Population Ecology Research Articles

Measuring effects of ivermectin-treated cattle on potential malaria vectors in Vietnam: A cluster-randomized trial.

Malaria elimination using current tools has stalled in many areas. Ivermectin (IVM) is a broad-antiparasitic drug and mosquitocide and has been proposed as a tool for accelerating progress towards malaria elimination. Under laboratory conditions, IVM has been shown to reduce the survival of adult Anopheles populations that have fed on IVM-treated mammals. Treating cattle with IVM has been proposed as an important contribution to malaria vector management, however, the impacts of IVM in this One Health use case have been untested in field trials in Southeast Asia. Through a randomized village-based trial, this study quantified the effect of IVM-treated cattle on anopheline populations in treated vs. untreated villages in Central Vietnam. Local zebu cattle in six rural villages were included in this study. In three villages, cattle were treated with IVM at established veterinary dosages, and in three additional villages cattle were left as untreated controls. For the main study outcome, the mosquito populations in all villages were sampled using cattle-baited traps for six nights before, and six nights after a 2-day IVM-administration (intervention) period. Anopheline species were characterized using taxonomic keys. The impact of the intervention was analyzed using a difference-in-differences (DID) approach with generalized estimating equations (with negative binomial distribution and robust errors). This intervention was powered to detect a 50% reduction in total nightly Anopheles spp. vector catches from cattle-baited traps. Given the unusual diversity in anopheline populations, exploratory analyses examined taxon-level differences in the ecological population diversity. Across the treated villages, 1,112 of 1,523 censused cows (73% overall; range 67% to 83%) were treated with IVM. In both control and treated villages, there was a 30% to 40% decrease in total anophelines captured in the post-intervention period as compared to the pre-intervention period. In the control villages, there were 1,873 captured pre-intervention and 1,079 captured during the post-intervention period. In the treated villages, there were 1,594 captured pre-intervention, and 1,101 captured during the post-intervention period. The difference in differences model analysis comparing total captures between arms was not statistically significant (p = 0.61). Secondary outcomes of vector population diversity found that in three villages (one control and two treatment) Brillouin's index increased, and in three villages (two control and one treatment) Brillouin's index decreased. When examining biodiversity by trapping-night, there were no clear trends in treated or untreated vector populations. Additionally, there were no clear trends when examining the components of biodiversity: richness and evenness. The ability of this study to quantify the impacts of IVM treatment was limited due to unexpectedly large spatiotemporal variability in trapping rates; an area-wide decrease in trapping counts across all six villages post-intervention; and potential spillover effects. However, this study provides important data to directly inform future studies in the GMS and beyond for IVM-based vector control.

Population ecology of the intertidal xanthid crab Leptodius exaratus (H. Milne Edwards, 1834) (Decapoda: Brachyura: Xanthidae) on rocky shores in Kuwait, Arabian (Persian) Gulf

Abstract Leptodius exaratus (H. Milne Edwards, 1834) is an exploited species that has been used as bait for recreational fishing in Kuwait. The biological and ecological aspects of the species required to manage this practice are limited. We investigated the life history and population ecology of L. exaratus in the northwestern Arabian (Persian) Gulf. The spawning season of the crab in Kuwait starts in the late spring and continues through the summer and ends in September. Fecundity is highly correlated to female body size and ranges 2,533–11,991 eggs clutch–1, with a mean number of 7,055 eggs clutch–1. Juveniles are generally recruited between July and September, with lower minor recruitment levels occurring in October and November. Growth is highly seasonal, being slow during the cold season (October-February) and high during the warmer season (March and September), with a higher growth rate in males than in females. The seasonality of growth and reproduction of L. exaratus in the region is strongly related to ambient air and water temperatures. Sexual dimorphism is highly significant between males and females with males, reaching reproductive maturity at 17.43 ± 0.53 mm carapace width (CW) and females at 9.58 ± 1.21 mm CW. The overall sex ratio for the species is 0.8:1 (males:females). Furthermore, the life span of 3–4 yr and an overall mortality slightly higher in males than in females. The results of our study could be used to determine fishery management strategies such as minimum catch sizes and closures periods. The results on life history and dynamics of the complex life cycle of L. exaratus contribute to conservation and sustainable exploitation of the species in Kuwait.

