Considering decoupled phenotypic diversification between ontogenetic phases in macroevolution: An example using Triggerfishes (Balistidae)

Across the Tree of Life, most studies of phenotypic disparity and diversification have been restricted to adult organisms. However, many lineages have distinct ontogenetic phases that do not reflect the same traits as their adult forms. Non-adult disparity patterns are particularly important to consider for coastal ray-finned fishes, which often have juvenile phases with distinct phenotypes. These juvenile forms are often associated with sheltered nursery environments, with phenotypic shifts between adults and juvenile stages that are readily apparent in locomotor morphology. However, whether this ontogenetic variation in locomotor morphology reflects a decoupling of diversification dynamics between life stages remains unknown. Here we investigate the evolutionary dynamics of locomotor morphology between adult and juvenile triggerfishes. Integrating a time-calibrated phylogenetic framework with geometric morphometric approaches and measurement data of fin aspect ratio and incidence, we reveal a mismatch between morphospace occupancy, the evolution of morphological disparity, and the tempo of trait evolution between life stages. Collectively, our results illuminate how the heterogeneity of morpho-functional adaptations can decouple the mode and tempo of morphological diversification between ontogenetic stages.

The Predation Behaviour of Fictor composticola on Parasitic Nematodes of Button Mushroom, Agaricus bisporus

In this study, the predation behaviour of male and female predatory nematode, Fictor composticola, was studied on five prey nematode species, Aphelenchus avenae, Aphelenchoides swarupi, Ditylenchus myceliophagus, Bursilla sp. and Panagrolaimus sp., found in the white button mushroom compost. The period of the study is of six months. The data recorded on number of encounters, part of the body of prey attacked, stage of the prey attacked, duration of feeding etc. The strike rate and prey susceptibility were calculated. The average number of encounters on all the five preys done by female F. composticola was 3.0 and that of the male was 6.0. Male F. composticola had more number of encounters on the prey nematode species than the females. Both the sexes preferred juvenile stages over adults as prey. The most attacked part by both females and males predator, was the posterior part of the prey body. In 80% of cases, female predators fed on the first encountered prey while males attacked the first encountered prey in 30% of cases only. The strike rate of female F. composticola was more (78.6%) than the male (48.2%). Mycophagous nematodes were more susceptible to predator’s attack than the microbivorous nematodes. The strike rate of the predator on different prey nematode species was found more on mycophagous nematodes than on microbivorous nematodes and minimum on Panagrolaimus sp. The average feeding duration of female F. composticola was 8 min and 31 sec and in the case of males it was 4 min and 11 sec.

­Redescription of Panonychus caglei Mellott, 1968, with ontogenetic development (Acari: Tetranychidae)

A redescription of the adult stages of Panonychus caglei Mellott, 1968 (Acari: Tetranychidae), is presented based on new material collected from Japan, and type specimens (holotype and paratypes). Morphological differences in the setation of legs have been reported and measurements of taxonomic characters are added. We also have described the ontogenetic development of the juvenile stages. The ventral idiosomal chaetotaxy in larval stage lacks pregenital and genital setae which are added consecutively through development. The pregenital pair of setae appears in the protonymphs while the first pair of genital setae is firstly observed in the deutonymphal stage.

The Overexpression of NUC Promotes Development and Increases Resistance to Nitrogen Deficiency in Arabidopsis thaliana

NUTCRACKER (NUC) is a transcription factor expressed in multiple tissues, but little is known about its physiological roles. In this study, we explored the physiological function of NUC with the Arabidopsis knockout, rescue, and overexpression lines. We found that NUC overexpression promoted development at the germination, seedling, and juvenile stages. NUC overexpression increased resistance to nitrogen (N) deficiency stress by increasing the chlorophyll content, suppressing anthocyanin accumulation, and increasing the biomass under N deficiency. In contrast, the absence of NUC did not affect such characteristics. N deficiency significantly increased the expression of NUC in leaves but did not affect the expression of NUC in roots. The overexpression of NUC promoted primary root length under both normal and N deficiency conditions. Furthermore, we found that the N-responsive and lateral-root-related genes TGA1 and NRT2.4 had NUC-binding sites in their promoter regions and that their expression was upregulated by NUC under N deficiency. The overexpression of the NUC increased the number and length of the lateral roots under N deficiency through inducible promotion. Multiple lines of investigation suggest that the regulatory function of the NUC could be bypassed through its redundant MAGPIE (MGP) when the NUC is absent. Our findings provide novel insight into NUC’s functions and will assist efforts to improve plants’ development and resistance to nutrient stresses.

