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1.
Pesticides are now chronically found in numerous ecosystems incurring widespread toxic effects on multiple organisms. For insects, the larvae are very exposed to pesticide pollution and the acute effect of insecticides on larvae has been characterized in a range of species. However, the carry‐on effects in adults of sublethal exposure occurring in larvae are not well characterized. Here, we use a collection of strains of Drosophila melanogaster differing in their larval resistance to a commonly used insecticide, imidacloprid, and we test the effect of larval exposure on behavioural traits at the adult stage. Focusing on locomotor activity and on courtship and mating behaviour, we observed a significant carry‐on effect of imidacloprid exposure. The heritability of activity traits measured in flies exposed to imidacloprid was higher than measured in controls and in these, courtship traits were genetically less correlated from mating success. Altogether, we did not observe a significant effect of the larval insecticide resistance status on adult behavioural traits, suggesting that selection for resistance in larvae does not involve repeatable behavioural changes in adults. This lack of correlation between larval resistance and adult behaviour also suggests that resistance at the larval stage does not necessarily result in increased behavioural resilience at a later life stage. These findings imply that selection for resistance in larvae as well as for behavioural resilience to sublethal exposure in adult will combine and impose a greater evolutionary constraint. Our conclusions further substantiate the need to encompass multiple trait measures and life stages in toxicological assays to properly assess the environmental impact of pesticides.  相似文献   

2.
An evaluation of a mechanical barrier to prevent movement of adult and larval lesser mealworm, Alphitobius diaperinus (Panzer); larder beetle, Dermestes lardarius L.; and hide beetle, Dermestes maculatus De Geer was conducted in caged-layer poultry facilities in New York and Maine. The barrier, a plastic collar wrapped around building support posts, proved highly effective at preventing movement of adult lesser mealworms. Significantly more lesser mealworm larvae were recovered from cardboard collar beetle traps placed below both washed and unwashed barriers than from traps placed above washed and unwashed barriers. Similarly, significantly more adult Dermestes were recovered from traps placed below washed barriers than from above both washed and unwashed barriers. The level of fly specking on the barrier was found to have no significant impact on the numbers of adult lesser mealworms and adult and larval Dermestes recovered either above or below barriers. Fly specking level did significantly impact the numbers of lesser mealworm larvae recovered above the barrier. Although washed barriers provided the greatest deterrent to adult lesser mealworms, the presence of the barrier, regardless of the level of fly specking, provided a significant deterrent to beetle climbing success. Washed barriers further reduced climbing success by lesser mealworm larvae by 17%, Dermestes adults by 7-28%, and Dermestes larvae by 33-38%. The high level of climbing observed by adult lesser mealworms suggests that the impact of adult beetle movement toward birds should be considered in its importance in building damage, disease transmission, feed infestation, and bird productivity and health. Observations on cost and maintenance of the barrier are discussed.  相似文献   

3.
It has been reported that insecticide‐detoxifying enzymes such as glutathione S‐transferases (GST) and esterases are affected by microbial infections in hemipteran insect vectors. The total protein content, and GST and α‐ and β‐esterase activities were quantified in ‘Candidatus Phytoplasma ulmi’‐infected and uninfected adults of Amplicephalus curtulus Linnavuori & DeLong (Hemiptera: Cicadellidae) at 25, 35, and 45 days after the acquisition access period (AAP) in the head‐thorax and abdomen sections. The total protein content was lower in phytoplasma‐infected leafhoppers 25, 35, and 45 days after the AAP. Thirty‐five days after the AAP, the GST and β‐esterase activities had increased (26 and 69%, respectively) compared to the control. However, 45 days after the AAP, the phytoplasma‐infected leafhoppers displayed lower GST (87%) and β‐esterase (253%) activities than the uninfected individuals. On the other hand, the α‐esterase activity proved to be unaffected by the phytoplasma infection. Forty‐five days after the AAP, females had a higher phytoplasma titer (46%) in their head‐thorax than in their abdomen sections, whereas males showed a higher titer in their abdomens (75%). In addition, the GST and β‐esterase activities in the abdomen were affected negatively by 96–98% as a result of the increasing ‘Ca. Phytoplasma ulmi’ titer. These results indicate that an infection of ‘Ca. Phytoplasma ulmi’ alters the metabolic activities of A. curtulus.  相似文献   

