Physiological Entomology最新文献

The Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae), is a global vector of dengue, chikungunya and zika viruses. With extreme adaptability of survival as diapause eggs, this mosquito has invaded and established in temperate climatic zones. The diapause eggs are specially programmed to overcome the harsh winter conditions in temperate habitats. In the laboratory, diapausing females are reared from early larval instars under short-day conditions (21°C and 16D:8 L photoperiods). Aedes albopictus is normally fed on Guinea pigs for the rearing of diapause mosquitoes which requires ethical approval from the animal use committee and costly arrangements. Therefore, the present study was conducted to find whether bovine serum albumin protein (10%) with sucrose (5%) solution (SAP-10) offered through a membrane-free feeding system would result in an alternative diet for the production of diapause eggs in comparison to blood-feeding. This feeding system shows a considerable rate of engorgement of diapausing females under short-day conditions and produced 30.8 diapause eggs/female in comparison to blood-feeding on a guinea pig (40.9 eggs/female). The diapause rate of viable eggs for the SAP-10 diet (95.28%) was similar to the blood-feeding (96.32%). The findings suggest that the present diet feeding system is a promising tool for the rearing of diapause Ae. albopictus mosquitoes under short-day conditions. Further studies are suggested to evaluate the physiological and developmental aspects of mosquitoes reared on the diet.

Caloric intake can greatly affect many aspects of an organism's life. A deficiency of calories can lead to stress resulting in decreased fecundity, insufficient calories to maintain tissues and increased lifespan. Conversely, increasing caloric density increases fecundity and decreases lifespan. Despite decades of work exploring food quality and quantity on physiology in the model species Drosophila melanogaster  Meigan 1830 (Diptera: Drosophilidae) and the melanogaster group in general, relatively little work explores the physiological responses to diet manipulation in other Drosophila species, like the obscura species group. Here, we looked at the effects of five different caloric densities (0.5×, 0.75×, 1.0×, 1.5× and 3.0×) on food intake, body weight, body fat, fecundity and longevity in D. pseudoobscura Frolova & Astaurov, 1929 (Diptera: Drosophilidae). Comparing longevity and fecundity across diets, we found that heavy caloric concentration (3.0×) decreases lifespan and that calorie restriction (0.5× and 0.75×) led to significant decreases in fecundity and body weight. However, calorie concentration did not significantly increase D. pseudoobscura body fat. By expanding our understanding of the physiological responses to diet stress to D. pseudoobscura, we establish the framework for comparative work across Drosophila species. With this information, we can then identify which physiological responses to diet manipulation might be most conserved and comparable across species.

Rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Plutellidae) is an important migratory pest in Asia. While many lepidopteran species are known to enhance adult life history by obtaining supplementary nutrition, little is known about the effects of adult diet on C. medinalis. We first examined the effects of offering five dilutions of honey solution (0%, 5%, 10%, 15% and 20%) on the longevity, fecundity and ovary development of adult C. medinalis. We then compared the effects of 10% honey solution to 25% glucose solution, which was previously reported to be the best adult diet for C. medinalis. We found that adult male and female C. medinalis fed 5%–20% honey solution lived significantly longer than those fed just water. Importantly, a honey–based diet accelerated and increased ovary development and prolonged the oviposition period, leading to higher fecundity. More specifically, females fed 5%–15% honey solution had the highest fecundity, followed by 20% honey solution, and the lowest when fed only water. In addition, the oviposition rate was 100% in females fed 10% and 15% honey solution. When we compared 10% honey solution to 25% glucose solution, those fed honey solution had significantly higher estimated female performance, which is a composite measure consisting of fecundity, percentage of egg-laying females and percentage of eggs that hatched. Overall, our findings indicate that adult diet quality significantly impacts C. medinalis performance and that using a 10%–15% honey solution is optimal for mass-rearing under laboratory conditions.

