02578nas a2200193   4500008004100000020001400041245013700055210006900192260001100261300001200272490000700284520185200291653002302143100002202166700002202188700002102210700001802231856013502249       2009                        eng d  a0007-485300aFlight take-off and walking behavior of insecticide-susceptible and -resistant strains of Sitophilus zeamais exposed to deltamethrin0 aFlight takeoff and walking behavior of insecticidesusceptible an  cAugust  a393-4000 v993 aInsects have evolved a variety of physiological and behavioral responses to various toxins in natural and managed ecosystems. However, insect behavior is seldom considered in insecticide studies although insects are capable of changing their behavior in response to their sensory perception of insecticides, which may compromise insecticide efficacy. This is particularly serious for insect pests that are physiologically resistant to insecticides since insecticide avoidance may further compromise their management. Locomotion plays a major role determining insecticide exposure and was, therefore, considered in investigating the behavioral responses of male and female adult insects from an insecticide-susceptible and two insecticide-resistant strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), a major pest of stored cereals. Different dose-dependent behavioral responses were expected among strains with behavioral resistance less likely to occur in physiologically resistant insects since they are able to withstand higher doses of insecticide. The behavioral responses to deltamethrin-sprayed surfaces differed among the maize weevil strains. Such responses were concentration-independent for all of the strains. Stimulus-independent behavioral resistance was unrelated to physiological resistance with one resistant strain exhibiting higher rates of flight take-off and the other resistant strain exhibiting lower flight take-off. Female mobility was similar for all strains, unlike male mobility. Males of each strain exhibited a pattern of mobility following the same trend of flight take-off. Behavioral patterns of response to insecticide are, therefore, variable among strains, particularly among insecticide-resistant strains, and worth considering in resistance surveys and management programs.10aSitophilus zeamais1 aGuedes, N., M. P.1 aGuedes, R., N. C.1 aFerreira, G., H.1 aSilva, L., B.  uhttps://weevil.myspecies.info/flight-take-and-walking-behavior-insecticide-susceptible-and-resistant-strains-sitophilus-zeamais-ex02937nas a2200193   4500008004500000020001400045245014700059210006900206260001100275300001200286490000700298520219400305653002302499100001902522700002202541700002402563700002102587856013502608       2008                        Engldsh    a0007-485300aEnhanced activity of carbohydrate- and lipid-metabolizing enzymes in insecticide-resistant populations of the maize weevil, Sitophilus zeamais0 aEnhanced activity of carbohydrate and lipidmetabolizing enzymes   cAugust  a417-4240 v983 aInsecticide resistance is frequently associated with fitness disadvantages in the absence of insecticides. However, intense past selection with insecticides may allow the evolution of fitness modifier alleles that mitigate the cost of insecticide resistance and their consequent fitness disadvantages. Populations of Sitophilus zeamais with different levels of susceptibility to insecticides show differences in the accumulation and mobilization of energy reserves. These differences may allow S. zeamais to better withstand toxic compounds without reducing the beetles' reproductive fitness. Enzymatic assays with carbohydrate- and lipid-metabolizing enzymes were, therefore, carried out to test this hypothesis. Activity levels of trehalase, glycogen phosphorylase, lipase, glycosidase and amylase were determined in two insecticide-resistant populations showing (resistant cost) or not showing (resistant no-cost) associated fitness cost, and in an insecticide-susceptible population. Respirometry bioassays were also carried out with these weevil populations. The resistant no-cost population showed significantly higher body mass and respiration rate than the other two populations, which were similar. No significant differences in glycogen phosphorylase and glycosidase were observed among the populations. Among the enzymes studied, trehalase and lipase showed higher activity in the resistant cost population. The results obtained in the assays with amylase also indicate significant differences in activity among the populations, but with higher activity in the resistant no-cost population. The inverse activity trends of lipases and amylases in both resistant populations, one showing fitness disadvantage without insecticide exposure and the other not showing it, may underlay the mitigation of insecticide resistance physiological costs observed in the resistant no-cost population. The higher amylase activity observed in the resistant no-cost population may favor energy storage, preventing potential trade-offs between insecticide resistance mechanisms and basic physiological processes in this Population, unlike what seems to take place in the resistant cost population.10aSitophilus zeamais1 aAraujo, R., A.1 aGuedes, R., N. C.1 aOliveira, M., G. A.1 aFerreira, G., H.  uhttps://weevil.myspecies.info/enhanced-activity-carbohydrate-and-lipid-metabolizing-enzymes-insecticide-resistant-populations-maiz