Birth: 20–40 live nymphs after about 28 days (supplier) to 48–64 days (study at 26 °C). Growth: 7 instars, about 6 months at 30 °C (Wu et al. 2013). Life span: males 12–18 months, females up to 2 years (DubiaRoaches.com; Alamer). Temperature: best 25–30 °C; nymphs died at 35 °C (Wu et al. 2017).
Dubia roach life cycle
The dubia roach life cycle is slow, and it has a twist: dubia roaches (Blaptica dubia) don't lay egg cases. The female forms an egg case of about 20–35 eggs and keeps it inside her body until the eggs hatch, then gives birth to live nymphs (Wikipedia's summary of Alamer 2013; DartFrog.pet). From there:
- Pregnancy: about 28 days according to a feeder supplier (DartFrog.pet), and 48–64 days at 26 °C in a 1996 study (Hintze-Podufal & Vetter, summarised by Wikipedia). Each litter is 20–40 nymphs (DartFrog.pet).
- Nymphs: seven instars — six moults — and "≈6 mo at 30 ± 2°C" to reach adulthood in an Auburn University study (Wu, Appel & Hu 2013). Feeder suppliers give 4–6 months (DartFrog.pet). Newborns are about ⅛ inch long (DubiaRoaches.com).
- Adults: up to about 4.5 cm long (Wu et al. 2013) — 1½ to 2 inches, says DubiaRoaches.com — and able to breed for a year or more.
Put together, the life cycle of a dubia roach takes around half a year from birth to breeding adult in a warm colony, and the whole life one to two years. That slow pace is the main thing new breeders underestimate: "Do not over-feed from a new colony until it is fully established!" (DartFrog.pet).
| Stage | Size | What it looks like | How long |
|---|---|---|---|
| Internal egg case | 20–35 eggs | carried inside the female | about 28 days (supplier) to 48–64 days (study at 26 °C) |
| Newborn nymph | about ⅛ in (3 mm) | small and wingless | the first of seven instars |
| Older nymphs | up to about 1¼ in | wingless; sex can't be told by wings yet | 4–6 months in total; 6 moults |
| Adult male | up to about 1¾ in | full wings covering the body | about 12–18 months (up to 1.5 years) in total |
| Adult female | up to about 1¾ in, broader | tiny wing stubs, about a quarter of body length | up to 12–24 months (up to 2 years) in total |
Sources: Wu, Appel & Hu 2013 (instars, development at 30 °C, adult size); Wikipedia's summaries of Alamer 2013, Hintze-Podufal & Vetter 1996 and Kesel et al. 2009; DubiaRoaches.com and DartFrog.pet (feeder suppliers, used to fill gaps). Freshly moulted dubias look "creamy white, but they return to normal within a few hours" (DubiaRoaches.com).
Male vs female dubia roach
Male vs female dubia roach is the easiest sexing job in the feeder world. Adult males "have full wings covering their body, while females have only tiny wing stubs — their tegmina (forewings) being around a fourth of their body length" (Wikipedia, citing Kesel et al. 2009). Females are "larger, bulkier" (DartFrog.pet). Nymphs of both sexes are wingless, so you can't sex them by wings until the final moult. Males' wings don't let them escape: in ramp tests, males glided and steered on the way down but "active powered flight did not maintain or increase their altitude", and females "showed no flight control" (Wikipedia's summary of Kesel et al. 2009).
Males also have shorter lives (see below), and suppliers suggest keeping about one male for every three to five females, because "Too many males will result in fighting and stress, which decreases breeding output" (DartFrog.pet). Surplus males are usually fed off first.
How long do dubia roaches live?
How long do dubia roaches live? About one to two years in total. The best-sourced figure is "Adults live for up to 2 years, females slightly longer than males" (Wikipedia's summary of Alamer 2013, a University of Bayreuth dissertation we couldn't access directly). Feeder suppliers agree: "males usually live 12-18 months while females may live up to 2 years" (DubiaRoaches.com). That dubia roach life span is far longer than a cricket's — the same supplier puts crickets at an average of nine weeks — which is why a dubia colony keeps supplying feeders for years.
| Sex | Birth to adult | Adult life | Whole life (birth to death) |
|---|---|---|---|
| Female | 4–6 months | 8–18 months (up to 1.5 years) | 12–24 months (up to 2 years) |
| Male | 4–6 months | 8–12 months (up to 1 years) | 12–18 months (up to 1.5 years) |
The adult figures are the whole-life figures minus 4–6 months as a nymph. Nobody we found has published a lower limit for females, so the calculator uses the same 12 months as for males; treat the female range as "up to two years". No study we could read measured adult lifespan at different temperatures.