Skeletal Deformities in Cultured Juvenile African Catfish Clarias gariepinus (Burchell, 1822)

Skeletal deformities in cultured fish are known worldwide and it had affected the survival, growth and appearance of the fish which contribute to production loss. Clarias gariepinus is known as number one farmed fish in Malaysia. C. gariepinus also effected in these deformities especially in cultured species. The objectives of this study are to identify the skeletal deformities that occur in juvenile stages and to compare the bone structure between the normal and deformed fish. A total of 50 juveniles’ fish were collected from Aquaculture Extension and Community Centre Machang, Kelantan. The juvenile was measured before undergo staining process. The fish were starved for one day then fixed in 70% ethanol for two weeks. The fish were then stained with alizarin red S for cartilage and Alcian blue for bone. The specimens were photographed in order to observe the deformities. The data showed only 13.0% juveniles have skeletal deformities, 10.9% with lordosis and 2.2% scoliosis. The cause of the deformities may be due to the heterogenous growth but other factors might also contribute to the problem. As the conclusion, the skeletal deformities observed in juvenile C. gariepinus were detected with the whole-mount staining method ranged from size 7.3 and 26.0 cm in total length. This study shows there is heterogenous growth rearing at low percentage even from skilled farm. Further study should concentrate on hidden factors that affected the deformity rate and mineralization of the juvenile fish.

Pilot study to investigate the effect of long-term exposure to high pCO2 on adult cod (Gadus morhua) otolith morphology and calcium carbonate deposition

To date the study of ocean acidification on fish otolith formation has been mainly focused on larval and juvenile stages. In the present pilot study, wild-captured adult Atlantic cod (Gadus morhua) were exposed to two different levels of pCO2, 422µatm (ambient, low pCO2) or 1091µatm (high pCO2), for a period of 30 weeks (from mid-October to early April 2014–2015) in order to study the effects on otolith size, shape and CaCO3 crystallization amongst other biological parameters. We found that otoliths from cod exposed to high pCO2 were slightly smaller (− 3.4% in length; − 3.3% in perimeter), rounder (− 2.9% circularity and + 4% roundness) but heavier (+ 5%) than the low pCO2 group. Interestingly, there were different effects in males and females; for instance, male cods exposed to high pCO2 exhibited significant changes in circularity (− 3%) and roundness (+ 4%) compared to the low pCO2 males, but without significant changes on otolith dimensions, while females exposed to high pCO2 had smaller otoliths as shown for length (− 5.6%), width (− 2%), perimeter (− 3.5%) and area (− 4.8%). Furthermore, while the majority of the otoliths analysed showed normal aragonite deposition, 10% of fish exposed to 1091µatm of pCO2 had an abnormal accretion of calcite, suggesting a shift on calcium carbonate polymorph crystallization in some individuals under high pCO2 conditions. Our preliminary results indicate that high levels of pCO2 in adult Atlantic cod might affect otolith growth in a gender-specific way. Our findings reveal that otoliths from adult cod are affected by ocean acidification, and we believe that the present study will prompt further research into this currently under-explored area.

