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Cassone BJ, Pilling BG, Borrego-Benjumea A, LeMoine CMR. Identification of nectar sources foraged by female mosquitoes in Canada. J Insect Sci 2024; 24:11. [PMID: 38501855 PMCID: PMC10949444 DOI: 10.1093/jisesa/ieae033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 02/15/2024] [Accepted: 02/28/2024] [Indexed: 03/20/2024]
Abstract
For many mosquito species, the females must obtain vertebrate blood to complete a gonotrophic cycle. These blood meals are frequently supplemented by feeding on sugary plant nectar, which sustains energy reserves needed for flight, mating, and overall fitness. Our understanding of mosquito nectar foraging behaviors is mostly limited to laboratory experiments and direct field observations, with little research into natural mosquito-host plant relationships done in North America. In this study, we collected nectar-fed female mosquitoes over a 2-year period in Manitoba, Canada, and amplified a fragment of the chloroplast rbcL gene to identify the plant species fed upon. We found that mosquitoes foraged from diverse plant families (e.g., grasses, trees, ornamentals, and legumes), but preferred certain species, most notably soybean and Kentucky blue grass. Moreover, there appeared to be some associations between plant feeding preferences and mosquito species, date of collection, landscape, and geographical region. Overall, this study implemented DNA barcoding to identify nectar sources forage by mosquitoes in the Canadian Prairies.
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Affiliation(s)
- Bryan J Cassone
- Department of Biology, Brandon University, Brandon, MB R7A 6A9, Canada
| | - Ben G Pilling
- Department of Biology, Brandon University, Brandon, MB R7A 6A9, Canada
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2
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Nikbakhtzadeh MR. A synthetic lure for Anopheles gambiae (Diptera: Culicidae) based on the attractive plant Parthenium hysterophorus. J Med Entomol 2023; 60:899-909. [PMID: 37364179 PMCID: PMC10848229 DOI: 10.1093/jme/tjad077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 05/15/2023] [Accepted: 06/08/2023] [Indexed: 06/28/2023]
Abstract
Sugar is the sole diet for male mosquitoes and a complementary meal for females. Searching for natural sources of sugar is mediated by semiochemicals. Floral nectars, extra floral nectaries, damaged tissues of plants and rotten fruits are the most common sources of sugar in nature. I provide laboratory evidence of the high attraction of Parthenium hysterophorus L., a weed that grows in tropical climates, to Anopheles gambiae Giles. This study has tried to identify the chemicals which might be involved in the chemical attraction of A. gambiae to this plant. Using quantitative GC-MS analysis, α-pinene, camphene, 1-octen-3-ol, β-pinene, cis-β-ocimene, bornyl acetate, α-caryophyllene, hexadecanoic acid, and α-linolenic acid were identified as the main constituents of P. hysterophorus volatiles. Successive olfactory assays helped a better understanding of the more attractive chemicals of P. hysterophorus to A. gambiae which was the basis for testing a possible synthetic blend. Olfactory experiments proved this synthetic blend to be as attractive as Parthenium intact plants for A. gambiae. A minimal blend, consisting of only α-pinene, camphene, and cis-β-ocimene, was also produced and laboratory experiments indicated its relative attraction for A. gambiae. This blend can be tested in the attractive toxic sugar bait stations for sampling, surveillance, or control programs of mosquitoes in tropical Africa, where A. gambiae sensu stricto transfer malaria among residents.
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Affiliation(s)
- Mahmood R Nikbakhtzadeh
- Department of Health Science & Human Ecology, California State University, San Bernardino, San Bernardino, CA, USA
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3
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Njoroge TM, Hamid-Adiamoh M, Duman-Scheel M. Maximizing the Potential of Attractive Targeted Sugar Baits (ATSBs) for Integrated Vector Management. Insects 2023; 14:585. [PMID: 37504591 PMCID: PMC10380652 DOI: 10.3390/insects14070585] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/23/2023] [Accepted: 06/24/2023] [Indexed: 07/29/2023]
Abstract
Due to the limitations of the human therapeutics and vaccines available to treat and prevent mosquito-borne diseases, the primary strategy for disease mitigation is through vector control. However, the current tools and approaches used for mosquito control have proven insufficient to prevent malaria and arboviral infections, such as dengue, Zika, and lymphatic filariasis, and hence, these diseases remain a global public health threat. The proven ability of mosquito vectors to adapt to various control strategies through insecticide resistance, invasive potential, and behavioral changes from indoor to outdoor biting, combined with human failures to comply with vector control requirements, challenge sustained malaria and arboviral disease control worldwide. To address these concerns, increased efforts to explore more varied and integrated control strategies have emerged. These include approaches that involve the behavioral management of vectors. Attractive targeted sugar baits (ATSBs) are a vector control approach that manipulates and exploits mosquito sugar-feeding behavior to deploy insecticides. Although traditional approaches have been effective in controlling malaria vectors indoors, preventing mosquito bites outdoors and around human dwellings is challenging. ATSBs, which can be used to curb outdoor biting mosquitoes, have the potential to reduce mosquito densities and clinical malaria incidence when used in conjunction with existing vector control strategies. This review examines the available literature regarding the utility of ATSBs for mosquito control, providing an overview of ATSB active ingredients (toxicants), attractants, modes of deployment, target organisms, and the potential for integrating ATSBs with existing vector control interventions.