4.
Abstract The potential for using imidacloprid (a neonicotinoid) and indoxacarb (an oxadiazine) as grain protectants was investigated in bioassays against resistant strains of five stored grain beetles. The species investigated were Rhyzopertha dominica (F.) (the lesser grain borer), Sitophilus oryzae (L.) (the rice weevil), Tribolium castaneum (Herbst) (the rust‐red flour beetle), Oryzaephilus surinamensis (L.) (the saw tooth flour beetle), and Cryptolestes ferrugineus (Stephens) (the flat grain beetle). Each of these species has developed resistance to one or more protectants, including organophosphorus insecticides, synthetic pyrethroids and the juvenile hormone analogue methoprene. Mortality and reproduction after a 2‐week exposure of adults to treated wheat depended on species, dose and insecticide. Imidacloprid had no effect on S. oryzae at any dose, but none of the other species produced any live progeny at 10 mg/kg. Indoxacarb had no effect on T. castaneum at any dose, but none of the other species produced any live progeny at 5 mg/kg. The results show that although both imidacloprid and indoxacarb can control at least four of the five key pests tested at doses comparable to those used for organophosphorus protectants, more potent neonicotinoid or oxadiazine insecticides would be needed than either of these to provide broad spectrum protection of stored grain.  相似文献   

5.
In Mexico, mosquito vector‐borne diseases are of public health concern as a result of their impact on human morbidity and mortality. The use of insecticides against adult mosquitoes is one of the most common ways of controlling mosquito population densities. However, the use of these compounds has resulted in the development of insecticide resistance. The aim of this study was to estimate susceptibility to six pyrethroids, two carbamates and two organophosphates in Mexican populations of Stegomyia aegypti (Linnaeus, 1762) (= Aedes aegypti) (Diptera: Culicidae) mosquitoes. Bottle insecticide susceptibility tests, with 1 h exposure, were performed on adult mosquitoes from 75 localities across 28 states. At 30 min of exposure, the proportion of fallen mosquitoes was recorded. After 60 min of exposure, mosquitoes were recovered in non‐treated containers and mortality was determined at 24 h after the set‐up of the experiment. In general, the carbamate insecticides represented the most effective group in terms of the proportion of mosquitoes fallen at 30 min (72–100%) and 24‐h mortality (97–100%). High and widespread resistance to pyrethroids Types I and II and, to a lesser extent, to organophosphates was observed. Insecticide susceptibility among and within states was highly variable.  相似文献   

6.
Transferring Trichogramma telengai Sorokina (Hymenoptera: Trichogrammatidae) from 17 to 30 °C or vice versa at different stages of pre‐imaginal development shows that the pupa (particularly late pupa) is a sensitive stage of the maternal thermal response. During this period, even a relatively short period (1–2 days) of cold or heat exposure results, correspondingly, in a marked increase or decrease in the percentage of diapausing progeny. Thus, the maternal thermal response has the same features of sensitivity as those of the previously investigated maternal photoperiodic response, suggesting that photoperiodic and thermal responses share the same mechanism. For the practice of rearing and storage Trichogramma as a biocontrol agent, it is important to note that even relatively short‐term environmental heating (i.e. for one to several days) immediately before adult emergence can drastically decrease the percentage of diapausing progeny.  相似文献   

