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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.

Knowledge of turtle hatchling ecology is fundamental for managing wild populations. Information on habitat selection by turtle hatchlings is particularly important to ensure that conservation programmes that release hatchlings into the wild give them the best chances of surviving to adulthood. Currently, knowledge of the ecology of turtle hatchlings worldwide is limited, which restricts evidence-based management for threatened species. Here, we used laboratory and field experiments to test for effects of captivity on habitat selection, movement, and short-term survival of Murray River turtle hatchlings (Emydura macquarii). This species has declined > 60% since the 1970s, and a conservation plan is urgently needed to manage their recovery. In both the laboratory and field, we found that hatchlings select aquatic vegetation when it is available. Hatchlings raised in captivity for a month, however, were radio-tracked in habitats significantly further from vegetation after release, and over three times as many of these hatchlings were attacked by predators, compared to those released immediately after hatching. Aquatic vegetation is clearly an important habitat for hatchling E. macquarii, and therefore, (i) hatchling conservation should prioritise areas with appropriate aquatic vegetation, and (ii) aquatic vegetation restoration should be prioritised to ensure E. macquarii hatchling survival in the wild. Moreover, since captivity affects hatchling habitat selection, E. macquarii hatchlings should be released immediately upon hatching. Further research on soft release techniques and longer-term captivity is required to determine whether the impact of captivity can be reduced.

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.

The conservation and nesting ecology processes of the hawksbill turtle (Eretmochelys imbricata) are described, as a result of systematic monitoring between 2018 and 2019 in the municipality of Rincon del Mar, San Onofre, Sucre. Between July and September, day and night patrols were carried out a 7 km stretch of beach with 1674 hours of effort for the two years. Six hawksbill turtle nests were recorded in situ, one nest was poached by humans. The nesting female spawned a total of 761 eggs in five clutches (mean ± SD: 152.2 ± 15.5 eggs per clutch). Hatching success was (mean ± SD: 78.2 ± 12.4%) and emergence success was (mean ± SD: 74.7 ± 14.1%) (n = 5). The incubation period was (mean ± SD: 54 ± 7.8 days; n = 4). 591 hatchlings were released into the sea, of which 22 (3.72%) were rescued and released with the community. In addition, physical measurements of the nests (width, depth, distance to the beach) and morphometric measurements of the hatchlings (SCW, SLC and weight) were carried out. More than 120 people participated in the different environmental education activities: local experts, releases, beach clean-ups, workshops, training and awareness. Finally, 14 natural and anthropogenic threats were identified for the species in Rincon del Mar and different degrees of threat, according to the beach sector, being high, medium and low for Chichiman, Ana Gomez and Balsillas with Punta Gorda respectively. Our results to contribute to the knowledge of the current status of the hawksbill turtle, as well as the indispensable of community participation, the importance of systematic and standardized monitoring, and the urgency of generating plans and management units for their conservation in Rincon del Mar.

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.

The largest colony of Cory's shearwaterCalonectris borealisnests on the island of Selvagem Grande in the north-eastern Atlantic. In 2002, a programme of eradication was conducted to remove two alien invasive mammals, the house mouseMus musculusand European rabbitOryctolagus cuniculus. Preliminary studies recorded beneficial effects of the eradications for a variety of plant and animal species, including Cory's shearwater. We recorded fledging rates of shearwaters for 1982–2001, prior to the eradication, and for 2002–2020, after the eradication, from two quadrats, each containing 134–329 nest sites. Although there was annual fluctuation in fledging rates in the quadrats, the mean rate of 40.74 ±SD 3.92 fledglings per 100 nest sites for the two quadrats combined prior to the eradication of mammals increased significantly, to 52.88 ± SD 5.03 per 100 nest sites, after the eradications. Because the two mammals were removed synchronously it is difficult to know which factors depressed fledging of Cory's shearwaters on Selvagem Grande. However, the predatory behaviour of house mice on other oceanic islands, and the fact that increased fledging was seen soon after the eradications occurred, suggest predation by house mice on shearwater hatchlings was the main cause of losses.

Increases in phenotypic variation under extreme (e.g. novel or stressful) environmental conditions are emerging as a crucial process through which evolutionary adaptation can occur. Lack of prior stabilizing selection, as well as potential instability of developmental processes in these environments, may lead to a release of phenotypic variation that can have important evolutionary consequences. Although such patterns have been shown in model study organisms, we know little about the generality of trait variance across environments for non-model organisms. Here, we test whether extreme developmental temperatures increase the phenotypic variation across diverse reptile taxa. We find that the among-individual variation in a key life-history trait (post-hatching growth) increases at extreme cold and hot temperatures. However, variations in two measures of hatchling morphology and in hatchling performance were not related to developmental temperature. Although extreme developmental temperatures may increase the variation in growth, our results suggest that plastic responses to stressful incubation conditions do not generally make more extreme phenotypes available to selection. We discuss the reasons for the general lack of increased variability at extreme incubation temperatures and the implications this has for local adaptation in hatchling morphology and physiology.

Los embriones de tortugas marinas son susceptibles a perturbaciones ambientales, las cuales se traducen en anomalías en su fenotipo. Uno de los principales parámetros para la medición de estas perturbaciones es la asimetría en los carapachos (caparazones), que puede ser obtenida a través del Índice de Inestabilidad de Desarrollo (DIx, por sus siglas en inglés). La temperatura juega un rol importante, influenciando no solo en la futura supervivencia de los neonatos en temperaturas extremas (altas o bajas), sino en atributos específicos, tales como la determinación del sexo, o incluso puede ser la causa del incremento en el número de apéndices dérmicos (escudos) sobre la parte dorsal del carapacho. Este estudio evaluó la relación entre la temperatura de incubación conla asimetría de carapacho de los neonatos de Lepidochelys olivacea incubados en condiciones relocalizadas en el tortugario del Área de Usos Múltiples Hawaii en Santa Rosa, Guatemala. Para lograrlo, se replicaron las condiciones de anidación seleccionadas por las hembras anidadoras en nidos relocalizados, utilizando dispositivos termosensitivos para la toma de la temperatura durante el período de incubación. A través del cálculo del DIx en 210 neonatos, y mediante las pruebas de correlación de Kendall y Jockheere-Terpstra, se obtuvo que en valores de temperaturas extremas tanto altas (Kendall tau = .23, p < .001; JT = 2,891, p < .001), como bajas (Kendall tau u= -.21, p < .001; JT = 5,005, p < .001), así como en altos rangos de variación durante el período de desarrollo embrionario (Kendall tau = .23, p < .001; JT = 6,619, p < .05), los neonatos presentan una mayor asimetría.

