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Silalahi CN, Yasin A, Chen ME, Ahmad I, Neoh KB. Behavioral responses and life history traits of Taiwanese and Indonesian populations of Aedes aegypti surviving deltamethrin-clothianidin treatment. Parasit Vectors 2024; 17:117. [PMID: 38454517 PMCID: PMC10921677 DOI: 10.1186/s13071-024-06189-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 02/08/2024] [Indexed: 03/09/2024] Open
Abstract
BACKGROUND Indoor residual spraying (IRS) capitalizes on the natural behavior of mosquitoes because Aedes aegypti commonly seeks indoor resting sites after a blood meal. This behavior allows mosquitoes to be exposed to insecticide-treated surfaces and subsequently killed. Combinations of deltamethrin and clothianidin with different modes of action have shown promise in IRS, effectively targeting both susceptible and pyrethroid-resistant malaria vectors. However, the effects of this approach on Aedes mosquitoes remain unclear. The present study tested the effects of deltamethrin-clothianidin mixture treatment on behavioral responses and life history traits of Taiwanese and Indonesian populations of Ae. aegypti. METHODS We adopted an excito-repellent approach to explore the behavioral responses of pyrethroid-resistant Ae. aegypti populations from Indonesia and Taiwan to a deltamethrin-clothianidin mixture used in contact irritancy and non-contact repellency treatments. We further evaluated the life history traits of surviving mosquitoes (i.e., delayed mortality after 7-day post-treatment, longevity, fecundity, and egg hatching) and investigated the potential transgenerational hormetic effects of insecticide exposure (i.e., development rate and survival of immatures and adult mosquitos). RESULTS All tested field populations of Ae. aegypti displayed strong contact irritancy responses; the percentage of escape upon insecticide exposure ranged from 38.8% to 84.7%. However, repellent effects were limited, with the escape percentage ranging from 4.3% to 48.9%. We did not observe immediate knockdown or mortality after 24 h, and less than 15% of the mosquitoes exhibited delayed mortality after a 7-day exposure period. However, the carryover effects of insecticide exposure on the survival of immature mosquitoes resulted in approximately 25% higher immature mortality than that in the control. By contrast, we further documented stimulated survivor reproduction and accelerated transgenerational immature development resulting from the sublethal effects of the insecticide mixture. In particular, the number of eggs laid by treated (both treatments) female mosquitoes increased by at least 60% compared with that of eggs laid by control female mosquitoes. CONCLUSIONS IRS with deltamethrin-clothianidin effectively deters Aedes mosquitoes from entering residential areas and thereby reduces mosquito bites. However, the application rate (deltamethrin: 25 mg/m2; clothianidin: 200 mg/m2) may be insufficient to effectively kill Aedes mosquitoes. Insecticide response appears to vary across mosquito species; their behavioral and physiological responses to sublethal doses have crucial implications for mosquito control programs.
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Affiliation(s)
| | - Aqsa Yasin
- Department of Entomology, National Chung Hsing University, 145 Xingda Rd., 402, Taichung, Taiwan
| | - Mei-Er Chen
- Department of Entomology, National Chung Hsing University, 145 Xingda Rd., 402, Taichung, Taiwan
| | - Intan Ahmad
- School of Life Sciences and Technology, Institut Teknologi Bandung, Bandung, West Java, 40132, Indonesia
| | - Kok-Boon Neoh
- Department of Entomology, National Chung Hsing University, 145 Xingda Rd., 402, Taichung, Taiwan.
