment strategy, organisms allocate resources to maximize current reproduction when their future reproductive opportunities are uncertain due to a high risk of mortality. However, whether the role of time lapse between stress and reproductive investment (courtship vs. courtship and mating) triggers the terminal investment strategy remains unknown. We examined this hypothesis in Tenebrio molitor using oxidative stress as the stressor. Given that this is the first time that oxidative stress is used to trigger terminal investment, we first conducted mate choice trials where males exposed to 5, 20, 40 or 80 mM of the pro‐oxidant, paraquat (PQ) engaged in courtship behaviour towards the females. Subsequently, we analysed the male mortality against each of these doses. Males exposed to a 5 mM treatment exhibited higher survival rates compared with the control group, whereas males exposed to 80 mM experienced a shorter lifespan. After courtship, no significant differences in mortality were observed between the control group and those treated with 20 or 40 mM of PQ. Notably, only males exposed to 40 mM of PQ were preferred over the control group. In a third experiment, we quantify the survival costs when males courted and mated at varying time intervals after oxidative stress (40 mM). When males were exposed to 40 mM of PQ and mated 3 h later, their mortality rates significantly decreased compared with males exposed to oxidative stress, courted and mated, but 24 h later. We suggest that the interaction of the dose of oxidative stress and the time lapse between courtship and mating may explain opposed results to support either the terminal investment or honest signalling.