Juvenile Body Research Articles

Toward a physiological explanation of juvenile growth curves

AbstractJuvenile growth curves are generally sigmoid in shape: Growth is initially nearly exponential, but it slows to near zero as the animal approaches maturity. The drop‐off in growth rate is puzzling because, everything else being equal, selection favors growing as fast as possible. Existing theory posits sublinear scaling of resource acquisition with juvenile body mass and linear scaling of the requirement for maintenance, so the difference, fuel for growth, decreases as the juvenile increases in size. Experimental evidence, however, suggests that maintenance metabolism increases sublinearly not linearly with size. Here, we develop a new theory consistent with the experimental evidence. Our theory is based on the plausible assumption that there is a trade‐off in the capacity of capillaries to supply growing and developed cells. As the proportion of non‐growing cells increases, they take up more macromolecules from the capillaries, leaving fewer to support growing cells. The predicted growth curves are realistic and similar to those of previous models (Bertalanffy, Gompertz, and Logistic) but have the advantage of being derived from a plausible physiological model. We hope that our focus on resource delivery in capillaries will encourage new experimental work to identify the detailed physiological basis of the trade‐off underlying juvenile growth curves.

Exposure to exogenous egg cortisol does not rescue juvenile Chinook salmon body size, condition, or survival from the effects of elevated water temperatures.

Climate change is leading to altered temperature regimes which are impacting aquatic life, particularly for ectothermic fish. The impacts of environmental stress can be translated across generations through maternally derived glucocorticoids, leading to altered offspring phenotypes. Although these maternal stress effects are often considered negative, recent studies suggest this maternal stress signal may prepare offspring for a similarly stressful environment (environmental match). We applied the environmental match hypothesis to examine whether a prenatal stress signal can dampen the effects of elevated water temperatures on body size, condition, and survival during early development in Chinook salmon Oncorhynchus tshawytscha from Lake Ontario, Canada. We exposed fertilized eggs to prenatal exogenous egg cortisol (1,000 ng/ml cortisol or 0 ng/ml control) and then reared these dosed groups at temperatures indicative of current (+0°C) and future (+3°C) temperature conditions. Offspring reared in elevated temperatures were smaller and had a lower survival at the hatchling developmental stage. Overall, we found that our exogenous cortisol dose did not dampen effects of elevated rearing temperatures (environmental match) on body size or early survival. Instead, our eyed stage survival indicates that our prenatal cortisol dose may be detrimental, as cortisol‐dosed offspring raised in elevated temperatures had lower survival than cortisol‐dosed and control reared in current temperatures. Our results suggest that a maternal stress signal may not be able to ameliorate the effects of thermal stress during early development. However, we highlight the importance of interpreting the fitness impacts of maternal stress within an environmentally relevant context.

Initial report of \u03b3-aminobutyric acidergic locomotion regulatory system and its 3-mercaptopropionic acid-sensitivity in metamorphic juvenile of sea urchin, Hemicentrotus pulcherrimus

The γ-aminobutyric acid (GABA) signal transmission system (GSTS) contributes to larval swimming through the regulation of ciliary beating. However, whether this system also contributes to the primary podia (PP)-generated motility of juveniles remained unclear. The present study aimed to elucidate the involvement of the GSTS in the motility of metamorphic juveniles (juveniles) (1) by immunohistochemically elucidating the location of molecular constituents of the PP, and (2) by inhibiting the activity of GΑΒΑ decarboxylase (GAD) with 3-mercaptopropionic acid (3-MPA). During metamorphosis, the echinus rudiment protrudes its PP out of the body surface in 8-arm plutei. The PP expresses immunopositive signal (-IS) of GAD, GABA, GABAA receptor and tropomyosin, and is constituted with the GABA-IS negative distal tip and the GABA/GAD-IS gaiter region. The latter radiates distal projections to the disc that contains a GAD-IS cellular network. The juvenile body cavity houses a GABA/βIII-tubulin-IS Penta-radial ring (PrR) that extends branches into each PP and several bridges to the GAD/GABA-IS Penta-radial plate (PrP) on the oral side but does not reach to the gaiter region. 3-MPA reversibly inhibits the juvenile motility and GABA-IS expression in the PrR/PrP complex. This indicates that the complex is the major contributor to the GABAergic motility in juveniles.