Effects of urban-induced mutations on ecology, evolution and health.

Increasing evidence suggests that urbanization is associated with higher mutation rates, which can affect the health and evolution of organisms that inhabit cities. Elevated pollution levels in urban areas can induce DNA damage, leading to de novo mutations. Studies on mutations induced by urban pollution are most prevalent in humans and microorganisms, whereas studies of non-human eukaryotes are rare, even though increased mutation rates have the potential to affect organisms and their populations in contemporary time. Our Perspective explores how higher mutation rates in urban environments could impact the fitness, ecology and evolution of populations. Most mutations will be neutral or deleterious, and higher mutation rates associated with elevated pollution in urban populations can increase the risk of cancer in humans and potentially other species. We highlight the potential for urban-driven increased deleterious mutational loads in some organisms, which could lead to a decline in population growth of a wide diversity of organisms. Although beneficial mutations are expected to be rare, we argue that higher mutation rates in urban areas could influence adaptive evolution, especially in organisms with short generation times. Finally, we explore avenues for future research to better understand the effects of urban-induced mutations on the fitness, ecology and evolution of city-dwelling organisms.

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.

Preface for the special feature on “Population ecology of COVID‐19: Similarities and differences between epidemiology and ecological population management”

Preface for the special feature on “Population ecology of <scp>COVID</scp>‐19: Similarities and differences between epidemiology and ecological population management”

Anopheles aquatic development kinetic and adults’ longevity through different seasons in laboratory and semi-field conditions in Burkina Faso

AbstractBackgroundAnopheles mosquitoes are ectothermic and involved in numerous pathogen transmissions. Their life history traits are influenced by several environmental factors such as temperature, relative humidity and photoperiodicity. Despite extensive investigations of these environmental conditions on vector population ecology, their impact on the different life stages of Anopheles at different seasons in the year remains poorly explored. This study reports the potential impact of these abiotic factors on the immature and adult stages of Anopheles gambiae sensu lato during different seasons.MethodsEnvironmental conditions were simulated in the laboratory using incubators to mimic the environmental conditions of two important periods of the year in Burkina Faso: the peak of rainy season (August) and the onset of dry season (December). Eggs from wild An. coluzzii and An. gambiae s.l. were reared separately under each environmental condition. For Anopheles coluzzii or An. gambiae s.l., eggs were equally divided into two groups assigned to the two experimental conditions. Four replicates were carried out for this experiment. Then, egg hatching rate, pupation rate, larval development time, larva-to-pupae development time, adult emergence dynamics and longevity of Anopheles were evaluated. Also, pupae-to-adult development time from wild L3 and L4 Anopheles larvae was estimated under semi-field conditions in December.ResultsA better egg hatching rate was recorded overall with conditions mimicking the onset of the dry season compared to the peak of the rainy season. Larval development time and longevity of An. gambiae s.l. female were significantly longer at the onset of the dry season compared than at the peak of the rainy season. Adult emergence was spread over 48 and 96 h at the peak of the rainy season and onset of dry season conditions respectively. This 96h duration in the controlled conditions of December was also observed in the semi-field conditions in December.ConclusionsThe impact of temperature and relative humidity on immature stages and longevity of An. gambiae s.l. adult females differed under both conditions. These findings contribute to a better understanding of vector population dynamics throughout different seasons of the year and may facilitate tailoring of control strategies.Graphical

Tracking Vibrio: population dynamics and ecology of Vibrio parahaemolyticus and V. vulnificus in an Alabama estuary.