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Agathokleous E, Blande JD, Masui N, Calabrese EJ, Zhang J, Sicard P, Guedes RNC, Benelli G. Sublethal chemical stimulation of arthropod parasitoids and parasites of agricultural and environmental importance. ENVIRONMENTAL RESEARCH 2023; 237:116876. [PMID: 37573021 DOI: 10.1016/j.envres.2023.116876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 08/14/2023]
Abstract
An increasing number of studies have reported stimulation of various organisms in the presence of environmental contaminants. This has created a need to critically evaluate sublethal stimulation and hormetic responses of arthropod parasitoids and parasites following exposure to pesticides and other contaminants. Examining this phenomenon with a focus on arthropods of agricultural and environmental importance serves as the framework for this literature review. This review shows that several pesticides, with diverse chemical structures and different modes of action, applied individually or in combination at sublethal doses, commonly stimulate an array of arthropod parasitoids and parasites. Exposure at sublethal doses can enhance responses related to physiology (e.g., respiration, total lipid content, and total protein content), behavior (e.g., locomotor activity, antennal drumming frequency, host location, and parasitization), and fitness (longevity, growth, fecundity, population net and gross reproduction). Concordantly, the parasitic potential (e.g., infestation efficacy, parasitization rate, and parasitoid/parasite emergence) can be increased, and as a result host activities inhibited. There is some evidence illustrating hormetic dose-responses, but the relevant literature commonly included a limited number and range of doses, precluding a robust differentiation between sub- and superNOAEL (no-observed-adverse-effect level) stimulation. These results reveal a potentially significant threat to ecological health, through stimulation of harmful parasitic organisms by environmental contaminants, and highlight the need to include sublethal stimulation and hormetic responses in relevant ecological pesticide risk assessments. Curiously, considering a more utilitarian view, hormesis may also assist in optimizing mass rearing of biological control agents for field use, a possibility that also remains neglected.
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Affiliation(s)
- Evgenios Agathokleous
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, 210044, Jiangsu, China; Research Center for Global Changes and Ecosystem Carbon Sequestration & Mitigation, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu, China.
| | - James D Blande
- Department of Environmental and Biological Sciences, University of Eastern Finland, P. O. Box 1627, 70211, Kuopio, Finland
| | - Noboru Masui
- School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, 4228526, Japan
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA
| | - Jing Zhang
- College of Ecological Technology and Engineering, Shanghai Institute of Technology, Shanghai, 201418, PR China
| | | | - Raul Narciso C Guedes
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, Via Del Borghetto 80, 56124, Pisa, Italy
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Agathokleous E, Blande JD, Calabrese EJ, Guedes RNC, Benelli G. Stimulation of insect vectors of pathogens by sublethal environmental contaminants: A hidden threat to human and environmental health? ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 336:122422. [PMID: 37604394 DOI: 10.1016/j.envpol.2023.122422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
Sublethal stimulation and hormetic responses are increasingly identified and acknowledged in scientific research. However, the occurrence and characteristics of such responses in insect vectors of pathogens are little explored and poorly understood. Here, we collate significant evidence from the scientific literature showing that sublethal doses of environmental contaminants, such as pesticides, microplastics, and plasticizers, induce stimulation and hormetic responses in insect vectors of pathogens of agricultural and public health importance, including mosquitoes, other dipterans, psyllids, aphids, and planthoppers. Physiological, behavioral, and demographic traits can be enhanced by exposure to lower subtoxic contaminant doses while being inhibited by higher toxic doses. Energetic trade-offs can also occur, especially at sublethal doses higher than the no-observed-adverse-effect level (NOAEL). The relevant literature is limited and so are the number of doses commonly included in the studies, precluding firm conclusions and enhanced understanding. Nevertheless, these effects are significant and could undermine human and environmental health, and thus sustainability agendas, if ultimately the transmission of pathogens and disease spread and severity are increased. Further research is urgently needed to tackle these phenomena, especially under field conditions. The findings discussed here are relevant to chemical risk assessment and chemical safety evaluations, in which all possible effects from the lowest to higher doses should be considered.
