Feeding Insects and Protein to Your Isopods

Isopods are detritivores at heart — their natural diet centres on decaying plant material, leaf litter, decaying wood, and fungi. But proper isopod husbandry properly includes regular protein supplementation, and dead insects are one valid option alongside fish meal, dried shrimp, and prepared invertebrate foods. This guide covers when and how to feed insects to your isopods, the alternatives worth considering, and the realistic pros and cons of each approach.

For broader dietary context including specialist diets beyond protein, see our companion article on specialist diets for isopods.

Why Isopods Need Protein

While leaf litter and decaying wood provide the dietary bulk for most isopod species, protein supplementation properly supports:

• Growth in juveniles and mancae — protein-rich diets produce larger, healthier adults
• Reproduction — females need adequate protein to develop egg masses; protein-deficient colonies show declining breeding
• Moulting success — protein supports the metabolic demands of moulting (alongside calcium)
• Long-term colony health — sustained protein deficiency leads to slow decline even when other husbandry is correct

Different species have properly different protein requirements. Premium Cubaris and Ardentiella are notably protein-hungry; they genuinely benefit from regular supplementation. Common Porcellio and Armadillidium species are more flexible but still benefit from periodic protein. Larger Porcellio species (P. expansus, P. magnificus, P. laevis) properly need consistent protein to avoid opportunistic predation on conspecifics.

Insects as Protein: The Honest Reality

Whole dead insects can be fed to isopods, but they're properly not the most common protein source in UK hobby practice. Most experienced UK keepers use fish flakes, dried shrimp, or specialist invertebrate foods rather than whole insects.

Pros of Insect Feeding

• Convenience for keepers who already breed feeders — if you have a cricket colony for reptiles, surplus dead crickets are properly free isopod food
• Nutritional variety — different insect species provide different amino acid profiles and trace nutrients
• Mimics natural opportunistic scavenging — isopods naturally encounter dead insects in the wild
• Long shelf life when frozen or freeze-dried — properly easier to keep than fresh foods

Cons of Insect Feeding

• Risk of attracting fruit flies and other pests — uneaten insect material in warm humid enclosures attracts secondary pests rapidly
• Mould risk — high-protein materials decompose quickly and grow mould fast in isopod enclosures
• Quality control — wild-caught insects may carry parasites or pesticide residues; only feed insects from clean, known sources
• Less calcium than commonly assumed — see below
• Whole insects are properly bulky — for small enclosures, processed protein sources (flakes, meal) are easier to portion

The Calcium Misconception

You may have read that insect exoskeletons are an excellent calcium source for isopods. This is properly WRONG. Insect exoskeletons are made of chitin, not calcium carbonate. Insects are genuinely notorious as calcium-poor feeders — which is why reptile keepers must gut-load and dust feeder insects with calcium supplements before feeding them to their lizards.

For calcium, isopods properly need dedicated calcium sources:

• Cuttlebone — best calcium option, leave in enclosure permanently
• Crushed eggshell — alternative or supplement
• Limestone pieces — passive calcium plus habitat enrichment
• Oyster shell flakes — similar to crushed eggshell

Don't rely on insects alone for calcium provision.

Types of Insects Suitable for Isopods

Crickets

Properly available through reptile shops and online feeder suppliers. Pros: easy to obtain, varied sizes, properly recognised as feeders. Cons: live crickets can stress isopods and disturb the colony; dead crickets attract fruit flies if not consumed quickly. Best practice is to use dead, properly thawed (if previously frozen) crickets in modest quantities.

Mealworms and Other Larvae

Mealworm larvae (Tenebrio molitor) are properly the standard reptile feeder larva and work as occasional isopod protein. They're higher in fat than crickets and lower in protein per unit weight, but still useful. Other larvae options include waxworms (very high fat, occasional treat only) and black soldier fly larvae (higher calcium content than most insects, properly genuinely useful).

Black soldier fly larvae (BSFL) are properly the most interesting larval option — they're naturally higher in calcium than other commonly-available feeders (typically 5-6% calcium by dry weight) and properly farmed sustainably. If you can source them dried or fresh, they're a genuinely good protein-plus-some-calcium option.

Beetles

Adult beetles can be fed but offer no advantage over crickets or larvae. The chitin-heavy exoskeletons of adult beetles are properly harder for isopods to break down than softer-bodied larvae. Generally not recommended unless you have surplus beetles from a feeder colony.

Earthworms

Properly genuinely useful if you have access. Earthworms are protein-rich, soft-bodied, easy for isopods to process. Chop into small pieces before offering. Don't confuse earthworms with worm castings — castings are worm droppings used as substrate amendment, not feeder material.