Maternal egg-caring behavior can often be observed in oviparous scincid lizards. The expression of such behavior is predictably affected by the trade-off between its resultant costs and benefits for mothers and/or offspring, which has been investigated in only a few scincid species. Here, post-ovipositional Plestiodon chinensis females were treated to care for their egg clutches without interference, under simulated predation pressure, or to be care-deprived. Potential maternal costs and offspring benefits associated with egg-caring behavior were then evaluated by measuring changes in maternal body condition, egg mortality, and hatchling performance. Egg-caring behavior caused post-ovipositional females to participate less in outside-nest activity, eat less food, and show relatively poorer body conditions at egg hatching. By contrast, compared with care-deprived females, egg-caring females gained mass slightly faster, and achieved a similar body condition within a few months of hatching. Eggs that were cared for by their mothers were more likely to hatch and produced larger, faster-running and better-growing hatchlings with higher survival than uncared-for eggs. Simulated exposure to a potential predator had no distinct impact on maternal egg-caring behavior expression and offspring performance. These results indicated that marked benefits of offspring viability but minor maternal energy costs might play a decisive role in the occurrence of maternal egg-caring behavior in P. chinensis. This article is protected by copyright. All rights reserved.

Thermal conditions during embryonic development affect offspring phenotype in ectotherms. Therefore, rising environmental temperatures can have important consequences for an individual's fitness. Nonetheless, females have some capacity to compensate for potential negative consequences that adverse developmental environments may have on their offspring. Recent studies show that oviparous reptiles exhibit behavioral plasticity in nest site selection, which can buffer their embryos against high incubation temperatures; however, much less is known about these responses in viviparous reptiles. We subjected pregnant viviparous skinks, Saiphos equalis, to current or projected midcentury (2050) temperatures to test (i) how elevated temperatures affect female thermoregulatory and foraging behavior; (ii) whether temperatures experienced by females during pregnancy negatively affect the morphology, performance, and behavior of hatchlings; and (iii) whether behavioral thermoregulation during pregnancy is costly to females. Females from the elevated temperature treatment compensated by going deeper belowground to seek cooler temperatures and eating less, and they consequently had a lower body mass relative to snout-to-vent length (condition estimator) compared with females from the current thermal treatment. The temperatures experienced by females in the elevated temperature treatment were high enough to affect foraging and locomotor performance but not the morphology and growth rate of hatchlings. By seeking cooler temperatures, mothers can mitigate some of the effects of high temperatures on their offspring (e.g., reduced body size and growth). However, this protective behavior of females may come at an energetic cost to them. This study adds to growing evidence of lizards' vulnerability to global warming, particularly during reproduction when females are already paying a substantial cost.

Sea turtle eggs incubation involves natural and artificial incubation of eggs, and indeed the depth will be varied and presumably affect the development of hatchlings. For nest relocation, the researcher needs to decide on the depth to incubate the eggs. Sea turtle eggs clutches may vary between 40 and 120 eggs for the green turtle, thus using a single value as the standard procedure might affect the quality of hatchlings. Here we quantify the dimension of the natural (in-situ) nest constructed by the nester and the artificial (ex-situ) built by our ranger during nest relocation. We suggest a linear regression calculation of Y = 0.2366X + 59.3267, better predict a more accurate nest depth based on the number of eggs to imitate the natural nest.

The environment experienced during embryonic development is a rich source of phenotypic variation, as environmental signals have the potential to both inform adaptive plastic responses and disrupt normal developmental programs. Environment-by-embryo interactions are particularly consequential for species with temperature-dependent sex determination, a mode of sex determination common in non-avian reptiles and fish, in which thermal cues during a discrete period of development drive the formation of either an ovary or a testis. Here we examine the impact of thermal variation during incubation in combination with developmental exposure to a common endocrine-disrupting contaminant on fitness-related hatchling traits in the American alligator (

The diversity and consequences of development in marine invertebrates have, for a long time, provided the opportunity to understand different evolutionary solutions to living in variable en...

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.

The study was carried out for six (6) weeks at the Department of Fisheries Teaching and Research farm, Modibbo Adama University, Yola, to compare the reproductive performance of Clarias gariepinus using synthetic (ovaprim) and natural (C. gariepinus pituitary extract) hormones . At the end of the feeding trial, the fecundity, percentage fertilization, hatchability, and survival rates of the hatchlings were estimated using standard procedure. The hatchlings were further raised for six weeks and the increase in weight was determined. The results showed that female broodstock injected with C. gariepinus pituitary extract (CgPE) had a higher fecundity (124,000) while the female injected with Ovaprim had 65,000 eggs. The weight of the testes significantly differed (p

All sea turtles exhibit temperature-dependent sex-determination, where warmer temperatures produce mostly females and cooler temperatures produce mostly males. As global temperatures continue to rise, sea turtle sex-ratios are expected to become increasingly female-biased, threatening the long-term viability of many populations. Nest temperatures are dependent on sand temperature, and heavy rainfall events reduce sand temperatures for a brief period. However, it is unknown whether these short-term temperature drops are large and long enough to produce male hatchlings. To discover if short-term temperature drops within the sex-determining period can lead to male hatchling production, we exposed green and loggerhead turtle eggs to short-term temperature drops conducted in constant temperature rooms. We dropped incubation temperature at four different times during the sex-determining period for a duration of either 3 or 7 days to mimic short-term drops in temperature caused by heavy rainfall in nature. Some male hatchlings were produced when exposed to temperature drops for as little as 3 days, but the majority of male production occurred when eggs were exposed to 7 days of lowered temperature. More male hatchlings were produced when the temperature drop occurred during the middle of the sex-determining period in green turtles, and the beginning and end of the sex-determining period in loggerhead turtles. Inter-clutch variation was evident in the proportion of male hatchlings produced, indicating that maternal and or genetic factors influence male hatchling production. Our findings have management implications for the long-term preservation of sea turtles on beaches that exhibit strongly female-biased hatchling sex-ratios.

