Juvenile Behavior Research Articles

An Analytical Study on the Relationship Between Parental Influence and Juvenile Delinquency

This critical study aims to examine the complex relationship between parental influence and juvenile delinquency. The research explores various factors within the realm of parental influence that contribute to the development of delinquent behavior in juveniles. By critically analyzing existing literature, empirical studies, and relevant theories, this research sheds light on the multidimensional nature of this relationship. Additionally, it investigates the impact of different parenting styles, family dynamics, and parental involvement on juvenile delinquency. The research method followed is descriptive research. The data collected through questionnaire and the sampling size is 206 collected through convenient sampling. The findings of this study provide valuable insights for policymakers, practitioners, and researchers, aiding in the development of effective intervention strategies to prevent and address juvenile delinquency. Keywords: Parental influence, Juvenile delinquency, Parental styles, Behaviour, Adolescence.

Interpopulation variation in dispersal behavior of fat minnow Rhynchocypris oxycephalus jouyi juveniles inhabiting fragmented habitats.

In many organisms, including fishes, downstream dispersal is often phenotype-dependent. Phenotype-dependent downstream dispersal can generate evolutionary pressure via spatial sorting, which non-randomly removes phenotypes enhancing downstream dispersal from upstream populations. Spatial sorting due to downstream dispersal could accumulate in fish populations in above-barrier habitats to which dispersed individuals cannot return, resulting in functional traits that reduce downstream dispersal. This evolutionary mechanism may be more important in smaller above-barrier habitats where downstream emigration occurs over shorter dispersal distances. This study observed the dispersal behavior of fat minnow Rhynchocypris oxycephalus jouyi juveniles in an experimental tank to examine whether juveniles from small above-barrier habitats show more behaviors favorable for reducing downstream dispersal than those from large above-barrier habitats. Juveniles from small above-barrier habitats avoided downstream dispersal for longer durations than those from large above-barrier habitats, but there was no difference in the frequency of ascending attempts. These results support the notion that behavioral traits of juveniles in small above-barrier populations have been refined by spatial sorting to reduce downstream dispersal. The finding that interpopulation variation in dispersal behavior occurred only for certain dispersal directions implies that the behavioral consequences of habitat fragmentation are more complex than previously assumed.

Parametric analysis of anxiety-like behavior in guppy (Poecilia reticulata) larvae and juveniles using the plus maze with ramp.

Parametric analysis of anxiety-like behavior in guppy (Poecilia reticulata) larvae and juveniles using the plus maze with ramp.

Maternal rejection but not protectiveness predicts juvenile Japanese macaque behavior without direct maternal influence.

Primates show large interindividual variability in the character and quantity of interactions between mothers and their immature offspring. Multiple studies have documented associations between maternal behavior and the occurrence or frequency of certain behaviors among offspring, but it remains unclear whether and how early maternal interactions generally affect behavioral development in offspring. We followed two wild groups of Japanese macaques on Yakushima island and investigated the relationship between maternal behavior and several types of behavior performed by 35 juvenile offspring. We further asked if the impact of maternal behavior on juvenile behavior persists regardless of the distance between mother and offspring, testing whether the influence extends beyond cases when the mother is nearby. We found that juveniles whose mothers frequently rejected them approached and played with others more often, independent of their mother's presence. Juveniles of more protective mothers were in proximity to fewer other individuals and played less, but only if their mothers were nearby. Maternal rejection appears to exert a generalized effect on offspring behavior that endures when mothers are absent. In contrast, effects of maternal protectiveness may be temporary and/or reflect direct maternal influences, such as active intervention in offspring interactions, or effects of the mother's own social relationships on offspring interactions. Our results suggest that understanding how maternal behavior affects offspring development requires paying attention to the context of juvenile behavior, including the mother's distance from her offspring.

Sex-specific associations of the maturation locus vgll3 with exploratory behavior and boldness in Atlantic salmon juveniles.