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Affiliation(s)
- Evgenios Agathokleous
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing, 210044, Jiangsu, China; Research Center for Global Changes and Ecosystem Carbon Sequestration & Mitigation, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu, China.
| | - James D Blande
- Department of Environmental and Biological Sciences, University of Eastern Finland, P. O. Box 1627, 70211, Kuopio, Finland
| | - Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA, 01003, USA
| | - Raul Narciso C Guedes
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, Via Del Borghetto 80, 56124, Pisa, Italy
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Agathokleous E, Sonne C, Benelli G, Calabrese EJ, Guedes RNC. Low-dose chemical stimulation and pest resistance threaten global crop production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:162989. [PMID: 36948307 DOI: 10.1016/j.scitotenv.2023.162989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 05/13/2023]
Abstract
Pesticide resistance increases and threatens crop production sustainability. Chemical contamination contributes to the development of pest resistance to pesticides, in part by causing stimulatory effects on pests at low sub-toxic doses and facilitating the spread of resistance genes. This article discusses hormesis and low-dose biological stimulation and their relevance to crop pest resistance. It highlights that a holistic approach is needed to tackle pest resistance to pesticides and reduce imbalance in accessing food and improving food security in accordance with the UN's Sustainable Development Goals. Among others, the effects of sub-toxic doses of pesticides should be considered when assessing the impact of synthetic and natural pesticides, while the promotion of alternative agronomical practices is needed to decrease the use of agrochemicals. Potential alternative solutions include camo-cropping, exogenous application of phytochemicals that are pest-suppressing or -repelling and/or attractive to carnivorous arthropods and other pest natural enemies, and nano-technological innovations. Moreover, to facilitate tackling of pesticide resistance in poorer countries, less technology-demanding and low-cost practices are needed. These include mixed cropping systems, diversification of cultures, use of 'push-pull cropping', incorporation of flower strips into cultivations, modification of microenvironment, and application of beneficial microorganisms and insects. However, there are still numerous open questions, and more research is needed to address the ecological and environmental effects of many of these potential solutions, with special reference to trophic webs.
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Affiliation(s)
- Evgenios Agathokleous
- Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, China; Research Center for Global Changes and Ecosystem Carbon Sequestration & Mitigation, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu, China.
| | - Christian Sonne
- Department of Ecoscience, Aarhus University, Arctic Research Center (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark; Sustainability Cluster, School of Engineering, University of Petroleum & Energy Studies, Dehradun, Uttarakhand 248007, India
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy
| | - Edward J Calabrese
- Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA
| | - Raul Narciso C Guedes
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
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Silalahi CN, Tu WC, Chang NT, Singham GV, Ahmad I, Neoh KB. Insecticide Resistance Profiles and Synergism of Field Aedes aegypti from Indonesia. PLoS Negl Trop Dis 2022; 16:e0010501. [PMID: 35666774 PMCID: PMC9203003 DOI: 10.1371/journal.pntd.0010501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/16/2022] [Accepted: 05/16/2022] [Indexed: 12/05/2022] Open
Abstract
Information on the insecticide resistance profiles of Aedes aegypti in Indonesia is fragmentary because of the lack of wide-area insecticide resistance surveillance. We collected Ae. aegypti from 32 districts and regencies in 27 Indonesian provinces and used WHO bioassays to evaluate their resistance to deltamethrin, permethrin, bendiocarb, and pirimiphos-methyl. To determine the possible resistance mechanisms of Ae. aegypti, synergism tests were conducted using piperonyl butoxide (PBO) and S,S,S-tributylphosphorotrithioates (DEF). The Ae. aegypti from all locations exhibited various levels of resistance to pyrethroids. Their resistance ratio (RR50) to permethrin and deltamethrin ranged from 4.08× to 127× and from 4.37× to 72.20×, respectively. In contrast with the findings of other studies, most strains from the highly urbanized cities on the island of Java (i.e., Banten, Jakarta, Bandung, Semarang, Yogyakarta, and Surabaya) exhibited low to moderate resistance to pyrethroids. By contrast, the strains collected from the less populated Kalimantan region exhibited very