Effects of perfluorooctane sulfonate (PFOS) and a legacy aqueous film-forming foam (AFFF) containing 91% PFOS (AFFF PFOS) on reproduction, chick survivability, and growth of Japanese quail (Coturnix japonica) were determined. Day-old Japanese quail were administered PFOS or AFFF PFOS at 6 dietary concentrations ranging from 0 to 21 mg kg-1 feed for a total of 20 wk. At the age of 4 wk, 16 male/female pairs per treatment were assigned to cages, and egg laying was induced by the age of 10 wk. Eggs were collected daily, set weekly, and incubated for 18 d for the following 10 wk. Hatchlings were fed uncontaminated feed for 2 wk and euthanized to collect blood and liver. After 10 wk of egg collection, adults were euthanized to collect blood, liver, and kidneys. Significantly increased myofiber numbers in the liver and glomerular sclerosis in the kidneys of adults indicated damage at greater doses. Perfluorooctane sulfonate or AFFF PFOS did not significantly affect egg production; however, hatchability was decreased at the highest PFOS dose. The no-observed-adverse-effect levels for chick survivability, considered the critical effect, were 4.1 mg PFOS kg feed-1 (0.55 mg kg body wt-1 d-1 ) and 5.0 mg AFFF PFOS kg feed-1 (0.66 mg kg body wt-1 d-1 ), resulting in calculated average toxicity reference values of 0.25 mg kg feed-1 and 0.034 mg kg body weight-1 d-1 . Environ Toxicol Chem 2021;40:2521-2537. © 2020 SETAC.

The growth of a nestling during the first few weeks after hatching is crucial for its further life and is sensitive to the conditions experienced during this period. Among species exhibiting Sexual Size Dimorphism (SSD), one of the most important factors influencing growth parameters is the sex of the hatchlings. In this study, we tested whether sex and other factors (hatching date, egg volume, brood size and sex ratio in the brood) were related to sex on growth parameters in Whiskered Tern (Chlidonias hybrida) chicks. In this species, males are 3%–10% larger than females when adult. At hatching, only the total head length was greater in males than females, but values close to fledging were greater for most of the measured parameters (3%—tarsus, 4%—total head length, 13%—body mass). Moreover, the maximum body mass growth rate was higher in males but females entered the rapid growth phase somewhat earlier and achieved the final total head length sooner. Nestling growth was also significantly correlated with brood size and hatching date, though mostly negatively (e.g. lower tarsus and total head length asymptote, lower maximum growth rate and growth rate constant of total head length in bigger and later clutches). The occurrence of SSD during the nestling period and higher maximum growth rate of body mass in males indicates that the costs of raising sons may be higher than of raising daughters. However, we did not find evidence of either sex-biased nestling mortality or skewed sex ratio.

Triclosan (TCS) used commonly in pharmaceuticals and personal care products has become the most common pollutant in water. Three days old hatchlings of an indegenous fish, Labeo rohita were given 96h exposure to an environmentally relevant (0.06mg/L) and two moderately lethal concentrations (0.067 and 0.097 mg/L) of TCS and kept for 10 days of recovery for recording transcriptomic alterations in antioxidant/detoxification (SOD, GST, CAT, GPx, GR, CYP1a and CYP3a), metabolic (LDH, ALT and AST) and neurological (AchE) genes and DNA damage. The data were subjected to Principal Component Analysis (PCA) for obtaining biomarkers for the toxicity of TCS. Hatchlings were highly sensitive to TCS (96h LC 50 = 0.126mg/L and risk quotient = 40.95), 96h exposure caused significant induction of CYP3a, AChE and ALT but suppression of all other genes. However, expression of all the genes increased significantly (except for a significant decline in ALT) after recovery. Concentration dependent increase was also observed in DNA damage [Tail Length (TL), Tail Moment (TM), Olive Tail Moment (OTM) and Percent Tail DNA (TDNA)] after 96h. The damage declined significantly over 96h values at 0.06 and 0.067 mg/L after recovery, but was still several times more than control. TCS elicited genomic alterations resulted in 5-11% mortality of exposed hatchlings during the recovery period. It is evident that hatchlings of L. rohita are a potential model and PCA shows that OTM, TL, TM, TDNA, SOD and GR (association with PC1 during exposure and recovery) are the biomarkers for the toxicity of TCS.

Synchronous digging activity and emergence from underground nests is important for sea turtle hatchlings, as it reduces predation risk and decreases energy consumption. However, patterns of underground hatching and diel digging activity prior to emergence are invisible and remain largely unknown. In this study, we acoustically monitored the activity of green turtle, Chelonia mydas, hatchlings from hatching to emergence in the field and laboratory. During the hatching period, we did not observe characteristic acoustic events corresponding to pipping and hatching. Hatchlings started digging even though there were still unhatched eggs above them, indicating that green turtles did not hatch as one synchronous group. This observation did not support our hypothesis that synchronized hatching facilitates synchronous emergence. Digging activity tended to increase at night as the hatchlings approached the sand surface and nest emergence became imminent. It is not surprising that there was diel variation in digging activity as the hatchlings approached the surface because diel fluctuations in sand temperature can provide a diel cue. Surprisingly, a diel change in digging activity was also observed when hatchlings were still at a sand depth where temperature remained relatively constant throughout the day (that is, a few days before emergence) and in the laboratory at a constant temperature. This study suggests that the diel activity pattern of hatchling green turtles may occur even in the absence of a diel temperature fluctuation cue.

The experiment was operated in 9 consecutive weeks in nine earthen nursery ponds having the same area (0.09 acre) and depth (0.8 m). Seven days old fries of Silver carp (Hypophthalmichthys molitrix) were stocked at 4000, 5000 and 6000 fries/decimal in three treatments with three replications as T-1, T-2 and T-3, respectively to observe the growth and survival. At stocking, hatchlings were the same batch-rearing with an average length and weight of 0.44 ± 0.05 cm and 0.14 ± 0.05 mg, respectively. Wet mustered oil cake and commercial nursery feed containing 30% crude protein were given by two weeks interval, initially according to the bodyweight; the feeding rate was 14% in the first two weeks, gradually reduced to 12, 10 and 8%, respectively in the following week intervals. Water quality parameters and plankton sufficiency were observed every 15 days interval and was found within the acceptable range. Growth performance (6.458 g), survival rate of fingerlings (85.76%) and total production (22151g/decimal) were found highest in T-1 followed by T-2 and T-3. The study concluded that expect better production of fry up to fingerlings, proper stocking density should be maintained in pond fish culture in Jashore region of Bangladesh.

