Do amphibious crabs have amphibious eggs? A case study of Armases miersii

The female reproductive cycles of the calanoid copepod Copidodiaptomus numidicus and the cyclopoid Acanthocyclops robustus were characterized by periodic changes in the oviducts. Females oscillated between a gravid and a non-gravid condition, and the whole cycle was strongly dependent on temperature. In both species, the maturation of new oocytes took place when the old egg sacs were still being carried, thus ensuring a rapid clutch succession. The embryonic and post- embryonic development duration of C.numidicus and A.robustus was investigated at five and four different temperatures, respectively. Embryonic development time was related to oviductal cycle duration at each temperature to estimate the minimum amount of non-ovigerous females expected under non-limiting mate and food conditions. Copidodiaptomus numidicus females spent 35-19% of the cycle without carrying eggs at 7-20°C. Acanthocyclops robustus females spent 31-33% of the cycle without carrying eggs at the same temperature interval. Both naupliar and copepodid durations were inverse functions of temperature with nauplii developing at a faster rate than copepodids. In general, A.robustus showed reproductive advantage over C.numidicus due to a faster oviductal cycle and shorter embryonic and post-embryonic development times. However, the influence of food quality may be crucial. Acanthocyclops robustus copepodid development time may lengthen well beyond the corresponding development stages of C.numidicus when growing only on algae. This retardation of development affects especially the later development stages of the cyclopoid.

The relationships of generation time to both adult body mass and temperature are critical to our understanding of numerous aspects of zooplankton behavior, ecology and evolution, yet these relationships remain poorly understood. Here, I use a meta-analysis to define the relationship of generation time to body mass and temperature for both marine and freshwater zooplankton species (rotifers, copepods and cladocera), for temperatures from 5–20°C. I also define a relationship for the constituent parts of generation time (embryonic and postembryonic development time) as a function of egg and body mass for zooplankton across this temperature range. These relationships provide powerful tools for evaluating differences in generation time between individual zooplankton species.

Purpose: Determine the relationship between the duration of embryonic and larval development of pink salmon (Oncorhynchus gorbuscha) under different temperature regimes and the timing of downstream migration of their juveniles. Research Material: Multiyear average daily data on water temperature and condition of pink salmon embryos and larvae bred in commercial volumes at the Kurilsky (Iturup Island), Lesnoy and Pugachevsky (Eastern Sakhalin) salmon hatcheries. Methods used: Comparative data analysis, descriptive statistics methods.Results: The known facts about changes in the timing of embryonic development in relation to water temperature were confirmed: The duration of the interval between the dates of hatching of embryos in the first and last batches developed under different thermal conditions was 2.5 times longer than the interval between the dates of fertilization of eggs from these batches. The extension of the embryonic development period in the last batches was accompanied by a shortening of the subsequent development period until the fry were ready to swim, which reduced the difference in the duration of development from egg fertilization to fry swimming at different temperatures. This process is not only associated with different hatching times and slowed development in the winter period. The identified peculiarities in the changes in the duration of intermediate developmental stages under different temperature regimes suggest that fry developing in colder water goes afloat as less developed. Such regulation of the total duration of embryonic and larval development of pink salmon provides mass migration of its juveniles from rivers in the average annual terms of mass development of zooplankton in the coastal sea. Practical Significance: The presented article is a scientific accompaniment of the monitoring of pink salmon juvenile downstream migration in order to forecast changes in the stocks of this species of Pacific salmon.

