Establishment of a medium-scale mosquito facility: optimization of the larval mass-rearing unit for Aedes albopictus (Diptera: Culicidae)

Dongjing Zhang,Xiaoying Zheng,Meichun Zhang,Hanano Yamada,Yu Wu,Yu Wu,Yu Wu,Yu Wu,Jeremie R L Gilles,Zhiyong Xi,Zhiyong Xi,Zhongdao Wu

doi:10.1186/s13071-017-2511-z

Abstract

BackgroundStandardized larval rearing units for mosquito production are essential for the establishment of a mass-rearing facility. Two larval rearing units, developed respectively by the Guangzhou Wolbaki Biotech Co. Ltd. (Wolbaki) and Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture (FAO/IAEA-IPCL), are tested to assess their potential uses to mass-rear the larval stages of Aedes albopictus in support of the establishment of a medium-scale mosquito facility for the application of mosquito genetic control strategies.MethodsThe triple Wolbachia-infected Ae. albopictus strain (HC strain) was used in this study. The effects of larval densities of two larval rearing trays (corresponding to 2.4, 3.0 and 3.6 larvae/cm2) and tray size/position (top, middle and bottom layers) on the pupae production and larval survival were assessed when trays were stacked within the larval rearing units. The male pupae production, female pupae contamination after sex separation, and male mating competitiveness were also studied by using both larval rearing units in their entirety.ResultsThe optimal larval rearing density for Wolbaki-tray (Wol-tray) was 6,600 larvae (equal to 3.0 larvae/cm2) and 18,000 larvae (3.6 larvae/cm2) for the FAO/IAEA-IPCL tray (IAEA-tray). No significant difference in pupae production was observed when trays were stacked within top, middle or bottom layers for both units. At thirty-four hours after the first pupation, the average male pupae production was (0.89 × 105) for the Wol-unit and (3.16 × 105) for the IAEA-unit. No significant difference was observed in female pupae contamination between these two units. The HC males showed equal male mating competitiveness to wild type males for mating with wild type females in large cages, regardless of whether they were reared in the Wol-unit or IAEA-unit.ConclusionsThe current study has indicated that both the Wol-unit and IAEA-unit are suitable for larvae mass-rearing for Ae. albopictus. However, the IAEA-unit, with higher male production and less space required compared to the Wol-unit, is recommended to be used in support of the establishment of a medium-sized mosquito facility.

Highlights

Standardized larval rearing units for mosquito production are essential for the establishment of a mass-rearing facility
Effects of larval rearing densities on pupae production and larval survival A significant difference was observed in pupae production from different larval rearing densities for both the Wol-tray and the International Atomic Energy Agency (IAEA)-tray at 34 h (Wol-tray: F(2, 6) = 192.4, P < 0.0001; IAEA-tray: F(2, 6) = 176.2, P < 0.0001) and 58 h (Wol-tray: F(2, 6) = 211.9, P < 0.0001; IAEA-tray: F(2, 6) = 26.2, P = 0.0011) after pupation, respectively (Table 1)
A significant difference was observed in male pupae production from the three tested larval rearing densities for both the Wol-tray at 34 h and 58 h (34 h: F(2, 6) = 41.7, P = 0.0003; 58 h: F(2, 6) = 26.7, P = 0.0010) and the IAEA-tray at 34 h (F(2, 6) = 24.9, P = 0.0012); this difference was not observed for the IAEA-tray at 58 h (F(2, 6) = 3.5, P = 0.1000) (Table 1)

Summary

Introduction

Standardized larval rearing units for mosquito production are essential for the establishment of a mass-rearing facility. (Wolbaki) and Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture (FAO/IAEA-IPCL), are tested to assess their potential uses to mass-rear the larval stages of Aedes albopictus in support of the establishment of a medium-scale mosquito facility for the application of mosquito genetic control strategies. The aim is to reduce or prevent the transmission of mosquito borne diseases [10, 14] Both the SIT and IIT, as a component of area-wide integrated pest management (AW-IPM) programs, depend on several important steps including mass-rearing, sex separation, sterilization, transportation, release and monitoring [15]

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