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Affiliation(s)
- Teresia Muthoni Njoroge
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
| | - Majidah Hamid-Adiamoh
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
- Eck Institute for Global Health, The University of Notre Dame, Notre Dame, South Bend, IN 46556, USA
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Yao S, Zhang Y, Chang Y, Li X, Zhao W, An S. Pyruvate Kinase Is Required for Sex Pheromone Biosynthesis in Helicoverpa armigera. Front Physiol 2021; 12:707389. [PMID: 34421647 PMCID: PMC8371337 DOI: 10.3389/fphys.2021.707389] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/29/2021] [Indexed: 01/27/2023] Open
Abstract
Pyruvate kinase (PYK) is a speed-limited enzyme of glycolysis that catalyzes the formation of pyruvate, and plays an important role in acetyl-CoA synthesis. The acetyl-CoA is the precursor of sex pheromone biosynthesis in Helicoverpa armigera. However, the role of PYK in sex pheromone biosynthesis remains elusive. Here, PYK in H. armigera (HaPYK) was found to be highly expressed in the pheromone glands (PGs). The developmental expression profile of HaPYK was consistent with the fluctuation of sex pheromone release. Function analysis revealed that the knockdown of HaPYK led to a decrease in the levels of pyruvic acid and acetyl-CoA in PGs, which in turn caused a significant decrease in cis-11-hexadecenal (Z11-16: Ald) production, female capability to attract males, and mating frequency. Further study demonstrated that sugar feeding (5% sugar) increased the transcription and enzyme activity of HaPYK, thereby facilitating sex pheromone biosynthesis. Moreover, pheromone biosynthesis activating neuropeptide (PBAN) upregulated HaPYK activity through protein kinase C (PKC), as shown by PKC-specific inhibitor analysis. Altogether, our results revealed that PBAN activated HaPYK by Ca2+/PKC, thereby regulating the synthesis of pyruvate and subsequent acetyl-CoA, ensuring the supply of sex pheromone precursor, and finally facilitating sex pheromone biosynthesis and mating behavior.
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Affiliation(s)
- Shuangyan Yao
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yunhui Zhang
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yanpeng Chang
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xiang Li
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Wenli Zhao
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shiheng An
- State Key Laboratory of Wheat and Maize Crop Science, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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Zhang Y, Zhang Y, Yao S, Wang G, Wei J, Du M, An S, Yin X. Supplemental Sugar Is Required for Sex Pheromone Biosynthesis in Mythimna separata. Front Physiol 2020; 11:605145. [PMID: 33391019 PMCID: PMC7775516 DOI: 10.3389/fphys.2020.605145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022] Open
Abstract
Supplemental nutrients of adult moths maximize moth fitness and contribute to the pollination of many plants. Previous reports have revealed that sugar feeding promotes to sex pheromone biosynthesis by increasing the haemolymph trehalose concentration in mating moths. Here, Mythimna separata adults were employed as a model to investigate the effect of sugar feeding on sex pheromone biosynthesis. Results showed that in virgin females, sugar feeding markedly increased the concentrations of trehalose, pyruvic acid, and acyl-CoA in pheromone glands (PGs), which in turn led to an increase in sex pheromone titer, female ability to attract males and successfully mating frequency in sugar-fed females. Consistently, sugar-fed females laid more eggs than water-fed females. Furthermore, the refeeding of starved females also caused significantly increase in the concentrations of trehalose, pyruvic acid, and acyl-CoA in PGs, thus facilitating a significant increase in sex pheromone production. Most importantly, RNAi-mediated knockdown of trehalase (leading to PG starvation) resulted in an increase in trehalose content, and decrease in the concentrations of pyruvic acid, and acyl-CoA in PGs, which in turn led to a decrease of sex pheromone titer, female ability to attract males and successful mating efficacy. Altogether, results revealed a mechanism by which sugar feeding contributed to trehalose utilization in PGs, promoted to significantly increased sex pheromone precursor by increasing the concentrations of pyruvic acid and acyl-CoA, and facilitated to sex pheromone biosynthesis and successful mating.