Studies linking genetics, behavior and life history in any species are rare. In Atlantic salmon (Salmo salar), age at maturity is a key life-history trait and associates strongly with the vgll3 locus, whereby the vgll3*E allele is linked with younger age at maturity, and higher body condition than the vgll3*L allele. However, the relationship between this genetic variation and behaviors like boldness and exploration which may impact growth and reproductive strategies is poorly understood. The pace-of-life syndrome (POLS) framework provides predictions, whereby heightened exploratory behavior and boldness are predicted in individuals with the early maturation-associated vgll3 genotype (EE). Here, we tested these predictions by investigating the relationship between vgll3 genotypes and exploration and boldness behaviors in 129 juveniles using the novel environment and novel object trials. Our results indicated that contrary to POLS predictions, vgll3*LL fish were bolder and more explorative, suggesting a genotype-level syndrome including several behaviors. Interestingly, clear sex differences were observed in the latency to move in a new environment, with vgll3*EE males, but not females, taking longer to move than their vgll3*LL counterparts. Our results provide further empirical support for recent calls to consider more nuanced explanations than the pace of life theory for integrating behavior into life-history theory.

Neurexin drives Caenorhabditis elegans avoidance behavior independently of its post-synaptic binding partner neuroligin.

Neurexins and their canonical binding partners, neuroligins, are localized to neuronal pre-, and post-synapses, respectively, but less is known about their role in driving behaviors. Here, we use the nematode C. elegans to show that neurexin, but not neuroligin, is required for avoiding specific chemorepellents. We find that adults with knockouts of the entire neurexin locus exhibit a strong avoidance deficit in response to glycerol and a weaker defect in response to copper. Notably, the C. elegans neurexin (nrx-1) locus, like its mammalian homologs, encodes multiple isoforms, α and γ. Using isoform-specific mutations, we find that the γ isoform is selectively required for glycerol avoidance. Next, we used transgenic rescue experiments to show that this isoform functions at least partially in the nervous system. We also confirm that the transgenes are expressed in the neurons and observe protein accumulation in neurites. Furthermore, we tested whether these mutants affect the behavioral responses of juveniles. We find that juveniles (4th larval stages) of mutants knocking out the entire locus or the α-isoforms, but not γ-isoform, are defective in avoiding glycerol. These results suggest that the different neurexin isoforms affect chemosensory avoidance behavior in juveniles and adults, providing a general principle of how isoforms of this conserved gene affect behavior across species.

Law’s Silence on Cyberbullying to Children in Indonesia

With the advancement of the Internet, cyberbullying is fast emerging as a significant issue and a new form of violence in Indonesia. Additionally, whether the Internet has become a catalyst for conventional bullying is a critical question that must be addressed. In Indonesia, cyberbullying is now recognized as an imminent concern with regard to juvenile behaviour and development outcomes. The Indonesian legal system, however, has no direct legislation on cyberbullying. The existing laws on juvenile crimes and online offenses do not adequately address specific concerns raised by cyberbullying. This article explores the correlation between high exposure to violent content over the Internet and the recent increase in violence among children in Indonesia. The effect of cyberbullying victimization and its potential to create perpetrators of bullying has been explored within the context of the inadequacy of the current Indonesian legal system’s response to online harassment, particularly the lack of adequate laws against cyberbullying.

Chemosensory behaviour of juvenile crown-of-thorns sea star (Acanthaster sp.), attraction to algal and coral food and avoidance of adult conspecifics.

Intraspecific and habitat-mediated responses to chemical cues play key roles in structuring populations of marine species. We investigated the behaviour of herbivorous-stage juvenile crown-of-thorns sea stars (COTS; Acanthaster sp.) in flow-through choice chambers to determine if chemical cues from their habitat influence movement and their transition to become coral predators. Juveniles at the diet transition stage were exposed to cues from their nursery habitat (coral rubble-crustose coralline algae (CCA)), live coral and adult COTS to determine if waterborne cues influence movement. In response to CCA and coral as sole cues, juveniles moved towards the cue source and when these cues were presented in combination, they exhibited a preference for coral. Juveniles moved away from adult COTS cues. Exposure to food cues (coral, CCA) in the presence of adult cues resulted in variable responses. Our results suggest a feedback mechanism whereby juvenile behaviour is mediated by adult chemical cues. Cues from the adult population may deter juveniles from the switch to corallivory. As outbreaks wane, juveniles released from competition may serve as a proximate source of outbreaks, supporting the juveniles-in-waiting hypothesis. The accumulation of juveniles within the reef infrastructure is an underappreciated potential source of COTS outbreaks that devastate coral reefs.