Vibrio spp. are bacteria found in estuaries worldwide; some species can cause illness and infections in humans. Relationships between Vibrio spp. abundance, salinity, and temperature are well documented, but correlations to other environmental parameters are less understood. This study identifies unique correlates (e.g., E-W wind scalar and harmful algal species) that could potentially inform the next iteration of predictive Vibrio models for the EMSS region. Additionally, these correlates may allow existing environmental monitoring efforts to be leveraged in providing data inputs for future Vibrio risk models. An observed correlation between salinity and V. vulnificus/particle-size associations suggests that predicted environmental changes may affect the abundance of Vibrio spp. in certain reservoirs, which may alter which vectors present the greatest vibrio risk.

Contributions and problems of mathematical models in COVID‐19 prevention in Japan

AbstractThis article reviews the essential role of mathematical models in understanding and combatting the pandemic of novel coronaviruses, in particular focusing the advance in the use of mathematical models in disease control in Japan. Highlighting the integral role of mathematical models in public health, the article introduces a model that factors in the heterogeneity of infectious contacts, concentrating on the effectiveness of testing and isolation, alongside a model that involves economic losses. The models exhibit how, given such heterogeneity, milder behavioral restrictions can still achieve suppression, rigorous testing and isolation can effectively curb the spread, and containment measures can mitigate economic losses. These models aid in grasping the complicated dynamics of disease transmission and optimizing interventions. The knowledge of population ecology is also considered effective for public health in statistical analysis, organizing concepts using dynamic mathematical models, which lead to policy proposals and deepen understanding. Evolution theory may help the understanding of virulence subject to change. However, effective prevention necessitates not only models but also the practical implementation of efficacious measures. The cooperation of various disciplines is particularly crucial in achieving a balance between health measures, economic interests, and human rights. Moreover, the article acknowledges the limitations of models and underscores the significance of real‐world execution. Overall, the article advocates for a broader outlook to tackle future pandemics and related challenges, underscoring the importance of ongoing academic cooperation and global governance to effectively address emerging infectious diseases and their far‐reaching implications.

Epigenetic age estimation of wild mice using faecal samples.

Age is a key parameter in population ecology, with a myriad of biological processes changing with age as organisms develop in early life then later senesce. As age is often hard to accurately measure with non-lethal methods, epigenetic methods of age estimation (epigenetic clocks) have become a popular tool in animal ecology and are often developed or calibrated using captive animals of known age. However, studies typically rely on invasive blood or tissue samples, which limit their application in more sensitive or elusive species. Moreover, few studies have directly assessed how methylation patterns and epigenetic age estimates compare across environmental contexts (e.g. captive or laboratory-based vs. wild animals). Here, we built a targeted epigenetic clock from laboratory house mice (strain C57BL/6, Mus musculus) using DNA from non-invasive faecal samples, and then used it to estimate age in a population of wild mice (Mus musculus domesticus) of unknown age. This laboratory mouse-derived epigenetic clock accurately predicted adult wild mice to be older than juveniles and showed that wild mice typically increased in epigenetic age over time, but with wide variation in epigenetic ageing rate among individuals. Our results also suggested that, for a given body mass, wild mice had higher methylation across targeted CpG sites than laboratory mice (and consistently higher epigenetic age estimates as a result), even among the smallest, juvenile mice. This suggests wild and laboratory mice may display different CpG methylation levels from very early in life and indicates caution is needed when developing epigenetic clocks on laboratory animals and applying them in the wild.