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Affiliation(s)
- Yaling Zhang
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yuanchen Zhang
- College of Biology and Food Engineering, Innovation and Practice Base for Postdoctors, Anyang Institute of Technology, Anyang, China
| | - Shuangyan Yao
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Gaoping Wang
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Jizhen Wei
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Mengfang Du
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Shiheng An
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xinming Yin
- Collaborative Innovation Center of Henan Grain Crops, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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Torto B. Innovative approaches to exploit host plant metabolites in malaria control. Pest Manag Sci 2019; 75:2341-2345. [PMID: 31050133 DOI: 10.1002/ps.5460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/14/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
Malaria is the most important vector-borne disease in sub-Saharan Africa (SSA). Recent reports indicate that the levels of malaria-associated mortality and morbidity in SSA have remained the same. Malaria vectors have modified their feeding behavior in response to the selective pressure from indoor-based interventions, and there is emerging malaria parasite resistance to artemisinin-based combination therapies. These challenges have created an altered malaria landscape, especially within local scales in some malaria-endemic countries in SSA. To address these challenges, complementary new strategies are urgently required for malaria control. This paper argues that to develop the next generation of vector and chemotherapeutic tools for malaria control, especially based on natural products with novel modes of action, a better understanding of mosquito bioecology and, more importantly, plant sugar feeding is needed. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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7
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Fiorenzano JM, Koehler PG, Xue RD. Attractive Toxic Sugar Bait (ATSB) For Control of Mosquitoes and Its Impact on Non-Target Organisms: A Review. Int J Environ Res Public Health 2017; 14:ijerph14040398. [PMID: 28394284 PMCID: PMC5409599 DOI: 10.3390/ijerph14040398] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/03/2017] [Accepted: 04/07/2017] [Indexed: 11/17/2022]
Abstract
Mosquito abatement programs contend with mosquito-borne diseases, insecticidal resistance, and environmental impacts to non-target organisms. However, chemical resources are limited to a few chemical classes with similar modes of action, which has led to insecticide resistance in mosquito populations. To develop a new tool for mosquito abatement programs that control mosquitoes while combating the issues of insecticidal resistance, and has low impacts of non-target organisms, novel methods of mosquito control, such as attractive toxic sugar baits (ATSBs), are being developed. Whereas insect baiting to dissuade a behavior, or induce mortality, is not a novel concept, as it was first introduced in writings from 77 AD, mosquito baiting through toxic sugar baits (TSBs) had been quickly developing over the last 60 years. This review addresses the current body of research of ATSB by providing an overview of active ingredients (toxins) include in TSBs, attractants combined in ATSB, lethal effects on mosquito adults and larvae, impact on non-target insects, and prospects for the use of ATSB.
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Affiliation(s)
- Jodi M Fiorenzano
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive Gainesville, FL 32608, USA.
- Anastasia Mosquito Control District, 120 EOC Drive, St. Augustine, FL 32092, USA.
| | - Philip G Koehler
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive Gainesville, FL 32608, USA.
| | - Rui-De Xue
- Anastasia Mosquito Control District, 120 EOC Drive, St. Augustine, FL 32092, USA.
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Qualls WA, Naranjo DP, Subía MA, Ramon G, Cevallos V, Grijalva I, Gómez E, Arheart KL, Fuller DO, Beier JC. Movement of Aedes aegypti following a sugar meal and its implication in the development of control strategies in Durán, Ecuador. J Vector Ecol 2016; 41:224-231. [PMID: 27860016 DOI: 10.1111/jvec.12217] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/20/2016] [Indexed: 05/15/2023]
Abstract
We evaluated how the presence of sugar sources impacted the distribution of Aedes aegypti in different habitats in Durán, Ecuador. Land cover and normalized difference vegetation index maps were used to guide a random point sampling routine to select study grids (30 m × 30 m) in low vegetation (LV) and high vegetation (HV). Five individual plants, at one home in the LV and HV grid, were treated with a different colored, non-attractive, 60% sucrose solution to determine mosquito feeding and movement. Sugar alone is not attractive to mosquitoes, so spraying vegetation with a dyed sugar solution can be used for visual determination of sugar feeding. Outdoor collections using BG sentinel traps and indoor collections using aspirators were conducted at the treatment home and with collection points at 20, 40, and 60 m surrounding the treatment home for three consecutive days. A total of 3,245 mosquitoes in two genera, Aedes and Culex, was collected. The proportion of stained Ae. aegypti females was 56.8% (510/898) and 0% for males. For Culex, 63.9% (248/388) females and 36.1% (140/388) males were collected stained. Aedes aegypti and Culex spp. were found up to 60 m stained in both LV and HV grids. Significantly more stained females Ae. aegypti were found inside homes compared to females and males of Culex spp. in both habitats. This study identifies that outdoor sugar feeding is a common behavior of Ae. aegypti and can be targeted as a control strategy in urban habitats in Latin America.