7.
The codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) is a serious pest of pome fruit crops. A natural enemy of codling moth, the larval ectoparasitoid Mastrus ridibundus (Gravenhorst) (Hymenoptera: Ichneumonidae) has been imported into South America from the USA but little is known about the biology and ecology of the wasp, knowledge that is needed to design an efficient strategy of release and establishment. Experiments were carried out to assess important traits of the biology of the parasitoid in relation to its possible use as a biocontrol agent for codling moth. When M. ridibundus females were offered larvae ranging in weight from 37 to 78 mg, they oviposited more eggs on heavier hosts. In another study, the adult wasps were offered honey, diluted honey (10%) or pollen in paired choice tests and both males and females preferred honey over the other two foods. Females preferred 10% honey over pollen, while the males showed the opposite preference. Honey‐fed females lived longer than starved females. Adults died rapidly at 35°C, while they lived 20 days at 25°C and 12–17 days at 15°C. Female wasps had on average 25 ± 14 and 18 ± 11 progeny at 15 and 25°C, respectively, but they did not had progeny at 35°C. The development time (egg to adult emergence) was on average 44 ± 7 and 24 ± 2 days at 15 and 25°C respectively. Immature insects did not reach the adult stage at 35°C.  相似文献   

8.
The sweet potato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), attacks a wide range of vegetables and ornamental plants in the tropics and subtropics. This study involved observations of adult whitefly courtship behaviours to determine the impact of acetylated glyceride treatment, which is currently being developed as a repellent for adults, on their progeny. In addition, the effect of acetylated glyceride treatment on acoustic‐based communication was evaluated, as this type of communication is known to play a pivotal role in the search for mating partners on host‐plant leaves in adult whiteflies. Adults were able to land on grape tomato leaves a few days after treatment, when the residual repellency had dissipated. Almost no male courtship behaviour in terms of searching for sexually mature females was observed throughout the observation period (60 min) under conditions in which adults of both sexes remained on a treated leaf or those in which an adult of either sex remained on a non‐treated leaf. By contrast, these behaviours accounted for 26.5% of the observation time under conditions in which both sexes remained on a non‐treated leaf. In cross‐tests performed for 4 days using one non‐mated female and two non‐mated males, the sex ratio (male/female) of the newly emerged adults on treated leaves (2.4) was 63.6% lower than that of the non‐treated controls (0.9). During courtship, acoustic signals produced by both sexes were exchanged rhythmically on non‐treated leaves, whereas the signals on treated leaves were irregular. The frequency of the vibratory sound produced by males was 66–81% lower on the treated leaves than on the non‐treated leaves. A large reduction in the acoustic signals produced by males on treated leaves caused a decrease in courting pair formation, leading to a significant reduction in the number of female progeny due to arrhenotokous parthenogenesis in virgin B. tabaci females.  相似文献   

9.
10.
Eggplant Solanum melongena L., is often colonized by two early season insect defoliators. The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and flea beetles Epitrix spp., emerge from their overwintering sites in early spring and seek out emerging host plants such as eggplant. During the 2009 and 2010 growing season, field studies were conducted to investigate the impact of inter‐planting eggplant into a crimson clover (CC), Trifolium incarnatum L., winter cover crop on populations of flea beetles, CPB and their associated arthropod predators. The experiment consisted also of two levels of insecticide usage such as an application of azadirachtins plus pyrethrins followed by several applications of spinosad or no insecticide sprays as subplot treatments. During both study years, significantly fewer (adults, larvae and egg masses) were found on eggplant inter‐planted into CC than in bare‐ground (BG) eggplant plots. Although flea beetle abundance was greater in BG eggplant during 2010, they appeared to be less influenced by the presence of CC than were CPB. Additionally, there was no apparent impact of insecticide treatment on CPB populations on eggplant inter‐planted into CC. However, there was a decline in CPB following treatments with insecticides in BG eggplant plots. This suggests that a winter cover crop such as CC can be used to help manage CPB in eggplant, however, using this tactic in tandem with insecticide sprays may not result in greater CPB management.  相似文献   

11.
Cannibalism, or intraspecific predation, can play a major role in changing individual fitness and population processes. In insects, cannibalism frequently occurs across life stages, with cannibals consuming a smaller or more vulnerable stage. Predation of adult insects on one another is considered to be uncommon. We investigated adult cannibalism in the Colorado potato beetle, Leptinotarsa decemlineata (Say), which is an oligophagous herbivore specializing on plants in family Solanaceae, and an important agricultural pest. Under laboratory conditions, starvation and crowding encouraged teneral adults to feed upon each other, which reduced their weight loss during the period of starvation. However, pupae were attacked and consumed before adults. Injured beetles had a higher probability of being cannibalized than intact beetles. Males were more frequently attacked than females, but that appeared to be a function of their smaller size rather than other gender‐specific traits. Cannibalizing eggs at a larval stage did not affect beetle propensity to cannibalize adults at an adult stage. When given a choice between conspecific adults and mealworms, the beetles preferred to eat conspecifics. Cannibalistic behavior, including adult cannibalism, could be important for population persistence in this species.  相似文献   

