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Insects, much like reptiles, like it hot. But also like reptiles, they have limits to what they can handle. A colony of insects might be okay in your garage on a hot day. But if you order a hundred feeders, shipped in a box, and accidentally leave it on your porch for too long, they might all die.
So how much heat is too much for a feeder insect? Which insects are best to order, if you need to buy some in the summer? In this article, we’ll talk about the heat tolerance of popular feeder insects, so you can plan smart and make sure you get your feeders alive and well.
Crickets
Temperature-wise, the brown house cricket (Acheta domesticus) is fairly heat resistant. They’re not the best, but they’re also not the worst. Crickets tend to stress, and may die quicker above 90°F. Above 96°F is generally considered fatal. And the high end of survival for crickets is 109°F, meaning rapid death.
So, for reference, they could probably make it to you alive, in the shady back of a shipping truck. But if you were to leave them on your porch in the summer heat, they would most likely die.
Superworms
Superworms (Zophobas morio) are a great feeder if you need high fat and low fiber. But they’re one of the least heat-tolerant feeder insects out there. Ideally, you want to keep superworms between 70 and 80°F. They will start to stress once they get above 80°F. Above 88°F, they will start to die. Higher temperatures will cause them to die quicker.
Depending on where you live, this sensitivity to temperature might cause all your superworms to die before they even get to your house.
Mealworms
Mealworms (Tenebrio molitor) are the smaller cousin of the superworm, both in the darkling beetle family. Mealworms have similar nutritional facts to superworms, but have much higher fiber. They’re also smaller. Like superworms, mealworms are also very heat intolerant, with an ideal temperature range from 70 - 80°F. For mealworms, above 90°F is considered fatal.
Hornworms
Many reptile owners still haven’t heard of hornworms. The hornworm (Manduca quinquemaculata) is a species of moth caterpillar. They have good nutritional quality, very low fiber content, and come in huge sizes. Hornworms can reach up to 4 inches long before they pupate into moths. This makes them great for any reptile that’s too big for other feeders.
They are a little more hardy than mealworms and superworms, preferring temperatures above 80°F. But above 90°F will stress them and cause health problems. Above 100°F is considered fatal. This puts them in the “moderately heat-tolerant” category with crickets. They may make it to your house, but you won’t want to let them sit on the porch.
Silkworms
The silkworm (Bombyx mori) is another less-common feeder. They are an extreme example of a “lean protein,” with almost no fat compared to protein. They also have very low fiber. Silkworms are large, like hornworms, reaching 2 1/2 to 3” before pupating.
Silkworms probably have the second lowest tolerance for heat, behind mealworms. They prefer temperatures in the 70-80°F range. Above 86°F will stress them and is considered unhealthy. Temperatures above 95°F are fatal.
Dubia Roaches
The dubia roach (Blaptica dubia) is a small-to-medium sized flightless cockroach. They’re our go-to lean protein, mainly because of how easy to keep they are. If you’re starting a colony of feeder insects, dubias are one of the easiest options to raise in your house. They’re also great roommates and have very minimal needs.
As a bonus, dubia roaches are also pretty heat tolerant. The optimal breeding temperature for dubia roaches is 90-95°F, much higher than other insects in this article. Above 95°F, they will start to stress and may have higher mortality. Above 105°F is considered fatal for them.
This makes dubias the best feeder insect we’ve covered so far. They are hardy enough to spend all day in the back of a truck, and might be able to sit on your porch for a bit if they need to.
The biggest downside of dubia roaches is that they’re illegal in Florida, as they could easily become invasive there. So if you live in Florida, what should you use instead?
Discoid Roaches
That’s right, discoid roaches. The discoid roach (Blaberus discoidalis) is very similar to the dubia in terms of nutritional value. It’s also flightless, and a slightly quicker prey item than the dubia. This makes them a little more fun to hunt for pets that like to chase their prey.
The best part about the discoid roach is that it’s native to Florida, so it’s legal there. If you live in Florida and can’t keep dubia roaches, we recommend using discoids instead.
Discoid roaches have a similar heat tolerance to dubias. Their optimal temperatures for breeding are 90-95. Above 95 can be stressful, and above 105 can be fatal.
The Most Heat-tolerant Feeder Insect
Overall, roaches like the dubia and discoid roach are the most heat-tolerant feeder insects. They are the best-suited to long journeys and may even stand up to a little time sitting on your porch, although you may find some of them dead.
Less heat-tolerant, but still okay are crickets, hornworms, and silkworms. Hornworms are probably the best behind our two roach species, and can stand up to 100°F or so. Crickets are slightly worse than hornworms in the heat, and will start to die above 95°F. Silkworms are about the same, and will die above 95°F.
The least heat-tolerant feeder insects, by far, are superworms and mealworms. And this makes sense- you can even put mealworms in your fridge to store. They both need temperatures in the 70-80°F range to stay healthy.
That’s all just fine indoors, but on a hot day, in a crowded cardboard box, it can get hot quickly. Superworms and mealworms will both start to die around 90°F. Depending on where you live, they may not even make it to your house before they all die off.