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This study aims to investigate the reproductive characteristics of Cernuella virgata (Da Costa, 1778) from Diyarbakır, Southeast Turkey. From October 2023 to February 2024, the reproductive activities of over 300 individuals were monitored in Yeniköy Cemetery in Diyarbakır. The snails were first observed mating on 18 October 2023, after the autumn rains, with the first egg laying observed on 3 November 2023. The last mating observation occurred on 8 January 2024. A total of 225 individuals were noticed mating during this period. The number of eggs per clutch ranged from 36 to 114, with an egg hatching time between 18 and 32 days. Eggs were deposited amidst damp mosses, beneath decomposing vegetation, or on the damp soil surface. The spawning period lasts 12–13 weeks. Egg weights varied from 0.60 to 1.20 mg, and egg diameters ranged from 1.10 to 1.42 mm. Hatchling snails had shells with 1.5–2 whorls (protoconch), weighing between 1.15 and 1.72 mg on. The height of the hatchling’s shells ranged from 0.75 to 0.94 mm, and the width ranged from 1.21 to 1.38 mm. This study offers a detailed insight into the reproductive biology of C. virgata and marks the first record of the species in the region. [ABSTRACT FROM AUTHOR]

Vital rates for small, non-breeding individuals are important components of population dynamics for many species, but often individuals of these sizes are difficult to locate, capture, and track. As such, biologists frequently lack reliable estimates of juvenile survival because sample sizes and recapture rates for this life stage are low. Long-lived animals often take many years to reach sexual maturity and spend much of this time in the smaller size classes, making them sensitive to changes in survival rates. We estimated the survival rates of all size classes for the northern map turtle (Graptemys geographica) using a mark-recapture dataset with >3,500 captures from 2019-2021 and 210 nests from 2018-2021. As turtle size increased, annual survival probability increased regardless of sex. Estimated annual survival probability for turtles >18 cm long (i.e., adult females >15 years) was about 0.95, over 4 times higher than turtles that were 3 cm long (i.e., hatchlings <1 year; 0.22 annual survival probability). Although we did not observe a difference in survival probability between sexes of any size class, adult females are nearly twice the size of adult males, leading to an increased annual survival probability for females of 0.95, compared to 0.80 for males. Changes in adult survival had the greatest influence on population estimates over time, with temporary decreases, such as those due to poaching or an environmental disaster, potentially leading to unrecoverable decreases in the overall population size. Our study provides detailed survival rates for all size classes in a long-lived turtle, which are necessary to assess population stability and can be used to determine the most effective conservation or management practices. [ABSTRACT FROM AUTHOR]

Evaluating the effects of temperature variations on animals plays an important role in understanding the threat of climate warming. The effects of developmental temperature on offspring performance are critical in evaluating the effects of warming temperatures on the fitness of oviparous species, but the physiological and biochemical basis of this developmental plasticity is largely unknown. In this study, we incubated eggs of the turtle Pelodiscus sinensis at low (24 °C), medium (28 °C), and high (32 °C) temperatures, and evaluated the effects of developmental temperature on offspring fitness, and metabolic enzymes in the neck and limb muscles of hatchlings. The hatchlings from eggs incubated at the medium temperature showed better fitness-related performance (righting response and swimming capacity) and higher activities of metabolic enzymes (hexokinase, HK; lactate dehydrogenase, LDH) than hatchlings from the eggs incubated at high or low temperatures. In addition, the swimming speed and righting response were significantly correlated with the HK activities in limb (swimming speed) and neck (righting response) muscles, suggesting that the developmental plasticity of energy metabolic pathway might play a role in determining the way incubation temperature affects offspring phenotypes. Integrating the fitness-related performance and the activities of metabolic enzymes, we predict that the P. sinensis from high latitude would not face the detrimental effects of climate warming until the average nest temperatures reach 32 °C. [ABSTRACT FROM AUTHOR]

Sea turtle hatchlings rely on their finite energy reserve to sustain embryonic development in underground nests and during the first few days of their post-hatch life, including nest escape, beach crossing, and swimming offshore. This study aimed to investigate if the grain size of the nest substrate has an impact on green sea turtle (Chelonia mydas) hatchlings' energy usage during nest escape. About-to-hatch green sea turtle eggs were incubated in laboratory chambers filled with either coarse-grain sand (ϕ = 0.507 phi) or fine-grain sand (ϕ = 2.028) at a temperature of 28°C. Open-flow respirometry was used to measure the hatchlings' oxygen consumption rate during nest escape, which was then converted to energy consumption values. Results showed that hatchling morphology, hatching success, emergence success, and synchronous emergence rate were not significantly different between the groups of hatchlings in coarse versus fine sand. Hatchlings that dug through coarse sand emerged significantly faster (168 ± 13.9 h) than those in fine sand (233.21 ± 12.6 h) (t (26) = -3.473, p = 0.002). Additionally, the hatchlings in coarse sand (310.55 ± 28.1 kJ) consumed significantly less energy than hatchlings in fine sand (474.85 ± 64.7 kJ) (t (17.739) = -2.328, p = 0.032). A difference in amount of energy reserve upon emergence was detected between coarse and fine sand groups. To improve hatchery management practices, relocating "doomed" clutches into coarse sand (ϕ = 0.507) could potentially maximise the hatchlings' energy reserve. [ABSTRACT FROM AUTHOR]

Strategies to improve the hatch success and survival of critically endangered hawksbill turtles (Eretmochelys imbricata) require knowledge of threats to them including pathological conditions. The objective of this study was to describe the mortality and pathology of embryos and dead-in-nest hatchlings on St. Kitts and Nevis. Over the 2019/20 and 2020/21 nesting seasons, the combined mean (SD) hatch success for the two islands was 81.9% (13.2%) and deceased individuals within excavated nests were early-stage embryos (70.7%), late-stage embryos (17.7%), pipped-hatchlings (8.2%) or dead-in-nest hatchlings (3.4%). From 2017 to 2021, a post-mortem examination was performed on 183 turtles, including histology for 116. Anatomical malformations affected 77 (42.1%) examined turtles and included abnormal scute shape or number (22.4%), dysmelia (8.7%), schistosomus reflexus (7.7%) and compressed carapace (7.7%). Microscopic lesions were found in 49.1% of turtles and included tissue mineralization (26.7%, including renal, fetal membrane, liver, heart or muscle), chorioallantoitis (16.2%) and skeletal muscle degeneration and necrosis (10%). Inflammatory lesions associated with fungal or bacterial infections were in the skin (n = 3), chorioallantois (n = 4), lung (n = 3) or yolk sac (n = 1). These lesions may reflect non-specific terminal conditions but their presence in-nest helps explain some of the mortality and pathology documented in hatchlings that die during rehabilitative care. All of the gonads adequately represented for histological determination of sex were female (n = 62), supporting concern for feminization of Caribbean hawksbill turtle nests. The study identifies lesions that could affect hatch and emergence success. The high frequency of skeletal malformations indicates the need for investigations addressing regional impact and pathogenesis, especially genetic and environmental aetiologies including nest temperature. Immediate examination of live hatchlings on nest emergence is warranted to better determine the prevalence of non-fatal malformations that could impact fitness and population genetics. [ABSTRACT FROM AUTHOR]

