Blattella

Pronunciation

How to pronounce Blattella: //blæˈtɛlə//

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Summary

Blattella asahinai, or the Asian cockroach, is a species characterized by its outdoor habitat preference, strong flying ability, and distinct behaviour related to light attraction. It is a beneficial predator but poses management challenges due to its similarity with the German cockroach.

Physical Characteristics

The Asian cockroach is small, typically 1.3 to 1.6 cm long, tan to dark brown in color with dark parallel stripes on the back of its head. It has longer wings than the German cockroach (B. germanica) and exhibits some minor morphological differences such as a groove in the abdomen and a distinct ventral surface of the left mandible.

Identification Tips

The easiest way to distinguish the Asian cockroach from the German cockroach is through behavior and morphology. The Asian cockroach is a strong flyer and is attracted to light, while the German cockroach tends to scatter away from bright light. Morphologically, differences can be noted in wing size, venation, and bristles on the cerci.

Habitat

Asian cockroaches are predominantly found outdoors in shaded, mulched, composted areas and damp locations. They prefer large areas of grass or leaf litter, where they can form large populations.

Distribution

Originally from Okinawa Island, Japan, it was first reported in the United States in Lakeland, Florida in 1986. Since then, it has expanded throughout much of Florida and is also reported in Alabama, Georgia, South Carolina, and Texas.

Diet

Asian cockroaches are omnivorous, feeding on human food, pet food, flowers, agricultural crops, and prey such as lepidopteran eggs in soybean and cotton crops, also including lettuce, cabbage, and strawberries.

Life Cycle

Females produce approximately four oothecae in their lifetime, with each containing 35-40 eggs. The lifecycle spans approximately 60-70 days for females to reach adulthood and they are most fertile during February-May and August-September.

Reproduction

Females carry their egg capsules until they hatch, producing fewer oothecae compared to the German cockroach. Their first ootheca is typically produced about 13 days after reaching adulthood, with an incubation period of about 19 days.

Predators

Adult and nymph Asian cockroaches have been identified as predators of bollworm eggs in crops, contributing to pest management in agricultural settings.

Ecosystem Role

Asian cockroaches serve as predators of agricultural pests, such as bollworm eggs, in their habitats, thus playing a beneficial role in pest control.

Economic Impact

The presence of the Asian cockroach can complicate pest management strategies due to its similarity with the German cockroach, potentially leading to ineffective control measures and economic losses.

Health Concerns

While the species does not carry pathogens, it may be in contact with outdoor pathogens, animal feces, and fungi, raising some health concerns similar to other cockroaches.

Evolution

Genetic analyses indicate that the Asian cockroach diverged from the German cockroach slightly over 2000 years ago, which is presumed to coincide with the German cockroach spreading to areas away from contact with the Asian cockroach.

Similar Taxa

• Blattella germanica

Misconceptions

Due to their similar appearance, they are often confused with the more common German cockroach, leading to issues with pest management strategies.

Tags

• cockroach
• Blattella
• insect
• pest
• entomology