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Affiliation(s)
- Whitney A Qualls
- University of Miami Miller School of Medicine, Department of Public Health Sciences, Miami, FL, U.S.A. 33136
- PROMETEO, Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, Quito, Ecuador
| | - Diana P Naranjo
- University of Miami Miller School of Medicine, Department of Public Health Sciences, Miami, FL, U.S.A. 33136
| | | | - Giovanni Ramon
- Instituto Nacional de Investigación en Salud Pública, Quito, Ecuador
| | - Varsovia Cevallos
- Instituto Nacional de Investigación en Salud Pública, Quito, Ecuador
| | - Isabel Grijalva
- Universidad Católica de Santiago de Guayaquil, Facultad de Ciencias Médicas, Guayas, Ecuador
| | - Eduardo Gómez
- Universidad Católica de Santiago de Guayaquil, Facultad de Ciencias Médicas, Guayas, Ecuador
- Ministerio de Salud Pública del Ecuador
| | - Kristopher L Arheart
- University of Miami Miller School of Medicine, Department of Public Health Sciences, Miami, FL, U.S.A. 33136
| | - Douglas O Fuller
- Department of Geography, University of Miami, Coral Gables, FL 33136, U.S.A
| | - John C Beier
- University of Miami Miller School of Medicine, Department of Public Health Sciences, Miami, FL, U.S.A. 33136
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Nikbakhtzadeh MR, Terbot JW, Foster WA. Survival Value and Sugar Access of Four East African Plant Species Attractive to a Laboratory Strain of Sympatric Anopheles gambiae (Diptera: Culicidae). J Med Entomol 2016; 53:1105-1111. [PMID: 27247348 PMCID: PMC5013815 DOI: 10.1093/jme/tjw067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Mosquitoes derive energy from plant sugar, thereby promoting survival and reproduction. Its survival value to females plays a key role in the vectorial capacity of mosquito populations. Previous olfactometry assays of responsiveness demonstrated that Senna didymobotrya Fresenius, Parthenium hysterophorus, L. Senna occidentalis, (L) and Lantana camara L were among the most attractive plants for the Mbita strain of Anopheles gambiae s.s. Giles in eastern Africa. Here, we provide experimental evidence that three of these four species also provide varying but substantial amounts of sugar for mosquito survival, whereas a fourth does not. Rank order of survival of both sexes of mosquitoes housed with these plants was as follows: S. didymobotrya was highest, followed by S. occidentalis and L. camara, whereas survival on P. hysterophorus was only slightly better than on only water. A positive control group, housed with 10% sucrose, survived well but fell significantly short of those with S. didymobotrya. A causal connection between survival and sugar availability was established by exposing mosquitoes to plants overnight, and then testing them for the presence and amount of undigested fructose. Fructose positivity was most frequent in those exposed to L. camara, whereas greatest amounts of fructose were obtained from S. occidentalis and S. didymobotrya. Parthenium hysterophorus scored lowest in both categories. We conclude that attractiveness and sugar availability are often, but not always, concordant. It remains unclear why P. hysterophorus should be attractive if it offers little sugar and does not prolong survival. Furthermore, the cause behind the superior survival benefit of S. didymobotrya, compared with 10% sucrose, is unknown.
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Affiliation(s)
- M R Nikbakhtzadeh
- Department of Evolution, Ecology & Organismal Biology, The Ohio State University, 318 W 12th Ave., Columbus, OH, 43210 (; )
- Current address: Department of Molecular & Cellular Biology, University of California, 1 Shields Ave., Davis, CA 95616
| | - J W Terbot
- Department of Entomology, The Ohio State University, 318 W. 12th Ave., Columbus, OH, 43210
- Current address: Department of Biology, University of Kentucky, 675 Rose St., Lexington, KY 40506
| | - W A Foster
- Department of Evolution, Ecology & Organismal Biology, The Ohio State University, 318 W 12th Ave., Columbus, OH, 43210 (; )
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Snyder D, Cernicchiaro N, Cohnstaedt LW. Sugar-feeding status alters biting midge photoattraction. Med Vet Entomol 2016; 30:31-38. [PMID: 26555011 DOI: 10.1111/mve.12144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 07/07/2015] [Accepted: 08/07/2015] [Indexed: 06/05/2023]
Abstract
The biting midge Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae) transmits pathogens to both livestock and wildlife. Biting midge surveillance relies heavily on light traps for collection; however, little is known about the light spectra preferences of C. sonorensis midges. A light assay arena was constructed and light-emitting diodes (LEDs) of various light spectra were used as light sources to evaluate midge photoattraction. A comparison of responses to light spectra indicated the highest proportions of C. sonorensis were attracted to ultraviolet (UV) light and that midges differentiated 10-nm differences in wavelength. Stronger intensities of UV light resulted in greater attraction. Midges exhibited both sugar-seeking and escape behaviours under different conditions of sugar supplementation before and during the experiment. These behaviours occurred with lights of 355 nm and 365 nm in wavelength. Based on the results of this study, the attraction of C. sonorensis to light traps can be improved through the use of bright LEDs at 355 nm or 365 nm.