Embryonic development times and the stage at which embryonic diapause occurs varied dramatically among 23 populations of the Melanoplus sanguinipes/ devastator species complex in California, USA. Grasshoppers were collected from a wide range of latitudes (32°57N to 41°20N) and altitudes (10m to 3031 m), spanning much of the variation in climatic conditions experienced by these insects in California. When reared in a "common garden" in the laboratory, total embryonic development times were positively correlated to the mean annual temperature of the habitat from which the grasshoppers were collected (varying from about 19 days to 32 days when reared at 27°C). These grasshoppers overwinter as diapausing eggs and the proportion of embryonic development completed prior to diapause was significantly higher in populations collected from cool habitats (>70%) than in populations collected from warm environments (<26%). The length of pre-diapause development time is determined by the stage of embryonic development at which diapause occurs, and varies considerably among populations of these grasshoppers; grasshoppers from warmer environments tend to diapause at very early stages of embryogenesis, while grasshoppers from cooler environments diapause at very late stages. The combined effect of variation in embryonic development times and variation in the stage at which diapause occurs results in a dramatic reduction in the time needed to hatch in the spring; populations from warm environments required up to 20 days (at 27°C) to hatch while populations from cool environments required as few as 5 days to complete embryonic development prior to hatching. Egg size also varied significantly among populations, but tended to be larger in populations with shorter embryonic development times. Significant family effects were observed for development time and stage of diapause, suggesting significant heritabilities for these traits, although maternal effects may also contribute to family level variation. We interpret these findings to support the hypothesis that embryonic development time and the stage of embryonic diapause have evolved as adaptations to prevailing season lengths in the study populations.

Parthenogenesis is documented in a few species of Amblypygi, but it is unknown how widespread in the order this reproductive behaviour is, and little has been researched regarding aspects of embryonic and post-embryonic development in the group. Here, we studied the parthenogenetic capacity of an Amazonian whip spider (Charinus guto) evaluating the time of egg and embryonic development and inter-moult period. We also provide a review on embryonic and post-embryonic development in Amblypygi, compiling and analysing data from 43 species in three families. Fifty-two females and 42 juveniles of C. guto were collected in fragments of a secondary forest in Belém (Brazil); specimens were kept in captivity and observed weekly from 2018 to 2020. Nineteen specimens were collected with and 32 without egg sacs. Fourteen of the non-ovigerous females developed eggs in captivity, six of them moulted (i.e. lost stored sperm from previous contacts with males) before developing an egg sac, proving to be parthenogenetic. The mean time between the first day in captivity and moult was 96 days. In both adults and juveniles, a mean of 147 days passed between first day in captivity and first moult, and 125 days for a second moult. After moulting, a mean of 113 days passed for the females to develop an egg sac; the embryonic development took a mean of 59 days. Juveniles left the mother’s abdomen after 10 days of hatching from the egg and the mean number of live free-living protonymphs was five. Other amblypygids, especially charinids, have similar embryonic development and post-embryonic growth and a detailed discussion with all known information for whip spiders is presented. We also demonstrate a positive correlation between clutch size and female size across Amblypygi, in which larger females carry more eggs and have larger offspring regardless of climate and habitat.

Gills are the primary organ for salt transport, but in land crabs they are removed from water and thus ion exchanges, as well as CO(2) and ammonia excretion, are compromised. Urinary salt loss is minimised in land crabs by redirecting the urine across the gills where salt reabsorption occurs. Euryhaline marine crabs utilise apical membrane branchial Na(+)/H(+) and Cl(-)/HCO(3)(-) exchange powered by a basal membrane Na(+)/K(+)-ATPase, but in freshwater crustaceans an apical V-ATPase provides for electrogenic uptake of Cl(-) in exchange for HCO(3)(-). The HCO(3)(-) is provided by carbonic anhydrase facilitating CO(2) excretion while NH(4)(+) can substitute for K(+) in the basal ATPase and for H(+) in the apical exchange. Gecarcinid land crabs and the terrestrial anomuran Birgus latro can lower the NaCl concentration of the urine to 5 % of that of the haemolymph as it passes across the gills. This provides a filtration-reabsorption system analogous to the vertebrate kidney. Crabs exercise hormonal control over branchial transport processes. Aquatic hyper-regulators release neuroamines from the pericardial organs, including dopamine and 5-hydroxytryptamine (5-HT), which via a cAMP-mediated phosphorylation stimulate Na(+)/K(+)-ATPase activity and NaCl uptake. Freshwater species utilise a V-ATPase, and additional mechanisms of control have been suggested. Crustacean hyperglycaemic hormone (CHH) has now also been confirmed to have effects on hydromineral regulation, and a putative role for neuropeptides in salt and water balance suggests that current models for salt regulation are probably incomplete. In a terrestrial crabs there may be controls on both active uptake and diffusive loss. The land crab Gecarcoidea natalis drinking saline water for 3 weeks reduced net branchial Na(+) uptake but not Na(+)/K(+)-ATPase activity, thus implying a reduction in diffusive Na(+) loss. Further, in G. natalis Na(+) uptake and Na(+)/K(+)-ATPase were stimulated by 5-HT independently of cAMP. Conversely, in the anomuran B. latro, branchial Na(+) and Cl(-) uptake and Na(+)/K(+)-ATPase are inhibited by dopamine, mediated by cAMP. There has been a multiple evolution of a kidney-type system in terrestrial crabs capable of managing salt, CO(2) and NH(3) movements.

