Life History Studies Research Articles

Hoplonemertean larvae are planktonic predators that capture and devour active animal prey

AbstractThe superficially simple ciliated planktonic larvae of hoplonemerteans have been assumed to be lecithotrophic direct developers, even though many develop from such small eggs that it is hard to imagine how they could give rise to a viable juvenile without some phase of larval feeding. Indeed, attempts to raise such larvae to settlement without food invariably fail. Observations that some hoplonemertean larvae are found in plankton samples at a range of sizes, and much larger than hatchlings, suggest that they must indeed feed somehow. Because these so‐called planuliform larvae lack apparent means to concentrate suspended algae or other unicellular food, one alternative hypothesis is that they are planktonic predators that hunt large prey. Here we provide direct evidence that this is indeed the case for six distinct species of hoplonemerteans. We recorded wild‐caught larvae of Paranemertes californica, Paranemertes sp., Gurjanovella littoralis, Emplectonema viride, Carcinonemertes epialti, and Ototyphlonemertes sp. attacking, subduing, and devouring pelagic crustaceans, including barnacle nauplii, cyprids, copepods and their nauplii, and others. Although there is no doubt that some hoplonemerteans are genuine lecithotrophs, our evidence suggests that many species in this group both feed and grow during an extended planktonic larval period. This conclusion has important consequences for biogeographic and life history studies in this group, because it implies enhanced potential for long‐distance dispersal. More broadly, the possibility that many animal larvae are actually carnivores invites reconsideration of prevailing stereotypes about metazoan developmental modes and the trade‐offs between them.

Conservation Assessment of a critically endangered endemic Polygonum samsunicum (Polygonaceae) with emended description from Turkey

Abstract Polygonum samsunicum is one of the endemic species from Turkey. Up to now, it has been only known from the type locality (Samsun /Ladik). This research intends to define the global conservation status and strategies of locally distributed endemic P. samsunicum which has been confronted with the danger of extinction due to anthropogenic effects in recent years. In this research, we did extensive field studies and collected all needed data for determining the precise conservation status of P. samsunicum. We reported nine additional populations from Upper Tersakan valley, where the Mediterranean climate is dominant, and the size of populations, altitude, coordinates, habitat types, and the threats it faces in each locality were given. GeoCAT analyses at global levels indicate the grade of occurrence 21.609 km2 and area of occupancy 10.094 km2 and there could be an inferred decline due to habitat loss and fragmentation of the original population, suggesting local endemic species might be classified as CR, based on criteria B1ab (i, ii, iii) + 2ab (i, ii, iii) in the Red List categorization. Its parts are also consumed by local people due to its medicinal features. For in-situ conservation, phenological life history and detailed ecological studies, as well as population monitoring and ex-situ conservation studies should be continued together. Establishing cooperation between universities, research institutes, and local management authorities is strongly needed for long-term monitoring of population size, distribution, overgrazing, and public awareness.

From molecular data to natural history: a new species of Apatelodes (Lepidoptera: Bombycoidea: Apatelodidae) from southern Brazil

Apatelodidae is a family of Neotropical bombycoids that is still poorly studied in several aspects. Besides being relatively large moths and abundant in light traps, only sources of information on the natural history of the family have been published, and basically none of this information has been used in the group’s systematics. Aiming to contribute to a better understanding of Apatelodidae life-history studies, we describe a new species of Apatelodidae (Lepidoptera: Bombycoidea) from the Atlantic Forest, southern Brazil, including information from all life stages of the species. We also use DNA barcodes to support species delimitation. Apatelodes je sp. nov. can be differentiated from other species of Apatelodes by the colour of the wings, the morphology of the genitalia, and molecular evidence. Its relationship to other Apatelodes species is discussed taking into account its systematic position, morphology, and natural history.

Length-weight relationships for eight Chondrichthyes from the north-eastern Atlantic Ocean

Length-weight relationships (LWRs) are pivotal for comparative life-history studies, conservation strategies and ecosystem modelling among regions. They provide essential information on the growth, fitness and wellbeing of a population in an ecosystem. Length and weight relationships and descriptive statistics for eight Chondrichthyes, caught off the Madeira archipelago between 2004 and 2019 from depths ranging from 350 to 2500 m, are herein reported. A total of 767 specimens was studied and it was observed that the parameter b (relative growth rate) oscillated between 2.558 for males of Centrophorus squamosus and 3.494 for females of Etmopterus princeps. This study is the first to include the LWRs for these 8 Chondrichthyes species in Madeira waters.