high resistance to pyrethroids. The possible reasons are discussed herein. Low levels of resistance to bendiocarb (RR50, 1.24–6.46×) and pirimiphos-methyl (RR50, 1.01–2.70×) were observed in all tested strains, regardless of locality. PBO and DEF synergists significantly increased the susceptibility of Ae. aegypti to permethrin and deltamethrin and reduced their resistance ratio to less than 16×. The synergism tests suggested the major involvement of cytochrome P450 monooxygenases and esterases in conferring pyrethroid resistance. On the basis of our results, we proposed a 6-month rotation of insecticides (deltamethrin + synergists ➝ bendiocarb ➝ permethrin + synergists ➝ pirimiphos-methyl) and the use of an insecticide mixture containing pyrethroid and pyrimiphos-methyl to control Ae. aegypti populations and overcome the challenge of widespread Ae. aegypti resistance to pyrethroid in Indonesia. Insecticide resistance is a major impediment to the successful management of vector-transmitted diseases because it increases the vector’s chances of surviving under insecticide treatment. In Indonesia, the implementation of insecticide resistance management at the national level is particularly challenging due to the vast area and regional disparities in terms of population, health, and socioeconomic status. Previous studies on determining insecticide resistance of Aedes mosquito only focused on several cities in some provinces of Indonesia, making resistance monitoring results difficult to interpret and arguably reflect the generality in Indonesia. To complicate the matter, data released by the Ministry of Agriculture of Indonesia in 2022 showed that approximately 82% of insecticides registered to control Ae. aegypti in Indonesia are pyrethroid-based products. Principally, we found that the synergists PBO and DEF significantly reduce the resistance of field Ae. aegypti from Indonesia toward permethrin and deltamethrin. Bendiocarb and pirimiphos-methyl remain highly toxic to the field strains of Ae. aegypti. We suggest the feasible choice of insecticide group for Ae. aegypti vector management based on the currently registered insecticide inventory. The finding also underscores the urgent need to approve other non-pyrethroid-based insecticides as alternative tools for reducing the risk of resistance development during an outbreak.
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Affiliation(s)
| | - Wu-Chun Tu
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
| | - Niann-Tai Chang
- Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - G. Veera Singham
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, Penang, Malaysia
| | - Intan Ahmad
- School of Life Sciences and Technology, Institut Teknologi Bandung, Bandung, West Java, Indonesia
- * E-mail: (IA); (KBN)
| | - Kok-Boon Neoh
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
- * E-mail: (IA); (KBN)
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Bibbs CS, Kaufman PE, Xue RD. Comparative Evaluation of Metofluthrin as an Outdoor Residual Treatment for Barriers and Harborage Against Aedes albopictus (Diptera: Culicidae). ENVIRONMENTAL ENTOMOLOGY 2020; 49:435-443. [PMID: 31958123 DOI: 10.1093/ee/nvz170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Indexed: 06/10/2023]
Abstract
Spatial repellent studies have demonstrated that volatile pyrethroids reduce human contact with mosquitoes, but field trials targeting the volatile qualities of spatial repellent pyrethroids for integrated pest management are lacking. To investigate the stability and utility of volatile pyrethroids in mosquito management, metofluthrin was formulated into a vegetation spray intended for use on foliage and mosquito harborage. A comparative field evaluation was conducted between Onslaught Fast Cap, the experimental metofluthrin formulation, and a blended treatment of Onslaught Fast Cap and metofluthrin. Environmental fate of the metofluthrin formulation was estimated using aging bioassays to stress the formulated product, while leaf samples were taken from the treated field sites to bioassay against Aedes albopictus (Skuse) and determine a comparative rate of decay. The combined data from the aging bioassays and leaf samples allow inference that the experimental formulation lasts 2-3 wk in most lighting and humidity conditions at ~26.6 ± 1°C. However, regular rainfall jeopardizes continued efficacy. In comparative field efficacy, adult mosquito reductions were comparable between the two products. Onslaught Fast Cap reduced eggs collected in the immediate vicinity by 80-90% but had no effect in adjacent areas. Metofluthrin treatments resulted in a 50-90% reduction of eggs collected for 4 wk up to 60 m away from treated vegetation. However, the blended treatment using metofluthrin as an additive to Onslaught Fast Cap provided ≥80% control of Ae. albopictus adults and eggs, proximal and adjacent to treated areas, for the study duration. Metofluthrin has a great potential as a supporting ingredient to other insecticides.