Insecticidal effects of wood vinegars produced from organic wastes on harmful almond leaf bee Cimbex quadrimaculata (Müller, 1766) (Hymenoptera: Cimbicidae)

In agricultural activities, there is an increasing need for organic products as alternatives to chemical pesticides. Wood vinegar (WV, pyrolysis liquid) from these alternative potential products is produced as a result of the carbonization process in which it is obtained from organic wastes together with useful products such as energy and biochar. This study was carried out to determine the insecticidal effects of WVs produced from broiler chicken litter and nutshells on the harmful almond leaf wasp Cimbex quadrimaculata Müller, 1766 (Hymenoptera: Cimbicidae). The study was carried out in an almond orchard in Diyarbakır (Eğil district) and Elazığ (Keban district) in the 2019-2021 production seasons. WV mixed solutions (1%, 3%, 5%, 7%, 10% and 25%) were applied with a back sprayer at the beginning and end of leafing in contaminated almond orchards. The effects of the applications were determined by impact and visual control methods on the 1st, 7th, 14th and 21st. In the analysis of the obtained data, first of all, normality test was performed. In the analysis of the obtained data, the Kruskal-Wallis test was applied. In conclusion; It has been determined that WV-added solutions have a insecticidal effect against harmful almond leaf bees, and the highest decrease in the number of larvae occurs at doses of 10% to 25%. It is important to test these vinegars in different locations with more detailed studies and to conduct detailed bioecological studies depending on the climatic factors and population ecology of the pest in terms of alternative control of the pest. The data of this study contain basic data for almond integrated pest management (IPM) studies.

Where the small things are: Modelling edge effects on mouse lemur population density and distribution in northwestern Madagascar.

Edge effects result from the penetration to varying depths and intensities, of abiotic and biotic conditions from the surrounding non-forest matrix into the forest interior. Although 70% of the world's forests are within 1 km of a forest edge, making edge effects a dominant feature of most forest habitats, there are few empirical data on inter-site differences in edge responses in primates. We used spatially explicit capture-recapture (SECR) models to determine spatial patterns of density for two species of mouse lemurs (Microcebus murinus and Microcebus ravelobensis) in two forest landscapes in northwestern Madagascar. The goal of our study was to determine if mouse lemurs displayed spatially variable responses to edge effects. We trapped animals using Sherman live traps in the Mariarano Classified Forest (MCF) and in the Ambanjabe Forest Fragment Site (AFFS) site within Ankarafantsika National Park. We trapped 126 M. murinus and 79 M. ravelobensis at MCF and 78 M. murinus and 308 M. ravelobensis at AFFS. For M. murinus, our top model predicted a positive edge response, where density increased towards edge habitats. In M. ravelobensis, our top model predicted a negative edge response, where density was lower near the forest edges and increased towards the forest interior. At regional and landscape-specific scales, SECR models estimated different density patterns between M. murinus and M. ravelobensis as a result of variation in edge distance. The spatial variability of our results using SECR models indicate the importance of studying the population ecology of primates at varying scales that are appropriate to the processes of interest. Our results lend further support to the theory that some lemurs exhibit a form of ecological flexibility in their responses to forest loss, forest fragmentation, and associated edge effects.

Connection between ecological niche changes and population trends in the Eurasian Skylark (Alauda arvensis) breeding in lowland and mountain areas of Southern Europe

Population responses to environmental changes can often vary geographically and between environments, potentially as a consequence of differing niche dynamics. The Eurasian Skylark Alauda arvensis is an open‐habitat passerine bird that is declining throughout Europe, mainly due to agricultural intensification. We compared population trends (1992–2021) of the species across three sub‐regions of northern Italy characterized by different environmental conditions and human pressures: the Alpine sub‐region (less anthropized mountains), the Plain (strongly anthropized and intensively cultivated) and the Oltrepò (extensively cultivated hills), with changes in the realized Grinnellian niches over three decades. In each sub‐region, niche comparisons did not show divergence over the study. However, we found an overall reduction in niche occupancy over time. In the Alpine sub‐region, a reduction in niche occupancy in hayfields and pastures was not associated with population decline; indeed, we found an increasing population (+164%), probably because high availability of natural grasslands counteracted niche contraction. Conversely, in the Plain and Oltrepò sub‐regions, the observed population declines (−99% and −36%, respectively) are associated with a general reduction of niche occupancy in arable lands that represented the core of the niche in these ranges. In the Plain, the lack of alternative suitable habitats might have limited any opportunity for the species to colonize new environments. Conversely, in the Oltrepò, the less severe population decline is combined with increased niche occupancy in hayfields and pastures at higher elevations. The joint application of population trend analysis and niche modelling as well as the decomposition of population changes across different environmental contexts can contribute to a better understanding of ecological processes affecting population dynamics, supporting policy‐makers to implement targeted conservation strategies.

