Present status and future prospects to safeguard Nepali citrus industry against Chinese citrus fly (Bactrocera minax Enderlein)

Unlike other Tephrid flies, the Chinese citrus fly (Bactrocera minax Enderlein) is univoltine and oligophagous species strictly restricted to citrus fruits. It has been a serious threat to the citrus industry in China, Bhutan, India and Nepal causing up to 100% of fruit drop before the harvest. Citrus groves, especially tight-skinned cultivars, sweet orange (Citrus sinensis L. Osbeck) in mid-hill districts like Ramechhap, Sindhuli, Dolakha, Kavre, Syangja, Gulmi, etc. have been threatened while in some pockets, lemon, acid lime, and mandarin have vanished due to the Chinese citrus fly (CCF). The driver behind the spread of this invasive pest seems to be poor research works on the phenology of the pest, ill-equipped management practices, flying nature of adult fly and easy movement of infested fruits. Therefore, with reviewing published data, this study aimed to figure out the most appropriate management technology for curbing the CCF and make comprehensive material for safeguarding the citrus industry in the future. Since Area-Wide Integrated Pest Management (AW-IPM) or Area-Wide Control Program (AWCP) was found to be an effective tool to control the CCF, individual practices are crucial to incorporate. Monitoring the pest with the lure of protein hydrolase (PH) and subsequently killing adults with attractive protein baits of 25% hydrolyzed protein + insecticide as lethal dinner is mentioned exceptionally better. In AWCP domestic practice: orchard sanitation is not so effective if the orchards are sloppy while shallow tillage adds less to the natural enemy mechanism of CCF pupae in the soil. Equally, we conclude that Sterile Insect Technology (SIT) is not so economical and the boons of natural enemies, parasitoid and entomo-pathogens against CCF, is yet to be exploited

Research Progress on Diapause in Flies (Diptera)

Diapause is a physiological process in which insects can survive in a natural environment that is not conducive to their survival, which is the result of long-term adaptation to environmental conditions. It provides a great adaptive advantage for insects, allowing insects to survive in unsuitable seasonal environments to synchronize their life cycles with those suitable for growth, development, and reproduction. The process of regulating insect diapause is a complex process interacting with multiple mechanisms. In this chapter, a review is given of the current knowledge of diapause types, environmental inducing factors, sensitive states, and the endogenous molecular mechanism associated with diapause in flies (Diptera). Research regarding both the diapause process and intrinsic mechanism is reviewed

Life cycle and eco-friendly management of Chinese fruit fly (Bactrocera minax) in sweet orange (Citrus sinesis Osbeck) in Nepal

Sweet orange (Citrus sinensis Osbeck) is a highly profitable fruit crop of Nepal. However, for the past five years, farmers experienced poor productivity partly attributed to the severe infestation of exotic Chinese fruit fly (Bactorcera minax), particularly in Sindhuli and Ramechhap district of Nepal. In this context, we attempted to review on identification, life cycle, and eco-friendly management of Chinese fruit fly. The review is documented based on a field visit and relevant works of literature from Journal articles, books, pamphlets, etc. The Chinese fruit fly has tremendous ability to take a long-range flight, thus,  migrated from China to Bhutan and crossing the Indo-Nepal eastern border, finally reached to eastern mid-hills of Nepal.  Moderate temperature and low humidity of mid-hills of Nepal are favorable for the exponential growth of the pest. Being sweet orange most preferable commodity, the host range of the fly includes almost all the citrus fruits. The fly has damaged 20-50% of the fruit every year and resulted in a loss of millions of rupees.  Therefore various pest management practices can be deployed for sustainable eco-friendly management of the pest. The Chinese fruit fly can be successfully managed by hydrolase protein baits, regular pruning, augmentation of bio-control agents, and using soft systemic insecticides. Various other options for the management of Chinese fruit fly are also discussed with their biological efficacy for the sustainable and eco-friendly management of pests

Life history, dormancy regulation, reproductive physiology and basic behaviour of the subtropical fruit fly Rhagoletotrypeta pastranai (Diptera:Tephritidae)