Development of Common Leaf-Footed Bug Pests Depends on the Presence and Identity of Their Environmentally Acquired Symbionts.

Many beneficial symbioses between bacteria and their terrestrial arthropod hosts are vertically transmitted from mother to offspring, ensuring that the progeny acquire necessary partners. Unusually, in several families of coreoid and lygaeoid bugs (Hemiptera), nymphs must instead ingest the beneficial symbiont, Burkholderia (sensu lato), from the environment early in development. We studied the effects of Burkholderia on development of two species of leaf-footed bug (Coreidae) in the genus Leptoglossus, Leptoglossus zonatus and Leptoglossus phyllopus. We found no evidence for vertical transmission of the symbiont but found stark differences in performance between symbiotic and aposymbiotic individuals. Symbiotic nymphs grew more rapidly, were approximately four times more likely to survive to adulthood than aposymbiotic bugs, and were two times larger. These findings suggest that Burkholderia is an obligate symbiont for the Leptoglossus species. We also tested for variation in fitness effects conferred by four symbiont isolates representing different species within the Burkholderia insect-associated stinkbug beneficial and environmental (SBE) clade. While three isolates conferred similar benefits to hosts, nymphs associated with the fourth isolate grew more slowly and weighed significantly less as adults. The effects of the four isolates were similar for both Leptoglossus species. This work indicates that both Burkholderia acquisition and isolate identity play critical roles in the growth and development of Leptoglossus. IMPORTANCELeptoglossus zonatus and L. phyllopus are important polyphagous pests, and both species have been well-studied but generally without regard to their dependance on a bacterial symbiont. Our results indicate that the central role of Burkholderia in the biology of these insects, as well as in other leaf-footed bugs, should be considered in future studies of coreid life history, ecology, and pest management. Our work suggests that acquisition of Burkholderia is critical for the growth and development of Leptoglossus species. Further, we found that there was variation in performance outcomes according to symbiont identity, even among members of the stinkbug beneficial and environmental clade. This suggests that although environmental acquisition of a symbiont can provide extraordinary flexibility in partner associations, it also carries a risk if the partner is suboptimal.

The life history of longnose emperors (Lethrinus olivaceus) and a data-limited assessment of their stock to support fisheries management at Rangiroa Atoll, French Polynesia.

The spawning aggregations of coral reef species support artisanal fisheries throughout the Pacific Islands, but they are vulnerable to overexploitation and need improved fisheries management. To this aim, the authors employed a combination of fishery methods including life-history studies to estimate the age, growth and reproductive parameters of longnose emperor (Lethrinus olivaceus), and a length-based stock assessment to provide the community of Rangiroa Atoll with an assessment of their longnose emperor spawning aggregation fishery. The von Bertalanffy growth parameters of this species were estimated to be L∞ =80 (75-87) cm TL, K=0.18 (0.15-0.24), t0 =-0.82 (-1.43-0.27) with a mean natural mortality rate of 0.309 ± 0.038. The sex ratios observed in this study support the belief that this species exhibits functional protogyny with females reaching sexual maturity at 38 cm TL and approximately 3 years of age, and sex change occurring at approximately 45 cm TL and 4 years of age. The spawning potential ratio (SPR) of the longnose emperor stock was estimated to be between 19% and 28% across the years of this study, and simulations of SPR and yield per-recruit indicate that if the community wanted to conserve >30% of the stock's SPR, the ideal minimum size limit for this species is 50 cm TL. The results provide the baseline life-history information required to evaluate the fisheries for this species in the South Pacific region and support community-led management actions for this spawning aggregation fishery on Rangiroa Atoll.

