Blattidae

Order characteristics,Taxonomy, and significance

1. BLATTIDAE by , Bharath Kumar Ayyapan Krishnasamy,

2. ORDER : DICTYOPTERA ( Dictyon = network,ptera =wings) Sub order : Blattodea (Cockroach) , Mantodea (Preying Mantis) Subclass : Pterygota Division : Exopterygota Sub Group : Neopteran orders Group : Orthopteroid orders Sub order : Blattodea (Cockroach) F amilies : Blattidae (Oriental Cockroach & American Cockroach) Blatellidae (German Cockroach)

3. ORDER CHARACTERS BODY : Medium to large sized nocturnal insect.Body is dorsoventrally flattened. Head : Hypognathous .Compound eyes large amd widely separated. Two ocelli present.Antenna is Filliform.Mouthparts biting and chewing type. Thorax : Tarsus is five segmented. Forewings are more or less thickened,leathery with marginal costal vein. They are tegmina. Hindwings are large ,membranous and folded like a fan and kept beneath the forewings. Abdomen : cerci are short and many segmented. Development: Eggs are contained in an ootheca or egg case.metamorphosis is gradual .Parental care is present.

4. SUBORDER : BLATTODEA EGG : Laid inside a chitinous ootheca. Hard ,regular shape ,16 eggs in two parallel rows Dropped on ground,glued to substrate retained within female’s body. NYMPH: Structurally similar to adults Not cannibalistic. Developing wingpads often visible on thorax.

5. ADULTS BODY: Oval , somewhat flattened Head: It is not mobile in all directions. Two fenestrae ( Degnerated ocelli ,sensitive to light ) occur in the place of dorsal ocelli. Antenna slender and filiform Thorax: Pronotum is oval,shield like,covering much of thorax and head) Meso and metathoracic segments are rectangular. Legs are cursorial,long and spiny, adapted for running. Autoamputation is absent. Tarsi 5 segmented Wings found in both sexes Forewings are thickened and hindwings are membramous,peated .

6. ABDOMEN: Cerci are short and multi_segmented . Anal styli are present only in males,which is used to hold females.(sexual dimorphic character). ANATOMY Gizzard is powerfully armed with chitinous teeth to grind food. Scent glands present in abdomen impart foul smell. BEHAVIOUR AND ADAPTATIONS Female does not devour the male during mating Body is well-adapted for running and squeezing into narrow openings They are positively thigmotrophic and weak fliers Rather than flying to escape danger ,cockroaches usually rush into cracks and crevices. No mimicry is found They are gregarious , nocturnal and omnivores.

7. Blatta orientalis (oriental cockroach) Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Blattodea Family: Blattidae Genus: Blatta Species: B.  orientalis

8. It is dark brown or black in color and has a glossy body. 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. Oriental cockroaches can be found in usually damp places such as sewer pipes, sink drains, and any other form of damp areas in households.

9. EGG Oothecae are formed a day after mating, and typically deposited a day or two after formation, though can be deposited up to 7 days later, typically in a sheltered area or attached to a substrate by oral secretion. They are initially a yellow white, turning reddish- then blackish-brown. Parthenogenesis occurs and resulting ones are female A female oriental cockroach produces an average of eight egg capsules per lifetime. Each egg capsule or ootheca contains about 16 eggs that are lined up vertically, two by two in the egg case. The incubation period for the oriental cockroach is about 42 to 81 days.

10. NYMPH The female gives no assistance to the young. Nymphs go through seven molts before becoming adults, which takes approximately one year. An adult  Blatta   orientalis  can live from 34 to 180 days.

11. ADULT The male has long wings, which cover two-thirds of the abdomen and are brown in color , and has a narrower body. Female oriental cockroaches have vestigial  tegmina  (reduced fore wings) and males have longer tegmina.

12. The female has a somewhat different appearance from the male, appearing to be wingless at casual glance, but is  brachypterous , having non-functional wings just below her head. She has a wider body than the male.

13. Periplanta americana (American cockroach) Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Blattodea Family: Blattidae Genus: Periplaneta Species: P. americana Binomial name Periplaneta americana ( Linnaeus ,  1758 )

14. NYMPH The number of times an American cockroach molts varies from six to 14 The first instar American cockroach is white immediately after hatching then becomes a grayish brown.

15. molting, subsequent instars of the cockroach nymphs are white and then turn reddish-brown, with the posterior margins of the thoracic and abdominal segments being a darker color. Wings are not present in the nymphal stages and wing pads become noticeable in the third or fourth instar. Complete development from egg to adult is about 600 days. The nymphs as well as the adults actively forage for food and water.

16. ADULT The adult American cockroach is reddish brown with a pale brown or yellow band around the edge of the pronotum. The males are longer than the females because their wings extend 4 to 8 mm beyond the tip of the abdomen.

17. Males and females have a pair of slender, jointed cerci at the tip of the abdomen. The male cockroaches have cerci with 18 to 19 segments while the females’ cerci have 13 to 14 segments. The male American cockroaches have a pair of styli between the cerci while the females do not.

18. ECONOMIC SIGNIFICANCE At least 22 species of pathogenic human bacteria, viruses, fungi, and protozoans, as well as five species of helminthic worms, have been isolated from field collected American cockroaches. Cockroaches are also aesthetically displeasing because they can soil items with their excrement and regurgitation.

19. COMPARISION OF ORIENTAL AND AMERICAN COCKROACH Roach Oriental cockroach American cockroach Size 25 mm (2.5 cm) to 30 mm (3.0 cm) 28 mm (2.8 cm) to 43 mm (4.3 cm) Habitat 20 °C (68 °F) to 29 °C (84 °F) Same as German Nymphal development time 6 to 12 months 4 to 15 months Lifespan 1 to 1.5 years 1 to 1.5 years Able to fly No [4] Ye