The study was conducted to assess the effect of Zingiber officinale and Carica papaya extract on the egg hatchability of the golden apple snail, Pomacea canaliculata. This is a freshwater snail that is considered a pest in agriculture as well as natural ecosystems. In combating the population of the aforementioned pest, this study evaluates the use of plant extracts such as biomolluscicides to control the production of new hatchlings from the clusters of eggs. The egg clusters were exposed to different concentrations of Z. officinale ethanolic extract and C. papaya methanolic extracts (25 ppm, 50 ppm, 100 ppm) using the direct single spraying method. Observation was made for a maximum of 30 days. The time taken for the eggs to hatch and the number of eggs successfully hatched were measured to reflect the potential of both extracts in affecting egg hatchability. The finding shows that the eggs hatch later when exposed to increasing concentrations (25 to 100 ppm) of Z. officinale extract. The number of eggs successfully hatched was significantly decreased from 86% to 9% after exposure to 25 ppm and above. Meanwhile, the extract of C. papaya did not show any significant effect on both parameters for egg hatchability of P. canaliculata, regardless of the increase in concentration from 25 to 100 ppm. Our findings reveal that the extract of Z. officinale contains higher molluscicidal activity than the extract of C. papaya. Therefore, it has the potential to be commercialized as a biomolluscicide to control the population of golden apple snails specifically at the egg stage.

Synchronized emergence of offspring may represent an adaptive strategy to reduce predation risk. This strategy swamps the short-term capacity of predators to consume prey before offspring disperse, inducing a dilution effect, thus improving an individual’s chance of survival. In the case of sea turtles, this occurs during emergence and mass migration to the sea, to avoid potential predators on the beach. In this study, we evaluated the effect of group size on predation rates of loggerhead turtle Caretta caretta hatchlings during the crawl to the sea on Boa Vista Island, Cabo Verde. Our results show that synchronous emergence reduced rates of predation by tufted ghost crabs Ocypode cursor. The mean estimated predation rate overall was 50.3%. Predation was highest (~75%) in the smallest group sizes and decreased to ~25% in larger groups, due to the lower probability of an individual being attacked by a ghost crab. Our observations also indicate significantly higher predation rates at night (55%) than during the day (22%). No relationship between predation rates and the distance between the nest and the surf zone of the sea was identified; however, this is likely due to the behaviour of ghost crabs, i.e. waiting close to the tide line for hatchlings during the night. Our results provide important information for the management and conservation of endangered sea turtle populations in areas with high densities of predatory ghost crabs. Specifically, to reduce predation rates, we recommend that hatchlings are released in large groups at twilight hours and in areas of low ghost crab densities.

Global increases in beach sand temperatures are predicted to skew hatchling sex ratios of marine turtle populations towards female bias. Currently, shade structures and freshwater irrigation are management strategies used to cool nest temperatures, but require resources that are limited at remote rookeries. Here, we report on a novel investigation that used seawater irrigation as a sand-cooling method. Various volumes of seawater were applied to sand to determine the optimal application required to lower sand temperatures at nest depth to produce male-biased sex ratios. We performed these experiments during the 2019-2020 nesting season at Heron Island on the southern Great Barrier Reef, Australia, and at Panasesa Island, Papua New Guinea. We found the amount of cooling at nest depth was site dependent and varied with the seawater irrigation regime used. At Heron Island, we used a one-off application of the equivalent of 120 mm of rainfall either as freshwater or seawater to the sand above incubating clutches 18 d after oviposition to determine whether this affected the hatching success of green turtle Chelonia mydas eggs. Both treatments had higher hatching success (83.8 ± 3.5% and 71.2 ± 6.3%, respectively, means ± SE) compared to control clutches (63.5 ± 6.0%). Our results indicate that a one-off application of seawater may be an effective management option for reducing nest temperatures during the sex-determining period of marine turtle clutches incubating in situ. Seawater irrigation could be used in areas where populations are at highest risk of feminisation caused by a hot drying climate where freshwater is not available for irrigation.

Snake-Turtle interactions have been rarely documented. We recorded a hatchling Chelodina oblonga within the stomach contents of a Western tiger snake (Notechis scutatus occidentalis). This is the first recorded observation of an interaction between snakes and hatchling freshwater turtles in Western Australia. Field based palpation failed to detect the hatchling, suggesting that without dissection, turtle hatchling predation by snakes more generally could be higher than commonly reported. Snake predation of hatchlings could be placing additional pressure on threatened populations of freshwater turtles in Australia, warranting further investigation.

Insufficient energy reserves are widely considered to be a primary factor contributing to high rates of early benthic phase mortality among benthic marine invertebrates, but this hypothesis has been based mostly on indirect, observational evidence, and remains largely untested. We therefore examined the role of initial energy reserves in regulating survivorship and growth during the early benthic phase. Recently settled or hatched individuals of six invertebrate species were collected from natural populations, maintained without food, and their survivorship was monitored. Contrary to expectations, starved individuals of all six species had high survivorship through the critical first 10 days of the early benthic phase, with half of the species experiencing, We examined the role of initial energy reserves in regulating survivorship and growth during the early benthic phase (EBP) in six invertebrate species. Contrary to expectations, starved individuals of all six species had high survivorship through the first 10 days of the EBP, but starvation did affect the ability to grow when food became available. Thus, depleted energy reserves would not be a significant cause of EBP mortality, nor would individuals require immediate access to food to survive the critical first of early benthic life.