Understanding predator-prey interactions at the vulnerable egg and hatchling stage of sea turtles is crucial to effectively manage these threatened marine species. Our research quantified ghost crab predation on loggerhead turtles Caretta caretta at Gnaraloo Bay and Bungelup Beach, two of the four principal nesting sites for this species in the Southeast Indian Ocean. We counted ghost crab burrows along belt transects as a proxy for crab densities. We used start- and end-of-season nesting inventories to determine egg predation rates, in-situ accelerometers to measure predation activity in nests, and infrared videography to assess predation rates on emerging hatchlings. Ghost crab densities and egg predation rates at Gnaraloo Bay were almost twice those at Bungelup Beach. Egg predation was most prevalent at night and in the first and third trimesters of incubation. We did not observe any hatchlings emerging from nests at Gnaraloo Bay, while we observed predation, mainly by ghost crabs and to a lesser extent by seagulls, on 43% of hatchlings at Bungelup Beach. The alarmingly high rate of mortality due to native predators highlights a need for immediate management actions to mitigate this threat to a globally important loggerhead turtle stock. Our multi-method approach provides a holistic estimation of reproductive success from when eggs were laid to when hatchlings reached the relative safety of the ocean. [ABSTRACT FROM AUTHOR]

Context. Quantifying marine turtle-nest depredation by daily observer monitoring requires substantial labour. Aims. To quantify nest depredation of the Vulnerable flatback turtle (Natator depressus) at one of its largest rookeries and to compare effectiveness of different monitoring methods. Methods. We used daily observer monitoring and passive infrared-camera traps separately or in combination to record nest depredation, and identified impacts on remaining eggs and hatchlings in depredated nests. Key results. More than a quarter (28%) of the 69 monitored nests were confirmed as depredated, although this figure is an underestimate of total losses because camera traps detected twice as many depredation events (39%) as did direct observation (17%) (P = 0.012). Cameras also provided important behavioural data and identified predators. Although reptile and bird predators were also recorded, the introduced red fox (Vulpes vulpes) was the primary predator identified, digging into 26% of the monitored nests. More than half of the depredation events by foxes (58% or 11/19 nests) occurred late term, between turtles hatching and emerging from the nest, which therefore means that losses calculated through counts of eggshell left in the nest are underestimates because predation of hatchlings is not included by the eggshell count method. Furthermore, almost half (42%) of all depredated nests were depredated more than once, with some nests opened up to five times, potentially exacerbating clutch losses due to environmental exposure. Conclusions. Egg losses for confirmed depredated nests (27 ± 37%, range 0–100%) were three times the background levels (i.e. 9.3% of eggs that failed to hatch as a result of embryo death during development). Implications. The results of this study strongly warrant the implementation of ongoing fox predator monitoring and mitigation strategies to protect nests at this nationally, and internationally, conservation-significant population of flatback turtles. [ABSTRACT FROM AUTHOR]

Effective management practices are critical for the successful reproduction of animals in captivity or in in situ environments. One of the techniques used in egg quality control is candling. In ex situ reproduction of Kinosternon scorpioides, it is important to establish incubation protocols, which, through egg management, allow control of embryonic development and improved birth rates. We incubated eggs and monitored embryonic development of K. scorpioides through egg candling. Fertile eggs were incubated, and candling analyses were performed weekly. Embryonic development in the early stages (first third of incubation) presented the following characteristics: presence of the vitelline circulatory system, expansion of this system, and descent of the embryo onto the yolk. Then, in the middle stages (second third of incubation), the intense pigmentation of the embryo was observed, with the body moving to prone position. Subsequently, in the late stages, the embryo grew, filling a large part of the internal space of the egg. The incubation period took on average 116.50 ± 13.11 days. Candling can be used to monitor the embryonic development of K. scorpioides. It is a useful tool to improve the production of hatchlings, from fertility detection to hatching.

Nest beach selection by sea turtles at a regional scale may depend on upper shore environmental cues. Thus, the variability of sandy beach conditions, including coastal erosion rates and urban development can affect their nesting ecology. Almost half of worldwide sandy beaches are suffering from erosion and most of them are located in highly developed areas. This can lead to shore stretches with coastal squeeze and loss of habitat for beach-dependent species such as sea turtles. Understanding whether an endangered species, such as the loggerhead sea turtle Caretta caretta (Linnaeus, 1758), selects certain beaches to nest is the first step in devising mitigation strategies for human activities and climate change impacts. We predicted that the occurrence of loggerhead nests along 62 km of sandy beaches in southeastern Brazil is negatively related to higher urbanization levels and extreme erosion. A total of 731 nests of the loggerhead sea turtle were recorded in the 2022-2023 nesting season. Only 6% of those nests were found on beach sectors with severe and extreme erosion. The probability of laying a nest was negatively related to erosion rate. Also, approximately 50% of nests were found on low-urbanized beaches; thus, the higher the urbanization, the lower the probability of a turtle laying a nest. Nature-based solutions to recover the beach-dune system are recommended in order to mitigate coastal erosion where loggerheads are avoiding nesting. This should be coupled with management planning of the protected areas where nests are laid and must include nest relocation and monitoring as priority actions.

Natal philopatry—the return of an animal to its place of birth to reproduce—can shape population genetics and link essential habitats across generations, yet examples from long-term mark-recapture studies are rare. In this study, we observed 136 nests of Northern Map Turtles at Mount Union, Pennsylvania, between 2000 and 2008 and then individually marked and released 691 hatchling turtles into the Juniata River. During a recent six-year period (from 2017 to 2022), 46 of the hatchling-marked turtles (6.7%) returned to Mount Union as adult females to nest. The ages of these turtles ranged from 11–22 years at first recapture, and their mean age was 17 years. Forty-one hatchling-marked females came from observed nests with known mothers, and remarkably, just four (of 52) mothers produced over half of the returning females. The minimum ages of the oldest female turtles were estimated at 39 years, with reproductive lifetimes of at least 23 years. Our results indicate that a few long-lived Super Moms have made extraordinary contributions to hatchling recruitment and population viability of Northern Map Turtles of the Juniata River. The timing of release also had a significant influence on the probability of a turtle returning, with hatchlings released in May returning at a higher rate than those released earlier in the spring. In addition, morphological characteristics of hatchling-marked females suggest that factors causing shell shape abnormalities in adult turtles have not abated over the past two decades as previously theorized and likely involve exposure of juveniles to contaminants in the Juniata River rather than any maternal influence. [ABSTRACT FROM AUTHOR]

Simple Summary: Leatherback sea turtle (Dermochelys coriacea) populations are experiencing significant declines and are at risk of global extinction. Sustaining reproductive success is vital to the recovery of populations. This study quantified nests and egg production between 2015–2019 on Levera Beach, Grenada and explored the association of select environmental variables with leatherback sea turtle embryonic development and hatching success rates. Annual variation was observed for the number of eggs per nest and embryo and hatching success rates. Nest location on the beach was found to be an influencing factor and development and hatching success rates decreased when nest depths were relatively shallow and when there was higher frequency of eggs with microbial growth and inspissated yolk. Relatively high temperatures recorded in a subset of nests suggest hatchling sex ratios may be skewed towards females and that increased temperatures are a risk to hatchling survival. Histopathology identified bacterial bronchopneumonia as a likely cause of morbidity and mortality in hatchlings. These findings help guide conservation strategies to support leatherback sea turtle hatchling survival. Annual monitoring of leatherback sea turtle (Dermochelys coriacea) nesting grounds in Grenada, West Indies has identified relatively low hatch rates compared to worldwide trends. This study investigated the impact of selected environmental variables on leatherback sea turtle embryonic development and hatching success rates on Levera Beach in Grenada between 2015–2019. The mean number of nests per year and eggs per nest were 667.6 ± 361.6 and 80.7 ± 23.0 sd, respectively. Within excavated nests, 35.6% ± 22.0 sd of eggs successfully developed embryos and 30.6% ± 22.6 sd of eggs successfully hatched. The number of eggs per nest, along with embryo and hatching success rates, differed by nesting year. Embryo development success rate was associated with nest location, and both embryo development and hatching success rates were positively associated with nest depth and negatively associated with the percentage of eggs exhibiting microbial growth and with the presence of inspissated yolk. There was no embryo development or hatchling success association with month of the nesting season, distance from the high-water mark, distance from vegetation, nor maternal carapace length. The mean nest temperature was 31.7 °C ± 1.64 sd and mean temperatures during the middle third of egg incubation suggest clutches are highly skewed towards a preponderance of female hatchlings. Histopathologic findings in hatchling mortalities included severe, acute, multifocal, heterophilic bronchopneumonia with intralesional bacteria in 4/50 (8%) hatchlings. Data from this study guide conservation strategies by identifying risk factors and further avenues of research needed to support reproductive success of leatherback sea turtles in Grenada and the greater Caribbean region. [ABSTRACT FROM AUTHOR]

