Time Of Hatching Research Articles

Effect of elevated carbon dioxide on chicken eggs during the early and late incubation periods

Carbon dioxide (CO2) is always maintained at ambient levels by ventilation in commercial egg incubators. However, elevated CO2 levels during the early and late periods have been reported to improve the quality of chicks and shorten the hatch window. This study investigated the effect of precise CO2 supplementation during the early and late periods of incubation on embryo growth and incubation performance by developing and using a CO2 supplementation system to increase the CO2 level in an experimental egg incubator. The CO2 level was maintained at 1% in the early period (from the beginning to the 10th day of incubation, E0–E10) and in the late period (from internal pipping (IP) to the 21st day of incubation (E21), IP–E21) in an incubator for the treatment group, whereas the CO2 level was maintained at the ambient level in the other incubators for the control group. A comparative assessment of embryonic development, hatching characteristics, and hormone and nutrient levels was conducted for each trial. The experiment comprised three trials, with 300 Jing Hong No. 1 breeding eggs in each incubator. The elevated CO2 treatment significantly shortened the chick hatching time (H0) by 4 h (P < 0.05) and the hatch window by 3 h (P < 0.05) without affecting hatchability, chick weight at 1 d of age, brooding period, or quality score. At external pipping (EP), the heart weight, intestinal weight, relative intestinal weight, and relative heart weight in the treatment group were significantly higher than those in the control group (P < 0.05). In addition, the embryonic intestine, relative intestine, and relative heart weights of the newly hatched chicks in the treatment group were significantly higher than those in the control group (P < 0.05) at H0. The treatment significantly increased the concentration of corticosterone in the embryonic plasma during the period from IP to EP (P < 0.05), promoted the secretion of triiodothyronine and tetraiodothyronine (P < 0.05), and increased the glycogen content of the embryonic liver on E21 (P < 0.05). This result indicates that elevated CO2 (1%) during the early and late periods of incubation accelerated embryonic organ development and shortened the chick hatching time and hatch window without affecting hatchability or hatchling quality, which can be explained by the synergistic functions of the secretion of plasma corticosterone and thyroid hormones and the accumulation of liver glycogen between the early and late periods of incubation.

The incubation of Tinfoil barb (Barbonymus schwanenfeldii) eggs using funnel system at different temperatures

Tinfoil barb (Barbonymus schwanenfeldii) is freshwater fish found in Borneo, Java, and Sumatera including in Aceh Province waters. It is known as a native species in Indonesia, locally known as Tengadak or Lampan and this species is popular for consumption due to its taste. Tinfoil barb is targeted species of inland water for fisheries production. In recent years, the fish population has declined because of overexploitation and habitat degradation. Therefore, this study aimed to analyze the effects of temperature on Tinfoil barb (B. schwanenfeldii) eggs incubation using a funnel system. It was conducted at Balai Benih Ikan (BBI) Lukup Badak, Central Aceh Regency. The Completely Randomized Design was used as a statistical analysis method with four treatments and three replications at 22±1 oC, 25±1 oC, 28±1 oC, and 31±1 oC. Hatching was carried out using a funnel system with 100 grain/liter of eggs density for incubation. The parameters measured were hatching time and rate, egg yolk absorption time, the survival rate of the embryo, larvae abnormality, and water quality. The ANOVA test results showed that temperature significantly affected hatching time and rate, egg yolk absorption time, and larvae abnormality (P0.05). In contrast, the effect was insignificant on the survival rate of an embryo, with P0.05. It is concluded that the optimum temperatures for Tinfoil barb eggs incubation were about 25±1 oC–31±1 oC. A funnel system was more effective for incubation than the conventional system.Keywords:Tinfoil barbFishIncubationTemperatureFunnel System

Research Note: Interaction between hatching time and chick pull time affects broiler live performance