Influence of anthropic disturbance in structure of plant populations along an elevation gradient in caatinga region

Elevation gradients are useful models for testing how the variation of abiotic factors and anthropogenic disturbance modulate the population structure of plant species. Despite the small range of elevation, mountains in the semi-arid region of Brazil are subject to different levels of anthropic pressure. We investigated whether structural parameters of two species (Croton blanchetianus Baill. and Cenostigma pyramidale (Tul.) Gagnon &amp; G.P. Lewis) with wide distribution in Caatinga, vary along an elevation gradient. We established 45 plots on three elevation levels. Next, we calculated abundance, percentage of tiller individuals, number of tillers, average diameter, average height, basal area, and above-ground biomass in each plot. Additionally, we recorded six metrics of chronic anthropogenic disturbance (CAD) in each plot. We tested whether species parameters differed between elevation levels and evaluated the influence of CAD on the structural parameters of each species. Abundance, percentage of tiller individuals, and number of tillers were higher at the gradient base for the two species. The metrics of CAD significantly influenced abundance and number of tillers, showing that there is an increase in these parameters in the most disturbing areas. The high capacity for regrowth of dry forest species provides resilience; however, it can contribute to proliferating populations of generalist species tolerant to environments with high rates of CAD. The study highlights relevant observations related to the ecology and distribution of plant populations in the Caatinga, mainly related to elevation gradient recognized as important refuges of biodiversity in this region of Brazil.

Differential Stage-Specific Mortality as a Mechanism for Diversification.

AbstractIndividual variability in mortality is widespread in nature. The general rule is that larger organisms have a greater chance of survival than smaller conspecifics. There is growing evidence that differential mortality between developmental stages has important consequences for the ecology and evolution of populations and communities. However, we know little about how it can influence diversification. Using an eco-evolutionary model of diversification that considers individual variability in mortality, I show that commonly observed differences in mortality between juveniles and adults can facilitate adaptive diversification. In particular, diversification is expected to be less restricted when mortality is more biased toward juveniles. Additionally, I find stage-specific differences in metabolic cost and foraging capacity to further facilitate diversification when adults are slightly superior competitors, due to either a lower metabolic cost or a higher foraging capacity, than juveniles. This is because by altering the population composition, differential stage-specific mortality and competitive ability can modulate the strength of intraspecific competition, which in turn determines the outcome of diversification. These results demonstrate the strong influence that ecological differences between developmental stages have on diversification and highlight the need for integrating developmental processes into diversification theory.

A historical contingency hypothesis for population ecology

Assessments of historical contingency have advanced our understanding of adaptive radiation and community ecology, but little attention has been given to assessing the importance of historical contingency in population ecology. An obstacle has been the unmet need to conceptualize historical contingencies for populations in a manner that allows for their explanatory power to be assessed and quantified so that it can be directly compared with the explanatory power of statistical models representing other hypotheses or theory-based explanations. Here we conceptualize historical contingencies as a series of random events characterized by (1) significant legacy effects that are comparable in length to the waiting time between such events, and (2) the disparate nature of individual events in the series. From that conceptualization, we present a simple quantitative framework for assessing the explanatory power of historical contingencies in population ecology and apply it to an existing long-term dataset on the predator-prey system in Isle Royale National Park. The population-level phenomenon that we focused on was predation rate because it is a synthesis of three basic elements in population ecology (predator abundance, prey abundance and kill rate). We also compared the explanatory power of models of the historical contingency hypothesis to a wide-range of alternative, theory-based, statistical models used to assess underlying mechanisms or forecast future dynamics. Models of the historical contingency hypothesis explained over half of the interannual variation in predation rate and performed similarly, or better than, the vast majority of alternative, theory-based, models. Those findings highlight the potential value of reconsidering the way that population ecologists traditionally attempt to explain phenomena. We also discuss how this new conceptualization of the historical contingency hypothesis can also be valuable for synthesizing several other important ecological concepts of broad significance, especially reddened spectra, tipping points, alternative stable states, and ecological surprises. If the historical contingency hypothesis were found to be broadly applicable, then it would likely explain why ecologists are conspicuously poor at forecasting future dynamics.