Diamondback terrapins (Malaclemys terrapin) inhabit estuarine environments, and adult females typically nest in coastal uplands. Hatchlings emerging from nests overwinter on land and in coastal salt marshes, but the proportions that use each land cover type is not well documented. From 2019 to 2021, we tracked movements and habitat use of hatchlings post‐emergence to determine the importance of upland overwintering sites to a terrapin population in Rhode Island, USA. In late summer and early fall, we attached a radio‐transmitter and passive integrated transponder (PIT) tag (n = 46) or only a PIT tag (n = 132) to carapaces of hatchlings emerging from nests. From August to June, we tracked the hatchlings via radio‐telemetry and a sweeping PIT tag antenna, successfully documenting the fates of 46.6% of them (n = 83). This group included 23 hatchlings that overwintered in the upland, 11 hatchlings that moved to the salt marsh in fall, 46 predated hatchlings, and 3 hatchlings dead from unknown causes. Upon emergence from their nests, 68% of hatchlings dispersed toward water and 32% of hatchlings dispersed away from water. In the uplands, hatchlings typically overwintered within about 2 m of habitat edges. Movement in the uplands peaked from late August to early October, then ceased until hatchlings re‐emerged in late April through early June. To protect terrapins, we recommend limiting the use of heavy equipment (e.g., mowers, tillers) in vegetated uplands near nest sites, and scheduling vegetation management for colder months (Nov–Mar in New England, USA) when hatchlings are inactive. [ABSTRACT FROM AUTHOR]

Life cycle definitions provide the background for conceptualizing meaningful questions to address the mechanisms that generate different life cycle patterns. This review provides explicit definitions and explanations of the steps in a cephalopod life cycle, from fertilization to death. Each large step, or phase, is characterized by a particular developmental process and morphology. Each phase is composed of smaller developmentally distinct steps, or stages. The cephalopod life cycle is comprised of all or some of the following phases: Embryonic, Paralarval, Juvenile, Subadult, Adult and Senescent, and each life cycle is taxon-specific. All cephalopods have direct development and maintain a consistent body plan throughout ontogeny (i.e., no true larval phase and no metamorphosis). Most cephalopods have a life cycle marked by a long early life and a short adult life followed by senescence. Cephalopods have two developmental modes: they produce either small planktonic hatchlings as paralarvae, or large hatchlings as juveniles. All cephalopods go through a Hatchling stage soon after eclosion during which they rely on two modes of nutrition: endogenous (yolk) and exogenous (prey). Many cephalopods with planktonic paralarvae will become benthic early in their life cycle during their Settlement stage or remain pelagic during their Metapelagic stage. Juvenile growth is fast and ontogenetic changes (outside of gonadal maturation) generally cease at the end of the Juvenile phase. The Subadult phase begins when the definitive adult morphology (except for size and body proportions) is acquired (e.g., full complement of photophores). Sexual organs undergo most of their development during the Subadult phase. The Adult phase starts with spawning competency and concludes when gonads are spent. The Senescent phase begins with spent gonads and ends with death. Using this new terminology, we examine the patterns of cephalopod life cycles and find that there are four main patterns based on the presence of a Paralarval phase and the habitat occupied by each phase: Holopelagic (all phases are pelagic), Holobenthic (all phases are benthic), Merobenthic and Meropelagic (phases alternate between benthic and pelagic environments). In these two last patterns, the main difference is the presence of a Paralarval phase in Merobenthic species. The definitions and terminology proposed here provide a unifying framework for future ecological, evolutionary and life cycles research on cephalopods.

ABSTRACT: The presence of Salmonella in hatchlings is the single most important risk factor for the introduction of Salmonella into poultry farms, and resistant strains are particularly worrisome, as they could affect treatment outcomes in humans infected through consumption of contaminated poultry products. This study estimated Salmonella prevalence, determined resistance profiles of strains recovered from hatchlings in Nigeria, and determined genetic relatedness between hatchling strains and strains from poultry farms. In this study, 300 fecal samples were collected. Salmonella was isolated by culture and confirmed by PCR, and isolates were tested for susceptibility to antimicrobials by the disk diffusion method. Strains were pair-end sequenced, and genomes were used to obtain serotypes and antibiotic resistance genes. Whole-genome based phylogenetic analysis was used to determine genetic relatedness between these isolates and strains from previously characterized older chicken within the same geographical area. A prevalence of 10.7% was obtained belonging to 13 Salmonella serovars. Resistance to kanamycin (30/32), ciprofloxacin (22/32), nalidixic acid (22/32), and sulfonamides (22/32) were the most commonly observed phenotypic resistances. Twenty-two (68.8%) isolates showed multidrug resistance. In silico predictions identified 36 antimicrobial resistance genes. Four (12.5%) and 22 (68.8%) strains showed point mutations in gyrA and parC. Commonly observed acquired resistance genes included sul1, sul2, sul3, and tet(A) as well as a variety of aminoglycoside-modifying genes. Eleven (34.4%) isolates were predicted to have genes that confer resistance to fosfomycin (fosA7, fosB). A strain of S. Stanleyville was predicted to have optrA, which confers resistance to furazolidone. Strains of S. Kentucky, S. Muenster, and S. Menston obtained from hatchlings showed close genetic relatedness by having less than 30 SNPs difference to strains recovered from chickens at farms previously receiving hatchlings from the same sources.