12.
Larvae of mealworms Tenebrio molitor L. (Coleoptera: Tenebrionidae) have been used as animal feed, but fungal pathogens rapidly downsize the populations, resulting in economic losses. In this work, we established an effective management strategy for fungal pathogens. An entomopathogenic fungus, Beauveria bassiana, was isolated from mealworm cadavers. The bioassay of some isolates of this species at >90% relative humidity revealed that the ERL1575 isolate had the highest virulence. At 20–30% RH, ERL1575 conidia when ingested produced 80% mortality but when sprayed topically produced only <10% mortality. Mealworms that had ingested conidia were exposed to 20, 25, 30 and 35°C and high humidity (>95%) for 5 days. This experiment produced about 90% mortality except at 35°C where mortality was <20%. When 40 fungicides were assayed against ERL1575, fluazinam (1000‐fold) and mancozeb (667‐fold) significantly inhibited conidial germination and/or hyphal growth. When fluazinam and mancozeb were added to the mealworm diet of conidia‐inoculated wheat bran, most were alive 3 days post application. However, 100% mortality resulted 3 days post application in the conidia‐inoculated wheat bran without any fungicides. In conclusion, B. bassiana isolates are pathogenic at <30°C when they are ingested by mealworms but fluazinam and mancozeb can be used for management to control the pathogen in their cultures.  相似文献   

13.
The adult mouse brain contains a population of constitutively proliferating subependymal cells that surround the lateral ventricle and are the direct progeny of the neural stem cell. Constitutively proliferating cells divide rapidly; 6 days after labeling, 60% of their progeny undergo cell death, 25% migrate to the olfactory bulbs, and 15% continue to proliferate within the subependyma. We have intraventricularly infused a cell survival factor N‐acetyl‐L ‐cysteine (NAC), which is known to have survival effects without concomitant proliferative effects on cells in vitro, and examined the resulting fate of cells spared from the normally occurring cell death. NAC infusion for 5 days results in a five‐fold increase in the number of retrovirally labeled subependymal cells compared to saline‐infused controls. The increase in the number of subependymal cells is directly proportional to the amount of time during which NAC is present and is not due to increased proliferation. While NAC is able to keep all the normally dying progeny alive, the cells spared from death remain confined to the subependyma lining the lateral ventricles and do not migrate to the olfactory bulbs (one normal fate of constitutively proliferating progeny) or into the surrounding brain parenchyma. When animals survive for an additional 6 days following NAC infusion, the number of retrovirally labeled subependymal cells returns to control values, indicating that the continued presence of NAC is necessary for cell survival. These data suggest that preventing cell death is not sufficient to keep all of the progeny of these cells in a proliferative mode. © 2000 John Wiley & Sons, Inc. J Neurobiol 42: 338–346, 2000  相似文献   

14.
Mesenchymal stem/stromal cells (MSC) are being widely explored as promising candidates for cell‐based therapies. Among the different human MSC origins exploited, umbilical cord represents an attractive and readily available source of MSC that involves a non‐invasive collection procedure. In order to achieve relevant cell numbers of human MSC for clinical applications, it is crucial to develop scalable culture systems that allow bioprocess control and monitoring, combined with the use of serum/xenogeneic (xeno)‐free culture media. In the present study, we firstly established a spinner flask culture system combining gelatin‐based Cultispher®S microcarriers and xeno‐free culture medium for the expansion of umbilical cord matrix (UCM)‐derived MSC. This system enabled the production of 2.4 (±1.1) x105 cells/mL (n = 4) after 5 days of culture, corresponding to a 5.3 (±1.6)‐fold increase in cell number. The established protocol was then implemented in a stirred‐tank bioreactor (800 mL working volume) (n = 3) yielding 115 million cells after 4 days. Upon expansion under stirred conditions, cells retained their differentiation ability and immunomodulatory potential. The development of a scalable microcarrier‐based stirred culture system, using xeno‐free culture medium that suits the intrinsic features of UCM‐derived MSC represents an important step towards a GMP compliant large‐scale production platform for these promising cell therapy candidates.  相似文献   