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Affiliation(s)
- D Snyder
- Department of Entomology, Kansas State University, Manhattan, KS, U.S.A
| | - N Cernicchiaro
- Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, U.S.A
| | - L W Cohnstaedt
- Center for Grain and Animal Health Research, Agriculture Research Service, U.S. Department of Agriculture, Manhattan, KS, U.S.A
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Qualls WA, Müller GC, Traore SF, Traore MM, Arheart KL, Doumbia S, Schlein Y, Kravchenko VD, Xue RD, Beier JC. Indoor use of attractive toxic sugar bait (ATSB) to effectively control malaria vectors in Mali, West Africa. Malar J 2015; 14:301. [PMID: 26242186 PMCID: PMC4524285 DOI: 10.1186/s12936-015-0819-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/22/2015] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Attractive toxic sugar bait (ATSB) solutions containing any gut toxins can be either sprayed on plants or used in simple bait stations to attract and kill sugar-feeding female and male mosquitoes. This field study in Mali demonstrates the effect of ATSB bait stations inside houses as a vector control method that targets and kills endophilic African malaria vectors. METHODS The studies were conducted in five villages located near the River Niger, Mali. Baseline village-wide assessments of densities for female and male Anopheles gambiae sensu lato were performed by pyrethrum spray collections (PSC) in ten houses in each of five villages. To determine the rate of mosquito feeding on bait stations, one bait station per house containing attractive sugar bait (ASB) (without toxin) plus a food dye marker, was set up in ten houses in each of the five villages. PSC collections were conducted on the following day and the percentage of female and male mosquitoes that had fed was determined by visual inspection for the dye marker. Then, a 50-day field trial was done. In an experimental village, one bait station containing ATSB (1% boric acid active ingredient) was placed per bedroom (58 bedrooms), and indoor densities of female and male An. gambiae s.l. were subsequently determined by PSC, and female mosquitoes were age graded. RESULTS In the five villages, the percentages of An. gambiae s.l. feeding inside houses on the non-toxic bait stations ranged from 28.3 to 53.1% for females and 36.9 to 78.3% for males. Following ATSB indoor bait station presentation, there was a significant reduction, 90% in female and 93% in male populations, of An. gambiae s.l. at the experimental village. A 3.8-fold decrease in the proportion of females that had undergone four or more gonotrophic cycles was recorded at the experimental village, compared to a 1.2-fold increase at the control village. CONCLUSION The field trial demonstrates that An. gambiae s.l. feed readily from ATSB bait stations situated indoors, leading to a substantial reduction in the proportion of older female mosquitoes. This study demonstrates that ATSB inside houses can achieve impressive malaria vector control in Africa.
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Affiliation(s)
- Whitney A Qualls
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Günter C Müller
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Kuvin Centre for the Study of Infectious and Tropical Diseases, Hebrew University, Jerusalem, Israel.
| | - Sekou F Traore
- Faculty of Medicine, Pharmacy and Odontostomatology, Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali.
| | - Mohamed M Traore
- Faculty of Medicine, Pharmacy and Odontostomatology, Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali.
| | - Kristopher L Arheart
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Seydou Doumbia
- Faculty of Medicine, Pharmacy and Odontostomatology, Malaria Research and Training Center, University of Bamako, BP 1805, Bamako, Mali.
| | - Yosef Schlein
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, Kuvin Centre for the Study of Infectious and Tropical Diseases, Hebrew University, Jerusalem, Israel.
| | | | - Rui-De Xue
- Anastasia Mosquito Control District, St. Augustine, FL, USA.
| | - John C Beier
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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Jackson BT, Stone CM, Ebrahimi B, Briët OJT, Foster WA. A low-cost mesocosm for the study of behaviour and reproductive potential in Afrotropical mosquito (Diptera: Culicidae) vectors of malaria. Med Vet Entomol 2015; 29:104-109. [PMID: 25294339 PMCID: PMC4319992 DOI: 10.1111/mve.12085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 06/24/2014] [Accepted: 06/26/2014] [Indexed: 06/03/2023]
Abstract
A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors.
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Affiliation(s)
- B T Jackson
- Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH, U.S.A
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Nikbakhtzadeh MR, Terbot JW, Otienoburu PE, Foster WA. Olfactory basis of floral preference of the malaria vector Anopheles gambiae (Diptera: Culicidae) among common African plants. J Vector Ecol 2014; 39:372-83. [PMID: 25424267 DOI: 10.1111/jvec.12113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/21/2014] [Indexed: 05/10/2023]
Abstract
Mosquitoes of both sexes feed on plants to obtain sugar. Nocturnal species probably locate the plants primarily by their volatile semiochemicals that also form the basis for the mosquitoes' innate plant-species preferences. To evaluate these olfactory preferences quantitatively, we used a two-choice wind-tunnel olfactometer to measure the upwind orientation of Anopheles gambiae Giles, an important vector of malaria in equatorial Africa, toward odor plumes produced by nine plant species common where this mosquito occurs. These plants are reported to induce feeding behaviors in An. gambiae and to produce floral or extrafloral nectar. Results presented here demonstrated that the volatiles of S. didymobotrya, P. hysterophorus, S. occidentalis, and L. camara, in descending order of numbers of mosquitoes responding, were all attractive, compared to a control plant species, whereas D. stramonium, R. communis, S. bicapsularis, T. stans, and T. diversifolia were not. As expected, chromatographic analysis of the headspace of attractive plants whose volatiles were captured by stir-bar sorptive extraction revealed a wide range of compounds, primarily terpenoids. Once their bioactivity and attractiveness for An. gambiae, alone and in blends, has been firmly established, some of these semiochemicals may have applications in population sampling and control.