Simple Summary: Microplastic accumulation in aquatic environments could represent a potential risk to wildlife health and survival. Their transfer along the trophic web could threaten ecosystem stability. Over the years, the common cuttlefish (Sepia officinalis) has represented an important resource for the fishery of the Adriatic Sea. In this study, for the first time, we assessed the presence of microplastics within cuttlefish eggs, more precisely in embryos and yolk. The presence of microplastics has already been described in common cuttlefish adult specimens. Our findings highlighted how this species is subjected to microplastic exposure starting from early-life stages. The possible effects of microplastic accumulation on embryo health and development should be investigated considering that the reproductive strategy of this species consists of adults laying eggs in separate batches during the single spawning season at the end of which both males and females die. Therefore, population stability primarily depends on the survival and correct development of embryos. Once they reach the aquatic environment, microplastics (MPs) are accidentally ingested by aquatic biota, thus entering the food chain with possible negative effects. The present study investigated, for the first time, MP presence in cuttlefish (Sepia officinalis) eggs and their association with embryonic development. Cuttlefish eggs were sampled from four different sites along the Marche region (Senigallia, Ancona, Numana, and San Benedetto del Tronto). Embryo and hatchling biometric parameters were evaluated and the internal structural integrity was examined through histological analysis. MPs were detected and characterized in embryos and yolk samples. MPs were identified in all sites (size < 5 µm), however, their presence has not been associated with an impairment of either embryo or hatchling internal structures. Noteworthy, the highest number of MPs (in both yolk and embryo samples) were found in Numana (37% of the total amount), where the lowest hatchling size was observed. On the other hand, the highest embryo mantle length was associated with the lowest number of MPs detected (9%) in Ancona. Overall, only MP fragments and sphere types (74 and 26%, respectively) were observed, and the most frequent polymers were Polyvinyl chloride (52%), Polypropylene, and Cellulose acetate (15% both). Further studies are needed to assess the possible MP effects on the yolk quality and assimilation. [ABSTRACT FROM AUTHOR]

Increasing hatchling survival is an important element of conservation of the critically endangered hawksbill sea turtle (Eretmochelys imbricata). Yet, there is little information regarding mortality-associated pathological states of hawksbill hatchlings. The aim of this study was to describe lesions affecting hawksbill hatchlings that died while under rehabilitative care. Forty-four turtles representing the nesting sites of two islands and a 7-yr study period were subjected to comprehensive postmortem examination. The most common lesions included dermatitis (34%), skeletal malformations (23%), and pneumonia (23%). Dermatitis and pneumonia were caused by a variety of presumptively opportunistic bacterial and fungal infections. Fungal infections affected 23% of study turtles, also causing rhinitis and esophagitis. Around half of the cases of dermatitis presented with history of skin lesions, and all those involving periocular areas had clinical history of eye lesions. Pneumonia was not predicted by clinical signs or time in rehabilitation. Malformations included carapace compressions, supra- or subnumerary scutes, and dysmelias with many of those affected having concurrent pathology involving other organs. Other lesions included bacterial yolk sacculitis (15%), skeletal muscle degeneration and necrosis (13%), and acute renal tubular necrosis (13%). The study population was female biased (93%), raising concern for skewed hatchling sex ratios and high incubation temperatures in the eastern Caribbean. The pathology described by this study improves our understanding of threats to hawksbill hatchlings and may be taken into consideration by clinicians when implementing strategies for rehabilitative care. [ABSTRACT FROM AUTHOR]

The Red Sea is characterized by its high temperature, pH and salinity in summary which affect greatly the eggs development and early hatched embryos of cephalopods. Therefore, the present work aims to study the structure of eyes and optic lobes of the hatchlings of the cuttlefish Sepia savignyi to know how these structures can help these juveniles to live in their habitats in the Red Sea. Also, the structures of these organs were compared with that in other hatchlings of cephalopods in other ecological niches. The results indicated that the anatomical structure of eyes and the optic lobes is related to their functions and the different needs of the lifestyle of hatchling of this cuttlefish in its environment in the Red Sea for swimming, sensation and foraging in its habitats. [ABSTRACT FROM AUTHOR]

The critically endangered hawksbill sea turtle (Eretmochelys imbricata) is of conservation concern worldwide. Conservation actions which act to reduce high levels of embryonic mortality aid to boost hatchling production. At Cousine Island, Seychelles, a mixed management method has been adopted to maximize the number of hatchlings entering the ocean. We examined the effectiveness of a hatchery at increasing hatching and emergence success from four seasons of data (2017–2021). Hatchery nests had significantly higher hatching and emergence success across all years relative to nests left in situ (i.e., natural), with inter‐annual variation observed. A greater percentage of in situ clutches was found to be influenced by both crab activity and predation as compared to relocated clutches. Overall, the mixed management approach increased hatching success (mean = 75.1%) relative to the various nest management techniques previously used (2004/2005–2016/2017; mean = 63.5%). By mitigating external influences such as tidal flooding, beach erosion, and crab activity/predation, this study provides evidence for the success of a hatchery in directly increasing hatchling recruitment. Strict and careful hatchery management as well as timely and efficient relocation procedures are needed to minimize potential negative effects of nest relocation. [ABSTRACT FROM AUTHOR]

Abstract The critically endangered hawksbill sea turtle (Eretmochelys imbricata) is of conservation concern worldwide. Conservation actions which act to reduce high levels of embryonic mortality aid to boost hatchling production. At Cousine Island, Seychelles, a mixed management method has been adopted to maximize the number of hatchlings entering the ocean. We examined the effectiveness of a hatchery at increasing hatching and emergence success from four seasons of data (2017–2021). Hatchery nests had significantly higher hatching and emergence success across all years relative to nests left in situ (i.e., natural), with inter‐annual variation observed. A greater percentage of in situ clutches was found to be influenced by both crab activity and predation as compared to relocated clutches. Overall, the mixed management approach increased hatching success (mean = 75.1%) relative to the various nest management techniques previously used (2004/2005–2016/2017; mean = 63.5%). By mitigating external influences such as tidal flooding, beach erosion, and crab activity/predation, this study provides evidence for the success of a hatchery in directly increasing hatchling recruitment. Strict and careful hatchery management as well as timely and efficient relocation procedures are needed to minimize potential negative effects of nest relocation.

The breeding biology of White-throated Kingfisher Halcyon smyrnensis was studied in plains and hilly areas from September 2008 to August 2011. Four villages under Savar upazilla were selected for plains, and Chittagong University Campus, Chattagram for the hilly area. The breeding season started in February in hills and April on plain. Mean (SD) time required to build a new nest was 11.3 (3.9) days in plains and 15.3 (0.57) days in hills. Clutch size was 3-4 in hills and 3-7 in plains. Mean egg parameters (length, width, and weight) and mean egg volume and surface area were similar in both areas. The mean incubation period on plains was 16.4 (1.2) days, in hills 14.1 (0.7) days. On plains fledging success was 52􀐹, compared to 57􀐹 in hills. The􀅌 by local inhabitants was a major reason for fledgling loss in plains, hence increased public awareness may reduce nestling mortality and increase breeding success. [ABSTRACT FROM AUTHOR]

ABSTRACT: Two hundred and twenty eggs from Transylvanian naked neck (TNN) chickens aged 30 wk were used to determine the effect of storage length on hatch window, chick quality, and organ development. Forty-four eggs (11 eggs in 4 replicates) were stored in cold room (16±1.5°C) in batches for 0, 3, 6, 9, and 12 d before setting in incubator. Data collected were subjected to one-way analysis of variance. Hatchability of set and fertile eggs declined (P < 0.001) progressively as duration of storage increased, however, storage for 6 and 9 d differed not from each other. For 50% hatch, there was a decrease of 30 min/d in hatching time by 3 d-stored eggs before fresh eggs, while eggs stored for 6, 9, and 12 d had delay of 70, 65, and 30 min/d, respectively. Hatching commenced earlier (P < 0.01) in eggs stored for 0 and 3 d than in prolonged storage of eggs for 6 to 12 d. Eggs stored for 12 d recorded shorter (P < 0.001) hatch window than those stored for 0 to 9d. Significantly (P < 0.01) more eggs hatched per hour during hatch window in fresh eggs (3.9%/h) than other storage durations (1.70–2.12 %/h). Fresh and 6 d eggs hatched into heavier (P < 0.05) chicks (37.2 and 37.5 g, respectively) than 12d (32.7g). Chicks from 9 and 12 d storage were shorter in length than those for 0 to 6 d. Toe (P < 0.01) and shank+toe (P < 0.001) were longer in 0 d chicks than others. Activity and appearance were poorer (P < 0.01) in 12 d chicks than other groups. The quality of eye was better (P < 0.05) in 0 to 6 d chicks than 12 d group, however, 9 d chicks were similar to 12 d. Larger membrane remnant were found in 6 to 12 d chicks (P < 0.001) than in 0 d chicks, though not different from 3 d group. Navel of chicks from eggs stored for 0, 3, and 6 d were more closed than in 9 d, though not different from 12 d. Yolk remnant was larger in chicks of 3, 9, and 12 d storage length than in fresh and 6 d storage length. Tona score was higher in 0 to 6 d chicks than in 9 and 12 d chicks. There was no (P > 0.05) effect of egg storage length on chick yield and relative weight of chick organs. It could be concluded that in order to ensure good hatchability and quality chicks, TNN eggs could be stored for 3 d, but not beyond 6 d without intervention such as prewarming of long-stored eggs.

