How Discoid Roaches Reproduce: A Keeper's Breeding Guide

I keep discoid roaches as a self-sustaining feeder colony, and the single best thing about them is how forgiving and slow their breeding is — slow enough that the colony never explodes on you, fast enough to feed a collection of reptiles. To run that colony well, it helps to actually understand how these animals reproduce, because their strategy isn't what most people assume from the word "roach."

First, the name correction I see botched constantly: discoid roaches are Blaberus discoidalis, family Blaberidae. They are not Blaptica dubia (the dubia roach). Different genus, different species, different size. People conflate the two all the time. This guide is about discoids specifically.

What discoid roaches are

Discoids are medium-to-large tropical roaches, roughly 1.5 to 2 inches long, with smooth, flattened, oval bodies in tan-to-dark-brown shades. They're native to Central and South America, where they live in leaf litter and break down organic matter. As feeders they're popular for three practical reasons: they're calm and don't bite, they cannot climb smooth vertical surfaces like glass or smooth plastic, and they're poor fliers. That combination makes them nearly escape-proof in a smooth-walled bin — a huge advantage over crickets. (You'll sometimes read that they "climb and hide on rough surfaces"; the key point for a keeper is that they can't scale a smooth wall, so a slick-sided tub holds them with no lid gymnastics.)

Egg-layer or live-bearer? Both, sort of

Here's the genuinely interesting part. Most roach species are oviparous — they form an egg case (an ootheca) and deposit it somewhere in the environment to hatch on its own. Discoid roaches do something different: they're ovoviviparous.

That means the female still forms an ootheca packed with eggs, but instead of dropping it, she retains it inside her abdomen. The eggs develop internally, drawing on the yolk in the egg (not a placenta — this isn't true live birth like a mammal), and when development is complete she gives birth to live, fully formed nymphs. So you'll never find egg cases scattered in a discoid bin the way you would with, say, a German cockroach. The "births" just appear as clusters of pale little nymphs.

This is why the common framing — "do they lay eggs or give birth?" — has a both-and answer. The egg case is real; it's just carried internally until the nymphs are ready to emerge.

Why ovoviviparity is an advantage

Carrying the ootheca internally protects the developing embryos from the things that kill exposed egg cases: predators, drying out, and temperature swings. The mother provides a stable, moist, temperature-buffered environment right up to the moment of birth. The trade-off is fewer offspring per cycle than a species that broadcasts hundreds of eggs — but each one has a much higher survival rate. For a keeper, that trade-off is a feature: it's the reason a discoid colony grows steadily instead of exploding.

Mating behavior

Discoid courtship runs on chemistry, not looks — they're nocturnal and largely operate in the dark, so chemical and tactile signals dominate. The male releases pheromones from specialized glands to advertise and assess receptivity. He approaches cautiously, often with wings slightly raised, and uses his antennae to tap and stroke the female. If she's receptive she stays put; if not, she simply moves off.

During copulation the male transfers a spermatophore — a packet of sperm — rather than mating for a prolonged period. The female can store that sperm and fertilize eggs over time, which means a single successful mating can fuel multiple broods. That sperm-storage trick is part of why a stable colony keeps producing without constant pairing.

The reproductive cycle, start to finish

1. ◆Mating — male attracts female via pheromones; spermatophore transferred.
2. ◆Ootheca formation — the female's glands package fertilized eggs into an egg case.
3. ◆Internal incubation — she retains the ootheca inside her abdomen for a gestation lasting several weeks.
4. ◆Live birth — she releases a brood of live nymphs, typically a few dozen at a time.
5. ◆Nymph development — nymphs are soft-bodied, paler, and wingless at first; they molt through several instars over several months before reaching adulthood.
6. ◆Repeat — under good conditions a mature female produces a new brood roughly every 30–60 days.

Compared to pest species like the German cockroach, this is a slow cycle — months to adulthood, modest brood sizes. That's exactly why discoids are considered a controllable, non-infesting feeder. They also can't establish in a typical temperate house: they need sustained tropical warmth and humidity to breed.

Setting up a breeding colony

If you want the colony to actually produce, you have to hit their tropical conditions. This is where keepers either succeed or stall out.

Temperature and humidity

Keep the colony at 80–90°F with humidity around 60–70%. This is the master control. Warm and humid, they breed steadily; let it drop into the low-to-mid 70s and reproduction slows or stops. I use temperature deliberately as a throttle — warmer when I need more feeders, cooler to coast.

The enclosure

A large, well-ventilated smooth-sided tub. Because discoids can't climb smooth walls, you often don't even need a tight lid — but I keep one (with screened vents) for humidity and pests. Stack vertical egg-crate flats inside; they multiply the usable surface area enormously and give the colony places to hide, rest, and birth. Vertical orientation also keeps the bin from getting fouled.

Feeding the colony

A breeding colony needs steady nutrition to keep producing. I give a protein-bearing dry base (a quality roach chow or a high-grade dry pet food) plus fresh produce — leafy greens, carrot, squash — for moisture and micronutrients. Provide water through a gel-based hydration source rather than an open dish so nymphs don't drown. What you feed the colony in the days before you feed them out is also gut-loading your reptiles, so keep the diet clean and varied.

Colony management

Pull out uneaten produce before it molds, keep the bin from getting filthy, and don't let it get overcrowded — crowding stresses the colony and depresses breeding. Harvest feeders by size: take the nymphs and sub-adults that fit your animals and leave the breeding adults to keep the colony self-sustaining. Done right, you start a bin once and feed off it for years.

When you're starting or restocking a colony, source from a clean, captive-raised line — I get mine through the discoid roach collection at All Angles Creatures so I know the starter stock is healthy and disease-free.

Clearing up the myths

• ◆"They breed like crazy / will infest my home." No — slow cycle, tropical requirements, can't climb smooth surfaces or fly well. They don't establish in temperate homes.
• ◆"They lay egg cases everywhere." No — the ootheca is carried internally; you won't find cases in the bin.
• ◆"Nymphs are just tiny adults." Mostly, but nymphs have softer exoskeletons, lack adult coloration and wing development, and grow gradually through molts.
• ◆"Mothers abandon young instantly." Newborn nymphs emerge fully able to fend for themselves; there's no extended parental care to rely on, so a good colony environment is what protects them.

Understanding the ovoviviparous cycle is really what lets you run the colony instead of just owning it — you know why no egg cases appear, why warmth is the throttle, and why the slow turnover is a feature, not a flaw.

For day-to-day husbandry once the colony is running, see keeping discoid roaches alive, and to round out a varied feeder rotation, my hornworm guide.