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Affiliation(s)
- Mahmood R Nikbakhtzadeh
- Department of Evolution, Ecology & Organismal Biology, The Ohio State University, Columbus, OH, U.S.A..
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Samson DM, Qualls WA, Roque D, Naranjo DP, Alimi T, Arheart KL, Müller GC, Beier JC, Xue RD. Resting and energy reserves of Aedes albopictus collected in common landscaping vegetation in St. Augustine, Florida. J Am Mosq Control Assoc 2013; 29:231-6. [PMID: 24199497 PMCID: PMC3921969 DOI: 10.2987/13-6347r.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The resting behavior of Aedes albopictus was evaluated by aspirating diurnal resting mosquitoes from common landscape vegetation in residential communities in St. Augustine, FL. Energy reserves of the resting mosquitoes were analyzed to determine if there was a correlation between mosquito resting habitat and energy accumulation. Six species of plants were selected and 9 collections of resting mosquitoes were aspirated from each plant using a modified John W. Hock backpack aspirator during June and July 2012. Eight mosquito species were collected, with Ae. albopictus representing 74% of the overall collection. The number of Ae. albopictus collected varied significantly with the species of vegetation. When comparing the vegetation and abundance of resting mosquitoes, the highest percentages of Ae. albopictus were collected resting on Ruellia brittoniana (Mexican petunia), Asplenium platyneuron (fern), Gibasis geniculate (Tahitian bridal veil), followed by Plumba goauriculata (plumbago), Setcreasea pallida (purple heart), and Hibiscus tiliaceus (hibiscus). There were significant differences in lipid and glycogen accumulation based on type of vegetation Ae. albopictus was found resting in. Resting mosquitoes' sugar reserves were not influenced by species of vegetation. However, there was an overall correlation between vegetation that serves as a resting habitat and energy reserve accumulation. The results of our study demonstrate the potential to target specific vegetation for control of diurnal resting mosquitoes.
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Affiliation(s)
- Dayana M Samson
- Department of Epidemiology and Public Health, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Stell FM, Roe RM, Arellano C, Kennedy L, Thornton H, Saavedra-Rodriguez K, Wesson DM, Black WC, Apperson CS. Proof of concept for a novel insecticide bioassay based on sugar feeding by adult Aedes aegypti (Stegomyia aegypti). Med Vet Entomol 2013; 27:284-297. [PMID: 23077986 DOI: 10.1111/j.1365-2915.2012.01048.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Aedes aegypti L. (Stegomyia aegypti) (Diptera: Culicidae) is the principal vector of dengue and yellow fever viruses in tropical and subtropical regions of the world. Disease management is largely based on mosquito control achieved by insecticides applied to interior resting surfaces and through space sprays. Population monitoring to detect insecticide resistance is a significant component of integrated disease management programmes. We developed a bioassay method for assessing insecticide susceptibility based on the feeding activity of mosquitoes on plant sugars. Our prototype sugar-insecticide feeding bioassay system was composed of inexpensive, disposable components, contained minimal volumes of insecticide, and was compact and highly transportable. Individual mosquitoes were assayed in a plastic cup that contained a sucrose-permethrin solution. Trypan blue dye was added to create a visual marker in the mosquito's abdomen for ingested sucrose-permethrin solution. Blue faecal spots provided further evidence of solution ingestion. With the sugar-insecticide feeding bioassay, the permethrin susceptibility of Ae. aegypti females from two field-collected strains was characterized by probit analysis of dosage-response data. The field strains were also tested by forced contact of females with permethrin residues on filter paper. Dosage-response patterns were similar, indicating that the sugar-insecticide feeding bioassay had appropriately characterized the permethrin susceptibility of the two strains.
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Affiliation(s)
- F M Stell
- Department of Entomology, North Carolina State University, Raleigh, NC 27695, U.S.A
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LOTHROP HUGHD, WHEELER SARAHS, FANG YING, REISEN WILLIAMK. Use of scented sugar bait stations to track mosquito-borne arbovirus transmission in California. J Med Entomol 2012; 49:1466-1472. [PMID: 23270177 PMCID: PMC3544359 DOI: 10.1603/me12117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Laboratory and field research was conducted to determine if Culex tarsalis Coquillett expectorated West Nile virus (WNV) during sugar feeding and if a lure or bait station could be developed to exploit this behavior for WNV surveillance. Experimentally infected Cx. tarsalis repeatedly expectorated WNV onto filter paper strips and into vials with wicks containing sucrose that was readily detectable by a quantitative reverse transcriptase-polymerase chain reaction assay. Few females (33%, n = 27) became infected by imbibing sugar solutions spiked with high concentrations (10(7) plaque forming units/ml) of WNV, indicating sugar feeding stations probably would not be a source of WNV infection. In nature, sugar bait stations scented with the floral attractant phenyl acetaldehyde tracked WNV transmission activity in desert but not urban or agricultural landscapes in California. When deployed in areas of the Coachella Valley with WNV activity during the summer of 2011, 27 of 400 weekly sugar samples (6.8%) tested positive for WNV RNA by reverse transcriptase-polymerase chain reaction. Prevalence of positives varied spatially, but positive sugar stations were detected before concurrent surveillance measures of infection (mosquito pools) or transmission (sentinel chicken seroconversions). In contrast, sugar bait stations deployed in urban settings in Los Angeles or agricultural habits near Bakersfield in Kern County supporting WNV activity produced 1 of 90 and 0 of 60 positive weekly sugar samples, respectively. These results with sugar bait stations will require additional research to enhance bait attractancy and to understand the relationship between positive sugar stations and standard metrics of arbovirus surveillance.