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Affiliation(s)
- Christopher S Bibbs
- Entomology and Nematology Department, University of Florida, Gainesville, FL
- Anastasia Mosquito Control District, St. Augustine, FL
| | - Phillip E Kaufman
- Entomology and Nematology Department, University of Florida, Gainesville, FL
| | - Rui-De Xue
- Anastasia Mosquito Control District, St. Augustine, FL
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Sasmita HI, Tu WC, Bong LJ, Neoh KB. Effects of larval diets and temperature regimes on life history traits, energy reserves and temperature tolerance of male Aedes aegypti (Diptera: Culicidae): optimizing rearing techniques for the sterile insect programmes. Parasit Vectors 2019; 12:578. [PMID: 31823817 PMCID: PMC6905064 DOI: 10.1186/s13071-019-3830-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 12/02/2019] [Indexed: 12/16/2022] Open
Abstract
Background Producing high quality sterile males is vital in Aedes aegypti rear-and-release birth control strategies. Larval diets, rearing temperatures, and their interactions determine the accumulation rates of essential nutrients in larvae, but these factors have been understudied in relation to mass-rearing techniques for producing eminent males. Methods We compared the effects of two larval diets, a cereal-legume-based diet (Khan’s diet) and a standard larval diet developed in the FAO/IAEA Insect Pest Control Laboratory (IAEA 2 diet). Diets were tested at selected temperatures for both larval and male adult life history traits, adult extreme temperature tolerance, and mating capacity relative to energy reserves of reared male adult Ae. aegypti. Results Khan’s diet resulted in shorter immature development time at each test temperature (except for 25 °C) than an IAEA 2 diet. Larvae reared at 28 °C and 32 °C with Khan’s diet demonstrated low pupation rates (c.80%). We accounted for these phenomena as secondary sex ratio manipulation, because a higher proportion of male adults emerged at 28 °C and 32 °C than that for the IAEA 2 diet. In general, the pupal development time shortened as temperature increased, resulting in higher teneral energy reserves in male mosquitoes. High energy reserves allowed male mosquitoes reared with Khan’s diet to have higher adult longevity (5–6 days longer when sugar-fed and 2–3 days longer when water-fed) and tolerance of heat stress than those fed on the IAEA 2 diet. The IAEA 2 diet produced larger male mosquitoes than Khan’s diet did: mosquitoes fed on Khan’s diet were 1.03–1.05 times smaller than those fed on the IAEA 2 diet at 28 °C and 32 °C. No evidence indicated reduced mating capacity for small mosquitoes fed on Khan’s diet. Conclusions Larvae reared at 28 °C and 32 °C with Khan’s diet were characterized by shorter immature development time compared with those fed on the IAEA 2 diet. Adult mosquitoes produced from that larval rearing condition exhibited a significant male bias, long lifespan, and better endurance against extreme temperatures relative to energy reserves. Thus, the larval diet at rearing temperature of 28 °C and 32 °C optimized rearing techniques for the sterile insect programmes. However, mating competitiveness and flight performance of adult males require further investigation.
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Affiliation(s)
- Hadian Iman Sasmita
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung, 402, Taiwan.,Center for Isotopes and Radiation Application (CIRA), National Nuclear Energy Agency (BATAN), Jl. Lebak Bulus Raya No. 49, Jakarta, 12440, Indonesia
| | - Wu-Chun Tu
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung, 402, Taiwan
| | - Lee-Jin Bong
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung, 402, Taiwan
| | - Kok-Boon Neoh
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung, 402, Taiwan.