This study investigated the effects of broiler chick hatching time and pull time on subsequent live performance. Hatching eggs were obtained from commercial broiler breeder flocks of Ross 308 at 29 and 30 wk of age in trials 1 and 2, respectively. Eggs were incubated in 2 identical setters on 2 consecutive days. In both trials, portion of the eggs (9,600), incubated on the first day of set, were assigned to delayed-pull (DP) treatment, and the other portion of the eggs (9,600), incubated on the second day of set, were assigned to normal-pull (NP) treatment. The hatching period was divided into 3 hatching time groups, and chicks were classified as hatching in the early (478 to 490 h), middle (490 to 496 h), or late period (496 to 510 h of incubation). At 510 h of incubation based on the NP set date, all chicks were transferred to a broiler research house. A total of 7,200 and 8,400 chicks within 2 chick pull time treatments × 3 hatching time groups were raised in trials 1 and 2, respectively. The primary difference between the DP and NP treatments was an additional 24 h holding period in the hatcher for the DP group. Therefore, chick BW was higher at placement in the NP treatment than in the DP treatment (P < 0.001). However, this advantage disappeared by 7 d, and the average BW did not differ between the DP and NP treatments at 41 d. Chick pull time did not affect feed consumption or feed conversion ratio (FCR) at 41 d. Similar to pull time, hatching time did not impact BW, feed consumption or FCR at 41 d. However, for mortality and European Production Efficiency Index (EPEI) at 41 d, a hatching time × pull time interaction was observed (P < 0.001). Mortality was higher and EPEI was lower in late hatch chicks than in chicks hatched early and middle in the NP treatment, whereas for chicks in the DP treatment, mortality and EPEI did not differ among the hatching time groups. These data indicated that the DP treatment, which held the chicks for an additional 24 h in the hatcher under optimum conditions, produced a lower initial BW accompanied by a period of compensatory weight gain through 41 d, and no differences (P > 0.05) in live performance occurred due to the holding time in the hatcher. Overall, sending the late hatched chicks to the broiler house shortly after hatching increased their mortality and negatively affected their live performance (as measured by EPEI), unlike holding early hatched chicks for a relatively long time after hatching (50 h) in the hatcher.

The function of glucose metabolism in embryonic diapause of annual killifish

Annual killifish could survive as diapaused embryos buried in soil during dry seasons. When the embryos in diapause III were incubated in water, the larvae could be hatched quickly. However, the mechanism of diapause and hatching of annual killifish was ambiguous. In the present study, Nothobranchius guentheri were used as the model to clarify the physiological mechanism of diapause and hatching of annual killifish. The results indicated that incubation with water could significantly enhance the heart rate and blood circulation of embryos. To clarify the molecular mechanism, the transcriptomic analysis was used to compare the embryos in diapause I, diapause III, and hatching period. The results showed that DNA replication-related genes, cell division cycle 45 and proliferating cell nuclear antigen were more highly expressed in diapause I compared to diapause III. In addition, the transcript levels of glucagon, glucokinase and phosphofructokinase were more abundantly detected in hatching period compared to diapause III, but insulin receptor and insulin-like growth factor-binding protein were lower. These results indicated glucose metabolism might play an important role in diapause and hatching of killifish. To further confirm this result, several reagents involved in glucose metabolism were used to incubate embryos in diapause III. The results displayed that glucose and glucagon could both shorten the hatching time of embryos. In contrast, 2-deoxy-d-glucose, metformin, and insulin could prolong the hatching time and reduce the hatching rate. The results further confirmed that glucose metabolism played an important role in the diapause and hatching of annual killifish.

Environmental relevant herbicide prometryn induces developmental toxicity in the early life stages of marine medaka (Oryzias melastigma) and its potential mechanism.

Triazine herbicides have been widely detected in marine environments because of their extensive usage in agriculture, but their impact on marine organisms is unclear. In this study, marine medaka (Oryzias melastigma) embryos were exposed to 0, 1, 10, 100, and 1000μg/L prometryn, one of the most detected triazine herbicides, to investigate its potential effects. The results showed that 1, 10, 100, and 1000µg/L prometryn not only induced yolk sac shrinkage and heart malformations, but also significantly delayed the hatching time and increased the heart rate and hatching failure rate of embryos. Moreover, 1, 10, 100, and 1000μg/L prometryn caused obvious malformations and decreased the body length of the newly hatched larvae. After 21 d of exposure, increased larval death rate, decreased body length and width, and higher lipid accumulation were observed in the larvae from all prometryn groups. Furthermore, prometryn exposure upregulated the expression levels of cardiac development-related genes GATA, COX, ATPase, SmyD1, EPO, FGF8, NKX2, and BMP4 in the larvae. Transcriptome analysis revealed that 10μg/L prometryn upregulated 604 genes, and the topmost pathways of differentially expressed genes were the complement and coagulation cascades and AMPK signaling pathways. qPCR results confirmed that prometryn exposure significantly increased the expression levels of the complement and coagulation cascade genes f2, f5, c3, and c5. This study demonstrated that environmentally relevant concentrations of prometryn induced significant toxicity in the early life stages of marine medaka. Therefore, the health risks of herbicides to marine organisms are of great concern.