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Clifton ME, Noriega FG. The fate of follicles after a blood meal is dependent on previtellogenic nutrition and juvenile hormone in Aedes aegypti. J Insect Physiol 2012; 58:1007-19. [PMID: 22626792 PMCID: PMC3389259 DOI: 10.1016/j.jinsphys.2012.05.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/30/2012] [Accepted: 05/03/2012] [Indexed: 05/10/2023]
Abstract
Juvenile hormone (JH) mediates the relationship between fecundity and nutrition during the gonotrophic cycle of the mosquito in three ways: (1) by regulating initial previtellogenic development, (2) by mediating previtellogenic resorption of follicles and (3) by altering intrinsic previtellogenic follicle "quality", physiology, and competitiveness thereby predetermining the fate of follicles after a blood meal. To support a role for JH in mediating the response of ovarian follicles after a blood meal, we explored three main questions: (1) Do changes in nutrition during the previtellogenic resting stage lead to relevant biochemical and molecular changes in the previtellogenic ovary? (2) Do hormonal manipulations during the previtellogenic resting stage lead to the same biochemical and molecular changes? (3) Does nutrition and hormones during the previtellogenic resting stage affect vitellogenic resorption and reproductive output? We examined the accumulation of neutral lipids in the previtellogenic ovary as well as the previtellogenic expression of genes integral to endocytosis and oocyte development such as the: vitellogenin receptor (AaVgR), lipophorin receptor (AaLpRov), heavy-chain clathrin (AaCHC), and ribosomal protein L32 (rpL32) under various previtellogenic nutritional and hormonal conditions. mRNA abundance and neutral lipid content increased within the previtellogenic ovary as previtellogenic mosquitoes were offered increasing sucrose concentrations. Methoprene application mimicked the effect of offering the highest sucrose concentrations on mRNA abundance and lipid accumulation in the previtellogenic ovary. These same nutritional and hormonal manipulations altered the extent of vitellogenic resorption. Mosquitoes offered 20% sucrose during the previtellogenic resting stage had nearly 3 times less vitellogenic resorption than mosquitoes offered 3% sucrose despite taking smaller blood meals and developed ∼10% more eggs during the first gonotrophic cycle. Mosquitoes treated with JH III during the previtellogenic resting stage and then offered a blood meal had a ∼40% reduction in the amount of vitellogenic resorption and developed ∼12% more eggs. Taken together, these results suggest that previtellogenic nutrition alters the extent and pattern of resorption after a blood meal through the effect of JH on mRNA abundance and lipid accumulation in previtellogenic follicles.
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Affiliation(s)
- Mark E Clifton
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
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Clifton ME, Noriega FG. Nutrient limitation results in juvenile hormone-mediated resorption of previtellogenic ovarian follicles in mosquitoes. J Insect Physiol 2011; 57:1274-81. [PMID: 21708165 PMCID: PMC3167010 DOI: 10.1016/j.jinsphys.2011.06.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 06/02/2011] [Accepted: 06/03/2011] [Indexed: 05/10/2023]
Abstract
Juvenile hormone (JH) is a central hormonal regulator of previtellogenic development in female Aedes aegypti mosquitoes. JH levels are low at eclosion and increase during the first day after adult emergence. This initial rise in JH is essential for female reproductive maturation. After previtellogenic maturation is complete, the mosquito enters a 'state-of-arrest' during which JH synthesis continues at a slower pace and further ovary development is repressed until a blood meal is taken. By examining the relationships between juvenile hormone, follicular resorption and nutrition in A. aegypti, we were able to define a critical role of JH during the previtellogenic resting stage. The rate of follicular resorption in resting stage mosquitoes is dependent on nutritional quality. Feeding water alone caused the rate of follicular resorption to reach over 20% by day 7 after emergence. Conversely, feeding a 20% sucrose solution caused resorption to remain below 5% during the entire experimental period. Mosquitoes fed 3% sucrose show rates of resorption intermediate between water and 20% sucrose and only reached 10% by day 7 after emergence. Follicular resorption is related to JH levels. Ligated abdomens separated from a source of JH (the corpora allata) showed an increase in resorption comparable to similarly aged starved mosquitoes (16%). Resorption in ligated abdomens was reduced to 6% by application of methoprene. The application of methoprene was also sufficient to prevent resorption in intact mosquitoes starved for 48 h (14% starved vs. 4% starved with methoprene). Additionally, active caspases were localized to resorbing follicles indicating that an apoptotic cell-death mechanism is responsible for follicular resorption during the previtellogenic resting stage. Taken together, these results indicate that JH mediates reproductive trade-offs in resting stage mosquitoes in response to nutrition.