A Life History Study about First-generation Mixed-race People

본 연구는 1세대 혼혈인의 생애를 조명하고 삶의 의미를 사회구조적인 측면에서 파악하기 위해 생애사 연구를 진행하였다. 생애사 분석을 위한 텍스트는 구술 면접을 통해 구성했으며 4명의 혼혈인이 연구에 참여하였다. 텍스트 분석을 위해 Mandelbaum이 제안한 삶의 영역(dimension), 전환(turnings), 적응(adaptation)의 틀을 적용하였다. 분석 결과, 삶의 영역은 <어쩔 수 없이 태어난 삶>, <일상화된 놀림과 차별의 삶>, <버려지고 내보내진 삶>, <부평초가 뿌리내리는 삶>으로 분석되었다. 전환은 <나와 같은 혼혈인-위로를 받다>, <준비 안 된 채 사회로 내보내짐>, <광야에서 살아냄>으로 나타났다. 적응은 <역경을 통해 살아냄>, <자랑스러운 아버지>, <명예를 회복해야 한다는 일념>으로 분석되었다. 연구 결과에 근거하여 차별과 배제의 억압된 삶을 산 1세대 혼혈인의 삶의 치유를 위한 프로그램과 자조집단의 필요성, 그리고 지역사회 기반의 맞춤형 지원의 필요성을 제언하였다.This research conducted a life history study to illuminate the lives of first-generation mixed-race people and to analyze the meanings of lives in terms of social structure. The text for life history analysis was constructed through oral interviews, and four mixed-race people participated in this study. For text analysis, Mandelbaum’s analytic framework of life dimension, turning point, and adaptation was applied. As a result of the analysis, the life dimensions were analyzed as <life born out of necessity>, <life of routine teasing and discrimination>, <life abandoned and thrown out> and <Life like floating weeds>. The turning points were found to be <receiving comfort from mixed-race people like me>, <sent out into society without preparation>, and <living in the wilderness>. The adaptation was analyzed as <survival through adversity>, <proud father>, and <determination to recover honor>. Based on the research results, this study proposed the necessity of a program to heal the lives of first-generation mixed-race people who lived repressed lives of discrimination and exclusion, and the need to support self-help groups and community-based social care for true inclusion.

The characteristics of lifespan in Cheyletidae and its response to environmental factors

This paper provides a survey of a collection of references on life history studies of eight species in the family Cheyletidae. It reviews some factors (including sex difference, temperature, humidity and prey) that affect the development time and lifespan in Cheyletidae. This paper also analyzes the effects these biotic and abiotic factors on the growth and development of cheyletid mites.

Predictive significance of the life history of children with gastroesophageal reflux for predicting the development of arrhythmias and conduction disorders

The aim: to improve the early diagnosis of cardiac arrhythmias and conduction disorders in children with gastroesophageal reflux, by studying the prognostic significance of the life history in this group of patients.&#x0D; Materials and methods. 56 children aged 8 to 18 years, mean age 14,93±2,62 years were examined. All examined children were divided into two alternative groups: Group I (main) was represented by 28 children with gastroesophageal reflux in combination with cardiac arrhythmias and conduction disorders, and Group II (control) - 28 children with only gastroesophageal reflux without cardiac arrhythmias and conduction disorders. Patients underwent clinical, anamnestic (with a detailed study of life history) and instrumental studies (electrocardiography, Holter daily ECG monitoring, esophagogastroduodenoscopy).&#x0D; Results. When analyzing the prognostic significance of the patient's life history, it was found that its very high level was observed for the number of foci of chronic infection (I=6.0) and the frequent incidence of a child up to year old of life (I=3.05).&#x0D; High prognostic value was registered relative to the number of diseases suffered by the child per year on average (I=2.35), and moderate predictor properties are characteristic of chickenpox (I=0.89) and the number of chronic diseases at present (I=0.71).&#x0D; The duration of breastfeeding showed low (I=0.30) prognostic significance.&#x0D; Suffered previously bacterial infections did not have predictor properties (I=0.12). In general, the prognostic significance of the patient's life history was high (I̅=2.20).&#x0D; Conclusions. It was found that in general the prognostic significance of the patient's life history was high (I̅=2.20)&#x0D; It is determined that in favour of the development of cardiac arrhythmias and conduction disorders evidence: the number of foci of chronic infection ≥1-2; lack of frequent morbidity in a child up to a year of life; the number of diseases suffered per year ≤5; the presence in past medical history of chickenpox; the number of chronic diseases in a child at present ≤2 and short-term (≤9 months) breastfeeding.&#x0D; It has been established what denies probability of development of the researched pathology: absence of the centers of a chronic infection; the presence frequent incidence of a child up to year old of life; the number of diseases suffered per year≥6, and chronic diseases at present ≥3; longer (≥9 months) breastfeeding and no history of chickenpox

Whether Mahatma Gandhi Was Misinterpreted Through the Dilemma of Irrelevant and Relevant Philosophies?