Effects of in ovo feeding of disaccharide and/or methionine on hatchability, growth performance, blood hematology, and serum antioxidant parameters in geese.

A completely randomized design employing a 2 × 2 factorial experiment was designed in this study to evaluate the effects of in ovo injection of disaccharide (DS) and/or methionine (Met) on hatchability, growth performance, blood hematology, and serum antioxidant parameters in geese. A total of 600 fertilized geese's eggs containing live embryo were randomly assigned into 4 groups with 6 replicates and 25 eggs per replicate. Factors in four groups comprised noninjection, DS injection (25g/L maltose + 25g/L sucrose + 7.5g/L NaCl), Met injection (5g/L Met + 7.5g/L NaCl), or DS plus Met injection (25g/L maltose + 25g/L sucrose + 5g/L Met + 7.5g/L NaCl), respectively. We found that the administration of DS in embryo increased hatching time, yolk sac-free carcass weight, yolk sac-free carcass indexes and decreased assisted hatching ratio, yolk sac weight, yolk sac indexes, but did not affect hatchability and mortality. Moreover, higher body weight and serum glucose concentrations in DS injection group compared with noninjection group were observed on day of hatching. The body weight and average daily gain (ADG) of geese in DS injection group were higher than noninjection group after incubation. In ovo injection of Met increased hatching time and yolk sac-free carcass indexes, but decreased yolk sac indexes. In addition, the strategy of in ovo feeding of Met led to higher body weight, ADG, serum uric acid, glutathione (GSH), and glutathione peroxidase concentrations, as well as lower GSSG/GSH ratio, serum glutathione disulfide (GSSG), and malondialdehyde (MDA) concentrations than the noninjection group on day of hatching. The post-hatching body weight, ADG, serum total protein, albumin, and uric acid concentrations increased, whereas post-hatching serum GSSG and MDA concentrations and GSSG/GSH ratio decreased when injected with Met. In addition, synergistic effects of in ovo injection of DS plus Met on hatching time as well as post-hatching body weight and ADG were observed. Therefore, in ovo injection of DS plus Met was demonstrated to be a way to improve the development of geese during early incubation stages.

Metabolic responses to crude oil during early life stages reveal critical developmental windows in the zebrafish (Danio rerio)

Morphological effects of crude oil exposure on early development in fishes have been well documented, but crude oil's metabolic effects and when in early development these effects might be most prominent remains unclear. We hypothesized that zebrafish (Danio rerio) exposed to crude oil as a high energy water accommodated fraction (HEWAF) would show increased routine oxygen consumption (ṀO2) and critical oxygen tension (PCrit) and this effect would be dependent upon day of HEWAF exposure, revealing critical windows of development for exposure effects. Zebrafish were exposed to 0%, 10%, 25%, 50% or 100% HEWAF for 24 h during one of the first six days post-fertilization (dpf). Survival rate, body mass, routine ṀO2, and PCrit were then measured at 7 dpf. Survival rate and especially body mass were both decreased based on both exposure concentration and day of crude oil exposure, with the largest decrease when HEWAF exposure occurred at 3 dpf. HEWAF effects on routine ṀO2 also differed depending upon exposure day. The largest effect occurred at 3 dpf, when ṀO2 increased significantly by ~60% from 10.1 ± 0.8 μmol O2/g/h compared to control group value of 6.3 ± 0.4 μmol O2/g/h. No significant effects of HEWAF exposure on any day were evident for PCrit (85 ± 4 mmHg in the control population). Overall, the main effects on body mass and ṀO2 measured at 7 dpf occurred when HEWAF exposures occurred at ~3 dpf. This critical window for metabolism in zebrafish larvae coincides with time of hatching, which may represent an especially vulnerable period in development.