Methylmercury Effects on Birds: A Review, Meta-Analysis, and Development of Toxicity Reference Values for Injury Assessment Based on Tissue Residues and Diet.

Birds are used as bioindicators of environmental mercury (Hg) contamination, and toxicity reference values are needed for injury assessments. We conducted a comprehensive review, summarized data from 168 studies, performed a series of Bayesian hierarchical meta-analyses, and developed new toxicity reference values for the effects of methylmercury (MeHg) on birds using a benchmark dose analysis framework. Lethal and sublethal effects of MeHg on birds were categorized into nine biologically relevant endpoint categories and three age classes. Effective Hg concentrations where there was a 10% reduction (EC10) in the production of juvenile offspring (0.55 µg/g wet wt adult blood-equivalent Hg concentrations, 80% credible interval: [0.33, 0.85]), histology endpoints (0.49 [0.15, 0.96] and 0.61 [0.09, 2.48]), and biochemical markers (0.77 [<0.25, 2.12] and 0.57 [0.35, 0.92]) were substantially lower than those for survival (2.97 [2.10, 4.73] and 5.24 [3.30, 9.55]) and behavior (6.23 [1.84, >13.42] and 3.11 [2.10, 4.64]) of juveniles and adults, respectively. Within the egg age class, survival was the most sensitive endpoint (EC10 = 2.02 µg/g wet wt adult blood-equivalent Hg concentrations [1.39, 2.94] or 1.17 µg/g fresh wet wt egg-equivalent Hg concentrations [0.80, 1.70]). Body morphology was not particularly sensitive to Hg. We developed toxicity reference values using a combined survival and reproduction endpoints category for juveniles, because juveniles were more sensitive to Hg toxicity than eggs or adults. Adult blood-equivalent Hg concentrations (µg/g wet wt) and egg-equivalent Hg concentrations (µg/g fresh wet wt) caused low injury to birds (EC1) at 0.09 [0.04, 0.17] and 0.04 [0.01, 0.08], moderate injury (EC5) at 0.6 [0.37, 0.84] and 0.3 [0.17, 0.44], high injury (EC10) at 1.3 [0.94, 1.89] and 0.7 [0.49, 1.02], and severe injury (EC20) at 3.2 [2.24, 4.78] and 1.8 [1.28, 2.79], respectively. Maternal dietary Hg (µg/g dry wt) caused low injury to juveniles at 0.16 [0.05, 0.38], moderate injury at 0.6 [0.29, 1.03], high injury at 1.1 [0.63, 1.87], and severe injury at 2.4 [1.42, 4.13]. We found few substantial differences in Hg toxicity among avian taxonomic orders, including for controlled laboratory studies that injected Hg into eggs. Our results can be used to quantify injury to birds caused by Hg pollution. Environ Toxicol Chem 2024;43:1195-1241. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Glutamate, glycine, and especially the secretions of Ruditapes phillipinarum induce efficient foraging by juvenile Rapa whelks

Chemical signals are known to influence interactions within and among species of aquatic organisms, including gastropods. However, despite the indispensable roles of chemical signals in species interactions, little is known about their effectiveness, especially in gastropods. The rapa whelk Rapana venosa (Valenciennes, 1846) is an ecologically and economically important gastropod, but it has also become a global invasive species. Currently, bottlenecks exist in the breeding of R. venosa related to foraging behaviour and efficiency in juveniles, while significant problems also exist in controlling invasive populations of the gastropod. Here, we aimed to identify chemical signaling molecules that could effectively improve their foraging behaviour and efficiency and potentially solve the bottlenecks in aquaculture production and control the invasiveness of R. venosa. The foraging behaviour of R. venosa during the search phase was evaluated in response to various signaling molecules as to activity time, motion path, and successful perception rate, and a standard scoring metric was proposed. The results showed that bivalve (Ruditapes philippinarum) secretion and glutamic acid and glycine, could effectively induce foraging behaviour in R. venosa. In contrast, 4-dodecylbenzene sulfonic acid and dodecyl sulfate, did not induce significant foraging behaviour. The induced foraging behaviour by a single amino acid was less effective than that of the entire bivalve secretion. These findings could be helpful in improving breeding efficiency, efficient trapping, and controlling invasive populations of aquatic gastropods.