In one of the articles published in Current Anthropology way back in 1973, David G. Mandelbaum talked about two approaches to understand the life of an individual. For him, to observe the lifestyle of a person or gain the knowledge about a lifestyle of a person, social scientists always succumb to two main approaches: life passage studies and life history studies. Life passage studies understand the contribution of society about the socialization and enculturation of their young ones, whereas life history studies emphasize the personified experiences and requirements of the individuals and how the individual copes up with the society. Here I have adopted the means of life history study to see some of the facets of Gandhiji’s life and its influence in the society. I shall do it by looking at some of his philosophies on health, food, sexual life, rather than going into the details of his whole life history. I shall do it without perplexing my own way of understanding “Mahatma” and linking sometimes my own life experiences that had been influenced by the philosophies of Gandhiji. I shall be carrying out an autoethnography by perceiving the virtues of Gandhiji in my own life. Nevertheless, it will rather be a futile exercise to describe his philosophies in a single paper and that too with a minimum experience on his whole life.

Shallow-emerged coral may warn of deep-sea coral response to thermal stress

In the Gulf of Alaska, commercially harvested fish species utilize habitats dominated by red tree corals (Primnoa pacifica) for shelter, feeding, and nurseries, but recent studies hint that environmental conditions may be interrupting the reproductive lifecycle of the corals. The North Pacific has experienced persistent and extreme thermal variability in recent years and this pattern is predicted to continue in coming decades. Recent discovery of deep-water emerged coral populations in Southeast Alaska fjords provided opportunity for detailed life-history studies and comparison to corals in managed habitats on the continental shelf. Here we show that sperm from deep colonies develops completely, but in shallow colonies, sperm development is prematurely halted, likely preventing successful production of larvae. We hypothesize that the divergence is due to differing temperature regimes presently experienced by the corals. Compared to deep populations below the thermocline, shallow populations experience much greater seasonal thermal variability and annual pulses of suspected near-lethal temperatures that appear to interrupt the production of viable gametes. The unique opportunity to comprehensively study emerged populations presently affected by thermal stress provides advance warning of the possible fate of deep corals in the Gulf of Alaska that will soon experience similar ocean conditions.

Early-life patterns of growth are linked to levels of phenotypic trait covariance and postfledging mortality across avian species.

Life history studies have established that trade‐offs between growth and survival are common both within and among species. Identifying the factor(s) that mediate this trade‐off has proven difficult, however, especially at the among‐species level. In this study, we examined a series of potentially interrelated traits in a community of temperate‐zone passerine birds to help understand the putative causes and consequences of variation in early‐life growth among species. First, we examined whether nest predation risk (a proven driver of interspecific variation in growth and development rates) was correlated with species‐level patterns of incubation duration and nestling period length. We then assessed whether proxies for growth rate covaried with mean trait covariance strength (i.e., phenotypic correlations ( rp), which can be a marker of early‐life stress) among body mass, tarsus length, and wing length at fledging. Finally, we examined whether trait covariance strength at fledging was related to postfledging survival. We found that higher nest predation risk was correlated with faster skeletal growth and that our proxies for growth corresponded with increased trait covariance strength ( rp), which subsequently, correlated with higher mortality in the next life stage (postfledging period). These results provide an indication that extrinsic pressures (nest predation) impact rates of growth, and that there are costs of rapid growth across species, expressed as higher mean rp and elevated postfledging mortality. The link between higher levels of trait covariance at fledging and increased mortality is unclear, but increased trait covariance strength may reflect reduced phenotypic flexibility (i.e., phenotypic canalization), which may limit an organism's capacity for coping with environmental or ecological variability.

Growth variability, dimensional scaling, and the interpretation of osteohistological growth data.