With the purpose of broadening knowledge on the evolution of life history strategies and behaviour of fruit flies within the tribe Carpomyini, the natural history and mating behaviour of the poorly known species Rhagoletotrypeta pastranai Aczl, are described for the first time. Larvae of R. pastranai were recovered from infested Celtis tala Gillies ex Planch and Celtis iguanaea (Jacq.) Sarg. during a 2-month fruiting period. Adults emerged from the recovered pupae after an average of 144.9 ± 3.9 days for females and 143.2 ± 3.38 days for males, suggesting that most individuals became dormant. Results of a variable winter length study suggested that environmental factors other than winter length may regulate dormancy/diapause duration in this subtropical species. Under laboratory conditions, R. pastranai adults lived an average of 51.13 ± 3.06 days in case of females and 48.08 ± 3.76 days in case of males, and required 5-15 days to reach sexual maturity. Behavioural observations under confinement revealed scarce sexual activity but sufficed to determine that, as in other members of the tribe Carpomyini, R. pastranai exhibits a male resource defence mating system. We discuss our findings emphasizing the importance of documenting the natural history and behaviour of unknown species of family Tephritidae and additionally, we highlight the necessity of future research to understand factors regulating dormancy/diapause and the evolution of life history strategies and sexual behaviour of subtropical species.Fil: Moyano, Andrea del Huerto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Abraham, Solana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Van Nieuwenhove, Guido Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Rull Gabayet, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentin

Insect Behavior and Physiological Adaptation Mechanisms Under Starvation Stress

Intermittent food shortages are commonly encountered in the wild. During winter or starvation stress, mammals often choose to hibernate while insects—in the form of eggs, mature larvae, pupae, or adults opt to enter diapause. In response to food shortages, insects may try to find sufficient food to maintain normal growth and metabolism through distribution of populations or even migration. In the face of hunger or starvation, insect responses can include changes in behavior and/or maintenance of a low metabolic rate through physiological adaptations or regulation. For instance, in order to maintain homeostasis of the blood sugar, trehalose under starvation stress, other sugars can be transformed to sustain basic energy metabolism. Furthermore, as the severity of starvation increases, lipids (especially triglycerides) are broken down to improve hunger resistance. Starvation stress simultaneously initiates a series of neural signals and hormone regulation processes in insects. These processes involve neurons or neuropeptides, immunity-related genes, levels of autophagy, heat shock proteins and juvenile hormone levels which maintain lower levels of physiological metabolic activity. This work focuses on hunger stress in insects and reviews its effects on behavior, energy reserve utilization, and physiological regulation. In summary, we highlight the diversity in adaptive strategies of insects to hunger stress and provides potential ideas to improve hunger resistance and cold storage development of natural enemy insects. This gist of literature on insects also broadens our understanding of the factors that dictate phenotypic plasticity in adjusting development and life histories around nutritionally optimal environmental conditions

