OBJECTIVES: To investigate how larval feeding regimens influence development and deltamethrin resistance of Aedes albopictus to provide evidence for standardizing larval feeding protocols in studies of insecticide resistance. METHODS: Aedes albopictus larvae of a laboratory resistant strain were divided into 3 groups (n=500) and reared with high, medium, and low food availability (100, 50, or 25 mg daily for the 1st and 2nd instars, and 500 mg 250, or 125 mg daily for 3rd and 4th instars). The developmental time, pupation rate, adult emergence rate, adult body weight, and wing length were recorded in each group, and deltamethrin resistance of the mosquitoes was assessed using larval bioassays and contact tube tests for adults. RESULTS: Significant developmental differences were observed across the 3 feeding groups. Larval development time decreased as the food availability increased, and both high- and low-food groups showed reduced pupation rates (χ²=16.282, 7.440) and emergence rates (χ²=4.093, 6.977) compared to the medium-food group. Adult body weight and wing length were positively correlated with the amount of larval food intake (P<0.05). In high, medium and low food intake groups, larval LC₅₀ values for deltamethrin were 0.110, 0.072 and 0.064 mg/L, adult KDT50 values were 97.404, 68.964 and 65.005 min, and adult mosquitoe mortality rates at 24 h after deltamethrin exposure were 12%, 16% and 19%, respectively. CONCLUSIONS The feeding amount during larval stage significantly impacts the development and deltamethrin resistance of Aedes albopictus, suggesting the importance of standardization of larval nutrition for ensuring comparability of resistance test data across laboratories.
Animals ; Aedes/physiology* ; Pyrethrins/pharmacology* ; Nitriles/pharmacology* ; Larva/physiology* ; Insecticide Resistance ; Insecticides/pharmacology* ; Feeding Behavior

Nanodrugs are widely utilized in the biomedical fields,exhibiting immense potential in cancer therapy in particular.However,tumors exist in an extremely complicated microenvironment where substances like collagen are continuously deposited and remodeled,leading to significant alterations in the mechanical properties of the extracellular matrix(ECM)during tumor development.Previous research has primarily focused on the specific physicochemical properties of nanodrugs,such as particle size,electric charge,shape,surface chemistry,etc.,and their effects on cellular uptake,cytotoxicity,and in vivo pharmacokinetics.Limited studies have been done to explore the impact of ECM mechanical properties on nanodrug delivery.In this review,we systematically summarized the relevant research findings on this topic from the perspective of the characteristics and testing methods of tumor ECM mechanics.Additionally,we made a thorough discussion of the potential mechanical and biological mechanisms involved in nanodrug delivery.We proposed several noteworthy research directions.Regarding the overall strategy,there is a need to emphasize targeted delivery that combines ECM mechanics and nanomechanics to achieve precise drug delivery.Regarding the spatial aspect,attention should be given to the nonlinear spatial mechanical heterogeneity within the interior of solid tumors and the construction of mechanic microenvironment-adaptive nanocarriers to improve the delivery efficiency.Regarding the temporal aspect,emphasis should be placed on the dynamic development and changes in the mechanical microenvironment during solid tumor growth and treatment processes.Based on the stromal mechanical characteristics of the tumor tissues of individual patients,personalized treatment strategies can be formulated,which will enhance treatment specificity and efficacy.In addition,issues such as mechanically targeted nanodrug delivery,degradation,and metabolism under dynamic ECM mechanical conditions warrant further investigation.