This study investigates the impact of imidacloprid insecticide, on the flesh fly Sarcophaga ruficornis, (Diptera: Sarcophagidae), a medically and veterinary significant species associated with myiasis. Lethal (0.02%) and sub-lethal (0.004%) doses were administered over 24 and 48 h, focusing on midgut histopathological, ultrastructural and biochemical alterations. Imidacloprid-induced disruptions in physiological and metabolic functions, leading to adult fly mortality. Histological and cytological analyses revealed significant cellular changes, including cell degeneration, cytoplasmic vacuolization, chromatin condensation, irregular epithelial borders, disrupted peritrophic membrane and the release of cell components into the midgut lumen. Biochemical analyses demonstrated a decrease in total protein, carbohydrate and lipid contents, correlating with insecticide concentration and duration. Antioxidant enzymes, particularly glutathione S-transferase (GST) and superoxide dismutase (SOD), resulted in a significant increase compared to the control, proportional to time and concentration. This research provides a comprehensive understanding of imidacloprid-induced toxicity in the midgut of Sarcophaga ruficornis, emphasizing its potential for effective pest population management.

Sensory mechanotransduction is the process of deciphering physical stimuli into neural electrical receptor potentials, essential to Drosophila, the fruit fly. Nearly every aspect of an adult Drosophila intricate behavioural repertoire that involves the senses of proprioception, hearing, touch, olfaction, balancing and graviception. Mechanotransduction are mediated by a wide variety of specialized sensilla and sensory neurons that comprise the antenna. The eye and antenna of Drosophila melanogaster are derived from a cluster of approximately 23 cells that are set aside during embryonic development and are constantly divided during the three larval stages, organizing into an epithelial sac known as the eye-antennal imaginal disc. During late larval and pupal development, the forward lobe of this epithelium, known as the antennal disc, gives rise to the antenna (an organized tripartite structure), whereas the posterior lobe, known as the eye disc, gives rise to the eye. The development of the antenna is a complex and intricate process that relies on the interplay of numerous genes. Each gene involved contributes to the regulatory network that governs the formation, differentiation, and patterning of specific structures within the antenna, ensuring its proper functionality. Thus, aberrant expression or mutation of any gene results in a faulty antenna. The defectiveness appears in terms of antennal structure leading to loss of function including defective behaviour found in an organism. A similar kind of structure–function relation of hearing with a behavioural defect has been reported in vertebrates. Some of the behavioural defects associated with genes are conserved in both vertebrates and Drosophila. Thus, a behavioural assay is an adaptable approach to studying the functionality of various genes associated with the antennae. Here a crucial relationship is established between the genetic regulation of mechanosensory neurons and an organism's behaviour. The current review summarizes antennae development, function and several methods used to study the mechanosensory behaviour associated with Drosophila antennae.

Cockroaches, ubiquitous pests known for significant reproduction and as potential vectors of diseases, are notorious for their adoptability to a variety of insecticides that cause substantial challenges in pest control. The present research evaluated the LC₅₀ concentrations of imidacloprid (0.65 mg/L) and clothianidin (2.5 μg/L) for Blattella germanica using topical and bait methods. The cockroaches were exposed to one-third concentration of LC₅₀ at a regular interval of 1, 2, 4, 8, 12, 16 and 20 days. During exposure, the activity of P450 monooxygenase increased, whereas the activity of brain acetylcholinesterase decreased. Lactate dehydrogenase, alkaline and acid phosphatase activity were highest on day 4, with a slight recovery on day 20. The elevated activities for superoxide dismutase and catalase, as well as increased lipid peroxidation levels on day 4, followed by a significant recovery in activity on day 20. The glutathione-S-transferase activity was elevated while the glutathione content was reduced, and a significant restoration was observed at the end of the experiment. The biochemical mechanisms of the organisms such as P450, esterase enzymes and oxidative systems, are actively involved in the detoxification mechanism. The study elucidated that the insecticide defence mechanism triggers detoxification pathways that encompass the metabolism of endogenous insecticidal compounds, with clothianidin showing greater efficacy and lower detoxification compared with imidacloprid.