Phanerochaete chrysosporiumstrain B-22, a nematophagous fungus parasitizing Meloidogyne incognita.

The root-knot nematode Meloidogyne incognita has a wide host range and it is one of the most economically important crop parasites worldwide. Biological control has been a good approach for reducing M. incognita infection, for which many nematophagous fungi are reportedly applicable. However, the controlling effects of Phanerochaete chrysosporium strain B-22 are still unclear. In the present study we characterized the parasitism of this strain on M. incognita eggs, second-stage juveniles (J2), and adult females. The highest corrected mortality was 71.9% at 3 × 108 colony forming units (CFU) mL-1 and the estimated median lethal concentration of the fungus was 0.96 × 108 CFU mL-1. Two days after treatment with Phanerochaete chrysosporium strain B-22 eggshells were dissolved. A strong lethal effect was noted against J2, as the fungal spores developed in their body walls, germinated, and the resulting hyphae crossed the juvenile cuticle to dissolve it, thereby causing shrinkage and deformation of the juvenile body wall. The spores and hyphae also attacked adult females, causing the shrinkage and dissolution of their bodies and leakage of contents after five days. Greenhouse experiments revealed that different concentrations of the fungal spores effectively controlled M. incognita. In the roots, the highest inhibition rate for adult females, juveniles, egg mass, and gall index was 84.61%, 78.91%, 84.25%, and 79.48%, respectively. The highest juvenile inhibition rate was 89.18% in the soil. Phanerochaete chrysosporium strain B-22 also improved tomato plant growth, therefore being safe for tomato plants while effectively parasitizing M. incognita. This strain is thus a promising biocontrol agent against M. incognita.

Studies on the juvenile body weights and some heat stress parameters in three genetic groups of synthetic coloured broilers exposed to heat stress during 4-6 weeks in growth chambers

Reddy, B.L.N., Rajkumar, U. and Prince, L.L.L. 2020. Studies on the juvenile body weights and some heat stress parameters in three genetic groups of synthetic coloured broilers exposed to heat stress during 4-6 weeks in growth chambers. Indian Journal of Poultry Science, 55(3): 179-182.

Growth and thermal tolerance of a Tibet fishSchizopygopsis younghusbandijuveniles acclimated to three temperature levels

Schizopygopsis younghusbandi is an endemic fish of Tibet characterized by slow growth. Artificial stock enhancement was applied to rebuild the natural population of S. younghusbandi in recent years. However, the optimal growth temperature and thermal tolerance of S. younghusbandi has not been studied, which restricts the production of S. younghusbandi fingerling for stock enhancement. The purpose of this paper is to determine the growth, critical thermal maximum (CTMax), lethal thermal maximum (LTMax) and acclimation response ratio (ARR) of S. younghusbandi juveniles (body weight 5.7 ± 1.2 g) at three acclimation temperature levels (10, 15, 20°C). The results showed that acclimation temperature significantly affected the growth, CTMax, LTMax and ARR of the experimental fish. Largest final weight (7.5 ± 2.3 g) was recorded in 15°C group. At a heating rate of 1°C/30 min, CTMax ranged from 30.98 to 32.01°C and LTMax ranged from 31.76 to 32.31°C in the three acclimation temperatures. Schizopygopsis younghusbandi had lower ARR value (0.097) than most other fish species. Low ARR value indicates that S. younghusbandi may have narrower thermal tolerance range and weaker acclimation ability to global warming. For successful aquaculture of S. younghusbandi juveniles, temperature should be maintained around 15°C.