Organismal miniaturization is defined by a reduction in body size relative to a large ancestor. In vertebrate animals, miniaturization is achieved by suppressing the energetics of growth. However, this might interfere with reproductive strategies in egg-laying species with limited energy budgets for embryo growth and differentiation. In general, the extent to which miniaturization coincides with alterations in animal development remains obscure. To address the interplay among body size, life history, and ontogeny, miniaturization in chelydroid turtles was examined. The analyses corroborated that miniaturization in the Chelydroidea clade is underlain by a dampening of the ancestral growth trajectory. There were no associated shifts in the early sequence of developmental transformations, though the relative duration of organogenesis was shortened in miniaturized embryos. The size of eggs, hatchlings, and adults was positively correlated within Chelydroidea. A phylogenetically broader exploration revealed an alternative miniaturization mode wherein exceptionally large hatchlings grow minimally and thus attain diminutive adult sizes. Lastly, it is shown that miniaturized Chelydroidea turtles undergo accelerated ossification coupled with a ~10% reduction in shell bones. As in other vertebrates, the effects of miniaturization were not systemic, possibly owing to opposing functional demands and tissue geometric constraints. This underscores the integrated and hierarchical nature of developmental systems.

While the effects of incubation environment on embryonic development and offspring traits have been extensively studied in oviparous vertebrates, studies into how genetic inheritance (population origin), maternal effects, and incubation environment interact to produce varying phenotypes, are rare. To elucidate the interactive role of those three factors during incubation in shaping offspring phenotypes through hydric conditions, we conducted a fully factorial experiment [arid and semiarid populations × maternal dry and wet treatments (MDT and MWT) × embryonic dry and wet treatments (EDT and EWT)] with a desert-dwelling lacertid lizard (Eremias argus). Female lizards in dry conditions produced larger clutch sizes but smaller eggs. The incubation period and hatching success were significantly affected by embryonic but not by maternal moisture treatments. Eggs in the EDT hatched later than those in the EWT in both arid and semiarid populations. Hatching success was lower in EDT than in EWT in the semiarid population, but not in the arid population. Hatchlings from the EDT had a slower post-hatch increase in body mass than those from the EWT. EDT would decrease the survival rates of hatchlings in the semiarid population only. In addition, structural equation models revealed that population had a stronger effect on embryonic and offspring survival than maternal and embryonic moisture. Our study demonstrates locally adaptive strategies of drought resistance at multiple life-history stages in lizard populations from diverse hydric habitats and highlights the importance of genetic factors in determining embryonic drought resistance in oviparous lizards.

The influence of nest incubation temperatures on carapace shape and morphological traits of Leatherback Turtle (Dermochelys coriacea (Vandelli, 1761)) hatchlings incubated in two hatcheries in Oaxaca, Mexico, was evaluated. This study was carried out from October 2016 through May 2017. On each beach, there are community groups consisting of volunteers not affiliated with universities who protect and relocate the nests to increase hatching success. In each translocated nest, a data logger was placed in the centre of the egg mass. Hatchlings were collected as they emerged from each nest. The carapaces of the hatchlings were photographed and subjected to geometric morphometric analysis; also, hatchlings were weighed and their bodies measured. The mean temperature of 12 nests in each hatchery was recorded, with no significant differences between hatcheries. The principal component analysis revealed an overlapping of the carapace shape under different temperature durations. Temperature had a significant influence on hatchling morphology. Higher mean incubation temperatures produced hatchlings with low mass, smaller appendages, narrower carapace widths, and shorter flipper lengths. Lower mean incubation temperatures produced hatchlings with greater mass, wider appendage widths, wider carapace widths, and longer flipper lengths. Results indicate that the Leatherback hatchlings incubated in hatcheries demonstrate morphology that varies in relation to nest incubation temperature in a similar way to hatchlings produced in natural environments.

Characterizing the breeding ecology of birds is important for understanding their population dynamics. One of the most common small resident birds in Egypt that acts as a biocontrol agent of insects is Graceful Prinia (Prinia gracilis). Despite its importance, there are few studies on its breeding ecology in Egypt. Accordingly, this study is the first in investigating the population density and the breeding ecology (including the clutch size, incubation period, fledging period, hatching success, fledging success, and breeding success) of P. gracilis at Akiad Pond, Sharkia Governorate, Egypt during 2019. Results of the current study showed that P. gracilis followed the pattern spring > summer > autumn > winter in abundance during 2019. Regarding its breeding ecology, P. gracilis laid from 2 to 5 eggs/clutch with an average of 3.75±0.25 eggs. 42 young hatched from 60 eggs recording a 70% hatching success rate throughout the study period at Akiad pond. Moreover, about 37 chicks fledged and 5 died recording 88 % fledging success rate. Clutches of two and three eggs had higher fledging success than the other clutches because of the inability of parents to meet the basic feeding needs in large broods. The incubation period was 12.56±0.20 days/nest to produce 2.6 hatchlings/nest, while the fledgling period was 14.62±0.27 days/nest to produce 2.315 young fledged/nest. The breeding success was 61.6% in relation to the number of eggs laid. The main threats to birdlife are human activities (as burning for regrowth, cattle grazing, fishing, and in some way desiccation to some patches around the pond in summer) that destroy its food and nests requirements.

Long-term monitoring studies on sea turtles give reliable data on population size and nest density estimates. In this context, this study provides reliable data about nesting and hatching activities of the loggerhead turtle on Cirali Beach based on an eight year (2013–2020) monitoring period. Moreover, the study evaluates long-term nesting trends over the years 2001–2020. A total of 852 nests with a mean of 107 nests per season was recorded during 2013–2020 on the Cirali Beach. A total of 68,443 eggs were deposited and 41,080 (60%) of them were hatched, and 37,830 of the hatchlings (92%) were able to reach the sea. The mean clutch size and hatching success were 81.9 eggs and 60%, respectively, and show interannual variation. The mean incubation duration was 47.4 days, and show similarity across years. The loggerhead turtle nest tended towards an upward trend over the 20 consecutive years. Moreover, the current nesting population size of Cirali loggerhead turtles are estimated as 96 females based on the clutch frequency calculation. This upward trend may raise from the nesting shift from the Tekirova beach. Cirali sea turtle conservation activity has an exemplary practice in terms of supporting the local community with conservation activities during nesting seasons.

