Sexual and developmental variations of ecto-parasitism in damselflies

The prevalence and intensity of parasitism can have different fitness costs between sexes, and across species and developmental stages. This variation could arise because of species specific sexual and developmental differences in body condition, immunity, and resistance. Theory predicts that the prevalence of parasitism will be greater in individuals with poor body condition and the intensity of parasitism will be greater in individuals with larger body size. These predictions have been tested and verified in vertebrates. In insects, however, contradictory evidence has been found in different taxa. Here, we tested these predictions on two species of Agriocnemis (Agriocnemis femina and Agriocnemis pygmaea) damselflies, which are parasitized by Arrenurus water mite ectoparasites. We measured body weight, total body length, abdomen area and thorax area of non-parasitized damselflies and found body condition varied between males and females, between immature females and mature females and between A. femina and A. pygmaea. Then, we calculated the parasite prevalence, i.e., the frequency of parasitism and intensity, i.e., the number of parasites per infected damselfly in eleven natural populations of both species. In line to our predictions, we observed greater prevalence in immature females than mature females but found no difference in parasite prevalence between males and females. Furthermore, we found that parasite load was higher in females than males and in immature females than mature females. Our result also showed that the frequency and intensity of parasitism varied between the two studied species, being higher in A. pygmaea than A. femina. Our study provides evidence that parasitism impacts sexes, developmental stages and species differentially and suggests that variation may occur due to sex, developmental stage, and species-specific resistance and tolerance mechanism.

The developmental variations of the sagitta otolith in the young and mature male of a hermaphrodite polynemidae fish, Eleutheronema tetradactylum (Shaw, 1804)

The Eleutheronema tetradactylum is a protandrous, hermaphrodite, marine perciformes fish. The body length of this fish acts as an important diagnostic marker for male and female discrimination. The present study describes for the first time the ultrastructural characteristics on the medial surface of the sagitta otolith in different body size groups of males of E. tetradactylum (Polynemidae: Perciformes) using scanning electron microscopy. The sagitta is a spindle-shaped structure that includes a well-developed rostrum and a poorly developed antirostrum. The sulcus is ostio-pseudocaudal type, almost straight and devoid of the collum. The ostium is a well-developed, vase-shaped structure. The cauda includes the colliculum and a well-developed caudal bulb with several distinct growth stripes. The length of the caudal bulb is significantly correlated to the growth of the body size of the fish. The excisura major is indistinct and the excisura minor is absent. The cristae are distinct on both sides of the sulcus. The one-way ANOVA test revealed that the development of several sagitta features shows significant differences in various body size groups of E. tetradactylum. The growth of the sagitta length is more closely related to the fork length than the sagitta width. Therefore, the sagitta length and the caudal bulb length can be used as important predictors to evaluate the fish size. The cauda region of the sagitta in E. tetradactylum is unique as well as more decorative than those of another Polynemidae fish and other hermaphrodite, marine perciformes fishes. The sagitta characteristics of E. tetradactylum might be advantageous in the identification of the sex and the taxonomy of the hermaphrodite fish species.

Notification alert! Effects of auditory text alerts on attention and heart rate variability across three developmental periods

In a modern world saturated with cellphone-related stimuli, surprisingly little is known about their psychological effects. A small number of previous studies have found global distracting effects of cellphone rings on cognitive performance in undergraduate students. However, moment-to-moment reactions to cellphone sounds have not been investigated, nor have physiological changes that might accompany the cognitive effects. Developmental variations also remain unexamined. Thus, two experiments were conducted to examine the effects of cellphone notification sounds on cognitive performance (i.e., reaction time and accuracy on math problems) and heart rate variability in three age groups: adolescents (mean age: 15 years); young adults (mean age: 20 years); and mid-life adults (mean age: 48 years). Effects were most pronounced in the adolescent group, whose math problem accuracy and reaction time was compromised in response to notification sounds. These compromises were accompanied by increases in heart rate variability.

Stability and Change of Psychopathology Symptoms Throughout Childhood and Adolescence

Assessing stability and change of children’s psychopathology symptoms can help elucidate whether specific behaviors are transient developmental variations or indicate persistent psychopathology. This study included 6930 children across early childhood (T1), late childhood (T2) and early adolescence (T3), from the general population. Latent profile analysis identified psychopathology subgroups and latent transition analysis quantified the probability that children remained within, or transitioned across psychopathology subgroups. We identified four psychopathology subgroups; no problems (T1: 85.9%, T2: 79.0%, T3: 78.0%), internalizing (T1: 5.1%, T2: 9.2%, T3: 9.0%), externalizing (T1: 7.3%, T2: 8.3%, T3: 10.2%) and the dysregulation profile (DP) (T1: 1.7%, T2: 3.5%, T3: 2.8%). From T1 to T2, 44.7% of the children remained in the DP. Between T2 and T3, 33.6% remained in the DP; however, 91.4% were classified in one of the psychopathology subgroups. Our findings suggest that for many children, internalizing or externalizing symptoms encompass a transient phase within development. Contrary, the DP resembles a severe at-risk state in which the predictive value for being in one of the psychopathology subgroups increases over time.

