Optimization of Mass-Rearing Methods for Anopheles arabiensis Larval Stages: Effects of Rearing Water Temperature and Larval Density on Mosquito Life-History Traits

Mamaï, Wadaka; Lobb, Leanne N.; Somda, Nanwintoum Séverin Bimbilé; Maïga, Hamidou; Yamada, Hanano; Lees, Rosemary Susan; Bouyer, Jérémy; Gilles, Jérémie

doi:10.1093/jee/toy213

Cited by 29 publications

(22 citation statements)

References 47 publications

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“…Eggs used for these experiments were generated following the An. arabiensis and Aedes rearing guidelines developed at the IPCL [23,24]. Anopheles arabiensis larvae were mass-reared in plastic trays (100 × 60 × 3 cm) containing 4 litres of deionized water.…”

Section: Source Of Mosquito Colonies and Mass-rearing Proceduresmentioning

confidence: 99%

A standardised method of marking male mosquitoes with fluorescent dust

et al. 2020

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Background: Prior to a major release campaign of sterile insects, including the sterile insect technique, male mosquitoes must be marked and released (small scale) to determine key parameters including wild population abundance, dispersal and survival. Marking insects has been routinely carried out for over 100 years; however, there is no gold standard regarding the marking of specific disease-transmitting mosquitoes including Anopheles arabiensis, Aedes aegypti and Aedes albopictus. The research presented offers a novel dusting technique and optimal dust colour and quantities, suitable for small-scale releases, such as mark-release-recapture studies. Methods:We sought to establish a suitable dust colour and quantity for batches of 100 male An. arabiensis, that was visible both by eye and under UV light, long-lasting and did not negatively impact longevity. A set of lower dust weights were selected to conduct longevity experiments with both Ae. aegypti and Ae. albopictus to underpin the optimal dust weight. A further study assessed the potential of marked male An. arabiensis to transfer their mark to undusted males and females. Results:The longevity of male An. arabiensis marked with various dust colours was not significantly reduced when compared to unmarked controls. Furthermore, the chosen dust quantity (5 mg) did not negatively impact longevity (P = 0.717) and provided a long-lasting mark. Dust transfer was found to occur from marked An. arabiensis males to unmarked males and females when left in close proximity. However, this was only noticeable when examining individuals under a stereomicroscope and thus deemed negligible. Overall, male Ae. aegypti and Ae. albopictus displayed a greater sensitivity to dusting. Only the lowest dust weight (0.5 mg) did not significantly reduce longevity (P = 0.888) in Ae. aegypti, whilst the lowest two dust weights (0.5 and 0.75 mg) had no significant impact on longevity (P = 0.951 and 0.166, respectively) in Ae. albopictus. Conclusion:We have devised a fast, inexpensive and simple marking method and provided recommended dust quantities for several major species of disease-causing mosquitoes. The novel technique provides an evenly distributed, long-lasting mark which is non-detrimental. Our results will be useful for future MRR studies, prior to a major release campaign.

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Section: Source Of Mosquito Colonies and Mass-rearing Proceduresmentioning

confidence: 99%

A standardised method of marking male mosquitoes with fluorescent dust

et al. 2020

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“…The combined IIT-SIT strategy involves several steps including mosquito mass rearing, sex separation, irradiation, packing, transportation, release and monitoring. Progress has been achieved on mosquito mass rearing by developing standard operation procedures (SOPs) for egg handling (quantification, hatching and storage) [15][16][17][18], larval rearing (larval diet, rearing density, rearing conditions and rack system) [19][20][21][22][23][24][25][26][27] and adult rearing (rearing density, blood-feeding and cages) [28][29][30], respectively. The importance of sex separation for mosquito IIT-SIT is self-evident, and despite efforts and progress being made, there is still a lack of available genetic sexing strains for Aedes spp.…”

Section: Introductionmentioning

confidence: 99%

Toward implementation of combined incompatible and sterile insect techniques for mosquito control: Optimized chilling conditions for handling Aedes albopictus male adults prior to release