Hatching distribution, abundance, and losses to freshwater diversions of longfin smelt inferred using hydrodynamic and particle-tracking models

The distribution of larval fishes is influenced by where they hatch and their movements after hatching. In the San Francisco Estuary, the threatened longfin smeltSpirinchus thaleichthysspawns adhesive eggs in fresh to brackish water. Attached eggs hatch and the larvae disperse seaward toward higher-salinity water. Actual locations of spawning and hatching are unknown, and cannot reliably be inferred from distributions of larvae because intense tidal mixing obscures the history of movement. Human interventions such as manipulations and diversions of freshwater flow may contribute to the ongoing decline of this species, and these effects depend on where the fish hatch. We combined movement estimated using hydrodynamic and particle-tracking modeling with trawl data using a Bayesian model to estimate the location and timing of hatching, as well as natural mortality of larvae and losses to freshwater diversions. Results indicate that longfin smelt may hatch further seaward than previously believed, and that estimated direct losses due to diversions were small relative to other sources of mortality. Abundance of this species varies ~100-fold with freshwater flow, but our results suggest that proportional entrainment was practically zero during an extreme wet year and relatively low (2%) in a moderately dry year. This method could be applied to other estuarine and coastal systems where strong mixing reduces the ability of simpler models to predict hatching locations and larval movements.

Evaluation of Metal‐Organic Framework MIL-89 nanoparticles toxicity on embryonic zebrafish development

Metal-Organic Framework MIL-89 nanoparticles garnered remarkable attention for their widespread use in technological applications. However, the impact of these nanomaterials on human and environmental health is still limited, and concerns regarding the potential risk of exposure during manipulation is constantly rising. Therefore, the extensive use of nanomaterials in the medical field necessitates a comprehensive assessment of their safety and interaction with different tissues of the body system. In this study, we evaluated the systemic toxicity of nanoMIL-89 using Zebrafish embryos as a model system to determine the acute developmental effect. Zebrafish embryos were exposed to a range of nanoMIL-89 concentrations (1 – 300 µM) at 4 h post-fertilization (hpf) for up to 120 hpf. The viability and hatching rate were evaluated at 24–72 hpf, whereas the cardiac function was assessed at 72 and 96 hpf, and the neurodevelopment and hepatic steatosis at 120 hpf. Our study shows that nanoMIL-89 exerted no developmental toxicity on zebrafish embryos at low concentrations (1–10 µM). However, the hatching time and heart development were affected at high concentrations of nanoMIL-89 (> 30 µM). Our findings add novel information into the available data about the in vivo toxicity of nanoMIL-89 and demonstrate its innocuity and safe use in biological, environmental, and medical applications.

FUZZY CONTROLLER APPLIED TO TEMPERATURE ADJUSTMENT IN INCUBATION OF FREE-RANGE EGGS

Temperature variation in egg incubation can negatively affect the hatching time and weight gain of chicks, hence improving the incubator temperature accuracy can improve hatching rates. Controllers based on the fuzzy methodology have shown great potential for use in controlling incubator temperature variations. Therefore, the objective of this study is to develop and evaluate a fuzzy logic-based controller for egg incubation. Four identical incubators were configured: two with a fuzzy controller and two with a conventional controller. After evaluation and validation, a case study of the incubating eggs of free-range chickens was conducted on where 12 incubation cycles consisting of 20 eggs per incubator. The variables obtained include hatchability and electricity consumption. The results showed that the fuzzy logic-based controller maintained uniform internal temperature and a 10.68% saving on electricity usage when compared with the conventional controller. Thus, the fuzzy methodology has great potential for use in the incubation of free-range eggs.

Distribution and harmfulness of Mordellistena parvuliformis Beetle in the left Bank Steppe of Ukraine

Harmfulness and spread of a new dangerous pest of Mordellistena parvuliformis Stshegol.-Bar, 1930 have been recorded in the north-east of Ukraine. The results of researches of the reasons of occurrence, harmfulness and distribution of this dangerous pest of sunflower are generalized.&#x0D; It was found that the larvae of the sunflower Mordellistena parvuliformis from the diapause occur from the end of the third decade of April after feeding on dead stem tissue. Depending on the time of hatching, the presence of pupae is observed until the end of May. From the third decade of May, you can see the flight of adults and after a short additional feeding on flowering vegetation — the beginning of mating. Adult flight lasts a little more than 1.5 months — until the second decade of July. Embryonic development lasts about two weeks. The last eggs laid were observed in early August. From the second decade of June there was a revival of larvae, which are in an active state inside the stems until mid-September until the end of feeding and transition to a state of rest for further wintering. Thus, the development of one complete generation of toadstools per year is established.

