Diet composition (yeast:carbohydrate ratio) is an important determinant of growth, development, and reproduction. Recent studies have shown that decreased yeast intake elicits numerous transcriptomic changes and enhances somatic maintenance and lifespan, which in turn reduces reproduction in various insects. However, our understanding of the responses leading to a decrease in yeast ratio to 0% is limited. In the present study, we investigated the effects of a sugar-only diet (SD) on the gene expression patterns of the oriental fruit fly, Bactrocera dorsalis (Hendel), one of the most economically important pests in the family Tephritidae. RNA sequencing analyses showed that flies reared on an SD induced significant changes in the expression levels of genes associated with specific metabolic as well as cell growth and death pathways. Moreover, the observed upregulated genes in energy production and downregulated genes associated with reproduction suggested that SD affects somatic maintenance and reproduction in B. dorsalis. As expected, we observed that SD altered B. dorsalis phenotypes by significantly increasing stress (starvation and desiccation) resistance, decreasing reproduction, but did not extend lifespan compared to those that received a normal diet (ND) regime. In addition, administration of an SD resulted in a reduction in antioxidant enzyme activities and an increase in MDA concentrations, thereby suggesting that antioxidants cannot keep up with the increase in oxidative damage induced by SD regime. The application of an SD diet induces changes in phenotypes, antioxidant responses, and gene expressions in B. dorsalis. Previous studies have associated extended lifespan with reduced fecundity. The current study did not observe a prolongation of lifespan in B. dorsalis, which instead incurred oxidative damage. The findings of the present study improve our understanding of the molecular, biochemical, and phenotypic response of B. dorsalis to an SD diet.
The neurohormone octopamine regulates many crucial physiological processes in insects and exerts its activity via typical G-protein coupled receptors. The roles of octopamine receptors in regulating behavior and physiology in Coleoptera (beetles) need better understanding. We used the red flour beetle, Tribolium castaneum, as a model species to study the contribution of the octopamine receptor to behavior and physiology. We cloned the cDNA of a β-adrenergic-like octopamine receptor (TcOctβ2R). This was heterologously expressed in human embryonic kidney (HEK) 293 cells and was demonstrated to be functional using an in vitro cyclic AMP assay. In an RNAi assay, injection of dsRNA demonstrated that TcOctβ2R modulates beetle locomotion, mating duration, and fertility. These data present some roles of the octopaminergic signaling system in T. castaneum. Our findings will also help to elucidate the potential functions of individual octopamine receptors in other insects.
is one of the major invasive pests worldwide. The acetic acid-enriched sweet bait trapping is an important method for monitoring and controlling this fly. Several studies showed that acetic acid is perceived by ionotropic receptors (IRs). Thus, we annotated 65 IR genes in the
Abstract The citrus pest Cacopsylla citrisuga (Yang & Li), a vector for Citrus Huanglongbing (HLB), exhibits distinct sensitivity to temperature variations. This study utilized an age-stage, 2-sex life table to evaluate the development and reproduction of C. citrisuga across 5 temperatures (17, 20, 25, 28, and 31 °C). The findings indicate that Cacopsylla citrisuga can complete its life cycle within the range of 17–28 °C, with optimal temperature at 20 °C, where the highest survival and fecundity rates in females were observed. An increase in temperature correlates with a decrease in developmental duration for all stages, with the shortest at 28 °C. The net reproductive rate (R0) peaked at 20 °C, while the intrinsic rate of increase (r) and the finite rate of increase (λ) increased with the increase of temperature. Conversely, the average generation time (T) decreased with the increase of temperature, underscoring the pivotal role of temperature in population dynamics. The developmental threshold temperature and effective accumulated temperature were determined for each stage, furnishing crucial parameters for pest management strategies. This research highlights the importance of temperature in dictating the distribution and prevalence of C. citrisuga, offering valuable insights for the development of targeted control measures against this HLB vector.
In this study, we investigated the effects of dietary restriction (DR) and variable diets on phenotypes and gene expression in oriental fruit fly, Bactrocera dorsalis (Hendel), one of the most economically important pests in the family Tephritidae around the world. As expected, we found that DR altered the B. dorsalis phenotypes by significantly increasing stress resistance and lifespan, but reduced egg production when compared with the control diet. The results suggested a trade-off between reproduction versus somatic maintenance (stress resistance) and lifespan in B. dorsalis. Diet also had a significant effect on hatchability, and DR could increase the egg hatching success of B. dorsalis. Furthermore, DR up-regulated metabolic pathways involved in energy homeostasis and down-regulated pathways in egg production, which might mediate trade-offs between somatic maintenance and reproduction under DR regimes. The gene expression profiles in response to the acute dietary switches indicated that the digestive and metabolic pathways maybe involved in the adaptability of flies to variable dietary resources. In summary, the research facilitates a better understanding of the molecular mechanisms responsible for the B. dorsalis' phenotypic adjustments to the different qualities of the available diets.
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