15.
The transgenic maize (Zea mays L.) event MON 88017 produces the Bacillus thuringiensis Berliner (Bt) toxin Cry3Bb1 to provide protection from western corn rootworm (Diabrotica virgifera virgifera LeConte) larval feeding. In response to reports of reduced performance of Cry3Bb1‐expressing maize at two locations in Illinois, we conducted a two‐year experiment at these sites to characterize suspected resistance, as well as to evaluate root injury and adult emergence. Single‐plant bioassays were performed on larvae from each population that was suspected to be resistant. Results indicate that these populations had reduced mortality on Cry3Bb1‐expressing maize relative to susceptible control populations. No evidence of cross‐resistance between Cry3Bb1 and Cry34/35Ab1 was documented for the Cry3Bb1‐resistant populations. Field studies were conducted that included treatments with commercially available rootworm Bt hybrids and their corresponding non‐Bt near‐isolines. When compared with their near‐isolines, larval root injury and adult emergence were typically reduced for hybrids expressing Cry34/35Ab1 either alone or in a pyramid. In many instances, larval root injury and adult emergence were not significantly different for hybrids expressing mCry3A or Cry3Bb1 alone when compared with their non‐Bt near‐isolines. These findings suggest that Cry34/35Ab1‐expressing Bt maize may represent a valuable option for maize growers where Cry3Bb1 resistance is either confirmed or suspected. Consistent trends in adult size (head capsule width and dry mass) for individuals recovered from emergence cages were not detected during either year of this experiment. Because of the global importance of transgenic crops for managing insect pests, these results suggest that improved decision‐making for insect resistance management is needed to ensure the durability of Bt maize.  相似文献   

16.
Resistance to the non‐selective herbicide dl ‐phosphinothricin (PPT) was introduced into commercial Lotus corniculatus cv. Bokor by co‐cultivation of cotyledons with Agrobacterium tumefaciens AGL1 harbouring the binary vector pDM805 which contains the bialaphos resistance gene (bar) from Streptomyces hygroscopicus encoding phosphinothricin acetyltransferase (PAT) and the uidA gene encoding β‐glucuronidase. The half‐cotyledon explants were precultured on regeneration Murashige and Skoog's (MS) medium supplemented with 6‐benzyladenine (BA) and 1‐naphthaleneacetic acid (NAA) at 0.5 mg L?1 each, 3 days prior to infection. Upon co‐cultivation, the explants were cultured on PPT‐free regeneration medium for 10 days, and then subcultured on regeneration/selection media with increasing PPT concentrations (5–7 mg L?1) for about 18 weeks. Out of 480 initially co‐cultivated explants, 272 regenerated shoots survived the entire PPT selection procedure. Resistant shoots were grown further, multiplied by tillering that was additionally promoted by PPT and rooted on hormone‐free MS medium containing 5 mg L?1 PPT. Established shoot cultures, continuously maintained on the same medium, have preserved PPT resistance up to now (more than 2 years). Transformed plants assessed in vitro and in a greenhouse were tolerant to the herbicide PPT at 300 mg L?1 equivalent to more than twofold the recommended field dosage for weed eradication. Applied PPT treatment did not affect the activities of glutamine synthetase (GS; EC 6.3.1.2) and NADH‐dependent glutamate dehydrogenase (NADH‐GDH; EC 1.4.1.2) in transformed plants. However, PPT did increase the mobility of glutamine synthetase isoforms GS1 and GS2 as well as the inhibition of an additional high mobility GS (hmGS) activity. In untransformed plants, PPT treatment reduced total GS activity by 4.4‐fold while contrary the activity of NADH‐GDH was increased by ninefold. All transformed herbicide‐resistant plants were phenotypically normal and exhibited genomic stability, as were the untransformed plants analysed by flow cytometry. Under greenhouse conditions, they grew to maturity, flowered and set seeds. Stable integration and expression of the bar gene in T0 and T1 plants were confirmed by Southern and Western blot analysis, while integration of the reporter uidA gene did not occur. The bar gene was inherited in a Mendelian fashion by the progeny, as detected by PPT resistance. The production of PPT‐resistant plants may have significant practical applications in weed control in fields of L. corniculatus.  相似文献   

