What is the Difference Between German and American Cockroach

The main difference between German and American cockroach is that German cockroach is a small cockroach whereas American cockroach is the largest common cockroach. 

German and American cockroach are two types of common household cockroaches found in different parts of the world. German cockroach has a colour variation from tan to almost black with two dark, roughly parallel, streaks on the pronotum running anteroposteriorly from behind the head to the base of the wings. In contrast, American cockroach has a reddish brown body and a yellowish margin on the pronotum, which is the body region behind the head.

Key Areas Covered

1. German Cockroach
     – Definition, Characteristics, Behavior
2. American Cockroach
     – Definition, Characteristics, Behavior
3. What are the Similarities Between German and American Cockroach
     – Outline of Common Features
4. What is the Difference Between German and American Cockroach
     – Comparison of Key Differences

Key Terms

American Cockroach, Body Colour, German Cockroach, Household Pests, Pronotum

German Cockroach – Definition, Characteristics, Behavior

German cockroach (Blattella germanica) is a small form of cockroaches among household cockroaches. Generally, the size of the German cockroach is around a half of an inch. The colour of a German cockroach can vary from light brown to black. Furthermore, it has two parallel lines running from their head to wingtip. However, the main feature of a German cockroach is their higher reproduction rate. Therefore, they become more frequent in number.

Figure 1: German Cockroach

Furthermore, German cockroaches prefer warm and humid places in houses like bathrooms and kitchens. They also nest in cracks and crevices around the house. Most probably, they are found crawling around the floor. That means; although they have wings, they rarely fly.

American Cockroach – Definition, Characteristics, Behavior

American cockroach (Periplaneta americana) is the largest variety among the household cockroaches. It is colloquially known as the waterbug. The other names for American cockroach are the ship cockroach, kakkerlak, and Bombay canary. Generally, it is much bigger than German cockroach and grows up to 1.5 to 2 inches. Moreover, American cockroach is reddish brown in colour. Also, they have a paler yellow or orange colour around the edge of the thorax. In addition, the reproduction rate of this variety is comparatively low, making them less frequent.

Moreover, American cockroaches make their nests outdoors or in basements. However, they often come indoors during winter in order to escape from the cold. These large cockroaches crawl around the ground although they are capable of flying.

Similarities Between German and American Cockroach

• German and American cockroach are two types of common household pests.
• They are scavenging insects that resemble a beetle, having long antennae, legs and typically a broad, flattened body.
• Moreover, they have chewing mouthparts.
• Also, both belong to the order Blattodea.
• Their body is made up of three parts: the head, thorax (three segments), and abdomen (ten segments).
• The head contains a pair of compound eyes.
• The second and third thoracic segments bear wings. The first pair of wings known as tegmina and serves as a tough protective shield for the membranous hind wings.
• However, they only use their hind wings in flight.
• Each thoracic segment is attached to a pair of legs. Front legs are the shortest and hind legs are the longest while hind legs provide the main propulsive force when running.
• Furthermore, each abdominal segment contains a pair of spiracles for respiration. The tenth segment contains a pair of cerci, a pair of anal styles, the anus and the external genitalia.
• Generally, both have an exoskeleton, containing calcium carbonate.
• Besides, females of both carry an egg case known as ootheca until the eggs hatch.
• They prefer warmth and moisture.
• Both help to transmit germs on the surfaces and they are known to cause infection by carrying bacteria such as Staphylococcus spp. & Streptococcus spp., hepatitis virus, coliform bacteria, as well as causing food poisoning by carrying Salmonella spp. and Shigella spp. Bacteria. They are also linked with typhoid, dysentery and cholera.
• A large number of these pests produce an overwhelming, musty odour, coming from their body fluid.
• Regular cleaning help to control cockroach problems.

Difference Between German and American Cockroach

Definition

German cockroach refers to a small active winged cockroach, probably of African origin, and is a common household pest in the U.S. American cockroach, in contrast, refers to a cockroach of the genus Periplaneta that is a common domestic pest infesting ships or buildings (as homes, warehouses, or bakeries) in the northern hemisphere. Thus, this is the basic difference between German and American cockroach.

Family

German cockroach belongs to the family Ectobiidae while the American cockroach belongs to the Blattidae.

Species

The scientific name of the German cockroach is Blattella germanica while the scientific name of the American cockroach is Periplaneta americana.

Habitat

There is also a difference between German and American cockroach in terms of their habitat. German cockroaches prefer indoors while American cockroaches generally prefer outdoors and move indoors during winter.

Location

While German cockroach mostly gathers in kitchens and bathrooms, American cockroach mostly lives in basements, crawl spaces and around or inside drains.

Preferred Temperatures

Furthermore, German cockroach prefers 15–35 °C while American cockroach prefers 20–29 °C.

Size

Their size is the main difference between German and American cockroach. German cockroach is small in size (1.1 to 1.6 cm in length) while American cockroach is the largest (4 cm in length).

Frequency

Furthermore, German cockroach is more common than American cockroach.

Colour

German cockroach has a colour variation from tan to almost black with two dark, roughly parallel, streaks on the pronotum running anteroposteriorly from behind the head to the base of the wings while American cockroach has a reddish brown body and a yellowish margin on the pronotum. Hence, this is the most visible difference between German and American cockroach.

Diet

Moreover, German cockroaches are scavengers that feed on almost anything, including things like toothpaste, paper, soap, leather, etc. while American cockroaches consume leaves, wood fragments, fungi, algae, smaller insects, and crumbs and scraps of human food.

Ootheca

Females of German cockroaches carry around 35 young in the ootheca while the females of American cockroach carry around 12 young in the ootheca.

The Dropping of the Ootheca

Females of the German cockroaches carry the ootheca until a day or two before it hatches while the females of the American cockroaches carry the ootheca for about a week before 2 months before hatching.

The Offspring Produced by a Single Female

In addition, the female German cockroach can produce up to 30,000 cockroaches in one year while the female American cockroach can produce up to 800 cockroaches in one year.

Nymphal Development

Besides, the nymphal development of the German cockroach takes 54–215 days while the nymphal development of American cockroach takes 150–360 days.

Lifespan

Another difference between German and American cockroach is their lifespan. The lifespan of German cockroach is around 200 days while the lifespan of American cockroach is around 90-706 days.

Conclusion

The German cockroach is a small cockroach, but it is the most frequent one in the households. Moreover, it is tan to blackish in colour and has two dark roughly parallel streaks on the pronotum, running towards the head to the wings. Furthermore, the reproduction rate of a German cockroach is high. On the other hand, the American cockroach is the largest form of household cockroaches. It is a reddish brown in colour and has a yellowish margin on the pronotum. However, it is less frequent when compared to German cockroaches. Therefore, the main difference between German and American cockroach is the size, colour, frequency, and habitat.

References:

1. “IDENTIFYING TYPES OF COCKROACHES.” Hitman Professional Pest Control, Pest Control Brisbane & Gold Coast – Hitman, 26 Jan. 2017. Available Here.

Image Courtesy:

1. “Blattodea. Cascuda. Santiago de Compostela 1” By Lmbuga – Own work (CC BY-SA 3.0) via Commons Wikimedia  
2. “American-cockroach” By Gary Alpert (CC BY 2.5) via Commons Wikimedia