The leaf-cutter ant Atta sexdens is crucial in ecological balance and economic activities, due to its contribution to the aeration and accumulation of organic matter in the soil, but it may also be an agricultural pest when it defoliates plants for the fungus growth used as a food source. This leaf-cutter ant exhibits a polymorphic worker caste system with distinct activities in the colony. These functions are performed by workers classified into subcastes, including gardeners, which are responsible for the fungus and brood care; cleaners (waste removers), which remove wastes; foragers, which collect and transport plant parts to the nest; and soldiers, which are responsible for colony defence and the support of foraging activities. In our previous work, we showed that A. sexdens has five types of circulating haemocytes in the haemolymph, which play a vital role in immune defence. Herein, we further investigated the population profile of circulating haemocytes in the haemolymph of different worker subcastes of A. sexdens using flow cytometry. Each subcaste exhibited a single population of haemocytes in the haemolymph. However, a detailed 3D dispersion analysis uncovered five distinct haemocyte subpopulations, two of which presented higher quantities. The soldier displayed haemocytes with high fluorescence intensity, compared with the gardener, waste remover, and forager, along with increased complexity, compared with the gardener subcaste. These results suggest that these cells may be granulocytes and plasmatocytes, which are known for their role in insect immune defence.

The Angoumois grain moth, Sitotroga cerealella (Olivier), is a significant cosmopolitan primary pest of cereals worldwide and has thrived in divergent environments. However, the mechanisms underlying its survival in multiple contrasting environments are poorly understood. Here, we hypothesised that when facing diverse environmental stress, F₁ generation exhibits transgenerational cross-protection as a mechanism to persist under divergent stressful environments. Notably, F₁ acclimation to cold or desiccation conditions could either enhance or lower heat tolerance in the F₂ generation. Specifically, we tested whether typical diurnal fluctuations and/or winter rapid or chronic cold temperatures (18–22°C) as well as desiccation acclimation of F₁ parental population yields transgenerational cross-protection/susceptibility to heat stress on F₂ offspring. F₁ moths were exposed to cold hardening (2 h), chronic (72 h) and variable (fluctuating between 18 and 22°C for 72 h) temperature treatment groups. Desiccation treatment included incubation at 0%–1% relative humidity (24 h). F₂ generation moths were then assessed for heat tolerance using critical thermal maxima (CT_max) at three different ramping rates (0.06, 0.25 and 0.5°C/min) as well as heat knockdown time (HKDT). Findings indicated that (i) desiccation, cold hardening and chronic low-temperature acclimations in F₁ reduced heat tolerance in F₂ populations and (ii) ramping rate was crucial to decipher differences between treatment groups, with lower ramping rates associated with lower CT_max. Transgenerational cross-susceptibility to heat stress indicates possible fitness costs of exposure to multiple contrasting stressors in the Angoumois grain moth and can be used in designing physical pest management strategies.

The primary function of odorant-binding proteins (OBPs) is thought to be binding and transporting odorants molecules. The research on the molecular mechanisms of SfruOBPs binding with sex pheromones is beneficial to the prevention and control of Spodoptera frugiperda (S. frugiperda). Herein, two screened SfruOBPs (Sfru10933 and Sfru21187) were knocked down by RNA interference, and then the changes in electroantennogram (EAG) and behavioral responses of male mutants to their main sex pheromone components were recorded. Upon interfering with Sfru10933, the EAG response and behavioural preferences of males to sex pheromones were significantly reduced or eliminated. The interference with Sfru21187 resulted in a weakening of the behavioural preference, while the EAG response remained unchanged. However, the co-interference of Sfru10933/Sfru21187 led to a significant reduction in the EAG activity of male to sex pheromones. These results reveal that Sfru10933 and Sfru21187 play a crucial role in sex pheromone recognition, and there may be a synergistic effect between them. Furthermore, these results will help clarify the perception of sex pheromones by S. frugiperda, which may provide new targets for the development of mating inhibitors in the future.