The effects of temperature and salinity of hatchery water on early development of chum salmon (Oncorhynchus keta)

Chum salmon Oncorhynchus keta is the most abundant and industrially important salmonid in Japan, of which Japanese hatcheries release about 1.8 × 109 fry annually. However, recent global warming and earthquake-induced crustal movement might have changed hatchery water environments. To sustainably maintain and operate hatcheries in Japan, we report the effects of rearing water temperature and salinity on the early development of chum salmon derived from the Chitose River. Effects are evaluated in terms of eyed-egg (Eer), hatching (Htr), and survival (Sur) rates, alevin body size, and the quality of the egg envelope. Fertilized eggs were reared in groundwater (GW) at different temperatures (4, 7, 10, 13, 16 °C). Alevin reared at 4 °C were larger but had less yolk, while those reared at 16 °C were smaller but hatched precociously. A significant decrease in Htr and Sur was observed in the 4 °C treatment, which we regard to be because of the small amount of residual egg yolk at the time of hatching. Eggs were also fertilized in GW or different concentrations of brackish groundwater (BGW 0.5, 1.0, 2.1, 4.1, 8.3 psu), and continuously reared under the same salinity conditions at fertilization. Those BGW treatments at 1.0 and 2.1 psu had much lower Htr values than those reared in GW and salinities of 0.5 psu, despite their having a comparable Eer. Mortality in BGW treatments of 1.0 and 2.1 psu occurred during hatching, because of precocious hatching. No change in egg membrane proteins occurred after fertilization in 4.1 and 8.3 psu treatments, and embryos did not develop to an eyed-egg stage. These results suggest that constant temperatures of 4 and 16 °C, and salinities exceeding 1.0 psu during fertilization can prevent or interfere with the normal early development of chum salmon eggs and larvae in the Chitose River. To avoid the adverse effects of salination, fertilization with GW and hardening of the egg envelope effectively increase Sur dramatically, even after transfer to BGW.

PERKEMBANGAN EMBRIO DAN PERFORMA AWAL LARVA IKAN TENGADAK (Barbonymus schwanennfeldii)

This experiment was conducted from May 2021 – September 2021 at the Freshwater Fishery Germplasm Research Installation in Cijeruk, Bogor, West Java. This study aimed to determine the stages of embryonic development and early larval performance that occurred in Tengadak fish (Barbonymus schwanenfeldii). This experimental study used two female fish, two male fish, and anaesthetic drugs. Parameters observed included observation of embryos and early performance of squirrelfish larvae. The embryo data were analyzed in a qualitative descriptive manner with pictures of each egg development phase and then data on egg hatching time. The results showed that the early development of the embryo in trout generally includes cleavage stages, morula, blastula (blastoderm formation), gastrula (closure of the yolk sac), segmentation and hatching. The initial performance of the scorpion fish larvae reared at a temperature of 28oC showed an abnormality value of 5.7±2.5%. The average diameter of the egg yolks of the tee-fish was 39.42±4.41 µm, and the average initial length of the trout larvae was 18.46±1.32 µm.

Dormant plasticity of rotifer diapausing eggs in response to predator kairomones.

In freshwater ecosystems, hatching strategy of diapausing eggs (DEs) under predation risk has important ecological implication for zooplankters. Although kairomones released by predators can induce phenotypic responses of prey, hatching patterns of DEs in response to kairomones have received contradictory conclusions in zooplankters. Maternal environment may also affect hatching strategy of DEs during predator-prey interactions. We used classical Brachionus calyciflorus-Asplanchna models to determine the timing and proportion of DE hatching in association with parental and embryonic exposure to kairomones. Results obtained from two Brachionus clones supported the hypothesis that DEs could detect Asplanchna kairomones and adjust hatching patterns. DEs showed early and synchronous hatching patterns in the environment with kairomones. Data also supported the prediction that DEs could gain information about predators from maternal environments and adjusted their hatching pattern in response to the presence of kairomones. Compared with DEs from Brachionus mothers not exposed to kairomones, DEs produced by mothers that were experienced with kairomones attained a higher hatching rate when both of them hatched in the environment either with or without kairomones. Our results suggest that DEs of B. calyciflorus possess dormant plasticity to defend against predation from Asplanchna, which may be regulated by maternal environmental effects during sexual life cycles.