Morphology of the nervous system of monogonont rotifer Epiphanes senta with a\xa0focus on sexual dimorphism between feeding females and dwarf males

BackgroundMonogononta is a large clade of rotifers comprised of diverse morphological forms found in a wide range of ecological habitats. Most monogonont species display cyclical parthenogenesis, where generations of asexually reproducing females are interspaced by mixis events when sexual reproduction occurs between mictic females and dwarf, haploid males. The morphology of monogonont feeding females is relatively well described, however data on male anatomy are very limited. Thus far, male musculature of only two species has been described with confocal laser scanning microscopy (CLSM) and it remains unknown how dwarfism influences the neuroanatomy of males on detailed level.ResultsHere, we provide a CLSM-based description of the nervous system of both sexes of Epiphanes senta, a freshwater monogonont rotifer. The general nervous system architecture is similar between males and females and shows a similar level of complexity. However, the nervous system in males is more compact and lacks a stomatogastric part.ConclusionComparison of the neuroanatomy between male and normal-sized feeding females provides a better understanding of the nature of male dwarfism in Monogononta. We propose that dwarfism of monogonont non-feeding males is the result of a specific case of heterochrony, called “proportional dwarfism” as they, due to their inability to feed, retain a juvenile body size, but still develop a complex neural architecture comparable to adult females. Reduction of the stomatogastric nervous system in the males correlates with the loss of the entire digestive tract and associated morphological structures.

Благополучие и неблагополучие семьи и ребенка в нарративах специалистов по профилактике безнадзорности и правонарушений несовершеннолетних Санкт-Петербурга

В статье представлены результаты подготовительного этапа лонгитюдного исследования, посвященного жизненным траекториям семей и детей, находящихся в контакте с системой профилактики безнадзорности и правонарушений несовершеннолетних г. Санкт-Петербурга. Ввиду недостаточной определенности критериев, регулирующих работу с семьей, в нормативно-правовой документации значительную роль в дальнейшей траектории семьи и несовершеннолетнего начинает играть субъективная оценка ситуации специалистом. Для понимания оснований этой оценки мы провели серию из 11 полуструктурированных экспертных интервью со специалистами Санкт-Петербурга, представляющими разные органы, входящие в систему профилактики безнадзорности и правонарушений несовершеннолетних. При оценке благополучия специалисты использовали как объективные, так и субъективные критерии, которые соответствуют современным научным и практическим тенденциям в понимании этого явления. В ходе интервью подтвердилась гипотеза о высокой субъективности принятия решений и значительной роли специалиста в развитии дальнейшей жизненной траектории семьи. Специалисты продемонстрировали понимание благополучия, созвучное современным представлениям о данном феномене. Они убеждены, что благополучие и неблагополучие семьи определяет благополучие или неблагополучие ребенка, проживающего в ней. Медиаторами благополучия и неблагополучия являются ресурсы (внутренние, внешние) семьи и ребенка. В представлении специалистов семья, соответствующая существующим в обществе нормам, — залог благополучия ребенка. Сообразно этим убеждениям, неблагополучная семья, а именно семья, отклоняющаяся от норм, формирует неблагополучие ребенка. Необходимо дальнейшее исследование критериев и стадий (не)благополучия и выделение индикаторов, позволяющих специалисту ориентироваться в принятии решения о возможностях дальнейшей работы с семьей или ребенком.
 Благодарность. Исследование выполнено в рамках проекта «Социальные траектории детства в современной России», поддержанного грантом Российского научного фонда № 16-18-10372.

Evolutionary quantitative genetics of juvenile body size in a population of feral horses reveals sexually antagonistic selection