Dubia roach gestation and breeding
Dubia roach gestation is the slowest step for a breeder. Two figures exist, and they don't agree. A 1996 study kept females at 26 °C on a 12-hour light cycle and recorded pregnancies of 48–64 days (Hintze-Podufal & Vetter, as summarised by Wikipedia). Breeders and suppliers quote about 28 days (DartFrog.pet), usually at hotter, breeding temperatures. The colony planner uses both ends rather than picking one. Either way, the female carries her egg case inside her and gives birth to 20–40 live nymphs (DartFrog.pet; Wikipedia), although stressed females may drop the case early (Alamer, via Wikipedia).
How fast do dubia roaches breed?
How fast do dubia roaches breed? Slowly at first, then steadily. A newborn needs about 4–6 months to become a breeding adult (DartFrog.pet), and the first litter follows one pregnancy later. After that, a female in a warm colony produces a litter about every one to two months. Over a year, one female could therefore give roughly 5 litters of 20 (about 100 nymphs) at the slow end to 13 litters of 40 (about 520) at the fast end. DubiaRoaches.com says they "are able to breed by 4 months of age and can continue breeding for a year or more".
Dubia roach colony size
How big should a starter colony be? That depends on how many feeders you need. The planner above multiplies your females by litters and litter size: with 20 females at 29 °C it estimates 800–4,800 nymphs in six months. As a rough guide, divide your pet's weekly feeder count by what one female gives — about 2 to 10 nymphs a week, from the published ranges (20 nymphs every 64 days to 40 every 28 days) — to see how many females you need. Start with a male-to-female ratio of about 1:3 to 1:5 (DartFrog.pet).
Two practical warnings. Escaped dubias rarely become house pests: "In order to breed, dubia roaches need higher temperatures and humidity than your house is able to provide" (DubiaRoaches.com). But they are restricted in some places — "Canada and some US states do not allow importation by the general public", and a Florida man was arrested in 2011 for ordering 500 with a doctored research permit (Wikipedia). Check your local rules before you buy.
Dubia roach sizes by age for feeding
Feeder suppliers sell dubias by length, and their size grades come with a suggested pet. The ages below are a rough guide, drawn as a straight line between the supplier's two dated points — "Extra Small Dubia Roach Nymphs (these are about 3-5 days old)" and "Extra Large Dubia Roach Nymphs (these are about 3.5 months old, nearly adults)" (DubiaRoaches.com) — at warm breeding temperatures. Real growth varies with food and warmth.
| Size grade | Length | Approximate age (warm colony) | Suggested for (supplier guide) |
|---|---|---|---|
| Extra small (¼ in) | 6.4 mm | about 3–5 days | newborn bearded dragons, baby leopard and crested geckos |
| Small (⅜ in) | 9.5 mm | about 17 days | baby bearded dragons, baby or juvenile geckos |
| Small (½ in) | 12.7 mm | about 29 days | baby or juvenile bearded dragons, juvenile geckos |
| Medium (⅝ in) | 15.9 mm | about 42 days | juvenile bearded dragons, adult geckos |
| Medium (¾ in) | 19.1 mm | about 55 days | adult bearded dragons, large adult geckos |
| Large (1 in) | 25.4 mm | about 80 days | large adult bearded dragons |
| Extra large (1¼ in) | 31.8 mm | about 105 days | large lizards such as blue-tongued skinks |
| Adult | 38–51 mm (1½–2 in) | 4–6 months and older | not listed as a grade in that guide |
Source of size grades and pets: DubiaRoaches.com, "What size dubia roaches do I need?" (a supplier). The ages are our interpolation between their two dated sizes, not measured.
Dubia roach size chart for reptiles
The dubia roach size chart for reptiles is only half the answer — the other half is your pet's own size and age. For a bearded dragon, the bearded dragon feeding schedule gives meals per day and insect size by age, and the bearded dragon size by age chart shows how big it should be. For geckos, see the leopard gecko size by age chart and the leopard gecko lifespan calculator. Smaller insect-eaters such as baby dart frogs need smaller feeders than any dubia grade; the flightless fruit fly culture calculator plans those. Because dubias keep growing, suppliers advise ordering only as many as your pet can eat "before they grow too big" (DubiaRoaches.com).
Best temperature for a dubia colony
Warmth drives everything in a dubia colony — but too much kills nymphs. Here's what the sources say:
- Optimum: growth and reproduction are "optimally 25–30°C and above 60% relative humidity" (Wikipedia's summary of Alamer 2013).
- Measured limits: in a 2017 Auburn study, "Nymphs developed to adulthood at 20, 25, and 30 °C, but all died before developing into fifth instar at 35 °C and into second instar at 40 °C" (Wu, Hu & Appel 2017).
