Evaluation of Optimal Reference Genes for qRT-PCR Analysis in Hyphantria cunea (Drury)

The relative quantification of gene expression is mainly achieved through reverse transcription-quantitative PCR (qRT-PCR); however, its reliability and precision rely on proper data normalization using one or more optimal reference genes. Hyphantria cunea (Drury) has been an invasive pest of forest trees, ornamental plants, and fruit trees in China for many years. Currently, the molecular physiological role of reference genes in H. cunea is unclear, which hinders functional gene study. Therefore, eight common reference genes, RPS26, RPL13, UBI, AK, RPS15, EIF4A, β-actin, α-tub, were selected to evaluate levels of gene expression stability when subjected to varied experimental conditions, including developmental stage and gender, different tissues, larvae reared on different hosts and different larval density. The geNorm, BestKeeper, ΔCt method, and NormFinder statistical algorithms were used to normalize gene transcription data. Furthermore, the stability/suitability of these candidates was ranked overall by RefFinder. This study provides a comprehensive evaluation of reference genes in H. cunea and could help select reference genes for other Lepidoptera species.

Effect of Larval Density of Helicoverpa armigera (Hubner) on Pod Damage and Yield of Chickpea

Background: Chickpea (Cicer arietinum L.) is cultivated in almost all parts of world covering more than 50 countries spread over Asia, Africa Europe, Australia, north America and South America countries and is the second most important food legumes crop after common bean (Phaseolus vulgaris L.). Chickpea has played a major role in realization of pulse Revolution in india making the country near self-sufficient in pluses. Gram is extensively grow in india. Due to its high nutritional value and its ability to fix atmospheric nitrogen, its more widely cultivated rabi pulse crop. The gram pod borer Helicoverpa armigera (Hubner) is most important pest of chickpea. Many pesticides were so far tested against this pest but due to over use of these pesticides resistance, residue and resurgence problems arises, beside destruction of natural enemies. Methods: To determination of per cent pod damage and yield of chickpea due to different larval density of H. armigera is an important tool to reduce the cost of cultivation by avoiding the unnecessary use of pesticides. Therefore, a pot experiment was conducted in arranged in a completed randomized design with four replications. The pots were placed under natural field conditions and take observation at Research farm, Rajasthan Agricultural Research Institute, Durgapura, Jaipur during 2015-16 and 2016-17. Result: The results revealed that least per cent pod damage (29.05, 24.78%) was recorded when the larval population was one per plant, while the maximum pod damage (64.55 and 67.76%) was recorded during 2015-16 and 2016-17, respectively. The simple liner correlation analysis indicated that there was a significant positive correlation (r= 0.989 and 0.999) between the larval density and per cent pod damage. Further, a significant correlation was noticed between larval density and number of healthy pods per plant, reduction in yield, yield per plant, total number of pod and damaged pods were -0.964, -0.976; 0.98, 0.986; -0.98, -0.986; 0.117, 0.126 and; 0.985 and 0.992, respectively during 2015-16 and 2016-17.

KEPADATAN JENTIK Aedes aegypti SEBAGAI VEKTOR DEMAM BERDARAH DENGUE (DBD) DI DESA KALIANCAR WONOGIRI

Dengue Hemorrhagic Fever (DHF) is a disease caused by the dengue virus which is transmitted through the bite of the Aedes sp. These mosquitoes are found throughout the world and their breeding is quite fast. Density of larvae found in breeding sites in an area. This density can be measured by entomological indicators. This larval density measurement can indicate the potential for larvae in Kaliancar Village, Selogiri District, Wonogiri Regency. This research is an observational study (survey) with cross sectional. The sampling technique used is simple random sampling with single larvae method. The samples of this study were 100 houses of residents of Kaliancar Village RW 01, RW 03, RW 04 and RW 05. The results showed that the HI value was 20%, CI 7,22%, BI 20%, ABJ 80% and DF 3,66. The conclusion of this study is that the larval density in Kaliancar Village, Selogiri District, Wonogiri Regency is classified as moderate because the DF value is on a scale of 3 to 4 with an average of 3,66.

Control effectiveness of APL formulation against dengue- and Zika-transmitting Aedes mosquitoes in Gia Lai province, Vietnam

Background: Dengue fever and Zika are two of the Aedes-borne diseases. Despite being widely used, synthetic mosquitocides become abortive for the mosquito control due to growing resistance and environmental pollution. In Gia Lai province (dengue-endemic area), a huge amount of cashew nut shell waste with roughly 100,000 tons/year has been disposed of into the environment, potentiating a high risk of pollution. Methodology/Principal findings: To utilize it, anacardic acid was extracted and combined it with ethanol extract of the local lime peel, which contains limonene, to generate APL formulation. APL robustly exhibited inhibition of egg hatching, larvicidal effect, and repellent effect against female mosquitoes from oviposition sites in the laboratory and field. The results showed that, at a dose of 12.5 ppm, the APL formulation after 24 hours of treatment demonstrated oviposition deterrence against Ae. aegypti (43.6%) and Ae. albopictus (59.6%); inhibited egg hatching of Ae. aegypti (49.6%) and Ae. albopictus (59.6%); caused larval lethality in Ae. aegypti (LC 50 = 9.5 ppm, LC 90 = 21 ppm) and Ae. albopictus (LC 50 = 7.6 ppm, LC 90 = 18 ppm). Under natural field conditions, it showed a 100% reduction in larval density after 48 and 72 hours of the APL treatment at a tested concentration of 120 mg a.i./m 2 and maintained a mortality rate of 100% in the next 14 days. Conclusions/Significance: The APL formulation is promisingly to become an environmentally friendly and highly effective biological product for future management programs of dengue and Zika-transmitting vectors. Here offer prospects in controlling critical illnesses transmitted by several mosquito species in dengue-endemic areas.

