Mealworms 101 – Part 1: Introduction

Edible insects have been receiving more and more attention since the UNFAO first published their 200 page 2013 report. In the US and Canada, the number of new start-ups in the insects as food sector has been growing quickly over the last couple of years and the same is now becoming true for Europe. Most of the North American companies are focussed on dealing with crickets in some way, and with the exception of a handful of start-ups and research institutions working with mealworms, the same goes for Europe.

FAO Report 2013

Crickets as “The Gateway Bug”

House Crickets

Crickets are fantastic for a number of reasons. Firstly, they have been affectionately coined “the gateway bug” by entomophagy enthusiasts because, of the many edible insects that are easy enough to farm, they are thought to be the easiest to swallow (pardon the pun) as far as public perception goes. People are familiar with the sound of crickets chirping at night and may associate this with feelings of being relaxed on holiday, for example. Once people try them for the first time, they tend to realise that they actually taste pretty good, and they are then (in theory) more susceptible to trying other types of insect in the future. Crickets are therefore a good place to start.

Secondly, as is the case for several of the edible insects in our Top 50 list, crickets have a very good nutritional profile and are much more environmentally sustainable when compared to the farming of larger livestock. Lastly, but most importantly, they taste good – while I find that they take a bit of getting used to, there’s nothing particularly offensive about their taste or texture. Overall, crickets are a smart introduction for people new to the world of entomophagy.

Re-branding Mealworms

This article, however, is clearly not about crickets, but about mealworms, another of these gateway bugs, if you will. Mealworms haven’t had as much of a following in the West so far, and this is mainly down to public perception. It’s all in the name: mealworms are so called because they look like worms and are often found in stores of grain (or “meal”). Worms themselves don’t have a very good rep – they’re slimy and they crawl through and eat dirt. Mealworms, however, are not, do not, and aren’t even worms anyway.

They are the larval form of the darkling beetle (Tenebrio molitor) and compared with crickets, for example, they have a more balanced nutritional content and more importantly, they taste a whole lot better; their unmasked taste is not as much of an acquired one as is the case with crickets. However, they obviously need re-branding if they are to one day appeal to the masses (as has also been suggested for the term “entomophagy”, covered by our very own guest writer, Olena), so with that in mind, there are a couple of options to the right to vote on.

How would you re-brand mealworms?

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This “Mealworms 101” article series will focus on why mealworms are pretty much the best overall edible insect out there. A bold statement, maybe, but there’s sound reasoning behind it which I’m sure you will come to appreciate. Here’s the plan for the series:

  1. Introduction
  2. Mealworm Recipes
  3. Nutritional Profile
  4. Sustainability
  5. Farming
  6. Versatility

For now though, let’s start with a few mealworm facts:

As mentioned above, mealworms are larvae of the darkling beetle (Latin name: Tenebio molitor). Beetles (Coleopterans) are insects, which are a Class of arthropods (see info box to the right). Insects (apart from a few exceptions) are characterised by their three body segments, six legs, two pairs of wings, and two antennae. Beetles are slightly different in that their outer wings have evolved to become hard and protect their inner wings and soft bodies beneath.

Insects (as well as other arthropods) have hard exoskeletons so they are only able to grow after they moult, before the exoskeleton hardens. The stages between moults are called “instars” and mealworms need to go through a number of these before they reach full size.

Arthropods also include crustaceans (lobsters, crabs, prawns), arachnids (spiders, scorpions, mites), and myriapods (centipedes and millipedes). As far as entomophagy goes, it’s usually the arthropods we refer to when we talk about “edible insects”, even though they aren’t all insects, and we normally exclude the crustaceans since they don’t need any help promoting!
Mealworm Life Cycle

After mating, the female beetle will burrow down to lay up to 500 eggs. In the wild, the eggs that survive predators will hatch into tiny mealworms, only a millimetre or so in length. These will then eat and grow while their bodies are still soft, each time hardening before moulting and beginning the next instar to repeat the process again (anywhere from 10-20 times). The last instar will then curl up and harden into a white alien-like pupa. The pupa then sits there dormant for a few days (dependent on temperature, humidity, etc.) while it hardens and darkens, eventually releasing the adult beetle. The beetle emerges with a white and orange soft body, which takes a few days to harden and turn brown, then eventually black (hence “darkling beetle”).

Mealworms are “holometabolous“, undergoing what’s called “complete metamorphosis” in that they have four distinct life stages: egg, larva, pupa, and adult. Other insects such as crickets and grasshoppers are “hemimetabolous” with no real larval form, but lots of miniature adult stages called “nymphs”.

We’ll go into this in more detail in a later episode of this series, but briefly:

  • They have all 9 essential amino acids, the necessary protein building blocks for our bodies.
  • High levels of Omega-3 and (especially) Omega-6 polyunsaturated fatty acids.
  • Rich in B vitamins and minerals such as iron, magnesium, zinc and selenium.

This one will be covered in more detail (with references) in a later episode of the series, but here are the main points:

  • Mealworms require very little water to farm. They get all of the water they need from the food they eat (e.g. waste fruit and vegetables) so the only real water needed in the farming process is for cleaning farm equipment.
  • Their food conversion ratio is 2.2 when feeding them wheat bran and carrots, meaning that 2.2 kg of feed is needed to produce 1 kg of edible mealworm protein. Compare this to a ratio of 2.5 for chickens, 5 for pigs, and 10 for cattle.
  • The greenhouse gases and ammonia they release per unit weight are a tiny, tiny fraction of those released by traditional livestock.

That’s all for now. The next in this series will be all about taste and mealworms as food, including a few mealworm recipes for good measure!

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