The question of how to program the removal of two invasive mammals, typically cats and rats, from a marine island without increasing risk to native prey species has received two general answers based on ecological theory: removal of cats must be accompanied by control of their mesopredator prey, and risk is minimized by removing both invaders simultaneously. Nonetheless, a 31-year study showed that in a 82-ha tropical marine bird sanctuary, predation on a native prey, the blue-footed booby, by a native predator, the Atlantic Central American milk snake, apparently diminished after removal of cats then increased 11-fold after the additional removal of black rats. These novel effects are explained in terms of a hypothetical three-link trophic web in which cat removal released rats to increasingly compete with or prey on the snakes that feed on hatchling boobies, and subsequent rat removal released snakes from all remaining predation. The upshot is a disturbing scenario in which approximately 200 milk snakes currently aggregate annually in roughly 1 hectare of booby colony and predate roughly forty percent of the hatchlings. Where the lowest link of an insular trophic web is a native mesopredator that feeds on native prey, the predictions of the classic mesopredator release scenario can be inverted, and removal of invasive mammals may endanger native prey species.

Permethrin is a commonly used, highly effective pesticide in poultry agriculture, and has recently been trialed in conservation efforts to protect Galápagos finch hatchlings from an invasive ectoparasite. Although permethrin is considered safe for adults, pesticides can have health consequences when animals are exposed during early life stages. The few studies that have examined permethrin's effects in embryonic chicks and rats have shown hydrocephaly, anencephaly, reduced cellular energy conversion, and disruption of developing heart muscle. To test whether trans-ovo exposure of permethrin affects early development in birds, we exposed Japanese quail (Coturnix japonica) eggs to cotton treated with 1% permethrin that was incorporated into nests in two amounts (0.2, 0.8 g), each with a paired untreated cotton control group. When measured on incubation Day 15, we found permethrin-treated developing birds were smaller and showed signs of microcephaly, although mortality rates were the same. Despite no difference in heart mass, ventricular tissue was less compact, cardiac arteries were reduced and heart rates were slower in permethrin-treated birds. Differences in heart development were also observed at 5 days of incubation, indicating that abnormalities are present from early in cardiac development. Future studies are needed to examine permethrin's effects on developmental pathways and to determine if these effects persist after hatching to affect offspring health. This study provides evidence that permethrin can cross the eggshell to cause non-lethal but adverse effects on embryonic development, and studies should look beyond hatching when monitoring the efficacy of permethrin on wild bird populations.

Subterranean foraging army ants (Labidus coecus) preyed on eggs and hatchlings of three species of Amazon River turtles (genus Podocnemis) in northeastern Peru. The raided nests were in a hatchery constructed atop the soil surface of a beach on the Tapiche River. The ant raid persisted across at least 9 days, and ant foraging impacted nests over an area of approximately 14 m2. Observations suggest the ant workers chewed through turtle egg shells and entered nestling turtle body cavities via their eyes and yolk sacks (when present). Our observations, combined with previous reports, show that ant predation on river turtle nests, and particularly predation by Labidus coecus, is geographically widespread in Amazonia. Ant predation may represent an under-recorded source of turtle egg and nestling mortality. We discuss how army ant behavior affects strategies for mitigating ant predation in turtle hatcheries.

Warming global temperatures are predicted to reduce population viability in many oviparous ectothermic taxa, with increased embryonic mortality likely to be a main cause. While research on embryonic upper thermal limits is extensive, sea turtle hatchling thermal tolerance has received less attention and our understanding of how incubation conditions influence hatchling thermal tolerance is limited. Here, we report green turtle Chelonia mydas hatchling hydration and thermal tolerance following incubation in dry and wet conditions. We used packed cell volume and total protein as indicators of hydration and measured the critical thermal maximum (CTmax) of hatchlings in air. Neither hydration nor thermal tolerance was directly influenced by moisture treatment. However, hatchlings from moister nests had longer incubation durations (wet: 60.11 d vs. dry: 54.86 d), and, using incubation duration as a proxy for incubation temperature, hatchlings from cooler nests had significantly lower CTmax (wet: 39.84°C vs. dry: 40.51°C). Thus, despite not directly influencing thermal tolerance, moisture treatment influenced nest temperature indirectly; hatchlings that experienced warmer conditions in dry nests had a higher thermal tolerance than hatchlings from cooler and wetter nests. Ectothermic neonates may have greater plasticity in their thermal tolerance than previously thought, but their ability to adapt to increasing temperature is likely limited. Additionally, common management techniques to reduce nest temperatures, such as watering and shading nests, may only reduce embryonic mortality at the cost of decreased hatchling thermal tolerance and increased hatchling mortality during emergence. Nesting-site management interventions designed to reduce embryonic mortality will need to consider mitigation of the possible effects of those interventions on hatchling mortality.

Ants have been suggested as one of many population pressures sea turtles face potentially affecting nesting-beach survival of eggs and hatchlings. However, little is known about the extent to which ants act as incidental or primary mortality factors. Most research has focused on New World fire ants (genus Solenopsis), with confirmed records of other ant species interactions with sea turtle nests in situ being rare. Our study documented the ant species associated with loggerhead sea turtle Caretta caretta (Linnaeus) (Testudines: Cheloniidae) nests in Georgia and determined if ant presence was linked to lower hatching or emergence success. Samples (n = 116) collected from sea turtle nests on eight islands contained 14 ant species including Solenopsis invicta Buren (Hymenoptera: Formicidae), the red imported fire ant, which was the most common ant species encountered. Ant presence was not correlated with lower hatching success, but when other known disturbances were removed, correlated with significantly lower nest emergence success (P < 0.0001). Logistic modeling suggests that proximity of sea turtle nests to the primary dune significantly increases risk of ant predation on hatchling sea turtles. Population managers can reduce this risk by maintaining a 1-m buffer shoreward between dune vegetation and relocated sea turtle nests. Our results suggest that ants may exert a density-dependent pressure on nesting sea turtle populations and call for additional investigations to determine if managing native and invasive ants augments other efforts to improve hatchling survival.

