Functional significance of conspicuous colouration in ontogenetic colour changing damselflies

Thesis by publication.Bibliography: pages 134-167.Introduction -- 1. Sexually dimorphic blue bands are intra-sexual aposematic signals in non-territorial damselflies -- 2. Ontogenetic colour change signals sexual maturity in non-territorial damselflies -- 3.Male-male interactions drives the evolution of conspicuous male colouration in a non-territorial mating systems -- 4. Ontogenetic habitat shifts reduce costly male-male interactions -- 5. Female red colouration is an anti-harassment signal in damselflies -- Conclusions.Conspicuous animal colouration is predicted to evolve via sexual selection either to increase mating frequency or to reduce unprofitable mating harassment. The selective agents of conspicuous colouration can vary between the sexes and at different developmental stages. The function of conspicuous colouration is well studied in territorial mating systems but poorly understood in non-territorial mating systems. Here, I aim to study the functional significance of males and females conspicuous colouration at different developmental stages in non-territorial damselflies. In ontogenetic colour changing animals, individuals change colour during adulthood but the causes and consequences of conspicuous colouration at different life stages are often unclear. I studied the functions of male conspicuousness in Xanthagrion erythroneurum damselflies. In this species, males but not females carry conspicuous blue bands on the terminal abdominal segments and thoracic colouration of males change from yellow to red during ontogenesis. I performed mating experiments with males before and after colour change and showed that yellow males are sexually immature and attain conspicuous red colouration upon sexual maturity. Then, I showed that male conspicuous colouration (blue abdominal bands and red thoracic colouration) do not increase mating success via female mate choice, but reduce male-male mating attempts and male aggression in breeding territories. By reducing male aggression, conspicuous males can persist in breeding territories, ultimately increasing their mating success. I investigated the conspicuous female colouration in Agriocnemis femina damselfly, where females change colour from conspicuous red to green upon sexual maturity. I showed that males avoid mating with sexually immature red females and preferred green females that are larger and carry eggs. The juvenile females signal their sexual unprofitability with conspicuous colouration, thereby reducing sexual harassment in the pre-reproductive stages. In conclusion, my thesis provides evidence for the selective benefits of male and females conspicuous colouration in non-territorial mating systems.Mode of access: Internet.1 online resource (xi, 167 pages, illustrations

OdoBD: An online database for the dragonflies and damselflies of Bangladesh.

Combining scientific data over a long-time period is necessary for generating large-scale datasets, which are an essential component of comparative analysis for understanding evolutionary processes. Furthermore, monitoring temporal and spatial distributions of animals at a global and regional scale is essential for studying climate change driven extinction risks. Regional and global datasets focusing on different animal groups are on the rise to meet such challenges. Although being one of the earliest and best-known insect groups, the data on Odonata remains rudimentary and dispersed, especially in the South Asian region. Bangladesh, being located within a biodiversity hotspot, possesses a large number of odonate species and many of them are endemic to the South Asian region. We have developed an online database for the Odonata of Bangladesh by compiling and digitizing data from our last four years of field studies, from previously published research articles and field guides, and also by collecting data from citizen scientists. The Odonata of Bangladesh database (accessible at http://www.odobd.org) contains phenotypic, genotypic, photographic, taxonomic, biogeographic and faunistic data of the Odonata of Bangladesh. The database will be a valuable resource for understanding diversity, distributions, extinction risks and conservation planning of the Odonata of Bangladesh. Finally, phenotypic, spatial and temporal data of Odonata of Bangladesh datasets can be integrated with other regional datasets for analyzing macroevolutionary trends and to monitor the effect of climate change on odonates

Online Support for Education, Medication, Agriculture and Relief Work at COVID-19 Pandemic Time

The future of Bangladesh belongs to the younger generation. All of us have to do our bit to get them involved in improving the lives of the rural poor. If we do not do so, there will be serious social conflicts. Unless we can provide basic amenities so that the rural poor can live a meaningful life, we will never become a great nation. This is a great challenge for all youngsters and it is our work’s dream that they will take it up so as to make Bangladesh a better place to live and work. This work describes an organization named “Neuron Group” which contains four fields: Edu-Care (Neuron Educational Support Center), Medi-Care (Neuron Medical Support Center), Agri-Care (Neuron Agricultural Support Center) and Relief-Care (Neuron Relief Support Center). Students will have the opportunity to study with the most talented doctors and engineers of the country. The contribution of this work is to keep the students in their studies at pandemic time (covid-19 period) with the help of our website and social media such as Facebook, twitter and Instagram. Other contributions of this work are social awareness, to develop rural areas, create employment, help increase the income of poor people, raise awareness among poor people, bringing poor people into the mainstream of society, assistance in agriculture and financial assistance of poor and marginal farmers. In the district where the "Neuron Group will have a branch", a list of rational poor and destitute based on the wards of each Upazila of the district will be prepared and they will be given food aid from time to time

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 absence or presence of parasites 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 intensity 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

Cooler and drier conditions increase parasitism in a subtropical damselfly population

Abstract Host–parasite interactions are impacted by climate, which may result in variation of parasitism across landscapes and time. Understanding how parasitism varies across these spatio‐temporal scales is crucial to predicting how organisms will respond to and cope under a rapidly changing climate. Empirical work on how parasitism varies across climates is limited. Here, we examine the variation of parasitism across seasons and identify the likely climatic factors that explain this variation using Agriocnemis femina damselflies and Arrenurus water mite ectoparasites as a host–parasite study system. We assessed parasitism in a natural population in Sylhet, Bangladesh which is located in subtropical climate between 2021 and 2023. We calculated prevalence (proportion of infected individuals) and intensity (the number of parasites on an infected individual) of parasitism across different seasons. Parasite prevalence and intensity were greater during cooler seasons (autumn and winter) compared to hotter seasons (spring and summer). Mean temperature and precipitation were negatively correlated with parasite prevalence, whereas only mean precipitation was negatively correlated with parasite intensity. Tropical, subtropical and mediterranean regions are predicted to experience extreme climatic events (extreme temperature, less precipitation and frequent drought) as a consequence of anthropogenic climate change, and our finding suggests that this might alter patterns of parasitism in aquatic insects