Osteohistological data are commonly used to study the life history of extant and extinct tetrapods. While recent advances have permitted detailed reconstructions of growth patterns, physiology and other features using these data, they are most commonly used in assessments of ontogenetic stage and relative growth in extinct animals. These methods have seen widespread adoption in recent years, rapidly becoming a common component of the taxonomic description of new fossil taxa, but are often applied without close consideration of the sources of variation present or the dimensional scaling relationships that exist among different osteohistological measurements. Here, we use a combination of theoretical models and empirical data from a range of extant and extinct tetrapods to review sources of variability in common osteohistological measurements, their dimensional scaling relationships and the resulting interpretations that can be made from those data. In particular, we provide recommendations on the usage and interpretation of growth mark spacing/zonal thickness data, when these are likely to be unreliable, and under what conditions they can provide useful inferences for studies of growth and life history.

Age-specific mortality and fecundity of a spider mite under diet restriction and delayed mating.

Numerous experimental life-history studies on aging are mainly baised on two classical models-fruit fly Drosophila melanogaster (Meigen) and nematode Caenorhabditis elegans (Maupas)-with relatively little attention given to other organisms with different life-history characters. Two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) differs from many other arthropods in that the females continue their growth in the early adult stage and can reproduce sexually and asexually. In this study, the influences of dietary restriction and delayed mating on the aging patterns of the spider mite were examined with the prevailing survival and reproduction trade-off hypothesis of aging being tested. Significant sex-specific responses of the spider mites were found. The females showed longevity extension on diet restriction (fasting for 2days in every 4days) compared with their counterparts being fed ad libitum, and after delayed mating for 9days, while the males displayed a decrease in lifespan when experiencing diet restriction but were not significantly influenced by delayed mating. Path analysis was used to investigate the relationship between mite survival and reproduction traits, including longevity, female lifetime reproduction, age at first reproduction, early reproductive efforts and late reproductive efforts, yielding no evidence for trade-offs between these life-history traits. The additive effects of dietary restriction and delayed mating in lifespan extension of female spider mites were confirmed, proving that diet restriction is a robust anti-aging intervention, and that later onset of reproduction can prolong adult lifespan in females.

A retrospective cohort study of the effects of the adverse childhood experience on chronic diseases of middle-aged and elderly

Objective: To investigate the adverse childhood experience (ACE) effects on the risk of chronic diseases among middle-aged and elderly. Methods: A retrospective cohort study was conducted using the China Health and Retirement Longitudinal Study data. We used life history study data in 2014 as baseline data and data of chronic diseases of middle-aged and elderly in 2015 as outcomes. A zero-inflated negative-binominal model was used to estimate the incidence rate ratio (IRR) for the association between ACE and chronic diseases. Results: Compared with the less than 4 points of ACE exposure in childhood, individuals with ACE exposure 4-, 6- and ≥9 were associated an increased risk of chronic disease, adjusted IRR (95%CI), 1.10(1.04-1.16), 1.18 (1.13-1.25), 1.34 (1.27-1.42), respectively, with a significant dose-response relationship that chronic diseases risks increase parallel with the increase of ACE exposure. Conclusions: ACE might serve as one of the critical risk factors of chronic diseases in middle-aged elderly. It's of public health significance for early screening and intervention of ACE, reducing the incidence of chronic diseases, and improving middle-aged and older adults' quality of life and health.

Impacts of loss of free-flowing rivers on global freshwater megafauna

The fragmentation of free-flowing rivers (FFRs) through major infrastructure development remains a pivotal threat to global freshwater biodiversity. More than 3400 large hydropower dams (>1 MW) are either planned or under construction, posing threats to freshwater megafauna (i.e., freshwater animals that can reach 30 kg). Here, we investigate the global patterns of river connectivity within distribution ranges of freshwater megafauna and explore how these patterns could change in the future. We found that the susceptibility of freshwater megafauna to reduced river connectivity in different dimensions depends on their life history. Freshwater megafauna taxa with a short accumulated length or low percentage of FFRs in their distribution ranges are more likely to be threatened. On average, there is higher freshwater megafauna richness in FFRs with proposed dams than in rivers that would remain free-flowing in the future or that are already fragmented. If all the proposed dams were built, 94 (18.9%) out of 497 remaining FFRs >500 km that provide habitat for freshwater megafauna would lose their free-flowing status. Our results highlight the reduced connectivity of rivers currently inhabited by freshwater megafauna and the future intensification of river fragmentation in megafauna-rich basins. Research and conservation efforts, including life-history studies, identification of critical habitats, updates of IUCN Red List assessments, advanced communication of the potential impacts on ecosystem services and livelihoods of affected communities, and strategic siting, design, and operations of proposed dams are urgently needed to safeguard freshwater megafauna and overall freshwater biodiversity.