The aim of the current study was to determine the impact of in-ovo injected D-Glucose monohydrate and ascorbic acid on hatchability, body weight and early post-hatch performance of geese. The 360 eggs from a 50-wk-old Embden crossbred breeder flock were set in a single-stage incubator with 4 treatments. The experimental treatments were: (1) non-injected Control, (2) Dextrose 24 mg / 0.5 mL, (3) Vitamin C 10 mg / 0.1 mL (4) Dextrose 24 mg / 0.5 mL + Vitamin C 10 mg / 0.1 mL. At 11 and 18 d of incubation, the eggs were injected into the albumen manually under sterile conditions. At 25 d of incubation, the same amount of the agents was injected into the yolk sac of the fertile eggs with the same procedure. The hatchability of the Control and Dextrose + Vitamin C groups were statistically different (P < 0.05). Although there was a statistically insignificant difference, the highest value was recorded in the Dextrose + Vitamin C group on the 25th-day. The hatchling weights were only influenced by the agents. The 25th-day Dextrose + Vitamin C treatment had the greatest values at body weights at hatch. There were no statistical differences by the injection days, agents and interactions regarding body weights at 7th-day post-hatch. In addition, there was no significant impact of different injection sites on both hatchling weight and, body weights of post-hatch 7th-day. It is suggested that the in-ovo injection should administrate on the 25th day of incubation into the yolk sac in goose eggs with a mixture of D-Glucose monohydrate and ascorbic acid.

Identifying intrinsic and extrinsic sources of variation in life history traits among populations has been well-studied at the post-embryonic stage but rarely at the embryonic stage. To reveal these sources of variation in the developmental success of embryos, we measured the physical characteristics of nest environments and conducted reciprocal egg-swap experiments in two populations of the toad-headed agamid lizard (Phrynocephalus przewalskii), isolated from each other by a mountain range. We determined the effects of population origin and nest environment on embryonic and offspring traits related to developmental success, including incubation period, hatching success, and offspring growth and survival. Females from the northern population constructed deeper nests that were colder and wetter than those from the southern population. Northern embryos had higher hatching success than the southern embryos when incubated at the northern nest environment, but not when they were incubated at the southern nest environment. The southern hatchlings grew faster than the northern hatchlings when incubated at the southern nest environment, but not after incubation at the northern nest environment. These phenomena likely reflect local adaptation of embryonic development to their nest environments among populations in lizards. In addition, the southern hatchlings had higher survivorship than the northern hatchlings regardless of nest environment, suggesting the southern population has evolved a superior phenotype at the hatchling stage to maximize its fitness.

The aim of this study was to assess whether possible metal contamination in the sediment of the nests of giant Amazon river turtle, Podocnemis expansa, could contaminate eggs and hatchlings, triggering genotoxic damage. Therefore, sediments of P. expansa nests from two sites in the Brazilian Amazon were evaluated, with the first being collected at Araguaia River and the second at Crixás-Açu River. Newly hatched offspring, eggs, and sediments were collected from the beaches of these two rivers and the quantification of metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn) was carried out by atomic absorption spectroscopy. All targeted metals were found in both sediment and P. expansa biological samples collected on the beaches presenting higher concentrations in the sediment of Crixás-Açu River. Metals found in the eggshells before nesting and in the egg contents were maternally transferred. Moreover, augmented concentration of metals led by metal transfer from the nests sediments were detected in the eggshells after nesting (ENH) and in the newly hatched offspring (H). Probably this metal relocation to the newly hatchlings augmented the frequency of micronuclei in their blood, presenting 15.25‰ in hatchling found in Crixás-Açu River beaches and 10‰ in newly hatched animals from Araguaia River beaches. These results indicate the occurrence of maternal transfer of metals (essential or not) to the eggs in testudines as well as a transference from the sediments to the nesting eggs, triggering genotoxic effects on the hatchlings.

In the last five years, two colossal environmental disasters involving iron-enriched mine tailings have occurred in Brazil, affecting many aquatic ecosystems over the short, medium and long-terms. This study investigated whether these iron-enriched mine tailings affect the main biotic strategy to restore zooplankton populations affected by severe stress, i.e., hatching of dormant stages. A 30 day hatching experiment was conducted, using a resting egg bank from a natural lake, exposed to 3 concentrations of mine tailings: control (0 g), T25 (25 g) and T50 (50 g). A total of 22, 15 and 16 species hatched in the control, T25 and T50, respectively. Conochilus sp., Filinia terminalis, Hexartha mira, Bosmina longirostris and Ceriodaphnia silvestrii hatched only in the control, which suggests that these species are sensitive to any concentration of mine tailings. A gradual decrease in richness and hatchling abundance was recorded, from the control (8.0 ± 1.0 SE species and 1597 ± 73.9 hatchlings) to T25 (4.6 ± 1.2 species and 1279 ± 136.5 hatchlings) and then to T50 (2.3 ± 1.2 species and 603.3 ± 61.9 hatchlings). Our results suggest that exposure of zooplankton resting eggs to iron-enriched mine tailings may negatively impact these egg banks in natural ecosystems, with potential impacts on the restoration of zooplankton communities after even short-term exposures.

We aimed to discern the seasonal movement patterns, home range sizes, and microhabitat associations of subadult Macrochelys temminckii in a West Tennessee population. Because this population was previously monitored (i.e., telemetry and habitat use) as juveniles after the initial release in 2005, studying the movement ecology and habitat use of the same released cohort 12 years later allows for unique comparisons between hatchling and subadult ecology. We used radio telemetry to collect movement and microhabitat data of 16 subadult M. temminckii during one year. Our results suggest that seasonal and ontogenetic variation in movement patterns and habitat selection occur within a cohort of M. temminckii. Compared to juveniles, subadults used deep slough areas with high overstory tree cover and had larger home ranges (100% minimum convex polygons [MCP]). Additionally, as subadults, the mean distance moved (m) varied among seasons and furthest during summer. Subadults used deeper water, with higher temperatures and significantly more tree canopy cover, than random locations. Overall, the home range estimate for subadults (mean MCP ± SE; 1.64 ± 0.57 ha) was greater than for juveniles (0.044 ± 0.021 ha). These home-range estimates and habitat usage patterns were similar to subadults in other studies. The seasonal and ontogenetic variations suggest that habitat heterogeneity is critical to sustain populations of introduced M. temminckii.