Inter-individual variation in juvenile body size can have important consequences for individual fitness, population dynamics, and adaptive evolution. In wild vertebrate populations, larger juvenile size is usually expected to be selected for. However, understanding how such selection may translate into adaptive evolution requires an understanding of the genetic underpinnings of early development and the factors modulating selection. In this study, we characterised the genetic basis of and selection pressures acting upon juvenile body size in a large insular population of feral horses on Sable Island, Canada, to gain insights into the evolution of juvenile body size in wild vertebrate populations. We used pedigree-based quantitative genetic ‘animal models’ to quantify the sources of phenotypic variation in withers-knee length, and assessed the influence of maternal age, sex, and temporal (birth year) and spatial environmental heterogeneity in modulating overwinter survival selection. We found that withers-knee length is moderately heritable and that there was a significant positive genetic correlation between males and females. There was no indication of directional selection in a pooled-sex analysis, but we did find evidence for significant sexually antagonistic selection, with a tendency for smaller body size to be favoured in males and larger body size to be favoured in females. These results suggest that juvenile body size has the potential to evolve in this population, and that selection on juvenile size may play an important role in modulating sex-specific contributions to population dynamics. However, our results also suggest that there is unlikely to be evolutionary change in the mean body size of Sable Island foals.

Estimating breeding values for juvenile body weight using trait associated SNP assisted BLUP in turbot (Scophthalmus maximus)

Turbot is an important marine aquaculture species with great economic value. Marker-assisted selection is an attractive breeding technique to improve economic traits in turbot. The objective of this study was 1) to validate SNPs associated with juvenile turbot body weight (BW) on a population scale and 2) to evaluate the performance of a marker-assisted BLUP (MA-BLUP) method to estimate breeding values for BW. Based on a previous study, four SNPs associated to candidate QTLs for juvenile BW were genotyped in a breeding population consisting of 926 individuals from 40 full-sib families. General linear models (GLM) and mixed linear models (MLM) were applied to identify associations between SNPs and juvenile BW. Individual breeding values were estimated by MA-BLUP based on associated SNP and traditional BLUP. Thereafter, we compared the accuracy of both estimators by cross validation. Both GLM and MLM obtained similar results, with SNP105 showing significant effect on juvenile BW. Least squares mean of genotypes AA, GA and GG at SNP105 were 10.635 ± 0.454 g, 9.953 ± 0.449 g and 9.897 ± 0.497 g, respectively. Cross validation revealed that the accuracy of estimated breeding values was 0.573 with MA-BLUP and 0.565 with traditional BLUP, and t-test suggested that the accuracy of both methods differed significantly (P < .001), which indicated that accuracy of estimators based on MA-BLUP was better than traditional method. The results suggested MA-BLUP was a feasible approach to apply trait associated markers in turbot breeding.

Graded Incorporation of Defatted Yellow Mealworm (Tenebrio molitor) in Rainbow Trout (Oncorhynchus mykiss) Diet Improves Growth Performance and Nutrient Retention.

Simple SummaryEfforts to find sustainable ingredients for aquaculture feeds have been increasing. Insect meal is a promising and emerging ingredient because insects are part of the natural diet of fish and have a low ecological footprint. Here, we studied the effect of a gradual replacement of fishmeal with insect meal from yellow mealworm on juvenile rainbow trout performance. Overall, fish grew faster with the incorporation of the insect meal in the feed, and their capacity to convert feed into fish biomass also increased. The retention of ingested key nutrients also increased with the incorporation of insect meal in the feed. In summary, juvenile trout fed an insect-based diet grew faster and required lower feed intake to grow than juvenile trout fed on a common diet with standard levels of fishmeal. These results support the transition of fishmeal to insect meal in aquafeeds, which will improve the sustainability of the aquaculture industry.Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficients of dry matter, protein, fat, phosphorus, and energy. Protein, phosphorus, and energy retention significantly increased in fish fed the diets with an insect protein meal. In conclusion, the yellow mealworm protein meal could effectively replace 100% of fishmeal in the diet of juvenile rainbow trout with positive effects on its overall zootechnical performance.

