The requirement for efficient insect mass rearing and especially mosquito mass rearing technology has been one of the major obstacles preventing the large scale application of the Sterile Insect Technique (SIT) against mosquitoes and other insect pests. Balestrino et al. (2012, 2014) developed and evaluated a larval rearing unit (see literature below) to successfully rear hundred thousands of larvae to pupae per mosquito rack.
Mosquito Tray and Rack Rearing System. The mosquito racks are efficiently holding 30 trays (standard configuration; IR-MMR-TR30) with developing larvae for medium-scale mass production. Details on the mosquito larvae rearing trays can be found on the tray website. The rearing unit is mechanically simple to handle, maintains minimal water temperature variation and negligible water evaporation (by closely stacked trays) and allows normal larval development in the special trays mimicking mosquito rearing environment. Racks can be automatically (electric gearbox, 24 V) or manually tilted for efficient collection and cleaning purposes, an collection system for the overflow (with sieves / collection containers for pupae and a tank for the water) is available. The close stacking of the trays in the rack and the possibility to tightly line up several racks (in modules) makes this rearing unit a valid solution for maximal use of space - thus reducing construction, heating and cooling costs. Up to four racks can be combined as modules, operated with one control unit for tilting (seperatly triggered per rack). XL Rearing Racks holding 50 trays are available as option (IR-MMR-TR50; see below). The low amount of labour required to operate the mosquito rack system also reduces labour costs, which represent one of the main expenditures in any mass-rearing facility operation. Labour costs can be further reduced by combining the mosquito tray & rack system with the dedicated automatic larvae liquid feeding station IR-401 / IR-402.
Please contact us if you require more information on the rack and tray system for mosquito larvae mass rearing or if you are looking for a technical solution for your mealworm etc. insect farming facility.
Mosquito Tray & Rack Modules. For the most efficient larval mass rearing setup, Mosquito racks are combined into functional rearing units (modules). Modules of 2, 3 (see illustration) or 4 racks are available (see Table 1, below). In particular, modules are more space efficient than single racks because less of the rearing facility's floor area needs to be left open for pupal/larvae collection/water tank positioning during pupae harvesting.
Modules share: Electrical tilting control unit, 1 common collection channel (removeable) for larvae/pupae and effluent when tilted ("harvested") per 2-4 racks, effluent collection tank with 2 sieves / collection baskets for larvae/pupae. The drawing shows a module of 3 TR30 racks ("IR-MMR-TR30-M3"; see Table 1 for all product variants), with collection areas per rack (green; back, bottom) leading the effluent (water, pupae, larvea) from the tilted rearing trays to a common collection channel (purple) and then to the sieves / collection baskets (gray) on top of the effluent collection tank (dark blue). One "collection unit" (sieves, tank) can be used to operate multiple modules. Please note that the shared collection channel and electrical cables (for the automatic tilting mechanism) must be removed/disconnected before the racks can be moved independently (e.g. if they are placed on wheels).
Table 1. Overview on the different Mosquito tray & rack configurations, with 30 or 50 trays per rack, single rearing units or modules of 2-4 racks, and accessories.