Nutrition and the lack of an established protocol for the larviculture of Octopus are some of the bottlenecks for the development of Octopus aquaculture. This study aims to start filling in these knowledge gaps by obtaining daily feeding rates (FR) of Octopus americanus paralarvae at different ages by testing different live prey types (Artemia nauplii, Acartia lilljeborgii copepods, and Callinectes sapidus zoeae) and densities (20, 40, 60, 80, 120, and 160 prey L−1). In addition, prey preference was assessed by exposing paralarvae to these prey types simultaneously. The dry weight (DW) of the prey was obtained and used to estimate the daily DW ingestion rate of paralarvae. Experiments were performed with 1- and 8–9-day-old paralarvae. The FRs recorded for different prey densities and the effect of different prey types on prey preference were analyzed through one-way ANOVA. The FRs recorded were quite different among the preys tested. The highest mean FRs for hatchlings was 26.2±6.9 zoeae paralarva−1 day−1 and for 8-day-old paralarvae was 63–69 Artemia nauplii paralarva−1 day−1. Therefore, the following prey densities are recommended for the larviculture of paralarvae up to 10 days of age: 80 copepods L−1, 160 Artemia nauplii L−1, and 80 zoeae L−1. Hatchlings showed a significant preference for zoeae, and Artemia nauplii and zoeae were significantly more preyed by 8-day-old paralarvae. Our results demonstrated that increasing prey density increases FR and predation by paralarvae, and zoeae were by far the preferred prey of hatchlings.

Effects of the in ovo injection of organic microminerals (OM) (zinc, manganese, and copper) and posthatch holding time (HT) on the daily body temperature (bt) of broilers during grow out were determined. The hatching eggs from a Ross 708 breeder flock at 32 wk of age were incubated under standard commercial conditions. At 17 d of incubation, eggs were randomly allocated to 3 in ovo OM injection treatment (TRT) groups, and at 21 d of incubation, male hatchlings were randomly allocated to 2 posthatch HT treatment groups. Eggs were either not injected or were in ovo injected with diluent only or diluent containing the OM mixture. A 0-hour HT group had immediate access to water and feed, and a 24-hour HT (24HT) group contained birds that were kept in transport baskets in their pens without access to feed and water for 24 h before being released. Fifteen male birds were placed in each of 36 litter floor pens in a temperature-controlled facility. Approximately 2 birds in each of 6 replicate pens belonging to each TRT-HT combination had temperature transponders inserted subcutaneous in the mid-dorsal region of the neck. All birds were brooded under standard commercial conditions and had ad libitum access to feed and water after their respective HT. The bt of the same birds were determined daily at the same time each day beginning at hatch and ending on 39 d of posthatch age (AGE). There were no significant main or interactive effects involving TRT or HT for bt. However, there was a significant (P ≤ 0.0001) main effect because of AGE. A general increase in bt occurred during the 39 d grow out period. At hatch, bt was 40.54 ± 0.056°C and at AGE 39 was 41.46 ± 0.055°C. Under standard brooding conditions, a general increase in bt occurred in the Ross 708 broilers. However, these birds did not exhibit a significant bt response to TRT or a 24HT before placement.

Bufonid toads generally possess cardiotoxic steroids called bufadienolides as defensive chemicals. Although knowledge of the life stages at which the toad species possess the poison is important for our understanding of diversity of toxicity among bufonid toads, this knowledge is limited. In the present study, we revealed that the Japanese common toad, Bufo japonicus formosus, possesses toxins at the unfertilized egg stage by conducting a bioassay experiment. Recent studies documented that hatchlings of B. j. formosus have lethal toxic effects on native frog tadpoles (Rana pirica) in the invasive area of the toad (Hokkaido). In our bioassay experiment using R. pirica tadpole as a predator, no tadpoles died when they did not consume any prey item during two-days experimental period. However, approximately 90% of R. pirica tadpoles immediately died when they consumed an unfertilized egg of B. j. formosus. These results suggest that the toxin at the early life stages of B. j. formosus is, at least partly, provided from female parent.

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.

The salinization of freshwaters due to the use of deicing road salts is a serious anthropogenic threat. We investigated the effects of the road deicer, which is mostly composed (ca. 70%) of NaCl, on the life cycle parameters of the cladoceran Moina macrocopa in acute and chronic toxicity tests and on the hatching success of resting eggs exposed to sediments contaminated with the road salt. The negative effects of the road salt on survival and life cycle parameters of animals were observed at concentrations above 5 g L−1. The 6-month exposure of resting eggs to contaminated sediments had a consistent but relatively weak effect on the postexposure hatching of resting eggs. Experiments demonstrated that the concentration of the deicer in the top water layer in the water-sediment systems is more important for the hatching success of resting eggs than the salt content in the sediment. Only 2.2 ± 1.9% of resting eggs hatched when the deicer content in the top water layer was equal to 12 g L−1. Lethal effects on hatchlings were observed starting from the deicer content in the water equal to 1 g L−1, and 97.0 ± 0.8% of hatchlings were dead at the deicer content in the water equal to 5 g L−1. Thus, the resilience of resting eggs to the contaminated sediments can ensure the replenishment of the population from the egg bank after the salinity disturbance is diminished but the negative effects of the elevated salt content in surface waters on active population will be manifested at lower salinities.

The development of the digestive system in the hatchling, especially in the critical stage of first feeding, is of great importance for rearing techniques of turtles. In the present study, the developments of intestinal histomorphology and microbiota during the first 30 days (0, 10, 20 and 30 days after hatched) of Chinese strip‐necked turtle (Mauremys sinensis) were investigated. The results showed that the height and width of intestinal villus and total length of intestine progressed with turtle's growth. The diversity of intestinal microbiota (Shannon and Simpson index) was no significant difference between first 30 days, but the richness indexes (Chao and Ace) significantly increased at 20 days after hatched. The phylum Firmicutes, Proteobacteria and Bacteroidetes dominated the turtle gut microbiota. The abundances of family Weeksellaceae, Aeromonadaceae, Cytophagaceae and Lachnospiraceae increased, whereas the family Ruminococcaceae decreased at 10 days after the first feeding. With turtle growing, the abundances of Bacteroidaceae and Methylobacteriaceae increased, which dominated at 30 days (28.49% and 22.08%, respectively). The order of Clostridiales and genus of Clostridium dominated in all the tested turtle samples in spite of the low abundance of environment including vermiculite, water and feed. Therefore, the members of Clostridium would be potential probiotic for turtles although future investigations should determine their roles in the turtle gut microbiota.