Silence of the Lambs: The Immunological and Molecular Mechanisms of COVID-19 in Children in Comparison with Adults

Children infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can suffer from severe coronavirus disease 2019 (COVID-19). However, compared to adults and the elderly, susceptibility to SARS-CoV-2 infection in children seems to be lower; when infection does develop, most infected children remain asymptomatic or develop a mild disease. Understanding why children seem generally protected from severe COVID-19 and only rarely develop clinical conditions that can cause hospitalization, admission to the pediatric intensive care unit and death can be important. More details on the mechanism of action of SARS-CoV-2 could be defined. Moreover, the role played by children in virus diffusion should be better analyzed, and the development of effective preventive and therapeutic measures against COVID-19 could be favored. The main aim of this paper is to discuss the present knowledge on immunological and molecular mechanisms that could explain differences in COVID-19 clinical manifestations between children and adults. Literature analysis showed that although most children are clearly protected from the development of severe COVID-19, the reasons for this peculiarity are not fully understood. Developmental variations in immune system function together with the potential role of repeated antigen stimulation in the first periods of life on innate immunity are widely studied. As the few children who develop the most severe form of pediatric COVID-19 have certain alterations in the immune system response to SARS-CoV-2 infection, studies about the relationships between SARS-CoV-2 and the immune system of the host are essential to understand the reasons for the age-related differences in the severity of COVID-19.

Unusual development of the celiac trunk and its clinical significance

We describe a case of unusual development of the celiac trunk observed in the cadaver of 1-year old male child. The celiac trunk branched into five vessels: the splenic, common hepatic and left gastric arteries, the left inferior diaphragmatic artery, and a short trunk that branched into the right inferior diaphragmatic artery and right accessory hepatic artery. Additionally, the manner of branching of the vessel was unusual: it was possible to distinguish two branching points that corresponded to its s-shaped trajectory. There were also other variations of vascular supply, such as the presence of a left accessory hepatic artery, an additional superior pancreatoduodenal artery, and others. It should be noted that multiple developmental variations can be common in clinical practice and clinicians should be aware of them during diagnostic and interventional procedures.

Dens evaginatus and dens invaginatus: A report of two cases

Introduction: Developmental disturbances of teeth at the stage of morpho-differentiation have been related to abnormalities associated with changes in the tooth shape and size. Dens evaginatus and dens invaginatus are the developmental variations of the human dentition. Dens evaginatus, a rare anomaly characterized by the presence of a tubercle on the occlusal surface of teeth is seen to occur due to abnormal proliferation and folding of the inner enamel epithelium and part of the dental papilla into the stellate reticulum of the enamel organ; whereas, dens invaginatus is seen to occur due to infolding of the enamel and dentine into the pulp cavity and sometimes extending to the root apex. Case report: We report cases with bilateral dens evaginatus in mandibular second premolars and dens invaginatus in maxillary lateral incisor. Conclusion: Such developmental anomalies of teeth deserve clinical importance, as high chances of early pulpal pathosis.

Resilience Following Child Maltreatment: Definitional Considerations and Developmental Variations

Resilience following childhood maltreatment has received substantial empirical attention, with the number of studies on this construct growing exponentially in the past decade. While there is ample interest, inconsistencies remain about how to conceptualize and assess resilience. Further, there is a lack of consensus on how developmental stage influences resilience and how protective factors affect its expression. The current systematic review uses a developmental lens to synthesize findings on resilience following child maltreatment. Specifically, this article consolidates the body of empirical literature in a developmentally oriented review, with the intention of inclusively assessing three key areas—the conceptualization of resilience, assessment of resilience, and factors associated with resilience in maltreatment research. A total of 67 peer-reviewed, quantitative empirical articles that examined child maltreatment and resilience were included in this review. Results indicate that some inconsistencies in the literature may be addressed by utilizing a developmental lens and considering the individual’s life stage when selecting a definition of resilience and associated measurement tool. The findings also support developmental variations in factors associated with resilience, with different individual, relational, and community protective factors emerging based on life stage. Implications for practice, policy, and research are incorporated throughout this review.