Multiple stressors and recruitment failure of long-lived endangered freshwater mussels with a complex life cycle

Multiple stressors can interactively affect the population of organisms; however, the process by which they affect recruitment efficiency remains unclear for empirical populations. Recruitment efficiency can be regulated at multiple stages of life, particularly in organisms with complex life cycles. Understanding the interactive effects of multiple stressors on recruitment efficiency and determining the bottleneck life stages is imperative for species conservation. The proportion of <20-year-old juveniles of the endangered freshwater pearl mussel Margaritifera togakushiensis, which has an obligate parasitic larval stage, was investigated in 24 rivers from eastern Hokkaido, northern Japan to reveal the influence of nutrients, fine sediment, and their combined effects on juvenile recruitment efficiency. The following indices for recruitment at adult, parasitic, and post-parasitic juvenile stages were obtained from 11 of these rivers: gravid female density, glochidia density (the number of glochidia infections per stream area), and juvenile survival rate. This study explored the bottleneck stages of recruitment efficiency and the interactive effects of the two stressors on these stages. Twenty-four population status assessments determined that the proportion of juveniles ranged from 0.00 to 0.53, and juveniles were absent from four rivers. The results showed that the parasitic and post-parasitic juvenile stages were bottlenecks for recruitment efficiency. Juvenile survival rates had a more significant positive effect on recruitment efficiency in rivers with a high glochidia density. Juvenile survival rate was decreased by the synergistic interaction of nutrients and fine sediment, although factors limiting glochidia density were not found. The nutrient concentration of rivers in the study region was well explained by the proportion of agricultural land cover and urban areas in the watersheds, but no relationship was detected between fine sediment abundance and land use. This study suggests that nutrient management at a catchment scale can be effective for re-establishing the recruitment of M. togakushiensis, particularly in rivers with a high content of fine sediments. The results also emphasise the importance of considering both parasitic and post-parasitic juvenile stages of mussels to maximise the positive effects of stressor mitigation.

Activation of EGFR signaling by Tc-Vein and Tc-Spitz regulates the metamorphic transition in the red flour beetle Tribolium castaneum

Animal development relies on a sequence of specific stages that allow the formation of adult structures with a determined size. In general, juvenile stages are dedicated mainly to growth, whereas last stages are devoted predominantly to the maturation of adult structures. In holometabolous insects, metamorphosis marks the end of the growth period as the animals stops feeding and initiate the final differentiation of the tissues. This transition is controlled by the steroid hormone ecdysone produced in the prothoracic gland. In Drosophila melanogaster different signals have been shown to regulate the production of ecdysone, such as PTTH/Torso, TGFß and Egfr signaling. However, to which extent the roles of these signals are conserved remains unknown. Here, we study the role of Egfr signaling in post-embryonic development of the basal holometabolous beetle Tribolium castaneum. We show that Tc-Egfr and Tc-pointed are required to induced a proper larval-pupal transition through the control of the expression of ecdysone biosynthetic genes. Furthermore, we identified an additional Tc-Egfr ligand in the Tribolium genome, the neuregulin-like protein Tc-Vein (Tc-Vn), which contributes to induce larval-pupal transition together with Tc-Spitz (Tc-Spi). Interestingly, we found that in addition to the redundant role in the control of pupa formation, each ligand possesses different functions in organ morphogenesis. Whereas Tc-Spi acts as the main ligand in urogomphi and gin traps, Tc-Vn is required in wings and elytra. Altogether, our findings show that in Tribolium, post-embryonic Tc-Egfr signaling activation depends on the presence of two ligands and that its role in metamorphic transition is conserved in holometabolous insects.

Safety Profile of Caesalpinia spinosa Aqueous Extract Tested in Oreochromis niloticus Toward Its Application in Dermocosmetics

Herbal extracts have been widely used in dermocosmetics as a source of biomolecules and also as a natural claim. Fruits from Caesalpinia spinosa show great potential for their polyphenolic content, preservative, and film-forming features, as previously reported in specialized literature; however, the toxicity requires investigation. We explored Oreochromis niloticus (tilapia) in larval, alevins, and juvenile stages to evaluate the ex vivo and in vivo genotoxicity and in vivo acute and chronic toxicity of C. spinosa aqueous extract in different concentrations. Cytotoxicity, animal behavior, morphological deformities, and DNA damage were evaluated. Our results showed genotoxic effect in ex vivo tests, but no DNA damage in in vivo erythrocytes. We suggest a mechanism of cell permeability involved in the toxicity of C. spinosa aqueous extract. Internal validation showed the feasibility of O. niloticus applied for toxicity evaluation. Further studies could contribute for better understanding the uses and safety of C. spinosa in cosmetics and topical pharmaceutical products.