Larval growth and survival of Echinometra lucunter (Echinoidea: Echinometridae) fed with microalgae Chaetoceros gracilis and Isochrysis galbana. Thirty sexually mature sea urchins (Echinometra lucunter; diameter 45.8 ± 17.5 mm) were collected at Macanao, Margarita Island, Venezuela (11°48’29” N / 64°13’10” W). They were injected potassium chloride (50 M) directly into the celomic cavity. After two minutes 90% spawned (17 females and 10 males), the others never spawned. Fertilization was 87.0 ± 12.6% (1:100 oocytes/sperm) at 29 ± 2ºC. The fertile eggs were placed in three treatment gropsu with nine containers (18 liters; 2 eggs/ml) each, all with bottom aeration. Treatments were: Chaetoceros gracilis; Isochrysis galbana, and a mixture of both microalgae (respectively: 20 000 and 60 000 cell/ml for each microalgae, 1:1 for the mixture). Salinity, pH, temperature and larval survival were determinated daily. The study ended when the post-metamorphic phase was completed. The embryonic development time was 16.3 ± 0.2 h until the prism stage at pH 8.4 ± 0.1; 38 ± 1 psu and 28 ± 1.4°C. The two-arms larval stage was reached at 24 h: 33 min, with a total length of 190 ± 16.3 μm fed on C. gracilis, 152 ± 19.0 μm with I. galbana and 182.4 ± 14.1 μm with the mixture. The larvae next to metamorphosis reabsorbed the arms and had the characteristic shape of juvenile urchins at 12 days with 670.2 ± 22.2 μm fed on C. gracilis, 665 ± 12.1 μm fed on I. galbana and 670 ± 14.1 μm fed on the mixture. The accumulated survival to the juvenile stage was 14.7 ± 3.8% when fed on C. gracilis, higher than the other treatments (5.4 ± 1.2; 14.0 ± 2.6). E. lucunter is an excellent prospect to be commercially cultured because of its short embryonic (16 hours) and larval development time (12 days) and good survival rate when fed on monoculture (C. gracilis and I. galbana) or mixed diet (we recommend C. gracilis). Rev. Biol. Trop. 53(Suppl. 3): 337-344. Epub 2006 Jan 30.

Ontogeny of urea and ammonia transporters in mahi-mahi (Coryphaena hippurus) early life stages