EXPERIENCE OF TWO-YEAR REARING OF CHERRY SALMON ONCORHYNCHUS MASOU JUVENILES AT FISH FARM ON ITURUP ISLAND

Results of cherry salmon juveniles rearing at Reidovo fish farm on Iturup Island during two annual cycles of cultivation are analyzed. Different variants of the breeders selection, feeding, preventive treatment, and release were tested. The breeders were caught in the river mouth and near the fish farm. Mass mortality of young fish in the first and second years was avoided by decreasing of their density and other preventive measures. Minced fish was used as a food for them that is less expensive in compare with a combined fodder. The best diet for the second year of rearing was the minced pink salmon with the daily ration of 2 % of the juveniles body weight; it provided a significant decrease of mortality and enhanced their growth. After 2-year rearing, percentage of females, anadromous males, and dwarf males was 42.1, 36.3, and 21.6 %, respectively. Their weights were similar, though a group of fast-growing males was found among the dwarfs. The mass of ovaries varied from 13 to 46 mg in close dependence on females’ body weight (r = 0.81). Before the release, the ovaries of all females contained oocytes of similar size (varied in 2–4 times) at the final stage of previtellogenesis. Number of the oocytes per transverse section varied from 4.7 to 32.3, on average for 5 cuts and their diameter varied from 164.3 to 279.2 mm and did not correlate with the females body weight. The mass of dwarf males’ testes varied from 14 to 488 mg in dependence on their body weight (r = 0.78). The elder oocytes of females would mature in a year, and majority of dwarf males would reach the maturity in autumn of the current year.

Size‐dependent stress response in juvenile Arctic charr (Salvelinus alpinus) under prolonged predator conditioning

Predator conditioning can be used to improve post-release antipredator recognition of hatchery-reared salmonids. However, possible negative stress-related effects of prolonged predator conditioning on juvenile fish physiology are poorly understood. We studied the effects of prolonged (91 days) predator odour exposure on whole-body cortisol level and spleen size in six full-sib families of juvenile hatchery-bred Arctic charr (Salvelinus alpinus). Chemical cues from water containing charr-fed pikeperch (Sander lucioperca) were used as the predator exposure stimuli and lakewater was used as a chemical control. Our study revealed that juvenile body cortisol levels post-predator conditioning were affected by treatment, fish size and their interaction. Importantly, among the smaller (i.e. slowest growing) charr, the predator-exposed fish had higher cortisol levels than control fish, while the opposite pattern was true for the larger fish. These results suggest that chemical cues from charr-fed predators induce a prolonged stress response in juvenile charr. As prolonged predation exposure seems to elevate stress levels in a size-dependent manner, the larger, faster growing fish could possibly have intrinsically lower stress responses to predation threats than smaller, slower growing fish. Possible coupling between stress sensitivity and growth requires further attention due to the likely implications for the management of unintended domestication among captive-reared salmonids.

Isolation and Molecular Identification of Entomopathogenic Nematodes (Steinernema and Heterorhabditis) from East Java and Bali

&lt;p&gt;Entomopathogenic nematode of the families Steinernematidae and Heterorhabditidae is one of the best biological control agents of insect pests. Native isolates maybe more efficacious in controlling insect pests than imported ones because they have adapted to local environment. This study aimed to isolate and identify both nematode families from East Java and Bali&lt;br /&gt;using DNA analysis. Sixty eight soil samples obtained from sandy soils in 16 sites of coastal regions and agricultural fields were tested for the presence of nematodes by baiting method with mealworm larvae (Tenebrio molitor). Five Heterorhabditis and two Steinernema were recovered from 7 soil samples (10% of total samples) of 7 sites (44% of total sites). Sequence analysis of&lt;br /&gt;internal transcribed spacer (ITS) 1 and 2 regions of ribosomal DNA revealed that all Heterorhabditis belonged to indica species, with 99–100% nucleotide sequence similarities to published sequences. One of the Steinernema isolates had short infective juvenile body length (360 μm to 547 μm) and shared 99% nucleotide similarity to that of S. huense, a member of “carpocapsae” group. The other Steinernema isolate (DKS1) showed longer infective juvenile body length (from 548 μm to 762 μm) and shared 95% nucleotide similarity to the sequence of S. pakistanense, which belongs to “bicornutum” group. More detailed studies with respect to morphology are required for species confirmation of DKS1 isolate. Further exploration to&lt;br /&gt;diverse habitat will likely to result in more previously unrecorded entomopathogenic nematode species in Indonesia.&lt;/p&gt;