Viral-mediated inflammation by Poly I:C induces the chemokine CCL5 in NK cells and its receptors CCR1 and CCR5 in microglia in the neonatal rat cerebellum.

To study the effect of viral inflammation induced by Polyinosinic:polycytidylic acid (PIC) on the cerebellum during a critical period of development in rats. Neonatal rat pups were treated with PIC on postnatal days (PN) 8 and 10 after which we quantified RNA using Nanostring, qRT-PCR and RNAscope and analyzed immune cells through flow cytometry and immunohistochemistry on PN11. Using the same paradigm, we also analyzed play juvenile behavior, anxiety-like behavior, motor balance using the balance beam and the rotarod assays as well as fine motor behavior using the sunflower seed opening test. We determined that male and female pups treated with PIC reacted with a significant increase in CCL5, a chemotactic cytokine that attracts T-cells, eosinophils and basophils to the site of inflammation, at PN11. PIC treatment also increased the expression of two receptors for CCL5, CCR1 and CCR5 in the cerebellar vermis in both males and females at PN11. In-situ hybridization (RNAscope®) for specific transcripts revealed that microglia express both CCL5 receptors under inflammatory and non-inflammatory conditions in both males and females. PIC treatment also increased the total number of CCL5+ cells in the developing cerebellum which were determined to be both natural killer cells and T-cells. There were modest but significant impacts of PIC treatment on large and fine motor skills and juvenile play behavior. Our findings suggest an important role for CCL5 and other immune cells in mediating inflammation in the developing cerebellum that potentially impact the maturation of cerebellar neurons during a critical period of development.

Changes in limb bone diaphyseal structure in chimpanzees during development.

This study tests if femoral and humeral cross-sectional geometry (CSG) and cross-sectional properties (CSPs) in an ontogenetic series of wild-caught chimpanzees (Pan troglodytes ssp.) reflect locomotor behavior during development. The goal is to clarify the relationship between limb bone structure and locomotor behavior during ontogeny in Pan. The latex cast method was used to reconstruct cross sections at the midshaft femur and mid-distal humerus. Second moments of area (SMAs) (Ix, Iy, Imax, Imin), which are proportional to bending rigidity about a specified axis, and the polar SMA (J), which is proportional to average bending rigidity, were calculated at section locations. Cross-sectional shape (CSS) was assessed from Ix/Iy and Imax/Imin ratios. Juvenile and adult subsamples were compared. Juveniles and adults have significantly greater femoral J compared to humeral J. Mean interlimb proportions of J are not significantly different between the groups. There is an overall decreasing trend in diaphyseal circularity between the juvenile phase of development and adulthood, although significant differences are only found in the humerus. Juvenile chimpanzee locomotion includes forelimb- and hindlimb-biased behaviors. Juveniles and adults preferentially load their hindlimbs relative to their forelimbs. This may indicate similar locomotor behavior, although other explanations including a diversity of hindlimb-biased locomotor behaviors in juveniles cannot be ruled out. Different ontogenetic trends in forelimb and hindlimb CSS are consistent with limb bone CSG reflecting functional adaptation, albeit the complex nature of bone functional adaptation requires cautious interpretations of skeletal functional morphology from biomechanical analyses.

Novel Microsatellite Tags Hold Promise for Illuminating the Lost Years in Four Sea Turtle Species.

After hatching, sea turtles leave the nest and disperse into the ocean. Many years later, they return to their natal coastlines. The period between their leaving and their returning to natal areas, known as the "Lost Years", is poorly understood. Satellite tracking studies aimed at studying the "Lost Years" are challenging due to the small size and prolonged dispersal phases of young individuals. Here, we summarize preliminary findings about the performance of prototype microsatellite tags deployed over a three-year period on 160 neonate to small juvenile sea turtles from four species released in the North Atlantic Ocean. We provide an overview of results analyzing tag performance with metrics to investigate transmission characteristics and causes of tag failure. Our results reveal that, despite certain unfavorable transmission features, overall tag performance was satisfactory. However, most track durations were shorter than those observed on individuals of similar size in other studies and did not allow for detailed analyses of trajectories and turtle behavior. Our study further suggests that tracking durations are correlated with the targeted species, highlighting a lack of robustness against some neritic behaviors. Unprecedented diving data obtained for neonate sea turtles in this study suggest that the vertical behaviors of early juveniles are already too strenuous for these miniaturized tags. Our findings will help to inform the biologging research community, showcasing recent technological advances for the species and life stages within our study.