In Vitro Antimicrobial, Antioxidant and Cytotoxic activities of Polygonum orientale (Bishkatali)

The aim of this present work is to investigate the antimicrobial, antioxidant and cytotoxic activities of methanol extract of Polygonum orientale (Family: Polygonaceae). Antimicrobial activity of methanol extract of Polygonum orientale was tested by Disc Diffusion Method. Standard antibiotic discs of Kanamycin (30µg/disc) for bacterial species was used as standard and crude extracts were used at a concentration of (20mg/disc) and (40mg/disc) for leaves and (10mg/disc) and (20mg/disc) for shoot extracts. The methanol extracts of leaves and shoots showed mild activity against gram positive bacteria, gram negative bacteria and fungi. Most of the organisms were susceptible to the extract in various degrees. The extract showed highest zone of inhibition (13mm) against the Gram (+)ve Bacillus megateriumand and gram (-)ve Escherichia coli (zone of inhibition 10mm). Antioxidant property of the plant extracts against stable DPPH (1, 1-Dipheny1-2-picrydrazole) radical was investigated. Ascorbic acid was used as standard. The extract was found low in antioxidant property. The absorbance was taken at 517nm by UV Spectrophotometer. The IC50 values were found in leaf extract and shoot extract are (1244.58µg/ml and (1506µg/ml). For ascorbic acid IC50 value was (139.19µg/ml). Cytotoxic activity of the crude extract by using Brine Shrimp Lethality Bioassay. Vincristin sulphate was used as standard. LC50 value of leaf extract was found (6.85µg/ml) and (9.7104µg/ml) for the shoot extract. In conclusion, the extract of the experimental plants have mild antimicrobial, low antioxidant and good cytotoxic properties

Study of Dissolution Enhancement of Furosemide by Solid Dispersion Technique Using Different Polymer

The oral route of drug administration is the most common and preferred method of delivery due to convenience and ease of ingestion. The objective of this study is to determine the dissolution enhancement quality of various polymers to Furosemide. Furosemide was selected as the model drug because it is therapeutically extremely important, having very low aqueous solubility and dissolution rate, but they are well permeable through membranes of the gastro-intestinal tract. Solid dispersions of Furosemide were also prepared by fusion method and solvent evaporation method. In this study, the effectiveness of the two methods for furosemide was investigated and compared while the effect of polymer on the dissolution kinetics of the drug was also observed. Poloxamer (two grades of Poloxamer; poloxamer 188 and poloxamer 407 were used in this study ), PEG and HPMC were expected to raise the dissolution rate of the poorly water-soluble furosemide and given its good permeation through GI membrane, to increase their oral bioavailability. To enhance the dissolution and efficacy of furosemide, Poloxamer188, PEG6000, and HPMC 6cps were used in different quantities. This work examined the influence of polymers such as Poloxamer 188 & 407, PEG6000 and HPMC 6cps in different amounts on release profile of furosemide. Through the dissolution studies, the in vitro release profile of the drug formulations was evaluated. An improved in vitro dissolution was obtained in all the systems

FOLIAR APPLICATION OF MICRONUTRIENTS PROMOTES GROWTH AND YIELD-RELATED ATTRIBUTES OF OKRA (Abelmoschus esculentus L.) IN A SLIGHTLY SALINIZED AREA

Background: Micronutrients are required in trace amounts, but are importantly associated with plant growth and development. While soil salinity causes a frequent micronutrient deficiency in soil, the condition withholds plant growth, development, and eventually crop production. Since foliar application of micronutrient provides rapid nutrient absorption compared to soil amendments, it may confer straightforward mitigation of salinity stress. However, micronutrients availability to plants under saline conditions has drawn limited attention. Objective: To study the role of four micronutrients namely boron (B), zinc (Zn), chlorine (Cl), and silicon (Si) as well as their combinations as foliar application on growth, development, and yield responses of ‘okra cv. Nulok F1’ in a naturally very slightly salinized soil. Methodology: The research site belongs to Young Meghna Estuarine Flood Plain under the soil of Agro-ecological Zones (AEZ)-18. The area of EC dsm-1 2.39 is used for the cultivation of horticultural and cereal crops. The one-factor experiment was designed in a randomized complete block design with three replications and six treatments. The factor having six different micronutrients and their combinations under saline soil viz. T1 = control (untreated), T2 = 0.2 % B as solubor®, T3 = 0.2 % ZnSO4, T4 = 0.2 % KCl, T5 = 0.2% SiO2, and T6 = 0.2% solubor® B + 0.2% ZnSO4 + 0.2% SiO2 + 0.2% KCl. Result: A number of foliar treatments of micronutrients substantially improved plant height, stem diameter, leaf number, depth of root, fruit length, number of fruits, single fruit weight, yield plot-1, and total yield. Implication: Among the treatments, Si, and a mixture of solubor® B, Zn, Cl, and Si significantly uphold growth and yield-related attributes of okra indicating them as suitable micronutrients for okra production in salt-affected areas. Conclusion: The foliar application of Si and the mixtures of the four aforementioned micronutrients might enhance the growth and yield attributes of ‘okra cv. Nulok F1’ under salinity stress