Gender, mental health and resilience in armed conflict: listening to life stories of internally displaced women in Colombia

For over 60 years, Colombia has endured violent civil conflict forcibly displacing more than 8 million people. Recent efforts have begun to explore mental health consequences of these contexts, with...

Getting old: an endangered seahorse (Hippocampus whitei) lives for up to 7 years in the wild

A long-term monitoring programme from 2005 to 2021 has allowed the assessment of age and longevity in an endangered seahorse Hippocampus whitei in the wild. Seahorses were marked using visible implant fluorescent elastomer (VIFE) which allows for individual identification. The longest period from marking to last sighting was 6 years 8 months and 17 days for a female. Using a von Bertalanffy growth function model for the species, this individual would have been approximately 7 years 7 months old on last sighting. These observations suggest that seahorses in the wild can live for over 7 years and demonstrate the benefits of using VIFE in long-term movement, population abundance and life-history studies of seahorses.

Heterogeneous Production and Enchained Consumption: Minoan Gold in a Changing World (ca. 2000 BCE)

Early and Middle Minoan goldwork has sparked numerous studies, with particular emphasis on possible foreign influences and the role of gold in the development of social hierarchies. This paper contends that the value and uses of gold can only be understood in connection to the broader organization of production and distribution. Through a biographical approach, we focus on the high-resolution study, including chemical and microscopic analyses, of 90 samples from gold assemblages found at Mochlos, Sissi, and Hagios Charalambos. Our results show that beneath the apparent simplicity in designs and techniques, there is a variety of technological choices and skill levels that are suggestive of the involvement of multiple hands. Our technical analyses reveal objects with long life histories of uses, reuses, and repairs, as well as instances of deliberate fragmentation through cutting, tearing, or separation of object parts. With complex life histories of shared production, curation, reuse, fragmentation, and recontextualization that did not conclude with burial, gold artifacts connected the dead and the living in a way that strengthened predominantly horizontal relationships. This evidence should therefore be considered in discussions of the emergence of social complexity. Our approach shows promise for studies of life histories of metalwork elsewhere.

A Life History Study of the Life Experienced by Adults with Dyslexia

목적 본 연구는 난독증 성인의 생애 경험 분석을 통해 개인적 그리고 사회 구조적인 원인과 경향을 살펴보고자 하였다. 방법 이를 위하여 개인이 경험한 삶과 생각에 대해 더 구체적으로 이해할 수 있는 질적 연구방법 중 생애사 분석 방법을 활용하였다. 난독증 성인 1명과 8회의 구술면담을 통해 수집한 자료를 분석하여, 인생진행 과정구조를 도출하고, 생애사적 발달과정 구조분석도 실시하였다. 결과 연구결과, 연구참여자는 학령기에 읽기/쓰기 어려움에 대한 적절한 지원을 받지 못하였으며, 본인이 학습부진이 아니라 난독증이라는 인식도 성인이 된 후에 하게 되었다. 학령기기에는 읽기/쓰기 어려움으로 낮은 학업성취와 창피함 등 정서적 어려움을 경험하였는데, 이러한 읽기쓰기로 인한 어려움은 학령기에만 국한되지 않았고, 직장생활과 가정생활에도 지속적으로 영향을 미쳤으며, 써야 하는 상황을 회피하며 불안과 두려움을 안은 채 살아오고 있었다. 결론 난독증으로 인한 어려움은 시간이 지난다고 저절로 나아지는 것이 아니었다. 난독증 성인에 대한 적절한 지원을 모색할 필요가 있으며, 본 연구는 난독증 성인에 대한 기초자료를 제공한 데 의의가 있다.