Natal philopatry—the return of an animal to its place of birth to reproduce—can shape population genetics and link essential habitats across generations, yet examples from long-term mark-recapture studies are rare. In this study, we observed 136 nests of Northern Map Turtles at Mount Union, Pennsylvania, between 2000 and 2008 and then individually marked and released 691 hatchling turtles into the Juniata River. During a recent six-year period (from 2017 to 2022), 46 of the hatchling-marked turtles (6.7%) returned to Mount Union as adult females to nest. The ages of these turtles ranged from 11–22 years at first recapture, and their mean age was 17 years. Forty-one hatchling-marked females came from observed nests with known mothers, and remarkably, just four (of 52) mothers produced over half of the returning females. The minimum ages of the oldest female turtles were estimated at 39 years, with reproductive lifetimes of at least 23 years. Our results indicate that a few long-lived Super Moms have made extraordinary contributions to hatchling recruitment and population viability of Northern Map Turtles of the Juniata River. The timing of release also had a significant influence on the probability of a turtle returning, with hatchlings released in May returning at a higher rate than those released earlier in the spring. In addition, morphological characteristics of hatchling-marked females suggest that factors causing shell shape abnormalities in adult turtles have not abated over the past two decades as previously theorized and likely involve exposure of juveniles to contaminants in the Juniata River rather than any maternal influence.

Annual monitoring of leatherback sea turtle (Dermochelys coriacea) nesting grounds in Grenada, West Indies has identified relatively low hatch rates compared to worldwide trends. This study investigated the impact of selected environmental variables on leatherback sea turtle embryonic development and hatching success rates on Levera Beach in Grenada between 2015–2019. The mean number of nests per year and eggs per nest were 667.6 ± 361.6 and 80.7 ± 23.0 sd, respectively. Within excavated nests, 35.6% ± 22.0 sd of eggs successfully developed embryos and 30.6% ± 22.6 sd of eggs successfully hatched. The number of eggs per nest, along with embryo and hatching success rates, differed by nesting year. Embryo development success rate was associated with nest location, and both embryo development and hatching success rates were positively associated with nest depth and negatively associated with the percentage of eggs exhibiting microbial growth and with the presence of inspissated yolk. There was no embryo development or hatchling success association with month of the nesting season, distance from the high-water mark, distance from vegetation, nor maternal carapace length. The mean nest temperature was 31.7 °C ± 1.64 sd and mean temperatures during the middle third of egg incubation suggest clutches are highly skewed towards a preponderance of female hatchlings. Histopathologic findings in hatchling mortalities included severe, acute, multifocal, heterophilic bronchopneumonia with intralesional bacteria in 4/50 (8%) hatchlings. Data from this study guide conservation strategies by identifying risk factors and further avenues of research needed to support reproductive success of leatherback sea turtles in Grenada and the greater Caribbean region.

Developing embryos of oviparous reptiles show substantial plasticity in their responses to environmental conditions during incubation, which can include altered sex ratios, morphology, locomotor performance and hatching success. While recent research and reviews have focused on temperature during incubation, emerging evidence suggests other environmental variables are also important in determining hatchling phenotypes. Understanding how the external environment influences development is important for species management and requires identifying how environmental variables exert their effects individually, and how they interact to affect developing embryos. To address this knowledge gap, we review the literature on phenotypic responses in oviparous non-squamate (i.e., turtles, crocodilians and tuataras) reptile hatchlings to temperature, moisture, oxygen concentration and salinity. We examine how these variables influence one another and consider how changes in each variable alters incubation conditions and thus, hatchling phenotypes. We explore how incubation conditions drive variation in hatchling phenotypes and influence adult populations. Finally, we highlight knowledge gaps and suggest future research directions. [ABSTRACT FROM AUTHOR]

The Slender Glass Lizard (Ophisaurus attenuatus) reproduces across parts of northern and central Kansas, but its distribution extends into southern Nebraska. In Nebraska, not a single aspect of reproductive activity has been reported for this species in the state. Herein, we report on the first documentation of reproduction in Nebraska. On 22 September 2021, we captured two hatchling Slender Glass Lizards at the Ash Grove Wildlife Management Area in Franklin County, Nebraska. We calculated that those individuals likely hatched around the first week of September. Presence and reproduction of Slender Glass Lizards at the study site likely was associated with ungrazed grasslands. Although Slender Glass Lizards were listed as extinct in the state prior to 2009 due to a lack of sightings for decades, a few recent observations have been reported in southern counties bordering Kansas. In Nebraska, additional surveys and studies are required to better understand the distribution and requirements for this species of conservation need in the state. [ABSTRACT FROM AUTHOR]

Limited information is available on the growth rates of turtles in head-starting programs. The current study provides vital information on the growth patterns of Batagur dhongoka, a critically endangered turtle inhabiting the Ganga River basin that were part of a head-starting program at Turtle Breeding and Rehabilitation Centre, Sarnath, India. Our results indicate that the post-hatchling stage shows the maximal growth with a reduced increment in the second year as compared to the first year. The study revealed a strong relationship between the weight and increments in carapace length, width and plastron length. [ABSTRACT FROM AUTHOR]

The altricial‐precocial spectrum describes patterns of variation in avian developmental mode that greatly influence avian life histories. Appraising a given species' position on this spectrum is therefore fundamental to understanding patterns of avian life history evolution. However, evaluating avian developmental mode remains a relatively subjective task reliant on untested assumptions, including the notion that developmental strategies are distributed along a single dimension of statistical variation. Here, we present a quantitative multivariate framework that objectively discriminates among meaningfully different modes of avian development. We gathered information on seven hatchling and post‐hatching traits for up to 4000 extant bird species, and find that most traits related to developmental mode show high phylogenetic signal and little intraclade variation, allowing unknown values to be reliably interpolated. Principal component analyses (PCAs) of these traits illustrate that most variation in hatchling state can be quantified along one dimension of trait space. However, our PCAs also reveal an important second dimension explaining variation in post‐hatching behavior, enabling factors related to hatchling state and post‐hatching behavior to be disentangled. In order to facilitate future macroevolutionary studies of variation in avian developmental strategies, as well as explorations of covariation between developmental mode and other aspects of avian biology, we present PC scores for 9993 extant avian species. [ABSTRACT FROM AUTHOR]

Once they reach the aquatic environment, microplastics (MPs) are accidentally ingested by aquatic biota, thus entering the food chain with possible negative effects. The present study investigated, for the first time, MP presence in cuttlefish (Sepia officinalis) eggs and their association with embryonic development. Cuttlefish eggs were sampled from four different sites along the Marche region (Senigallia, Ancona, Numana, and San Benedetto del Tronto). Embryo and hatchling biometric parameters were evaluated and the internal structural integrity was examined through histological analysis. MPs were detected and characterized in embryos and yolk samples. MPs were identified in all sites (size < 5 µm), however, their presence has not been associated with an impairment of either embryo or hatchling internal structures. Noteworthy, the highest number of MPs (in both yolk and embryo samples) were found in Numana (37% of the total amount), where the lowest hatchling size was observed. On the other hand, the highest embryo mantle length was associated with the lowest number of MPs detected (9%) in Ancona. Overall, only MP fragments and sphere types (74 and 26%, respectively) were observed, and the most frequent polymers were Polyvinyl chloride (52%), Polypropylene, and Cellulose acetate (15% both). Further studies are needed to assess the possible MP effects on the yolk quality and assimilation.