A Functional Genomics Approach to Overwintering Mechanisms in Insects

Insects living in temperate and polar environments have developed numerous adaptations to increase survival at low temperatures. A majority of insects are freeze-intolerant and die from internal ice formation, but some are freeze-tolerant and can survive ice formation in extracellular spaces. Both categories of insects prepare for winter with a combination of seasonal and rapid acclimation responses, which differ both in time course and in underlying mechanisms. In this dissertation, I examine adaptations for winter survival in several insect species with a specific focus on molecular mechanisms. To better understand the underpinning mechanisms of these adaptations, I leverage functional genomics approaches and tools. In my first research chapter, I established a cell culture system for studying rapid cold hardening (RCH) in Drosophila S2 cells. RCH is a process whereby a brief non-lethal exposure to cold greatly increases survival to a subsequent cold shock. Tissues are capable of undergoing RCH ex vivo, indicating that RCH is largely regulated at the cellular level. In my work, I demonstrated that cultured Drosophila S2 cells are also capable of RCH, which opens the door to use cell culture tools to identify the cell signaling mechanisms that underly RCH. In my second research chapter, I characterized transcriptomic responses during distinct stages of reproductive diapause in the lady beetle Hippodamia convergens. Diapause is a programmed period of dormancy for surviving adverse seasons, and in the case of H. convergens, diapause creates challenges for its use as a biological control agent. Diapausing females either leave fields upon release or remain close by without feeding. Characterizing the molecular regulation of diapause may facilitate strategies to manipulate diapause in this economically important species. Further, molecular studies of diapause are currently dominated by studies in Diptera, so my work will contribute fundamental insights into the evolutionary physiology of diapause. For this study, I assembled and annotated a de novo transcriptome for H. convergens and found that diapause is accompanied by the upregulation of genes involved in locomotion to facilitate dispersal to overwintering grounds and by the downregulation of genes regulating reproduction. In my third research chapter, I identified molecular processes specific to freezing by comparing gene expression profiles in frozen and supercooled larvae of Belgica antarctica larvae. This Antarctic species is freeze-tolerant, and in wet conditions, larvae freeze due to inoculation from ice crystals in the environment, while in dry conditions, larvae supercool their internal fluids to avoid freezing. These dual strategies offer a rare opportunity to directly compare gene expression changes following both freezing and supercooling, a commonly used strategy for freeze-intolerant species. Despite the challenges associated with ice formation, freezing did not elicit greater overall levels of differential expression or stronger expression of antioxidant and detoxification genes than supercooling. These results indicated that gene expression changes are largely driven by changes in temperature rather than ice formation. Overall, my dissertation highlights that while insect overwintering appears passive on the surface, it is regulated by a dynamic web of gene expression, protein function, and hormone signaling. Furthermore, while some molecular hallmarks are shared across species, overwintering mechanisms can be highly unique to individual species. Thus, continuing to advance understanding of insect overwintering mechanisms will require careful coordination of study species, methodological approaches, and thorough data analysis. Together, my work provides critical insights into how insects survive winter at the molecular level

Research Progress on Reference Genes of Insect for Quantitative Real-time Reverse Transcription PCR (RT-qPCR)

Abstract Quantitative real-time reverse transcription PCR (RT-qPCR) has become the most important method for the quantification of mRNA transcription levels owing to its, specificity, sensitivity, reproducibility, and efficiency. In order to avoid sample-to-sample and run-to-run variations particularly in RNA extraction, RNA quality and cDNA reverse transcription level ,etc. it is necessary to use housekeeping gene which stably expressing as reference gene. Ideally, the housekeeping gene should not be regulated or influenced by the experimental procedure or co-regulated with the target gene. Studies insect models have shown that the expression levels of commonly used reference genes can differ among different tissue, organ types or physiological conditions. However, improper selection of reference genes will result in inaccurate calculation results and consequently obscure actual biological differences among samples, even opposite conclusion. Therefore, reference genes which specific stably expression in each experimental system should be selected in different insects and different experiments. This review aims to provide research achievements of domestic and foreign scholars on insect reference genes, which provide great promise for the future

Area-wide Integrated Pest Management

Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non-target species, air, water and soil. The extensive reliance on insecticide use reduces biodiversity, contributes to pollinator decline, destroys habitat, and threatens endangered species. This book offers a more effective application of the Integrated Pest Management (IPM) approach, on an area-wide (AW) or population-wide (AW-IPM) basis, which aims at the management of the total population of a pest, involving a coordinated effort over often larger areas. For major livestock pests, vectors of human diseases and pests of high-value crops with low pest tolerance, there are compelling economic reasons for participating in AW-IPM. This new textbook attempts to address various fundamental components of AW-IPM, e.g. the importance of relevant problem-solving research, the need for planning and essential baseline data collection, the significance of integrating adequate tools for appropriate control strategies, and the value of pilot trials, etc. With chapters authored by 184 experts from more than 31 countries, the book includes many technical advances in the areas of genetics, molecular biology, microbiology, resistance management, and social sciences that facilitate the planning and implementing of area-wide strategies. The book is essential reading for the academic and applied research community as well as national and regional government plant and human/animal health authorities with responsibility for protecting plant and human/animal health

Area-wide Integrated Pest Management

Extensive reliance on insecticides reduces biodiversity, contributes to pollinator decline, destroys habitat and threatens endangered species. This book offers a more effective application of the Integrated Pest Management (IPM) approach, on an area-wide (AW) or population-wide (AW-IPM) basis. It addresses the importance of problem-solving research, planning and baseline data collection, integrating tools for appropriate control strategies, and pilot trials. The 48 chapters authored by 184 experts cover advances in genetics, molecular biology, biological control, resistance management, modelling, automated surveillance and unmanned aerial release systems