Gene-environment interactions at the foraging locus of Drosophila

Environmental variability during the development of an organism has known impacts on the expression of certain behavioural patterns. We used the fruit fly Drosophila melanogaster to investigate how different environmental conditions interact with the allelic variants of rover (forR) and sitter (fors) at the foraging locus to affect food-related behaviour of larvae. We discovered that larval density and nutrient availability were key environmental factors affecting the larval behaviour during early development. High larval density decreased the tendency of rovers to leave a food patch and reduced their travelled path lengths, such that rovers and sitters showed no more significant differences regarding their behaviour. Similar results were obtained when starving the larvae. Furthermore, cutting the availability only of specific nutrients such as sugar, fat or protein during development all affected larval foraging behaviour and locomotion.

Larvae of migratory Characiformes species in an archipelago in the Lower Amazon River

In the Amazon basin, most of the migratory Characiformes species represent an important fishing resource for local people. However, the lack of information about the main areas and periods of reproduction and the importance of certain environments for the maintenance of species may jeopardize the renewal of fish stocks. Thus, the aim was to examine the spatial and seasonal variation in the density of larvae of migratory Characiformes species in an archipelago in the Lower Amazon River and to assess the importance of this environment for the biological recruitment of the studied species. The capture of larvae was carried out in places close to restinga swamps, steep ruts, and inlet areas with a plankton net (300 µm) in monthly sampling from January to December 2013. An analysis of variance was used to verify differences in larval density between seasons and sampling months. A total of 30,997 larvae were captured and showed no significant differences in their distributions between habitats. However, a variation between the phases of the hydrological cycle was evident, in which the highest larval concentrations were observed during the flooding (17.72 larvae.10m-3) and the drought (1.33 larvae.10m-3). The study area has a great capacity to assist in the maintenance and renewal of regional fish stocks, as it is an important retention and nursery site for larvae of Characiformes that drift along the main channel of the Amazon River.

Density-by-diet interactions during larval development shape adult life-history trait expression and fitness in a polyphagous fly

Habitat quality early in life determines individual fitness, with possible long-term evolutionary effects on groups and populations. In holometabolous insects, larval ecology plays a major role in determining the expression of traits in adulthood, but how ecological conditions during larval stage interact to shape adult life-history and fitness, particularly in non-model organisms, remains subject to scrutiny. Consequently, our knowledge of the interactive effects of ecological factors on insect development is limited. Here, using the polyphagous fly Bactrocera tryoni, we conducted a fully-factorial design where we manipulated larval density and larval diet (protein-rich, standard, and sugar-rich) to gain insights into how these ecological factors interact to modulate adult fitness. As expected, a protein-rich diet resulted in faster larval development, heavier and leaner adults that were more fecund compared with standard and sugar-rich diets, irrespective of larval density. Females from the protein-rich larval diet had overall higher reproductive rate (i.e., eggs per day) than females from other diets, and reproductive rate decreased linearly with density for females from the protein-rich but non-linearly for females from the standard and sugar-rich diets over time. Surprisingly, adult lipid reserve increased with larval density for adults from the sugar-rich diet (as opposed to decreasing, as in other diets), possibly due to a stress-response to an extremely adverse condition during development (i.e., high intraspecific competition and poor nutrition). Together, our results provide insights into how ecological factors early in life interact and shape the fate of individuals through life-stages in holometabolous insects.

Larval densities of the protected Striped lychnis moth Shargacucullia lychnis (Lepidoptera: Noctuidae) in Buckinghamshire

Natural history information is essential for ecologically-relevant inferences about (adaptive) responses in organismal biology. Yet, natural history data can be difficult to obtain, particularly for the developmental stages of holometabolous insects. This gap can compromise our ability to design controlled experiments that provide useful understanding of insect responses to changing environments and precludes our ability to understand how natural populations may respond to unpredictable climatic changes in their natural environment. In this study, we collated data from previous reports from the Butterfly Conservation Upper Thames Branch on the larval population density of Shargacucullia lychnis (Lepidoptera: Noctuidae) in Buckinghamshire. In the UK, S. lychnis is a protected species, for which natural history information can be invaluable for its effective conservation. We report here that the natural range of larval densities observed for S. lychnis across locations and years is 0.001 to 6.417 larvae per spike. More importantly, S. lychnis larval density has overall declined from 1996 to 2020, which could support previous reports of a contraction in population range for this species. Overall, this study provides invaluable information about larval population density for an important protected Lepidopteran species of the UK.

Modeling the effects of Aedes aegypti’s larval environment on adult body mass at emergence

Mosquitoes vector harmful pathogens that infect millions of people every year, and developing approaches to effectively control mosquitoes is a topic of great interest. However, the success of many control measures is highly dependent upon ecological, physiological, and life history traits of mosquito species. The behavior of mosquitoes and their potential to vector pathogens can also be impacted by these traits. One trait of interest is mosquito body mass, which depends upon many factors associated with the environment in which juvenile mosquitoes develop. Our experiments examined the impact of larval density on the body mass of Aedes aegypti mosquitoes, which are important vectors of dengue, Zika, yellow fever, and other pathogens. To investigate the interactions between the larval environment and mosquito body mass, we built a discrete time mathematical model that incorporates body mass, larval density, and food availability and fit the model to our experimental data. We considered three categories of model complexity informed by data, and selected the best model within each category using Akaike’s Information Criterion. We found that the larval environment is an important determinant of the body mass of mosquitoes upon emergence. Furthermore, we found that larval density has greater impact on body mass of adults at emergence than on development time, and that inclusion of density dependence in the survival of female aquatic stages in models is important. We discuss the implications of our results for the control of Aedes mosquitoes and on their potential to spread disease.