17.
Stable isotope analysis (SIA) has emerged as an important tool for understanding consumer diets and diet shifts. However, although the general idea behind SIA is clear, the interpretation of data is often fraught with problems because tissue turnover and fractionations are not known. We investigated shifts in stable isotope composition of spiders following a diet shift, using mealworms fed either maize (C4) or wheat (C3) flour. Mealworms had different carbon isotope composition depending on their diet and this difference was reflected in spider body parts. In the experiment, we first fed the spiders on a diet of either maize‐fed or wheat‐fed mealworms and then switched diet at the time of the second molt. Spiders were then sampled repeatedly until the next molt. We sampled both legs and abdomens, as these are presumed to have different turnover of tissue, and also molt remains were sampled when this was relevant. The data indicated that the spider legs had a turnover of about 20 days, whereas the spider abdomens had a turnover of about 8 days. Molt remains had the slowest turnover and reflected the diet at the previous molt, when the exoskeleton was formed. Both these observations indicate that SIA may be successfully used for elucidating diet shifts. More problematic was the fact that fractionation of carbon isotope ratios varied with body parts and diets. When spiders were fed maize‐mealworms then the fractionation was larger for abdomens, but when the spiders were fed wheat‐mealworms then the fractionation was larger for legs. The mechanisms underlying this pattern are unclear and deserve further attention.  相似文献   

18.
19.
We examined avoidance, tolerance, and resistance strategies of nestling and adult tree swallows Tachycineta bicolor in response to ectoparasitic blowflies Protocalliphora sialia. Tree swallows avoided settling in north‐facing nest boxes early in the breeding season. These boxes were more likely to be parasitized later in the season, suggesting that box selection may facilitate blowfly avoidance. After experimentally manipulating blowfly intensity, we found that nestlings were generally tolerant of parasitism. Parasites significantly reduced nestling blood hemoglobin but had no effect on nestling body mass, primary feather growth, age at fledging, or fledging success. Parents of parasitized nestlings did not increase their food provisioning rate to promote nestling tolerance. Adult female tree swallows demonstrated both tolerance and resistance: blowfly parasitism had no effect on adult hemoglobin and body mass, and those with higher P. sialia‐binding antibody levels had fewer blowfly larvae in their nests. Nestling antibodies were unrelated to blowfly intensity. Despite considerable variation among years, our results suggest that the costs of blowfly parasitism to nestling and adult tree swallows are modest, and limited to blood loss in nestlings. Future work should examine the effects of reduced blood hemoglobin on fledgling survival and the importance of parasite‐specific antibodies.  相似文献   

20.
The ectoparasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) is an important biological control agent for lepidopterous pests of stored products. We investigated the effects of low temperature storage on the quality of adult parasitoids and their progeny. Newly emerged females were stored for 10, 20, 30, 40, 50, and 70 days at 5 ± 1 °C. Several reproductive and developmental parameters were then assessed to determine the quality of the adult parasitoids and their progeny. After more than 30 days of storage, there was a decrease in parental parasitism, but low temperature storage of parents had no effect on parasitism of the F1 generation. Parental longevity and fecundity decreased after more than 20 days of storage, but there was no effect of storage duration on the fecundity and longevity of the F1 generation until a storage duration of 50 days. Development time varied with storage duration but differences were within 2 days. Storage duration had no effect on the sex ratio of F1 and F2 generations. Our data show that H. hebetor can be cold stored for up to 20 days without adversely affecting the performance of the parasitoid. Therefore, short-term storage of H.hebetor adults could be used for maintaining and accumulating large numbers of parasitoids in mass rearing programs.  相似文献   

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