Multiple behavioral mechanisms shape development in a highly social cichlid fish

Early-life social experiences shape adult phenotype, yet the underlying behavioral mechanisms remain poorly understood. We manipulated early-life social experience in the highly social African cichlid fish Astatotilapia burtoni to investigate the effects on behavior and stress axis function in juveniles. Juveniles experienced different numbers of social partners in stable pairs (1 partner), stable groups (6 fish; 5 partners), and socialized pairs (a novel fish was exchanged every 5 days; 5 partners). Treatments also differed in group size (groups vs. pairs) and stability (stable vs. socialized). We then measured individual behavior and water-borne cortisol to identify effects of early-life experience. We found treatment differences in behavior across all assays: open field exploration, social cue investigation, dominant behavior, and subordinate behavior. Treatment did not affect cortisol. Principal components (PC) analysis revealed robust co-variation of behavior across contexts, including with cortisol, to form behavioral syndromes sensitive to early-life social experience. PC1 (25.1 %) differed by social partner number: juveniles with more partners (groups and socialized pairs) were more exploratory during the social cue investigation, spent less time in the territory, and were more interactive as dominants. PC5 (8.5 %) differed by stability: socialized pairs were more dominant, spent less time in and around the territory, were more socially investigative, and had lower cortisol than stable groups or pairs. Observations of the home tanks provided insights into the social experiences that may underlie these effects. These results contribute to our understanding of how early-life social experiences are accrued and exert strong, lasting effects on phenotype.

Exploring diurnal and nocturnal valve gaping behavior in winged pearl oyster Pteria penguin juveniles

The diurnal and nocturnal valve gaping behavior of the pearl oyster Pteria penguin was characterized through video analysis aided by open-source software. Juvenile pearl oysters were video-recorded for 48 hours under laboratory conditions, using commonly used surveillance hardware. The direct measuring of the distance changes between the two valve edges effectively revealed the pearl oysters’ tendency to open their valves wider at night-time, than during day-time. Moreover, the differences observed were also attained at the individual level. The description for the first time of this behavior has broader implications for the research in pearl oyster aquaculture. Moreover, it introduces a non-invasive tool for comprehensive assessment of adult oyster behavior.

Corticosterone Contributes to Diet-Induced Reprogramming of Post-Metamorphic Behavior in Spadefoot Toads.

Stressful experiences in early life can have phenotypic effects that persist into, or manifest during, adulthood. In vertebrates, such carryover effects can be driven by stress-induced secretion of glucocorticoid hormones, such as corticosterone, which can lead to developmental reprogramming of hypothalamic-pituitary-adrenal/interrenal axis activity and behavior. Nutritional stress in the form of early life nutrient restriction is well known to modify later life behaviors and stress activity through corticosterone-related mechanisms. However, it is not known whether corticosterone is also mechanistically involved in carryover effects induced by a different form of nutritional variation: the use of alternate or entirely novel types of dietary resources. The plains spadefoot (Spea bombifrons) presents an excellent system for testing this question, since larvae of this species have evolved to use 2 alternate diet types: an ancestral detritus-based diet and a more novel diet of live shrimp. While previous work has shown that feeding on the novel shrimp diet influences juvenile (i.e., post-metamorphic) behavior and corticosterone levels, it is unclear whether these diet-induced carryover effects are mediated by diet-induced corticosterone itself. To test for the mechanistic role of corticosterone in diet-induced carryover effects, we experimentally treated S. bombifrons larvae with exogenous corticosterone and measured subsequent effects on juvenile behavior and corticosterone levels. We found that while shrimp-fed larvae had elevated corticosterone levels, treatment of larvae with corticosterone itself had effects on juvenile behavior that partially resembled those carryover effects induced by the shrimp diet, such as altered food seeking and higher locomotor activity. However, unlike carryover effects caused by the shrimp diet, larval corticosterone exposure did not affect juvenile corticosterone levels. Overall, our study shows that corticosterone-related mechanisms are likely involved in carryover effects induced by a novel diet, yet such diet-induced carryover effects are not driven by corticosterone alone.