Despite the importance of maternally selected nests in shaping offspring phenotypes, our understanding of how the nest environment affects embryonic development and offspring traits of most non‐avian reptiles is rather limited largely due to the logistical difficulty in locating their nests. To identify the relative contributions of environmental (temporal [seasonal] and spatial [nest‐site]) and intrinsic (clutch) factors on embryonic development and offspring traits, we conducted a cross‐fostering experiment by swapping eggs between maternally‐selected nests of the toad‐headed agama (Phrynocephalus przewalskii) in the field. We found that nest environment explained a large proportion of variation in incubation duration, hatching success, and offspring size and growth. In contrast, clutch only explained a small proportion of variation in these embryonic and offspring traits. More significantly, compared with spatial effects, seasonal effects explained more phenotypic variation in both embryonic development and offspring traits. Eggs laid early in the nesting season had longer incubation durations and produced smaller hatchlings with higher post‐hatching growth rates than did later‐laid eggs. Consequently, hatchlings from early‐laid eggs reached larger body sizes prior to winter. In addition, we found that female toad‐headed agama did not select nests specific to reaction norms of their own offspring because hatchlings from original or translocated nests had similar phenotypic traits. Overall, our study demonstrates the importance of seasonal variation in nest environments in determining embryonic development and offspring phenotypes, which has not been widely appreciated at least in non‐avian reptiles. [ABSTRACT FROM AUTHOR]

Habitat fragmentation has negative consequences on threatened and endangered species by creating isolated populations. The Texas horned lizard (Phrynosoma cornutum) is experiencing population declines and localized extirpations throughout its range and has been classified as a species of greatest conservation need in Oklahoma, USA. Younger age classes have been poorly studied but may be vital to the stability of remaining populations. To address gaps in knowledge concerning subadult (hatchling and juvenile) morphometrics, survivorship, and home range sizes, we studied 2 cohorts of subadults, for 2 years each, covering their hatching and juvenile years (2016–2019). We used a combination of radio‐telemetry and novel harmonic radar methodology to study a closed population of Texas horned lizards in 15 ha of native grassland at Tinker Air Force Base, Oklahoma. Population abundance for adults and juveniles was estimated as 56.5 ± 5.5 lizards and density as 7.96 lizards/ha. Our lowest estimates of survival indicated an average survival probability for the hatchling life stage of 0.285 (95% CI = 0.15–0.44), which is lower than for adults on the site. Average home range size increased from hatchling to adult life stages. Our results will have an immediate effect on the planning and assessment of ongoing headstart and management programs for Texas horned lizards. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society. We estimated Texas horned lizard hatchling survivorship using direct, field‐based monitoring methodology, and report ontogenetic increases in morphometrics and home range area from hatchling to adult life stages. Our results can be used in the planning and assessment of future headstart and management programs for this threatened lizard. [ABSTRACT FROM AUTHOR]

Dispersal is one of the most fundamental components of ecology. Dispersal is also particularly relevant in an era of unprecedented habitat loss and climate change. We used a unique dataset to examine dispersal in gray ratsnakes (Pantherophis spiloides). Over a decade, we marked and released >1,500 hatchlings while monitoring the population of ratsnakes over a large area (≈1,900 ha). We tested the hypotheses that dispersal should be (a) largely restricted to within the local population given previous genetic evidence of limited gene flow at greater distances and (b) male biased because male gray ratsnakes are under strong sexual selection. We recaptured 69 gray ratsnakes that had been marked as hatchlings after periods ranging from 1 day to 11 years. We found that dispersal distance increased with time, but was not significantly sex‐biased, and that gray ratsnakes are extremely faithful to their communal hibernacula (only 2.8% of 497 juvenile and adult ratsnakes captured at least twice at communal hibernacula changed sites between years). Thus, dispersal is largely limited to the period from hatching until an individual joins a communal hibernaculum. Based on the spatial patterns of dispersal we observed, the most plausible explanation for dispersal is that hatchling ratsnakes disperse from their natal site to join a neighboring communal hibernaculum. Our study yielded the most reliable data on dispersal distances from birth by a snake to date. [ABSTRACT FROM AUTHOR]

Adaptive developmental plasticity allows individuals to match their phenotype with their environment, increasing fitness where threats are inconsistently present. However, despite clear advantages of plasticity, adaptive traits are not ubiquitously nor infinitely plastic. Trade‐offs between benefits and costs or limits are therefore theoretically necessary to constrain the evolution of plastic responses. Systems in which extreme risk can be reliably detected are ideal for investigating trade‐offs, as even costly responses may be adaptive where risk is severe. Cane toads (Rhinella marina) are abundant in Australia and produce large clutches (frequently >10,000 eggs), but asynchronous breeding and rapid development result in variable larval densities within breeding pools. In the field, we found that cannibalism by older cohorts often reduces the survival of conspecific eggs and newly hatched pre‐feeding larvae ("hatchlings") by >99%, as feeding larvae ("tadpoles") use chemical cues from the relatively immobile hatchlings to locate and consume them. After hatchlings become free‐swimming, however, they cannot be cannibalized. Hatchlings can reduce this period of vulnerability by accelerating development when they detect cannibal cues. However, this developmental acceleration decreases initial tadpole mass, reduces subsequent survival, growth, and development, affects behavior, and compromises feeding structures. Reaction norms differ among clutches, and greater developmental acceleration is followed by greater impairment of larval function in plastic clutches, whereas nonresponsive clutches are unaffected by cue exposure. More plastic clutches ultimately exhibit both poorer performance and greater variation among siblings in exposed and (to a lesser degree) control treatments. Variation among clutches in tadpole viability is driven by differences in plasticity rather than phenotype; fitness reductions are linked to developmental acceleration, not rapid development per se. Clutches with intrinsically slow pre‐feeding developmental rates exhibit stronger acceleration (i.e., steeper reaction norms), but clutches with intrinsically rapid development reach invulnerable stages more quickly than those that accelerate development. As a result, high cannibalism risk may favor canalized rapid development rather than facultative developmental acceleration. Cannibalism plays an important role in the recruitment of this invasive species, and hatchling defenses against this threat demonstrate how the limits and costs associated with an inducible defense can favor canalized defenses over phenotypic plasticity. [ABSTRACT FROM AUTHOR]