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Affiliation(s)
- Mark E Clifton
- Department of Biological Sciences, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA.
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Abstract
The first 2-4 days after an Anopheles gambiae female mosquito emerges are critical to her survival and reproductive success. Yet, the order of behavioural events (mating, sugar feeding, blood feeding) during this time has received little attention. We discovered that among female cohorts sampled from emergence, sugar feeding had a higher probability than blood feeding of occurring first, and mating rarely occurred before a meal was taken. The night after emergence, 48% of females fed on sugar in mesocosms, and 25% fed on human blood; in the absence of sugar, 49% of females fed on human blood. After 5 days, 39% of the sugar-supplied females had blood fed and mated, and were fructose negative, whereas only 8% of the sugar-denied females had both blood fed and mated by this time. The model that best explained the transitions suggests that females made use of two distinct behavioural pathways, the most common one being to sugar-feed, then mate, and then seek blood. Other females sought blood first, then mated, and forwent a sugar meal. Lipid levels were higher in females with access to sugar than in females without access to sugar, particularly for those in later gonotrophic stages, while glycogen levels in the sugar-supplied group were higher throughout. In single-night experiments with females having had access to sucrose since emergence, those given a blood meal 1 day before spending a night with males had higher insemination rates than those not receiving the blood meal. These results indicate that the trade-off between survival and immediate reproduction is resolved by young adult females in accordance with availability of resources and gonotrophic state.
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Affiliation(s)
- C.M. Stone
- Department of Entomology, The Ohio State University, 318 West 12th Avenue, Aronoff Laboratory, Columbus, OH 43210, U.S.A
| | - I.M. Hamilton
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Aronoff Laboratory, Columbus, OH 43210, U.S.A
- Department of Mathematics, The Ohio State University, 231 West 18th Avenue, Math Tower, Columbus, OH 43210
| | - W.A. Foster
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, 318 West 12th Avenue, Aronoff Laboratory, Columbus, OH 43210, U.S.A
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Stone CM, Taylor RM, Roitberg BD, Foster WA. Sugar deprivation reduces insemination of Anopheles gambiae (Diptera: Culicidae), despite daily recruitment of adults, and predicts decline in model populations. J Med Entomol 2009; 46:1327-37. [PMID: 19960677 PMCID: PMC2824499 DOI: 10.1603/033.046.0611] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Our research tests the hypothesis that the inability to sugar-feed reduces the insemination rate in mosquito populations. To test this, we measured the effects of sugar availability on cumulative insemination performance of male Anopheles gambiae Giles s.s. (Diptera: Culicidae) during 10-d periods of continual emergence of equal numbers of both sexes, and we evaluated the implications at the population level with a matrix population model. On each day of each of four replicates, 20 newly emerged mosquitoes of each sex were recruited into the populations within two mesocosms, large walk-in enclosures with simulated natural conditions. Each mesocosm contained a cage to replicate the experiment on a small scale. Scented sucrose was absent or present (control). A human host was available nightly as a bloodmeal source in both mesocosms. Sugar availability and enclosure size significantly influenced female insemination. In the mesocosms, with sugar 49.7% of the females were inseminated, compared with 10.9% of the females without sugar. In the small cages, the insemination rates were 76.0 and 23.5%, respectively. In the mesocosms, cumulative survival of females after 10 d was 51.6% with sugar and 25.6% without sugar. In the cages, female survival was 95 and 73%, respectively. Sensitivity analysis of the population projection matrix shows that both reduced male survival and reduced mating capability due to a lack of sugar contributed to lower insemination rates in females, and in the absence of sugar the insemination rate was lowered to an extent that led to population decline.
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Affiliation(s)
- C M Stone
- Department of Entomology, The Ohio State University, 318 West 12th Ave., Aronoff Laboratory, Columbus, OH 43210, USA.
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Abstract
A key characteristic of overwintering dormancy (diapause) in the mosquito Culex pipiens is the switch in females from blood feeding to sugar gluttony. We present evidence demonstrating that genes encoding enzymes needed to digest a blood meal (trypsin and a chymotrypsin-like protease) are down-regulated in diapause-destined females, and that concurrently, a gene associated with the accumulation of lipid reserves (fatty acid synthase) is highly up-regulated. As the females then enter diapause, fatty acid synthase is only sporadically expressed, and expression of trypsin and chymotrypsin-like remains undetectable. Late in diapause (2-3 months at 18 degrees C), the genes encoding the digestive enzymes begin to be expressed as the female prepares to take a blood meal upon the termination of diapause. Our results thus underscore a molecular switch that either capacitates the mosquito for blood feeding (nondiapause) or channels the adult mosquito exclusively toward sugar feeding and lipid sequestration (diapause).
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Affiliation(s)
- Rebecca M Robich
- Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA
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