Symbiosis Evolution of Regional Knowledge Innovation Ecosystem: The Relevance of Lotka–Volterra Model

Knowledge innovation is the driving force and guarantee of regional development. Inspired by population ecology, this article uses symbiosis theory to explore the symbiotic relationship of subjects in the regional knowledge innovation ecosystem. The nonlinear Lotka–Volterra model is constructed with the main subjects to measure the knowledge innovation ability of knowledge innovation subjects. The symbiotic relationships among the knowledge innovation subjects in each region are identified. Taking Beijing, Shanghai, and Guangzhou as examples, a sensitivity analysis of the initial value and coopetition relationship is conducted. The results show that the initial value change has no significant effect on the development of knowledge innovation subjects. The interaction relationships among subjects directly affect the symbiotic evolution trend. The study extends the application scope of the symbiosis theory and develops a theoretical framework for the development of subjects in regional knowledge innovation ecosystem. It offers regions a reference to use Lotka–Volterra model adjusting the knowledge innovation structure in various regions.

Application of Univariate Diversity Metrics to the Study of the Population Ecology of the Lizard Lacerta bilineata in an Ecotonal Habitat

The expansion of human activities across natural environments is now well known. This includes agricultural activities that effectively render many former natural environments sterile habitats for animals. Very often, what remains of the natural habitat are hedgerows that serve as habitat or pathways for movement between habitats for many species, including reptiles. In this study, we describe population changes in the western green lizard, Lacerta bilineata, in a hedgerow system in western France. The results are derived from a univariate diversity analysis of photographic data to identify individual lizards over a 4-year study period. Lizards were sighted from March April to October early November but there was a midsummer gap in sightings during July–August. The annual presence of individual lizards was low, both between and within years, but based on the diversity analysis, the overall stability of the population was high. Female numbers varied and were highest in 2020, but juveniles were highest in 2023; the numbers of males present each year were approximately the same. Individual lizards that were present before the midsummer gap were mostly absent after the midsummer gap and were replaced by new individuals. Incidences of autotomy were low in males and juveniles and were not recorded in females. In general, the results suggest that the lizards move through hedgerow systems but remain in a specific section for reproduction from March to July. Through this study, we also highlight the importance of univariate diversity formulas to obtain robust results in investigations of the demographic aspects of animal populations that are easy to monitor.

Morphological and genetic analysis for the diversity conservation of rare species, Thamnaconus multilineatus (Tetraodontiformes: Monacanthidae).