The finned or dumbo octopods (Octopoda: Cirrata) constitute a cephalopod (Mollusca: Cephalopoda) taxon almost exclusively comprising organisms that inhabit the deep-sea. This renders studying the general biology of adult cirrate specimens a difficult task, but even more so when it comes to gathering knowledge on their early life stages. During his comprehensive research exploits on cephalopod development, the late Sigurd von Boletzky (1942–2020) also sought to shed light on specific adaptations that eggs and embryos of these enigmatic deep-sea octopods might show. Based on his seminal work, the present article sets out to provide additional data on a broad range of early cirrate life stages, including egg capsules without any obvious embryonic stage as well as those containing embryos. These previously unreported specimens obtained from museum collections were analyzed using conventional morphological as well as modern three-dimensional imaging techniques. The present overview includes specimens from four of the five oceans, i.e., the Atlantic, Pacific, Indian, and Southern Ocean. Based on information on cirrate ovum, chorion, and egg capsule size as well as shape gathered from the literature, an attempt is made here for the first time to identify von Boletzky's as well as the specimens introduced here down to at least genus level. The combined data provide novel insights into early life stages of finned octopods, aiming to continue von Boletzky's legacy with regard to developmental research on a still largely enigmatic taxon of extant deep-sea cephalopods. [ABSTRACT FROM AUTHOR]

This study evaluated the growth rate and reproductive parameters of cow dung and vermicomposting reared earthworms Eisenia fetida. The experiment was done at the Department of Zoology, CT University Ludhiana. A sample of ten earthworms each were exposed to cow dung and vermicompost treatments with three replications over a period of eleven weeks. The results revealed that the worms attained sexual maturity after 48.70± 1.07 daysand 50.43± 1.19 days in vermicompost and cow dung, respectively. The worms started to release cocoon on the 4th week in vermicompost and on 5th week in cowdung. For each worm, maximum weight achieved was 1122.36± 8.51 mg, net weight gain was 945.45± 12.07mg/worm), growth rate was 94.55± 1.21 mg/worm, and growth rate/worm/day was 12.28± 0.16 mg/worm, thus being more with vermicompost. The results confirm the superiority of vermicompost over cow dung. [ABSTRACT FROM AUTHOR]

Nesting site selection is of great ecological and evolutionary importance for turtles, because it is a key determinant of individual reproductive success. In this study we evaluated the effects of two types of nesting substrate (sand bank and clay banks) on the incubation success of a generalist nesting species, Podocnemis unifilis, in a floodplain area in the Brazilian Amazon. Nesting characteristics were recorded during the nesting seasons of 2012-2014, when 634 nests were monitored throughout the incubation period. Mean size of laying females did not vary between substrate types (sand = 24.71 cm; clay = 25.44 cm; P = 0.2054), nor was clutch size related to females' sizes. However, females that nested on sand bank exhibited a clearer pattern of nest positioning relative to distances to vegetation and water line than those laying eggs on clay banks. Mean egg size (40.24 ± 2.68 mm) and weight (21.09 ± 5.46 g) did not vary between types of nesting substrate, and there was no variation in clutch size across the reproductive seasons for either substrate. On the other hand, clutch sizes were higher in nests in clay banks (28 ± 8) than those that were deposited in sand bank (22 ± 7). Mean incubation time was shorter in sand bank (62 ± 5.98) than in clay banks (77 ± 4.33). Although eclosion success for sand and clay nests was high (84.82 and 72.97%, respectively), incubation success was relatively low in both substrate types (sand = 57.34%; clay = 25.80%). On sand bank, clutch losses were mainly due to human predation (16%), on clay banks, human predation also affected 16% of the nests, but floods compromised another 30%. Natural predation was mostly due to ovivory by the lizard Tupinambis teguixin, although fire ants, Solenopsis geminata, also contributed to egg predation on clay banks. Hatchlings incubated on sand bank were on average larger and heavier than those from clay banks nests. Our results suggest that differences found in the life histories of different populations of P. unifilis reflect flexible responses that are largely linked to the diversity of habitats this species utilizes for nesting. Furthermore, the presence of source-sink and habitat patches should be considered for short term population management, beyond the creation of networks of reserves that incorporate and protect a variety of nesting sites that these small local groups depend on for their survival. [ABSTRACT FROM AUTHOR]

This work relates data from field sampling of Eisenia lucens and from laboratory-based culture. Field sampling used soil sorting and vermifuge extraction and took place in beech-dominated forests of southwest Poland. Initial work derived population estimates from four sub-communities of the forest looking for seasonal dynamics and later work employed targeted sampling in summer within rotting wood to obtain live specimens for laboratory culture. A preliminary examination within and below rotten wood during winter was also undertaken. In the laboratory, clitellate earthworms were kept at 20 °C, the substrate changed every 6 months, and the population examined. Cocoons were incubated individually at 15 °C, with number of hatchlings per cocoon and the mass of each determined. Hatchlings were grown at 15 °C in field-collected wood and compared with growth in a 1:1 volume ratio of wood and horse manure. Further hatchlings were fed with horse manure only (at 10 °C) and after 19 weeks, half were transferred to 15 °C. In the field, mature individuals varied significantly (p < 0.01) in biomass between 2 sampling sites where found, with an overall mean density across sites of 4.14 ± 3.53 m−2 with a mean biomass of 2.21 ± 1.93 g m−2. Numbers in soil varied over the sampling period, with a suggestion that this species moves from mineral soil to organic-rich dead wood as conditions permit. In summer, all life stages were recovered from rotting wood above the mineral soil. Sampling in winter found cocoons in rotting wood below snow. These hatched rapidly (within 2 weeks) when taken to the laboratory. Laboratory culture allowed maintenance of a population for 2 years. Mean cocoon mass was 50.6 mg with a mean of 2.9 hatchlings per cocoon and hatchling mass was inversely proportional to number per cocoon. Growth with 50% horse manure was significantly greater (p < 0.001) than with wood. Increased temperature from 10 to 15 °C brought more significantly (p < 0.05) rapid growth. To culture this species through its life cycle, a natural substrate is needed, but then it is necessary to acclimate the animals to something more easily obtainable. More work is needed from field sampling to fully understand the seasonal dynamics of this species, which utilises different parts of the soil profile throughout the year. [ABSTRACT FROM AUTHOR]

Sea turtle hatchlings experience high mortality rates during dispersal. To minimize time spent in predator-dense waters, hatchlings typically undergo a period of hyperactivity termed the 'frenzy', characterized by almost continuous swimming for ~24 h. Research has focused on swimming performance during the frenzy, but our understanding of changes in swimming performance post-frenzy is limited. Thus, we measured green turtle (Chelonia mydas) hatchling swimming performance during the frenzy and post-frenzy when the turtles were 4, 12 and 24 weeks old. Using load cells, we recorded thrust production, stroke rates and the time turtles spent performing various swimming gaits. We found that the proportion of time spent powerstroking and the thrust generation per powerstroke were the main determinants of overall swimming performance. Older, larger turtles generated more thrust per stroke, but the proportion of time spent powerstroking throughout the entire swimming trial did not differ among age groups. Hatchlings have been thought mainly to use currents to reach nursery foraging grounds, and our findings suggest that hatchling swimming might also play an important role in directing hatchlings to optimal nursery habitats, supporting recent studies. Additionally, turtle size is positively related to swimming performance in post-frenzy turtles, suggesting that faster-growing turtles might have fitness advantages over slower-growing turtles. [ABSTRACT FROM AUTHOR]