Zhang

et al. 2020

PLoS Negl Trop Dis

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Combined incompatible and sterile insect technique (IIT-SIT) has been considered to be an effective and safe approach to control mosquito populations. Immobilization of male adults by chilling is a crucial process required for the packing, transportation and release of the mosquitoes during the implementation of IIT-SIT for mosquito control. In this study, effects of chilling on the Aedes albopictus males with triple Wolbachia infections (HC line), a powerful weapon to fight against the wild type Ae. albopictus population via IIT-SIT, were evaluated under both laboratory and field conditions. Irradiated HC (IHC) males were exposed to 1, 5 and 10˚C for 1, 2, 3, 6 and 24 h. The survival rate of the post-chilled IHC males was then monitored. Longevity of post-chilled IHC males was compared to non-chilled males under laboratory and semi-field conditions. Mating competitiveness of IHC/HC males after exposure to 5 or 10˚C for 0, 3 and 24 h was then evaluated. Effects of compaction and transportation under chilled conditions on the survival rate of IHC males were also monitored. The optimal chilling conditions for handling IHC males were temperatures between 5 and 10˚C for a duration of less than 3 h with no negative impacts on survival rate, longevity and mating competitiveness when compared to non-chilled males. However, the overall quality of postchilled IHC/HC males decreased when exposed to low temperatures for 24 h. Reduced survival was observed when IHC males were stored at 5˚C under a compaction height of 8 cm. Transportation with chilling temperatures fluctuating from 8 to 12˚C has no negative impact on the survival of IHC males. This study identified the optimal chilling temperature and duration for the handling and transportation of Ae. albopictus IHC male adults without any detrimental effect on their survival, longevity and mating competitiveness. Further studies are PLOS NEGLECTED TROPICAL DISEASES

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“…arabiensis and Ae. aegypti mass-rearing procedures developed at the IPCL [ 8 , 9 ]. Larvae were mass-reared in a large climate-controlled room (with an area of 88 m 2 ) where temperature and humidity were maintained at 30 ± 1 °C, 70 ± 10% RH, respectively.…”

Section: Methodsmentioning

confidence: 99%

Longevity of mass-reared, irradiated and packed male Anopheles arabiensis and Aedes aegypti under simulated environmental field conditions

et al. 2018

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BackgroundTo ensure the success of a mosquito control programme that integrates the sterile insect technique (SIT), it is highly desirable to release sterile males with a maximal lifespan to increase release effectiveness. Understanding sterile male survival under field conditions is thus critical for determining the number of males to be released. Our study aimed to investigate the effect of mass rearing, irradiation, chilling, packing and release time on irradiated male mosquito longevity.MethodsAnopheles arabiensis and Aedes aegypti immature stages were mass-reared using a rack and tray system. Batches of 50 males irradiated at the pupal stage were immobilised, packed into canisters and chilled for 6 hours at 6 °C. Mosquitoes were then transferred either in the early morning or early evening into climate chambers set to simulate the weather conditions, typical of the beginning of the rainy season in Khartoum, Sudan and Juazeiro, Brazil for An. arabiensis and Ae. aegypti, respectively. The longevity of experimental males was assessed and compared to mass-reared control males subjected either to simulated field or laboratory conditions.ResultsThe combined irradiation, chilling and packing treatments significantly reduced the longevity of both An. arabiensis and Ae. aegypti under simulated field conditions (P < 0.001). However, packing alone did not significantly reduce longevity of Ae. aegypti (P = 0.38) but did in An. arabiensis (P < 0.001). Overall, the longevity of mass reared, irradiated and packed males was significantly reduced, with the median survival time (days) lower following an early morning introduction (4.62 ± 0.20) compared to an evening (7.34 ± 0.35) in An. arabiensis (P < 0.001). However, there was no significant difference in longevity between morning (9.07 ± 0.54) and evening (7.76 ± 0.50) in Ae. aegypti (P = 0.14).ConclusionsOur study showed that sterile mass-reared males have a reduced lifespan in comparison to laboratory-maintained controls under simulated field conditions, and that An. arabiensis appeared to be more sensitive to the handling process and release time than Ae. aegypti. Longevity and release time are important parameters to be considered for a successful area-wide integrated vector control programme with a SIT component.

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Optimization of Mass-Rearing Methods for Anopheles arabiensis Larval Stages: Effects of Rearing Water Temperature and Larval Density on Mosquito Life-History Traits

Cited by 29 publications

References 47 publications

A standardised method of marking male mosquitoes with fluorescent dust

A standardised method of marking male mosquitoes with fluorescent dust

Toward implementation of combined incompatible and sterile insect techniques for mosquito control: Optimized chilling conditions for handling Aedes albopictus male adults prior to release

Longevity of mass-reared, irradiated and packed male Anopheles arabiensis and Aedes aegypti under simulated environmental field conditions

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