- Supplier practice: 85–90 °F (29–32 °C) to trigger breeding, with room temperature enough just to keep them alive (DartFrog.pet); DubiaRoaches.com suggests 90–95 °F (32–35 °C) for breeding, "or as low as 68 degrees F if breeding is not desired".
The upper supplier figure reaches the 35 °C at which every nymph died in the Auburn study, so the planner accepts only 20–34 °C and flags anything above 30 °C as "warm: watch for losses". Below 25 °C it still runs but warns that breeding will be slower than its estimate.
Dubia roach breeding temperature
The safest dubia roach breeding temperature is therefore about 28–30 °C (82–86 °F): inside the published optimum, inside the supplier breeding range and comfortably below the lethal 35 °C. Use a thermostat-controlled heat mat under one side so the roaches can move to a cooler end (DartFrog.pet). Keep humidity moderate — DartFrog.pet suggests 40–60%, warning that "extreme moisture" breeds mould, while Alamer's optimum is above 60% — and never use an open water dish, because nymphs drown; water crystals or moist vegetables are the usual alternative (DartFrog.pet; DubiaRoaches.com). Egg crates stacked vertically give them surface area and hiding places (DartFrog.pet).
How this colony planner works
Both modes use the same shared cockroach data model as the pest species on this site, with the dubia's sources labelled:
- Life cycle & lifespan: birth to adult 4–6 months (DartFrog.pet; about 6 months at 30 °C, Wu et al. 2013); whole life 12–18 months for males and up to 24 for females (DubiaRoaches.com; Alamer via Wikipedia). These aren't temperature-adjusted, because the full temperature tables of Wu et al. (2017) aren't publicly available; your temperature sets a warning band instead.
- Colony planner: starting adult females are assumed mated. Each gives a litter every 64 days (slow) to 28 days (fast), with 20 (slow) to 40 (fast) nymphs. Low estimate = slow litters × 20; high estimate = fast litters × 40. Only your starting females are counted; home-born females could start breeding after about 5 to 8 months (one pregnancy plus 4–6 months of growth), which the planner reports but doesn't add.
- Feeder sizes: the oldest nymphs' approximate length each month, from the supplier size points above, matched to the supplier's size grades.
The result is an estimate for planning, not a forecast. Crowding, food, humidity and the number of males all change real output.
Frequently asked questions
What is the dubia roach life cycle?
The female carries an egg case of 20–35 eggs inside her body, gives birth to 20–40 live nymphs, and the nymphs take about 4–6 months and six moults to become adults (Alamer via Wikipedia; DartFrog.pet; Wu et al. 2013).
How long do dubia roaches live?
About one to two years: males usually 12–18 months, females up to 2 years (DubiaRoaches.com, a supplier; Alamer via Wikipedia).
How long is dubia roach gestation?
About 28 days according to a supplier (DartFrog.pet), and 48–64 days at 26 °C in a 1996 study (Hintze-Podufal & Vetter, via Wikipedia).
How many babies do dubia roaches have?
20–40 live nymphs per litter (DartFrog.pet; Wikipedia).
How long do dubia roaches take to grow?
About 6 months at 30 °C (Wu et al. 2013) or 4–6 months in supplier colonies (DartFrog.pet).
What is the best temperature for breeding dubia roaches?
About 28–30 °C (82–86 °F): within the 25–30 °C optimum (Alamer via Wikipedia) and below the 35 °C at which nymphs died (Wu et al. 2017).
How do you tell male and female dubia roaches apart?
Adult males have full wings covering the body; females have tiny wing stubs and are larger and bulkier (Wikipedia; DartFrog.pet).
Can dubia roaches fly or climb?
Males can only glide down; females can't fly. Neither can climb smooth glass or plastic (Wikipedia; DubiaRoaches.com).
Will dubia roaches infest my house if they escape?
Unlikely: they need higher temperatures and humidity to breed than a house provides (DubiaRoaches.com).
Are dubia roaches legal everywhere?
No. Canada and some US states don't allow importation by the general public (Wikipedia). Check local rules.
What size dubia roach should I feed my reptile?
Supplier guides pair ¼ in nymphs with hatchling bearded dragons and baby geckos, up to 1 in for large adult dragons (DubiaRoaches.com). See the bearded dragon feeding schedule.
Should dubia roaches have a water dish?
No — nymphs can drown. Use water crystals or moist vegetables (DartFrog.pet; DubiaRoaches.com).
Husbandry figures come from university, zoo and peer-reviewed sources where we could find them, and from feeder suppliers only to fill gaps (labelled as such). Every colony differs with temperature, food and crowding. Check local rules before buying live roaches: some places restrict them (see the FAQ), and never release pet or feeder insects outdoors.