The East Asian common octopus Octopus sinensis is a bottom-dwelling species, but goes through a planktonic phase as 'paralarvae' during the first several weeks of life. As the swimming performance of the paralarvae is relatively poor, their dispersion relies primarily on ocean currents; however, vertical swimming may play an important role in their horizontal dispersion by controlling their buoyancy in the current. Within this context, ontogenic changes in vertical swimming in relation to the ambient water flow are key to understanding the dispersion properties of the paralarvae and the subsequent onset of settlement, yet this information remains largely unknown. Here, we investigated the effects of different water flows (downward × 4 velocities, stagnant and upward × 5 velocities) on the vertical swimming position in test columns using laboratory-raised O. sinensis paralarvae aged 0, 5, 10 and 15 days during the day and at night. Paralarvae younger than 10 days (< 3 mg in dry weight) tended to swim upwards regardless of the water flow conditions, but their swimming was disrupted under downward water flows, while they exhibited repeating upward swimming and downward pushing-back movements. Thus, for early paralarvae, an upward water flow may have a positive effect on dispersion by supporting their innate upward swimming, while a downward water flow may impact paralarvae negatively due to exhaustion through excess swimming activities. Paralarvae aged 15 days (> 5 mg) commenced short clinging behaviour, and their swimming positions dispersed downwards during daytime regardless of the water flow, indicating the onset of the transition to settlement. In contrast, their position shifted to near the upper limit at night by swimming upwards, even under downward water flows. Our results suggest that O. sinensis exhibits characteristic behaviour that alternates between diurnal descent dispersion with clinging (hyperbenthic trait) and nocturnal upward swimming (planktonic trait) during the transition to permanent benthic life. [ABSTRACT FROM AUTHOR]

The carapacial scute pattern is a conserved trait in sea turtles that provides taxonomic information, although hatchlings with aberrant scute numbers are commonly described in all extant species. These anomalies have been associated with reduced individual fitness, but very little is known about their occurrence in the juvenile and adult portion of the population. Here, we compared the frequencies of major non‐modal scute patterns (i.e. number of vertebral/coastal scutes ≠ 5, MNMSP) in hatchling, juvenile and adult loggerhead turtles (Caretta caretta) from the Central Tyrrhenian Sea. 20.5% of the analysed hatchlings exhibited MNMSP (N = 1047, range 0–52%). These individuals were significantly lighter than modals, but no other morphological difference was observed. Hatchlings from relocated nests (N = 241) had a lower rate of scute variation compared to those from natural nests (N = 806, MNMSP frequencies 10.37 and 23.57% respectively). The proportion of MNMSP decreased in early juveniles (12.1%, N = 149, SCLst < 41 cm) and even further in late juveniles/adults (4.8%, N = 124, SCLst > 41 cm). These results are coherent with those from previous studies and suggest that individuals with modal scute pattern may have a greater survival rate. However, selection against abnormal scute patterns may not occur within the first few days of life, as previously suggested, but it is probably a much slower process that may require several years. It is unlikely that alterations of the scute pattern affect survival directly; they may be a phenotypic expression of underlying morphological or physiological anomalies that stem from environmental stressors similar to those causing scute variations during embryonic development. [ABSTRACT FROM AUTHOR]

Identification of tardigrade species is still reliant mostly on morphological and morphometric traits. Given that the number of taxonomically significant traits available in the genus Milnesium is exceptionally low, ontogenetic variability may provide additional methods for species delineation. However, it is notoriously difficult to establish whether both immature and sexually mature instars are present in examined populations. Here, we developed a simple analytical morphometric method that helps in testing whether both immature and mature life stages are present in a given set of individuals. In order to achieve this, we analysed 21 populations representing 11 Milnesium species, with developmental tracking data available for four species. Using cluster analysis, individuals were assigned accurately to three groups of instars: hatchlings, juveniles and adults (third instar onwards). Our analyses revealed that the most useful character in life-stage classification is buccal tube length. The method of classification of instars presented herein could be used as a simple tool for identification of the number of life stages present in a population. Finally, using our algorithm, we analysed morphometric datasets underlying the descriptions and redescriptions of all known Milnesium species to date and concluded that the majority of them did not include all three life-stage groups. [ABSTRACT FROM AUTHOR]

The Chinese many-toothed snake (Sibynophis chinensis) is an endangered species in South Korea. To determine its reproductive activity, here we captured a gravid S. chinensis from Mulyeongari Oreum Wetland Conservation Area, Jeju Island, on May 27, 2018, and reared it at Animal Taxonomy and Morphology Laboratory, Jeju National University, South Korea. The snake oviposited a clutch of six eggs between June 12 and 20, 2018, with an average size of 24.86 ± 1.36 mm in length and 9.86 ± 0.49 mm in width, which were artificially incubated at a constant temperature of 27 °C. After incubating for 34–41 days, five of these six eggs successfully hatched. Average snout-vent length (SVL), tail length (TL), and body weight (BW) of hatchlings were 136.5 ± 5.17 mm, 47.76 ± 2.80 mm, and 1.66 ± 0.12 g, respectively. This study observed the reproductive activity of S. chinensis and characterized its eggs and hatchlings for the first time, providing valuable information for the long-term conservation plan of S. chinensis in South Korea. [ABSTRACT FROM AUTHOR]

Multiple paternity in crocodilian broods would increase effective population size and slow down the loss of genetic variation due to inbreeding and random genetic drift in real populations. Multiple paternity may also explain variation among offspring of the same brood with respect to characteristics of commercial interest to crocodile farmers. Foetal membranes may provide a non-invasive source of DNA from which to determine the genotypes of Nile crocodile (Crocodylus niloticus) hatchlings. The aims of this study were to determine the effectiveness of using the foetal membranes remaining inside the hatched eggs to determine the genotypes of Nile crocodile hatchlings, and to determine whether a brood (the hatchlings from a clutch of eggs) from a communal breeding pond on a commercial farm may have more than one sire. DNA profiles were determined on 4-6 (mean 4.4) foetal membrane specimens (FMSs) from each of 25 broods from the same breeding pond on a commercial Nile crocodile farm. Eleven microsatellite loci were used. DNA amplification occurred at all 11 loci in 95 of the 110 genotyped individuals, at 1-10 loci in 13 and at no locus in two. Three to 20 alleles were found per locus. Single-locus assessment showed that 13 broods had at least two sires. A multilocus programme (Colony) inferred that 19 broods had at least two sires, with polyandry and polygyny being common. Further research is necessary to determine the utility of foetal membranes as a source of DNA from nests in the wild and, using more FMSs per brood, to more precisely determine the extent of polyandry and polygyny in farmed and wild Nile crocodiles. [ABSTRACT FROM AUTHOR]

Sea turtles are vulnerable immediately after emerging from nests and before they reach the surf. Mortality rates during this brief period are largely unknown. Many sea turtle monitoring programs measure hatchling production from nest inventories. These inventories rarely account for post-emergence mortality, leaving an unknown bias in hatchling production estimates. This study addresses the nest-to-surf data gap for Florida’s east coast nesting assemblages of loggerhead sea turtles (Caretta caretta). Five locations were surveyed during the 2016-nesting season. Across all beaches, 7.6% of the observed hatchlings did not survive to reach the water. Mortality sources varied by location. Observed predators include: mammals, birds, and crabs. Hatchling disorientation and misorientation due to photopollution occurred more frequently in urban areas than natural areas. Factors identified as important in hatchling mortality included numbers of hatchlings emerging, nest-to-surf distance, and level of urbanization. The results of this study may help sea turtle nesting managers address nest-to-surf mortality and improve hatchling production estimates.