German Cockroach

• GeneralThe hardest household cockroach to get rid of: one female produces as many as 300 offspring.
• Unlike other cockroaches, the female carries the ootheca attached to her abdomen right up to the moment of hatching, which shields the eggs from insecticides and predators.
• Whole populations have developed an aversion to glucose: sugary baits kill those that accept sugar and those that refuse it survive, a case of evolution observed within a few years inside people's homes.
• Its allergens are a recognised cause of childhood asthma in homes with chronic infestations.
• It is the most troublesome household cockroach in the world, and it owes that to three things: small size, a short life cycle and an extraordinary readiness to develop insecticide resistance.
• A single female can leave between 200 and 400 descendants; at any given moment 75 to 80% of an infestation is nymphs, which means eggs and nymphs have to be targeted too, not just adults.
• Resistance is documented to pyrethroids, fipronil, clothianidin, indoxacarb and hydramethylnon.
• Its droppings, cast skins and corpses contain allergens that trigger asthma, and that is its main impact on health.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Kitchens, restaurants, bars and warm damp premises

Size at birth

Ootheca 6 to 8 mm; the newly hatched nymph measures about 3 mm

Sexual maturity

Six to seven nymphal instars over 6 to 31 weeks; the females begin to mate four days after emerging

Gestation / incubation

3-4 weeks of ootheca incubation

Litter / clutch size

30-40 eggs per ootheca

Sources consulted: Wikipedia (es): Blattella germanica · ScienceDirect (Hughes 1989) · Science Advances, How colonial animals evolve · Wikipedia, Zooid · Rutgers NJAES, ficha German cockroach · University of Florida · University of Florida, ficha German cockroach · LSU AgCenter · Animal Diversity Web, Blattella germanica · ficha de identificacion de la especie · LSU AgCenter, ficha Blattella germanica · Insects Limited