Oriental cockroach

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Oriental cockroach
a, female; b, male; c, side view of female; d, young.
a, female; b, male; c, side view of female; d, young.
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Blattodea
Family: Blattidae
Genus: Blatta
Species: B. orientalis
Binomial name
Blatta orientalis
Linnaeus, 1758

The Oriental cockroach or waterbug (Blatta orientalis) is a large species of cockroach, measuring about 1 inch in length at maturity. It is dark brown to black in colour and has a glossy body. The female Oriental cockroach has a somewhat different appearance to the male, appearing to be wingless at casual glance but has two very short and useless wings just below its head. It has a wider body than the male. The male has long wings, which cover a majority of its body and are brown in colour, and has a more narrow body. The odd male is capable of very short flights, ranging about 2-3 meters. The female Oriental cockroach looks somewhat similar to the Florida woods cockroach, and may be mistaken for it.

Contents

[edit] Habitat

The Oriental cockroach tends to travel somewhat more slowly than other species. They are often called "waterbugs" since they prefer dark, moist places. They can often be found around decaying organic matter, and in sewers, drains, damp basements, porches, and other damp locations. They can be found outside in bushes, under leaf groundcover, under mulch, and around other damp places outdoors.

[edit] Adaptation

In order to thrive, cockroaches need a place to hide. They prefer warm places and a relatively high humidity if possible; they also need a source of food/liquid. The optimum temperature for Oriental cockroaches is between 20–29 °C; thus they are rarely found outdoors in the U.K. Female Oriental cockroaches have vestigial tegmina (reduced forewings) and males have longer tegmina.

Cockroaches are mainly nocturnal. Oriental cockroaches can be elusive in that a casual inspection of an infested dwelling during the day may show no signs of roach activity.

Collection of Oriental roaches caught on monitoring trap
Collection of Oriental roaches caught on monitoring trap

[edit] Distinction

Signs of cockroaches are their oothecae, which are “egg cases” containing up to 16 individual eggs in the case of Oriental cockroaches. These oothecae are dropped by females and hatch on their own in about two months.

Comparison of size between Oriental and Brown Banded Cockroach Oothecae
Comparison of size between Oriental and Brown Banded Cockroach Oothecae

Oriental cockroaches can be harder to get rid of than other roaches. Although adults can be fairly easily killed by the application of residual insecticide, the insecticides can get washed away, and two months later females can hatch new larvae.

The Oriental cockroach fecal pellet is on the bottom and the mouse dropping on the top
The Oriental cockroach fecal pellet is on the bottom and the mouse dropping on the top

Roaches leave fecal marks, which are larger and drier when water is scarce. It is difficult to see in the photo, but Oriental cockroaches' fecal pellets have lines running along the length of the dropping which is caused by pads in the rectum which extract water out of the pellet before it is ejected. The arrow shows where one of the lines runs along the length of the roach dropping.

[edit] Comparison of the three common roaches

Roach German Oriental American
Size(mm) 12-15 mm 25-30 mm 28-43 mm
Habitat heated buildings - optimum 32 degrees Celsius 20-29 °C same as German
Nymphal development time 6-12 weeks 6-12 months 4 months - 15 months
Life Span 6-9 months 1.5 years 1.5 years
able to fly? no no yes

[edit] References

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