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Feng WB, Bong LJ, Dai SM, Neoh KB. Effect of imidacloprid exposure on life history traits in the agricultural generalist predator Paederus beetle: Lack of fitness cost but strong hormetic effect and skewed sex ratio. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 174:390-400. [PMID: 30849660 DOI: 10.1016/j.ecoenv.2019.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 02/21/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
A trade-off between life history traits in the evolution of insecticide resistance is common in insects because energy acquisition is mainly channeled for detoxification enzyme production. In addition, sublethal exposure to insecticides may have an effect on the physiology and behaviors of surviving insects. Similar to other agricultural pests, pesticide use may have led to insecticide resistance in populations of Paederus fuscipes Curtis. In this study, we determined the median lethal time of 10 field-collected strains in Taiwan for three insecticides that are commonly employed to manage agricultural pests. We determined that the susceptibility of these strains to cyhalothrin and fenitrothion were similar, with resistance ratios (RRs) ranging from 1 to 4; however, significantly different to imidacloprid (RRs: 1-16). The effect of imidacloprid resistance on the life history traits studied of Paederus beetles was limited; only a prolonged egg incubation period, and adult longevity decreased as imidacloprid resistance increased. Regarding sublethal exposure to imidacloprid, adult sex ratios were female biased in most combinations, though nonsignificant. The quality of offspring, particularly the length of eggs significantly decreased. In addition, a hormetic effect was apparent when the individual was exposed to LT25 and LT50; mean fecundity per female increased from 12.80 ± 8.95 (± standard error [SE]) to 42.70 ± 13.77 eggs compared with that of the control (7.10 ± 1.32). However, the hormetic effect was inconsistent among the tested strains, possibly because of the difference in insecticide resistance levels given that reproductive compensation was absent among the resistant population.
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Affiliation(s)
- Wen-Bin Feng
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung 402, Taiwan
| | - Lee-Jin Bong
- National Mosquito-borne Diseases Control Research Center, National Health Research Institute, Zhunan, Miaoli County, Taiwan, ROC
| | - Shu-Mei Dai
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung 402, Taiwan
| | - Kok-Boon Neoh
- Department of Entomology, National Chung Hsing University, 145, Xingda Rd. South District, Taichung 402, Taiwan.
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Bibbs CS, Hahn DA, Kaufman PE, Xue RD. Sublethal effects of a vapour-active pyrethroid, transfluthrin, on Aedes aegypti and Ae. albopictus (Diptera: Culicidae) fecundity and oviposition behaviour. Parasit Vectors 2018; 11:486. [PMID: 30157907 PMCID: PMC6114540 DOI: 10.1186/s13071-018-3065-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/17/2018] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND It is assumed that mosquitoes surviving exposure to spatial repellents when attempting to bite a host will not have significant adverse impacts on their downstream biology. Therefore, a critical knowledge gap is understanding the extent to which sublethal exposure to volatile pyrethroids may damage the performance of mosquitoes that survive exposure to vapour-active pyrethroids. To address this, laboratory-reared Aedes aegypti (L.) and Ae. albopictus (Skuse) were exposed to one of three sublethal concentrations of transfluthrin before being offered a blood-meal, after which their survival, fecundity, fertility, and egg-laying behaviour was assessed. RESULTS Both species expressed reduced skip-oviposition behaviour at all exposures. Both species also suffered a major reduction in viable eggs (50-75% reduction in viable eggs laid). A phenotype where eggs collapsed after laying was observed in Ae. aegypti, and this response increased with exposure concentrations. Dissected females of both species retained 50% or fewer of their eggs, with Ae. albopictus retaining a significant proportion of melanised oocytes following the highest exposure. CONCLUSIONS Our findings suggest that volatile pyrethroids can reduce skip-oviposition, which may improve source reduction outcomes during integrated management. The additional fecundity reduction caused by sublethal exposures to volatile pyrethroids improves our confidence in recommending them for urban vector management. Furthermore, we suggest that volatile pyrethroids should be adapted into delivery methods compatible with mosquito abatement programs.
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Affiliation(s)
- Christopher S. Bibbs
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611 USA
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092 USA
| | - Daniel A. Hahn
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611 USA
| | - Phillip E. Kaufman
- Entomology and Nematology Department, University of Florida, 1881 Natural Area Drive, Gainesville, FL 32611 USA
| | - Rui-de Xue
- Anastasia Mosquito Control District of St. Johns County, 120 EOC Drive, St. Augustine, FL 32092 USA
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