|Product number||Trays per rack (n)||Racks / Trays per module (n)||Description|
|IR-MMR-TR30||30||1 / 30||Standard Mosquito Mass Rearing Unit, 1 rack TR30 (manual and automatic tilting), 30 trays, collection channel, incl. 1x effluent collection tank (500 L, with tap) and 2x pupae collection baskets (stainless steel, 200 µm mesh), 4 legs (adjustable)|
|IR-MMR-TR30-M2||30||2 / 60||Mosquito Mass Rearing Module, 2 racks TR30 (manual and automatic tilting, individual per rack), 60 trays, shared control unit for automatic tilting, shared collection channel, incl. 1x effluent tank and 2x collection baskets|
|IR-MMR-TR30-M3||30||3 / 90||as above, with 3 racks TR30, 90 trays|
|IR-MMR-TR30-M4||30||4 / 120||as above, with 4 racks TR30, 120 trays|
|IR-MMR-TR50||50||1 / 50||Mosquito Mass Rearing Unit XL (anodized aluminum), 1 rack TR50 (manual and automatic tilting), 50 trays, collection channel, incl. 1x effluent tank (with tap), and 2x pupae collection baskets (stainless steel, 200 µm mesh), 4 legs|
|IR-MMR-TR50-M2||50||2 / 100||Mosquito Mass Rearing Module, 2 racks TR50 (manual and automatic tilting, individual per rack), 100 trays, shared control unit for automatic tilting, shared collection channel, incl. 1x effluent tank and 2x collection baskets|
|IR-MMR-TR50-M3||50||3 / 150||as above, with 3 racks TR50, 150 trays|
|IR-MMR-TR50-M4||50||4 / 200||as above, with 4 racks TR50, 200 trays|
|IR-MMR-Tray||Mosquito Rearing Tray. Individual trays are available in sets of 10.|
|IR-MMR-WT500||Water / effluent collection tank (500 l, stainless steel)|
|IR-MMR-CB200||Collection baskets, stainless steel, 200 µm mesh on 3 sides, set of 2|
|IR-MMR-TR-WH||Wheels, turnable (with lock), 4 per TR rearing unit; factory set option (standard: height adjustable legs)|
|IR-401 / IR-402||Automatic Feeding Station for TR30 / TR50 racks|
[Read more on mosquito rearing tray preparation.] First pupation is usually recorded at day 6 from L1 introduction, effective harvest time at local facilities need to be established and will depend on environmental conditions, feed etc.
In any case, the automatic electrical system of the Tray & Rack Rearing Unit (or Module) is used for tilting. Up and down buttons (of the respective rack) allow for gentle tilting of the trays. As a fallback option in case of power cuts, use the manual jack (per unit) to slowly create a gradually increasing slope that will slowly pour the water out of the trays towards the collection area (in the back). Care should be taken not to tilt the trays too fast (manually) / too much at one time to prevent water containing larvae and pupae from spilling out. Since the standard rack holds a total of approximately 150-180 L (for 30 trays) of water when fully loaded, collection should be done slowly in batches of approximately 30 L per tilt into the large 200-µm screen baskets / sieves (placed on top of the collection tank). Parts of the collected water can be retained for washing trays, and rearing remaining larvae (after size-based sorting).
Pour/rinse the water from the collection basket into an external ~300-μm sieve to concentrate the larvae and pupae and discard the debris, and finally transfer them to small trays with 1-2 L of osmosis water / collected effluent. Continue tilting until all the water has been drained from one rack. Some larvae and pupae will remain on the inner edges of the rearing trays and must be washed off for collection (e.g. with some of the retained water); alternatively, water hoses with spray nozzles are used for rapid rinsing of the trays (if low salinity, Cl-free tap water is available). Continue to harvest the other racks per rearing module (if available); racks are individually tiltable (automatically and manually). The larval rearing water collected in the mobile tank can be reused for rearing the remaining mosquito larvae after pupation; potentially supplement with some fresh water. However, performing more than one tilting/sorting event can be be considered a trade-off between pupae production, female pupal contamination and cost efficiency (FAO/IAEA, 2020). Continue reading on size separation of larvae, male and female pupae ...
Mosquito mass rearing techniques, including racks, have improved significantly over the last few decades. However, we have designed/conceptualized a number of modifications to further optimize the space utilization and handling of mosquito mass rearing racks, especially in medium to large facilities. Given the predicted increase in demand for mosquito rearing facilities worldwide, we would be happy to develop a joint R&D proposal to prototype and test our ideas in close interaction with future users, scientists. We are particularly interested in further increasing space efficiency and automation levels (filing, feeding, rinsing, refilling, etc.). If this may be of interest to you, please contact us to discuss funding options / ideas.