Climate changes have altered biodiversity and ultimately induced community changes that have threatened the survival of certain aquatic organisms such as fish species. Obtaining biological and genetic information on endangered fish species is critical for ecological population management. Thamnaconus multilineatus, registered as an endangered species by the IUCN in 2019, is a Data Deficient (DD) species with a remarkably small number of habitats worldwide and no known information other than its habitat and external form. In this study, we characterized the external and osteological morphology of a T. multilineatus specimen collected from eastern Jeju Island, South Korea, in 2020. We also investigated the phylogenetic relationships among related fish species through complete mitochondrial DNA (mtDNA) analysis of the T. multilineatus specimen. The external and skeletal characteristics of T. multilineatus were similar to those of previous reports describing other fish of the genus Thamnaconus, making it difficult to classify T. multilineatus as a similar species based only on morphological characteristics. As a result of analyzing the complete mtDNA of T. multilineatus, the length of the mtDNA was determined to be 16,435 bp, and the mitochondrial genome was found to have 37 CDCs, including 13 PCGs, 22 tRNAs, and 2 rRNAs. In the phylogenetic analysis within the suborder Balistoidei, T. multilineatus mtDNA formed a cluster with fish of the genus Thamnaconus. This study is the first to report on the skeletal structure and complete mtDNA of T. multilineatus. Since the current research on T. multilineatus has only been reported on morphology, the results of this study will be utilized as important information for the management and restoration of T. multilineatus as an endangered species and significant fishery resource.

Characterization of the Ovarian Development and Associated Factors during the Breeding Migration of Coilia nasus in the Yangtze River

Coilia nasus is a typical anadromous migratory fish found in the lower reaches of the Yangtze River. Every year, C. nasus clusters offshore and swims upstream along the Yangtze River into the tributaries and lakes in the middle and lower reaches of the Yangtze River to breed. In this study, female C. nasus were collected as study subjects from the Chongming section of Shanghai, the Taizhou section of Jiangsu, and the Anqing section of Anhui. Their ovaries were used to examine tissue sections and investigate gene expression, including the follicle-stimulating hormone receptor (fshr), the luteinizing hormone receptor (lhr), kisspeptin-1 (kiss1), and forkhead box l2 (foxl2), which are related to reproductive development, while the serum levels of estrogen (including estradiol, E2) and progestins (including 17α,20β-dihydroxy-4-pregenen-3-one, 17α,20β-DHP) were also analyzed. Our results showed that, first, the growth period of the oocytes was small in stage II of ovarian development, in which both E2 and 17α,20β-DHP levels and gene expression were low. Then, in stage III, the growth period of the oocytes became large, and the yolk granules and oil droplets began to appear. Simultaneously, E2 and the expression of kiss1 and foxl2 were significantly elevated. Finally, stage IV was the period of a large amount of accumulation of nutrients in the oocytes, and 17α,20β-DHP levels and the expression of fshr and lhr were significantly elevated. These results enrich the theoretical study of ovarian development in the natural population of C. nasus, supplementing the biological basis of C. nasus reproduction and scientifically supporting the study of C. nasus population ecology and resource conservation.

Different ecological demands shape differences in population structure and behaviour among the two generations of the small pearl-bordered fritillary.

The population structure and behaviour of univoltine butterfly species have been studied intensively. However, much less is known about bivoltine species. In particular, in-depth studies of the differences in population structure, behaviour, and ecology between these two generations are largely lacking. Therefore, we here present a mark-release-recapture study of two successive generations of the fritillary butterfly Boloria selene performed in eastern Brandenburg (Germany). We revealed intersexual and intergenerational differences regarding behaviour, dispersal, population characteristics, and protandry. The observed population densities were higher in the second generation. The flight activity of females decreased in the second generation, but remained unchanged in males. This was further supported by the rate of wing decay. The first generation displayed a linear correlation between wing decay and passed time in both sexes, whereas the linear correlation was lost in second-generation females. The proportion of resting individuals in both sexes increased in the second generation, as well as the number of nectaring females. The choice of plant genera used for nectaring seems to be more specialised in the first and more opportunistic in the second generation. The average flight distances were generally higher for females than for males and overall higher in the first generation. Predictions of long-distance movements based on the inverse power function were also generally higher in females than in males but lower in the first generation. Additionally, we found protandry only in the first but not in the second generation, which might correlate with the different developmental pathways of the two generations. These remarkable differences between both generations might reflect an adaptation to the different ecological demands during the flight season and the different tasks they have, i.e., growth in the spring season; dispersal and colonisation of new habitats during the summer season.