Male and female embryos differ in their response to oxygen concentration

To determine whether the crustacean Rh1 protein functions as a dual CO2 /ammonia transporter and investigate its role in branchial ammonia excretion and acid-base regulation. Sequence analysis of decapod Rh1 proteins was used to determine the conservation of amino acid residues putatively involved in ammonia transport and CO2 binding in human and bacterial Rh proteins. Using the Carcinus maenas Rh1 protein (CmRh1) as a representative of decapod Rh1 proteins, we test the ammonia and CO2 transport capabilities of CmRh1 through heterologous expression in yeast and Xenopus oocytes coupled with site-directed mutagenesis. Quantitative PCR was used to assess the distribution of CmRh1 mRNA in various tissues. Western blotting was used to assess CmRh1 protein expression changes in response to high environmental ammonia and CO2 . Further, immunohistochemistry was used to assess sub-cellular localization of CmRh1 and a membrane-bound carbonic anhydrase (CmCAg). Sequence analysis of decapod Rh proteins revealed high conservation of several amino acid residues putatively involved in conducting ammonia transport and CO2 binding. Expression of CmRh1 in Xenopus oocytes enhanced both ammonia and CO2 transport which was nullified in CmRh1 D180N mutant oocytes. Transport of the ammonia analog methylamine by CmRh1 is dependent on both ionized and un-ionized ammonia/methylamine species. CmRh1 was co-localized with CmCAg to the apical membrane of the crustacean gill and only experienced decreased protein expression in the anterior gills when exposed to high environmental ammonia. CmRh1 is the first identified apical transporter-mediated route for ammonia and CO2 excretion in the crustacean gill. Our findings shed further light on the potential universality of dual ammonia and CO2 transport capacity of Rhesus glycoproteins in both vertebrates and invertebrates.

Study question Does embryo culture media affect gender at birth and why? Summary answer More male children were born after culture in the Sage 1-Step media compared to the G-TL media. What is known already ART increases the proportion of male children at birth. Laboratory techniques and culture conditions is known to impact secondary sex ratio (SSR). Physiological development differs in male and female embryos, leading to different metabolic requirements at the preimplantation stage. The composition of commercial culture medias varies and thus, the different medias may have different impact on embryo development and quality according to gender. This, in turn, may influence SSR, as embryos are selected based on morphological scoring systems and developmental speed. Study design, size, duration The study was designed as a retrospective registry-based study with all data collected at a single clinic. All embryos resulting in live birth from frozen and fresh single blastocyst transfers, in the period from 1. January 2017 to 31. December 2020 were included. Donor embryos and embryos cultured in more than one culture media were excluded. A total of 1371 SET embryos were included. Participants/materials, setting, methods Embryos were cultured in either the G-TL media, Vitrolife (n = 686) or the Sage 1-Step media, Origio (n = 685). All embryos were monitored for 5-6 days in a time-lapse incubator, Vitrolife, before single blastocyst transfer. Multivariate logistic analysis of cycle and embryo characteristics was performed to identify all factors associated to sex. The association between culture media and embryo morphokinetic according to sex was evaluated using a mixed model analysis. Main results and the role of chance Significantly more male singletons were born after culture in 1-Step media compared to G-TL media (risk ratio (RR) 1,1 95% CI [1,0, 1,3], P = 0,01). The female/male ratio was 42,3/57,7% in 1-Step media and 48,5/51,5% in G-TL media. The multivariate regression analysis displayed a higher chance of a male child with higher expansion grade (grade 5) (RR, 1,2 95% CI [1,0, 1,4] P = 0,04), lower inner cell mass grade (grade B) (RR 1,13 95% CI [1,0, 1,3] P = 0,02) and second embryo transfer (RR 1,2 95% CI [1,0, 1,3] P = 0,03). Trophectoderm (TE) grade B reduced the probability of male child compared with TE grade A (RR 0,8 95% CI [0,8, 0,9] P &amp;gt; 0,05). Male embryos developed significantly faster in the 1-Step media compared to the G-TL media for the stages of; blastocyst (tB) (-1,1 hours 95% CI [-2,1, -0,1]), expanded blastocyst (tEB) (-1,3 hours 95% CI [-2,3, -0,3]) and hatched blastocyst (tH) (-1,7 hours 95% CI [-3,0, -0,5]). Timing of development were the same for female embryos in the G-TL media compared to the 1-Step media. There was no significant difference in timing of development between female and male embryos in identical culture media. Limitations, reasons for caution This study was a retrospective study with data collection from only a single clinic, and as such in risk of confounding. Apart from culture media, culture conditions were similar during the two time periods. Paternal factors and type of infertility was not included. Wider implications of the findings Our observations suggest that culture media impact male embryo quality selectively, thus favoring selection of male embryos. As the impact appears to vary between different culture media, and has a measurable impact on gender after birth, the influence of culture media on embryo quality deserves more attention. Trial registration number not applicable