Ontogeny of eDNA shedding during early development in Chinook Salmon (Oncorhynchus tshawytscha)

AbstractKnowledge of the timing of major life history events in aquatic species is important for informing conservation and resource management planning. Accordingly, surveys of environmental DNA (eDNA) have been performed to determine the efficacy of eDNA for providing information on life history events, primarily focusing on the timing of events associated with spawning, and these studies have proved successful. However, spawning represents only one part of the life history, and therefore, information on eDNA shedding during other life history stages is needed to fill gaps in knowledge. Here, we explored eDNA shedding during early life history (from fertilized eggs until near yolk sac absorption) in Chinook Salmon (Oncorhynchus tshawytscha) at three biomasses in a laboratory environment. We found that fertilized eggs shed little eDNA prior to hatching. Hatching coincided with a spike in eDNA, and we observed a significant and positive relationship between eDNA concentration and the number of hatched eggs. The concentration of eDNA shed by larvae after hatching was not consistent across post‐hatch sampling days, suggesting developmental and behavioral changes associated with larval ontogeny may affect eDNA shedding rate. These results indicate that eDNA data may be used to identify hatch timing and verify successful reproduction in oviparous aquatic fishes. The application of eDNA to early life history broadens the capacity of eDNA‐based methods for assessing population status and trends.

Species' traits and taxonomic distance can predict the hatching phenology of ostracod (Crustacea) resting eggs from tropical floodplain lakes

AbstractFreshwater ostracods are commonly found in temporary ponds and lakes, surviving drought periods by producing resting eggs. We investigated the hatching phenology of ostracod resting eggs from the sediments of temporary floodplain lakes, considering both the taxonomic distance between species and their functional traits, such as carapace size (length and height) and shape, valve ornamentation, and reproductive mode. In addition, we tested the hypotheses: (1) that the hatching time is more similar between congeneric ostracod species than between noncongeneric species; (2) that differences in hatching time between congeneric species are often related to differences in functional traits; (3) that both species composition and functional traits composition of hatchlings change over the incubation time, but with a reduction in the variability over time. The experiment was conducted for 98 days in the laboratory, and the microcosms were monitored weekly. The first hatching of an ostracod was recorded during the second week of incubation after hydration of the sediments. A total of 12 ostracod species hatched, belonging to the families Cyprididae and Candonidae. The above three hypotheses were corroborated. The time between inundation and first hatching was mostly similar for congeneric species in the genus Chlamydotheca, but was different between some species of Strandesia, which might be owing to differences in functional traits. The species composition and functional trait composition of the hatched ostracods were significantly different over the 14 weeks of incubation due to the different hatching phenology of different species. Furthermore, our results show that both taxonomic distance and functional traits can influence the hatching time of ostracod resting eggs from temporary floodplain lakes. Thus, future studies addressing the hatching phenology of ostracod resting eggs (and resting stages from other invertebrates) should also emphasize the use of functional traits.

Taxonomic and genetic confirmed findings of snow crab (Chionoecetes opilio) larvae in the Barents Sea

The snow crab (Chionoecetes opilio) is an Arctic cold-water species native to the northwestern Atlantic Ocean and the northern Pacific Ocean. During the recent decades, a population has established in the Barents Sea. Several aspects of the snow crabs’ biology in this area have not been described, including time of hatching, intermoult duration of the different larval stages and larval distribution. Insight into the early-life stages might increase the understanding of the population's dynamics and further spreading in the Barents Sea as well as inform basis for making monitoring and management decisions. The present study investigated the presence and developmental stage of snow crab larva in plankton samples obtained in the central Barents Sea during a research survey in June and July 2019. Presence of snow crab larvae was confirmed through taxonomic and genetic identification. All larvae were identified as zoea I, which gives an indication of the timing of the hatching period. Morphological measurements coincide well with those reported in studies from the species native distribution range. No larvae of native Hyas spp. were found and overlap in temporal and spatial distribution is discussed. The study provides important information for development of further research into the biology of the snow crab in the Barents Sea.

A histological survey of avian post-natal skeletal ontogeny.