RESPONSES OF JUVENILE AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) TO CONTACT CALLS

Abstract Crocodylians are known for their ability to vocalize throughout their lives in a variety of social and ecological contexts, particularly during their vulnerable juvenile life stage. However, few studies have analyzed juvenile calls in laboratory settings, fewer still have analyzed them across large sample sizes or with respect to sex and body size, and no studies to date have analyzed crocodylian vocalizations with respect to human conditioning in captivity or animal personality profiles. This study tests juvenile American alligators' (Alligator mississippiensis) ability to respond via movement and callback vocalizations to pre-recorded conspecific contact calls across a large sample size (n=36), and tests for relationships between response rates and juvenile body size and sex. Seventeen and sixteen individuals out of a total of thirty-six responded via movement toward the source of pre-recorded vocalizations across the first and second experimental trials, respectively, whereas none responded through movement toward control sounds; 75% of juveniles who vocalized did so only in response to contact calls rather than controls (though the latter difference was not significant given that only four vocalized in Trial 1, and only a single animal vocalized in Trial 2); there was also no significant difference in movement toward recorded vocalizations across size or sex. However, one particularly vocal individual whose upbringing in captivity was known was identified as a possible unique personality profile given its propensity for callback vocalizations in comparison to its fellow study subjects.

Study on performance evaluation and crossbreeding effects for juvenile body weights in duck

A 3×3 complete diallel experiment was made using three populations of ducks namely indigenous duck (D), Khaki Campbell (K) and White Pekin (W). Standard feeding and management practices were followed. Body weight at first day, 1, 3, 5 and 7th week of age were recorded. Data were analysed to derive the differences between genetic groups. The traits showing significant difference were used for the analysis of combining ability. Heterosis per cent was also calculated. Significant differences between different genetic groups were observed for all the traits studied. Body weight at 7 weeks of age were 995, 1069, 2145, 1185, 1707, 1316, 1815, 1633 and 1559 g, respectively. W recorded significant higher body weight amongst the purebreds irrespective the age. Body weights were higher in the crosses having White Pekin as one parent. Significant general combining ability (GCA), specific combining ability (SCA) and reciprocal effect (RE) were observed for all the traits indicating importance of additive genetic effects, non-additive genetic effects and maternal/sex linked effects. Heterosis per cent decreased with the advancement of the age. The study indicates that for meat purpose KW and DW are useful as they recorded higher body weight, whereas for medium weight type duck WD and WK are the preferred crosses and may be used as dual purpose duck. For smaller duck DK and KD are the best choice which may be used for egg laying purpose.

Does urbanization cause stress in wild birds during development? Insights from feather corticosterone levels in juvenile house sparrows (Passer domesticus).

Urban landscapes are associated with abiotic and biotic environmental changes that may result in potential stressors for wild vertebrates. Urban exploiters have physiological, morphological, and behavioral adaptations to live in cities. However, there is increasing evidence that urban exploiters themselves can suffer from urban conditions, especially during specific life‐history stages. We looked for a link between the degree of urbanization and the level of developmental stress in an urban exploiter (the house sparrow, Passer domesticus), which has recently been declining in multiple European cities (e.g., London, UK). Specifically, we conducted a large‐scale study and sampled juvenile sparrows in 11 urban and rural sites to evaluate their feather corticosterone (CORT) levels. We found that juvenile feather CORT levels were positively correlated with the degree of urbanization, supporting the idea that developing house sparrows may suffer from urban environmental conditions. However, we did not find any correlation between juvenile feather CORT levels and body size, mass, or body condition. This suggests either that the growth and condition of urban sparrows are not impacted by elevated developmental CORT levels, or that urban sparrows may compensate for developmental constraints once they have left the nest. Although feather CORT levels were not correlated with baseline CORT levels, we found that feather CORT levels were slightly and positively correlated with the CORT stress response in juveniles. This suggests that urban developmental conditions may potentially have long‐lasting effects on stress physiology and stress sensitivity in this urban exploiter.

