Based on recent studies using both field surveys and laboratory experiments, we review a number of central reproductive traits of the androdioecious barnacle Scalpellum scalpellum. For the first time in any scalpellid species, development has been followed from cypris settlement until a mature dwarf male and compared with the early ontogeny of hermaphrodites. Cyprids settled in preformed receptacles on mature hermaphrodites started to deviate structurally from hermaphrodites almost immediately after attachment. After 14 days they had matured into adult dwarf males that do not resemble any stage in hermaphrodite ontogeny. Therefore, S. scalpellum males are not hermaphrodites arrested in development but the result of a much more profound evolutionary history. Settlement experiments showed that all cyprids are capable of settling and developing into hermaphrodites. Development into males happens only in cyprids attached in receptacles on adult hermaphrodites and must therefore be governed by environmental sex determination (ESD), presumably induced by some chemical factor(s) present only in the receptacle area. We observed mating between hermaphrodites and between a hermaphrodite and its dwarf males. Hermaphrodite to hermaphrodite mating resembles that seen in balanomorphan barnacles, except that adjacent specimens often check their environment with their cirri for the presence of a mating partner. Dwarf male mating is by means of a unique penis structure, made almost exclusively of cuticle and extending from inside the male and bending down into the brood chamber of its partner. This male penis is much larger (relatively to body size) than the structurally very different penis of the hermaphrodite individuals. The hermaphrodite recognizes when the dwarf male extends its penis and arrests its cirral motion so as not to damage or disturb its tiny partner. For the adult hermaphrodites we showed that their allocation of resources to male and female functions is in agreement with predictions from sex allocation theory. As predicted, solitary hermaphrodites allocated fewer resources to male function than those settled gregariously, where one or several hermaphrodite partners are within mating distance. The solitary individuals had both a shorter penis and less developed testes than the gregarious ones. As also predicted, solitary hermaphrodites were more likely to carry males than the gregarious ones.
Environmental DNA (eDNA) detection in aquatic systems is influenced by multiple environmental factors that can be broadly classified into physical and biological processes. Physical factors include water flow, turbidity, and ultraviolet radiation, whereas biological factors include microbial activity that promotes DNA degradation. River dynamics, which are often disrupted by flooding and flow events, can affect eDNA detection. The increased flow during floods and sediment drift cause turbidity. The effects of sediment drift on eDNA, including adsorption, degradation, and PCR inhibition, and the effects of flow on eDNA, including dilution, have been previously studied. However, the combined effects of flow and sediments on eDNA detection have not been extensively explored. In the present study, we investigated the influence of flow and sediment on eDNA concentrations in closed-bottle aquariums with zebrafish to distinguish the effects of these physical forces from those of eDNA dilution. Our results revealed that flow affects eDNA concentration not only through dilution, but also through physical destruction, indicating that fast flows can physically degrade eDNA. Additionally, the effects of sediment on eDNA varied with the presence of flow. The eDNA settled in the sediment and could potentially be preserved without flow. However, in the presence of flow, sediment particles caused physical damage to suspended eDNA, thereby accelerating its eDNA degradation. This study represents a first step toward understanding eDNA degradation behavior during floods while considering sediment drift.
This study examined the feasibility and preliminary signals of change associated with PEACE, an intervention designed to reduce emotional distress and support emotional regulation in children with developmental disorders attending after-school care facilities in Japan. The program was delivered using narrated slides and worksheets, and staff members received training to support implementation. A total of 13 children were initially assigned to the intervention group, of whom 7 were included in the final analysis, and 32 children were included in the control group. The study employed a quasi-experimental design with pre-intervention, post-intervention, and three-month follow-up assessments. Outcome measures included caregiver and staff ratings of emotional problems, hyperactivity/inattention, and social skills. Caregiver ratings suggested a reduction in emotional problems, whereas no consistent changes were observed in staff ratings. Given the small and imbalanced sample, these findings should be interpreted as preliminary. Qualitative data indicated variability in children’s engagement and responses, suggesting that the program’s acceptability and usefulness may depend on individual characteristics such as developmental level and cognitive functioning. Overall, the findings support the feasibility of implementing the program in after-school care settings while highlighting the importance of adapting content and delivery to individual needs. Further research with larger samples and more detailed measures is needed to clarify the mechanisms underlying observed changes and to evaluate effectiveness more rigorously.
The family Scalpellidae is a large family of barnacles containing ca. 200+ nominal species. These barnacles inhabit a wide range of depths, although most species live in the deep sea. These species are dioecious (with large females and dwarf males) or androdioecious (with large hermaphrodites and dwarf males), with one or more dwarf males settling in a specific location (the receptacle) in the larger individuals. We studied the reproductive ecology of six dioecious scalpellid barnacle species in the deep sea, which differ in size and habitat depth. Intraspecific analyses revealed that there was a positive relationship between female size and egg number in all the species, but no significant relationship existed between female size and egg size. No trade-off was detected between the size and number of eggs in a brood. Moreover, there was a positive relationship between female size and the number of dwarf males in three species that possess receptacles that carry more than one male. On the other hand, interspecific analyses suggested that female size was positively related to egg size, egg number, and the number of dwarf males. Considering the large variety of reproductive traits and the many species in this group, further research is needed to elucidate how reproductive traits have evolved in scalpellids.
Ga2Se3 and Ga2Te3 crystallize to the cubic zincblende structure, where 1/3 of the cation sites are vacant. Semiconductors with large concentrations of vacancies are actively studied due to their potential for application. In this article, the modulated structure in quenched Ga2Te3 has been studied using single crystal X-ray diffraction data. Analysis of satellite reflections observed at q = (0.06, 0.06, 0.00)(c) revealed that the real structure is tetragonal and belongs to the superspace group I4 m2(alpha, 0, 0)0(0, alpha, 0)0. The structure is characterized by an occupational modulation caused by Ga vacancies, and accompanying displacement modulations of both Ga and Te atoms. The origin of the displacement modulations was discussed and attributed to the expanding motions around the Ga vacant sites. These motions are concave downward (toward -z) along [110](c), while they are upward (toward +z) along [-110].