Embryonic development time is thought to impact life histories through trade-offs against life-history traits later in life, yet the inference is based on interspecific comparative analyses only. It is largely unclear whether intraspecific variation in embryonic development time that is not caused by environmental differences occurs, which would be required to detect life-history trade-offs. Here we performed a classical common-garden experiment by incubating fresh eggs of free-living common terns (Sterna hirundo) in a controlled incubation environment at two different temperatures. Hatching success was high but was slightly lower at the lower temperature. While correcting for effects of year, incubation temperature, and laying order, we found significant variation in the incubation time embryos required until hatching and in their heart rate. Embryonic heart rate was significantly positively correlated within clutches, and a similar tendency was found for incubation time, suggesting that intrinsic differences in embryonic development rate between offspring of different parents exist. Incubation time and embryonic heart rate were strongly correlated: embryos with faster heart rates required shorter incubation time. However, after correction for heart rate, embryos still required more time for development at the lower incubation temperature. This suggests that processes other than development require a greater share of resources in a suboptimal environment and that relative resource allocation to development is, therefore, environment dependent. We conclude that there is opportunity to detect intraspecific life-history trade-offs with embryonic development time and that the resolution of trade-offs may differ between embryonic environments.

Embryonic development and larval cultivation of Paphia schnelliana (Dunker), a unique economic species of the Beibu Gulf

Summary Body size scaling relationships allow biologists to study ecological phenomena in terms of individual level metabolic processes. Recently, dynamic energy budget (DEB) theory has been shown to offer novel insights on the effect of body size on biological rates. We test whether DEB theory and its unique partitioning of biomass into reserve and structural components can explain the effect of egg size on hatch time and the time course of respiration in insect embryos. We find that without any parameterization (calibration), DEB theory is able to predict hatch time for eggs sizes spanning four orders of magnitude from fundamental biological processes. We find, however, that the standard DEB model poorly predicts the time course of respiration, particularly in early embryonic development where a strong effect of egg size is observed. Further, we show that other theoretical models also poorly predict early embryonic respiration. By modifying the assumption that a fresh egg is entirely reserve, we show that embryonic respiration and hatch time can be better predicted by the DEB model. Useful theories in metabolic ecology, such as DEB theory, can help explain universal scaling patterns in development times. However, simple theoretical models must be expanded if they are to capture the scaling of metabolic rate in insect eggs. A Lay Summary is available for this article.

Trichostatin A (TSA) induces histone hyperacetylation by inhibiting histone deacetylases and consequently increasing gene expression. The hypothesis was that TSA supplementation during the in vitro culture (IVC) of bovine embryos would increase the blastocyst rate, particularly in low-quality and female embryos. Oocytes were fertilised separately with X and Y spermatozoa and, 70 h after IVF, the IVC medium was supplemented with 5 nM and 15 nM TSA for 48 or 144 h. Incubation of female embryos with 5 nM and 15 nM TSA resulted in similar increases in acetylated histone H3K9 levels. However, to see comparable effects on acetylated histone H3K9 levels in male embryos, the culture medium needed to be supplemented with 15 nM TSA (as opposed to 5 nM TSA for female embryos). Treatment of male and female embryos with 5 nM TSA for 48 h or female embryos with 5 nM for 144 h had no effect on blastocyst rates, although 15 nM TSA compromised embryonic development. The terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assay revealed increased apoptosis in female embryos treated with 5 nM TSA for 144 h, as well as in male and female embryos treated with 15 nM TSA for 48 h, but this increase in apoptosis was not observed in low-quality embryos. The results of the present study suggest that TSA treatment promotes histone hyperacetylation, but has no beneficial effects on the in vitro production of male and female bovine embryos during preimplantation development.