Thermal constraints on body size depend on the population’s position within the species’ thermal range in temperate songbirds

AbstractAimThere is mounting evidence that climate warming can induce morphological changes locally, particularly size reduction. However, the direction of thermal stress may differ between climatic regions. We predicted that morphological response to temperature fluctuations should vary throughout species ranges, depending on the local climate. Hot temperature anomalies are expected to induce size reduction in hot regions where species live close to their upper thermal limit, whereas size stasis (or increase) would be expected in cold regions, where species live close to their lower thermal limit.LocationFrance (204 sites).Time period2000–2014 springs.Major taxa studiedSongbird species (n = 9).MethodsWe tested whether the effect of temperature anomalies on juvenile body size varied along an 11 °C thermal gradient.ResultsIn warmer springs, juveniles were larger overall at the coldest sites, but this effect decreased toward the hottest sites, becoming negative for two species.Main conclusionsWarming should induce body size increases more frequently at the cold edge of species distribution ranges, and rather body size declines at the hot edg. The climate dependency of the effect of weather fluctuations on body size is still under‐acknowledged, and the pattern identified deserves to be investigated over broader climatic gradients and taxonomic coverage. Climate‐driven changes in body size are therefore not uniform across climatic regions and within species ranges.

Subjects of criminal proceedings and juvenile justice, which carry out prevention of crime of minors in FRG

The article is devoted to the study of certain aspects of the functioning of the juvenile justice bodies of the Federal Republic of Germany, which carry out the prevention of juvenile delinquency. In particular, the police, probation services, educational institutions, judiciary, employment services and other organs of juvenile justice of the Federal Republic of Germany. The author has studied and analyzed modern scientific literature, original results of scientific research and the legal framework of a foreign language country in the original language. The basic principles of work and peculiarities of functioning of each separate subject of juvenile delinquency prevention in the Federal Republic of Germany are analyzed, as well as the expediency and possibility of harmonizing the work of juvenile justice bodies in Ukraine and the Federal Republic of Germany. The necessity of close cooperation and more thorough coordination of work between state authorities, local self-government and youth organizations, volunteer movements, private sector entities, and other non-state associations were substantiated. Studying the experience of working with minors in the relevant structures of Germany is especially important for our country towards the introduction of European standards in the field of juvenile justice, which is a priority within the framework of interaction between Ukraine and the EU, especially taking into account in the implementation of modern trends of criminal-law and criminological policy on the reform of the juvenile justice bodies of Ukraine. The importance of work of the juvenile justice bodies of the Federal Republic of Germany is emphasized in the fundamental idea of accomplishment, which is embodied in the special juvenile criminal legislation of the Federal Republic of Germany, and in its use by the relevant authorities in practice.

Feeding performance of juvenile marble goby (Oxyeleotris marmorata Bleeker, 1852) fed acidified diets

Abstract The present study aimed to evaluate the feeding performance of juvenile marble goby (Oxyeleotris marmorata) on acidified diets. Five fish meal-based diets at various pH levels (2.5, 3.2, 4.3, 5.3, and 6.0 (control)) were prepared, and each of them was fed to 10 wild-caught O. marmorata juveniles (body length 7.7–9.3 cm; each fish was placed in an aquarium, hence each dietary treatment was in 10 replicates) for 20 days. Throughout the feeding trial, O. marmorata juveniles showed clear increments in the daily ingestion ratio (IR) values of AD 2.5, AD 3.2, and AD 4.3. The control diet and AD 5.3 were almost totally rejected by the fish. On day 20, the IR of AD 2.5 (0.46) and AD 3.2 (0.36) were significantly higher (P &lt; 0.05) than those of AD 5.3 (0.1) and the control diet (0.02). In addition, 70% of fish fed AD 2.5 achieved a high IR value (0.6 – 1.0), and this was the best result among all the treatments (AD 3.2, 60%; AD 4.3 50%; AD 5.3 and control, 10%). These results suggested that acidified diets can be used to wean O. marmorata juveniles, and the recommended pH level was 2.5.