Bone histology of crown-group birds is a research topic of great interest, permitting insight into the evolution of remarkably high growth rates in this clade and variation across the altricial-precocial spectrum. In this study, we describe microanatomical characteristics of the humerus and femur in partial growth series from 14 crown group birds representing ten major clades (Struthioniformes, Galliformes, Apodiformes, Columbiformes, Charadriiformes, Accipitriformes, Strigiformes, Psittaciformes, Falconiformes, and Passeriformes). Our goals were to: (1) describe the microanatomy of each individual; (2) make inter-and intra-taxonomic comparisons; (3) assess patterns that correspond with developmental mode; and (4) to further parse out phylogenetic, developmental, and functional constraints on avian osteological development. Across taxa, the femoral and humeral tissue of neonates can be broadly characterized as highly-vascularized, disorganized woven bone with great variation in cortical thickness (inter-and intrataxonomically, within an individual specimen, and within a single section). The tissue of precocial chicks is relatively more mature at hatching than in altricial, but other categories along the developmental spectrum were less easy to distinguish, thus we were unable to identify a definitive histological proxy for developmental mode. We did not find evidence to support hypotheses that precocial chicks exclusively have thicker cortices and more mature bone in the femur than the humerus at time of hatching; instead, this is a characteristic of nearly all taxa (regardless of developmental mode), suggesting deep evolutionary origins and the effects of developmental channeling. Bone tissue in adults exhibited unexpected variation, corresponding to differences in body size. Large-bodied birds have cortices of fibrolamellar bone, but organization of tissue increases and vascularity decreases with diminishing body size. The outer circumferential layer (OCL) also appears at earlier growth stages in small-bodied taxa. Thus, while the OCL is indicative of a cessation of appositional growth it is not always indicative of cortical maturity (that is, maximum organization of bony tissue for a given taxon). Small size is achieved by truncating the period of fast growth; manipulation of the timing of offset of bone growth is therefore an important factor in changing growth trajectories to alter adult body size.

Effects of Soil Temperature and Moisture on the Development and Survival of Grasshopper Eggs in Inner Mongolian Grasslands

Grasshopper eggs overwinter in soil for almost half a year. Changes in soil temperature and moisture have a substantial effect on grasshopper eggs, especially temperature and moisture extremes. However, the combinatorial effect of temperature and moisture on the development and survival of grasshopper eggs has not been well studied. Here, we examined the effects of different soil moistures (2, 5, 8, 11, 14% water content) at 26°C and combinations of extreme soil moisture and soil temperature on the egg development and survival of three dominant species of grasshopper (Dasyhippus barbipes, Oedaleus asiaticus, and Chorthippus fallax) in Inner Mongolian grasslands. Our data indicated that the egg water content of the three grasshopper species was positively correlated with soil moisture but negatively correlated with hatching time. The relationship between hatching rate and soil moisture was unimodal. Averaged across 2 and 11% soil moisture, a soil temperature of 35oCsignificantly advanced the egg hatching time of D. barbipes, O. asiaticus, and C. fallax by 5.63, 4.75, and 2.63 days and reduced the egg hatching rate of D. barbipes by 18%. Averaged across 26 and 35°C, 2% soil moisture significantly delayed the egg hatching time of D. barbipes, O. asiaticus, and C. fallax by 0.69, 11.01, and 0.31 days, respectively, and decreased the egg hatching rate of D. barbipes by 10%. The hatching time was prolonged as drought exposure duration increased, and the egg hatching rate was negatively correlated with drought exposure duration, except for O. asiaticus. Overall, the combination of high soil temperature and low soil moisture had a significantly negative effect on egg development, survival, and egg hatching. Generally, the response of grasshopper eggs to soil temperature and moisture provides important information on the population dynamics of grasshoppers and their ability to respond to future climate change.

Pre-fertilization exposure of sperm to nano-sized plastic particles decreases offspring size and swimming performance in the European whitefish (Coregonus lavaretus)

Exposure of aquatic organisms to micro- and nano-sized plastic debris in their environment has become an alarming concern. Besides having a number of potentially harmful impacts for individual organisms, plastic particles can also influence the phenotype and performance of their offspring. We tested whether the sperm pre-fertilization exposure to nanoplastic particles could affect offspring survival, size, and swimming performance in the European whitefish Coregonus lavaretus. We exposed sperm of ten whitefish males to three concentrations (0, 100 and 10 000 pcs spermatozoa−1) of 50 nm carboxyl-coated polystyrene spheres, recorded sperm motility parameters using computer assisted sperm analysis (CASA) and then fertilized the eggs of five females in all possible male-female combinations. Finally, we studied embryonic mortality, hatching time, size, and post-hatching swimming performance of the offspring. We found that highest concentration of plastic particles decreased sperm motility and offspring hatching time. Furthermore, sperm exposure to highest concentration of plastics reduced offspring body mass and impaired their swimming ability. This suggests that sperm pre-fertilization exposure to plastic pollution may decrease male fertilization potential and have important transgenerational impacts for offspring phenotype and performance. Our findings indicate that nanoplastics pollution may have significant ecological and evolutionary consequences in aquatic ecosystems.