The effect of yellow and red illuminations on the swimming behaviour, mortality and growth rates of yellowfin tuna juveniles (Thunnus albacares)

The effect of yellow and red illuminations on the swimming behaviour, mortality and growth rates of yellowfin tuna juveniles (<i>Thunnus albacares</i>)

Etiologija maloletničke delinkvencije

In contemporary societies characterized by advanced information technology and widespread accessibility to various resources, social and psychological factors leading to adverse personal and societal consequences significantly influence minors, providing fertile ground for the emergence of juvenile delinquency. Juvenile delinquency is a serious problem for all contemporary societies, encompassing different forms of deviant behaviors among minors, including criminal acts that trigger legal proceedings and sanctions. Since there are a lot of theories and studies which focus on the distinctions between delinquency and criminality, this paper does not deal with that in greater detail. Instead, it focuses on elucidating juvenile delinquency as a foundational concept for understanding diverse forms of deviant behavior from criminal, psychological, and sociological perspectives. The paper identifies causes of juvenile behavior and early indicators for identifying young offenders. The primary research objective is to explore delinquency prevention strategies tailored to offenders. The examples illustrate the most frequent criminal acts perpetrated by reported, accused, and convicted minors, categorized by gender, age, and type of criminal sanction.

Temperature during embryonic development in brown trout influences juvenile behaviour in encounters with predators

AbstractVariation in thermal conditions during embryogenesis can have far‐reaching impact throughout ontogeny and may give rise to behavioural variation. Many animals, such as salmonids, exhibit behavioural trade‐offs related to foraging and predator avoidance. How embryonic temperature affects these behaviours has remained unexplored. Not only abiotic conditions during embryogenesis but also biotic factors such as predator conditioning may affect fish behaviour, especially anti‐predator responses. We examined how elevated temperatures and predator odours throughout embryogenesis affect the behaviour of 28–37 mm young‐of‐the‐year brown trout (Salmo trutta) in encounters with predators, namely Atlantic salmon (Salmo salar; 20 cm) and burbot (Lota lota; 40 cm). Juvenile brown trout were more active and aggressive if they were incubated in warmer water as eggs than if they were incubated in colder water, and trout remained inactive longer when encountering predators if they were cold incubated. Brown trout were less active and aggressive when an Atlantic salmon was present than when a burbot or no predator was present. Behavioural responses did not differ between trout that had been subjected to water with versus without predator odours during embryogenesis, possibly because brown trout were not subjected to conspecific alarm cues during egg incubation. This study shows that thermal conditions during embryogenesis can influence fish behaviour early in life and thus contribute to behavioural variation, with potential effects on life history. Considering the rapid warming of northern regions, elevated embryonic temperatures may contribute substantially to variation in salmonid behaviour in the near future.

Influence of Walker Sex and Familiarity on Scent-Marking Behavior of Juvenile and Mature Shelter Dogs

Many mammals living on farms, in zoos, and in research settings behave differently with familiar people versus strangers, and the sex of the person can also influence interactions. We conducted two studies to examine the influence of a dog’s sex and maturity and a walker’s sex and familiarity on the behavior of shelter dogs during leash walks. In Study 1 with unfamiliar walkers (n = 113 dogs), we found that mature males urinated at higher rates when walked by a woman than by a man, whereas mature females urinated at similar rates. Mature males and mature females were less likely to defecate when walked by a man than by a woman. Juvenile dogs were generally less affected than mature dogs by a walker’s sex, suggesting a role for experience in mature dogs’ responses. In Study 2, when dogs were walked more than once by a man and a woman (n = 81 dogs), we found patterns of urination and defecation like those in Study 1. Importantly, the effects of the dog’s sex and maturity and the walker’s sex on dogs’ patterns of urination and defecation did not change over walks as dogs became familiar with walkers. Dogs in shelters are directly exposed to so many people that they may be less responsive to differing degrees of familiarity than mammals living in other settings. Our data indicate that dog maturity and sex and human sex influence dog–human interactions.