Temperature
If you don’t use climate control to grow mealworms, then climate will play a major factor in how productive your colony is. If you haven’t already, visit this “Choosing the Right Mealworm Species for your Climate” to choose the correct species for your climate.
Yellow Mealworms
- Ideal temperatures are 25-28 oC (77-82 oF) degrees for yellow mealworms, however their productivity will greatly reduce below or above these ranges. The reproductive stages (pupa and beetles) are prone to high death rates at higher temperatures.
- Reproduction stops at around 20 oC (68 oF)
- Moderate growth rates is achieved at 20-25 oC (68-77 oF).
- Mealworms go into torpur (sleep like state) below 10 oC (50 oF).
- Mealworms can be placed into a fridge (around 4 oC (39 oF) for up to a few months. You will need to take them out every few weeks and let them get active for an hour, then place them back into the fridge. This is common for wildlife carers who wish to preserve the worms over longer periods.
- They survive to approximately 0 oC (32 oF) or below.
Ink Bird Temperature Controllers which have a cool and heating input allowing you to lower temperate with air conditioner and add heat with heater.
Pupa stage is the most sensitive life stage. In good temperature ranges it is not uncommon to get 15-30% mortality and with higher temperatures this is much higher (80-90%).
Giant Mealworms
- Giant mealworms do well above 28 oC (82 oF) degrees and can handle much higher temperatures. In summer without climate control, we have had them at maximum day temperatures between 35-39 oC (95-102 oF) and they retained productive rates.
- We subsequently co-house yellow and giant mealworms together at 25-28 oC (77-82 oF) with climate control. Giants still retain high production rates (similar to yellow mealworms) at these lower temperatures.
- Giant mealworms do not tolerate low temperatures and should not be placed in the refrigerator like you can yellow mealworms. Temperatures below 12oC (54oF) degrees will result in death or a state of torpor (sleep like state) so make sure your clients don’t put them in the fridge. This is a common mistake as this is common practice for yellow mealworms.