Other Options

Fly larvae (maggots), grasshoppers, dubia roach pieces, and similar feeder insects can all be used opportunistically. The principle is variety — rotating protein sources provides broader nutritional coverage than relying on one type.

The Alternatives Most UK Keepers Actually Use

Properly the reality is that most UK isopod keepers don't feed whole insects — they use processed alternatives that are easier to portion, have better shelf life, and don't attract secondary pests as readily.

Fish Flakes

The most common protein supplement in UK isopod keeping. Aquarium fish flakes are properly inexpensive, easy to portion (just sprinkle a small amount), protein-rich, and don't attract fruit flies as much as fresh insect material. Tetra and similar mainstream brands work well. Offer once or twice weekly.

Freeze-Dried Shrimp and Bloodworm

Dried aquarium foods — freeze-dried bloodworm, dried shrimp pieces, krill meal — are properly excellent protein sources for isopods. Long shelf life, easy storage, no fly attraction. Available from aquatic shops and online.

Insect-Based Powders and Meals

Cricket meal, mealworm meal, BSFL meal, and similar dried insect protein products give you the nutritional benefits of insects without the bulk and fly-attraction issues of whole insects. Available from reptile shops, online specialist suppliers, and increasingly from invertebrate-specific retailers.

Repashy Gel Diets

Several Repashy products work properly well for isopods:

• Bug Burger — protein-rich invertebrate diet, mixed with hot water to create a gel that can be portioned and frozen
• Morning Wood — specifically designed as a leaf litter and detritus substitute, useful when leaf litter stocks run low

Repashy products properly aren't currently in our PostPods range but are widely available through specialist invertebrate retailers and reptile shops.

How Often Should You Feed Protein?

The right frequency depends on species and colony goals:

• Premium Cubaris and Ardentiella — once or twice weekly; properly essential, not optional
• Larger Porcellio species — once weekly minimum to prevent cannibalistic behaviour
• Common Porcellio (Dairy Cow, scaber) — once weekly is fine; properly tolerates occasional missed feedings
• Armadillidium species — every 1-2 weeks is sufficient
• Porcellionides (Powder Orange, Powder Blue) — once weekly; faster-growing colonies appreciate more frequent protein

Active breeding colonies properly benefit from more frequent protein than maintenance colonies. If you want to maximise reproduction, increase protein frequency; if you want to maintain a stable colony size, reduce frequency.

Feeding Technique

Whichever protein source you use, follow these principles:

• Small quantities — easier for isopods to consume completely before mould develops. Better to offer less more often than dump large portions
• Spread thinly — distributing protein across the substrate gives all isopods access rather than just dominant individuals
• Place in a consistent area — many keepers use a small dish or flat stone, making removal of uneaten material easier
• Remove uneaten material within 24-48 hours — particularly critical with whole insects which mould fast
• Watch for response — colonies that consume protein eagerly properly need it; colonies that ignore offered protein may already have adequate intake from other sources

Pest Management

Insect-based feeding does create fruit fly risk in warm humid enclosures. To manage:

• Use fine mesh ventilation — keeps adult fruit flies out
• Strong springtail populations — compete with fly larvae for substrate resources
• Remove uneaten material promptly — the main prevention strategy
• BTI granules (Bacillus thuringiensis israelensis) — targets fly larvae only, safe for isopods. Useful for persistent fungus gnat issues

What Not to Feed

Some "protein sources" you'll see suggested are properly poor choices:

• Crushed dog or cat food — high salt content, additives, preservatives. Not suitable for isopods
• Cooked meat scraps from your kitchen — typically too salty, may have spices or oils that harm isopods
• Wild-caught insects from sprayed areas — pesticide contamination is real and can devastate colonies
• Old or rancid feeder insects — should be properly stored and used within shelf life
• Live insects (in most cases) — can stress isopods and disturb settled colonies; dead insects are properly more practical

The Honest Bottom Line

For most UK isopod keepers, dead insects aren't the most practical protein source. Fish flakes, freeze-dried shrimp, and insect-based meals deliver the same nutritional benefits with better storage, easier portioning, and less pest attraction. Whole insects are useful if you already keep feeder colonies for reptiles, but they're not a necessary addition to standard isopod husbandry.

What matters genuinely is:

• Regular protein supplementation (whatever form)
• Always-available calcium sources (cuttlebone, eggshell, limestone)
• Continuous leaf litter and decaying wood
• Variety in food types rotated through the diet

For setup essentials including calcium sources, browse our accessories collection. For comprehensive dietary guidance, see our specialist isopod diets article. For broader new keeper guidance, see our first isopods guide.

Whatever protein source you choose, the principle is properly the same — varied, modest portions, removed if uneaten. The right protein supplementation properly transforms colony health, breeding success, and individual lifespan over time.