Blattellidae

These cockroaches carry the eggcase externally. The majority of species turn the eggcase on its side after formation. This position is more streamlined and probably maintains their ability to move into narrow harborages. These cockroaches are characterized by legs that are long, slender, and with small and large spines; the ventral surface of the tarsi has spines. Many species have fully developed wings, but some have reduced wings in one or both sexes. Sternum 7 of the female is broad and rounded, not divided into lobes or valves. Tergum 10 of both sexes is usually triangular, and with long, tapering cerci.

Asiablatta kyotensis Adult males are 14-18 mm long and females are 16-18 mm long. The body is reddish brown; the legs and antennae are brown. Male antennae are about equal to body length; female antennae are slightly longer than the body. The ootheca contains about32 eggs and hatching occurs in about 41 days at 25 °C. The ootheca surface has about 30 distinct longitudinal ridges extending from end to end. These ridges may be responsive to environmental humidity, and have a role in providing water to developing embryos. Nymph development is about 150 days, but extends to 2 years in dry habitats. Adult males live about 92 days and females live about 109 days. Natural habitats include moist or damp locations. This species was first described from Kyoto, Japan, but it is distributed in several areas of Japan and Korea.

Asian cockroach, Blattella asahinai Adults are 12-16 mm long; the body is light brown or yellowish brown and females are slightly darker than males. Wings cover the abdomen of the female and all except the tip of the male abdomen. Male front wings are about 3.3 mm wide and 11.6 mm long; female front wings are about 3.4 mm wide and 12 mm long. Males and females are capable ofdirected and sustained flight. This species closely resembles B. germanica, but is distinguished by its flight capabilities and morphological features. The prono-tum ofadults and nymphs has two longitudinal, parallel black bands. The ootheca is 6-8 mm long and brown; there are distinct indentations outlining each egg. Nymphs are blackish brown to black; the margins of abdominal segments are pale brown. Adults mate soon after maturation; the first ootheca appears in about 14 days, and it is carried until just prior to hatching. The initial preoviposition period is about 13 days and successive preoviposition periods are about 8 days. The ootheca contains 38-44 eggs; incubation is about 20 days at about 25 °C. Fecundity in the laboratory is 5-6 oothecae; in the field it is 1-2 oothecae. Nymph development at 25 °C is about 66 days for males and 68 days for females. Adult males live about 45 days and females about 103 days.

Natural habitats include grassy areas and leaf litter; they feed on dead insects, pollen and nectar in plants, and on honeydew. In the urban environment, they occur outdoors in vegetation. Adults fly to reflected light, such as illuminated areas and light-colored walls adjacent to a light source. They are capable of moving 10-200 m or more in controlled flight from wooded or grassy areas toward illuminated buildings. Flights occur at sunset if the temperature is 21 °C or above, and winds are light. Once indoors, they usually occur in moistloca-tions, such as in kitchens and bathrooms, and in potted plants. B. asahinai was described in 1981 from sugarcane fields in Okinawa Island, Japan. It is widely distributed in Asia, including China, Malaysia, Myanmar, and India. Itwas firstrecorded in the western hemisphere in 1985-1986 near Lakeland, Florida. The original distribution area extended about 50 km, from the port ofTampa northeast to Lakeland. Habitats in three counties were initially infested, but by early 1989 there were 10 counties infested. Field populations of this species range from 30 000 to nearly 300 000 individuals per 0.4 ha.

German cockroach, Blattella germanica (Fig. 4.1f; 4.5a, b, f)

Adults are 13-16 mm long, light brown to yellowish brown, and females are slightly darker than males. The pronotum has two reddish brown to black longitudinal stripes; the extent of the stripes is variable. The wings cover the abdomen of the female and all except the tip of the male abdomen; male front wings are about 2.8 mm wide and 10.6 mm long, while female frontwings are about3.i mm wide and 11.2 mm long. The female abdomen is darker brown and much more round than that of the male. Powered flight is rare, but gliding flight is possible, especially for males. Male cerci are 11-segmented, and female cerci are 12-segmented. Nymphs are generally black; the margins of abdomen are brown and with a light stripe to the mid-dorsum. First-stage nymphs are 2-3 mm long and the body is dark gray or nearly black. Thoracic segments 2 and 3 are pale brown, and this band characterizes the newly emerged nymph. In late-stage nymphs the pale brown band narrows and extends in both directions to become a median longitudinal stripe.

The ootheca is 7-9 mm long, and with indentations showing the position of the eggs. The ootheca contains 35-48 eggs, and hatching is in about 14 days at 35 °C; fecundity is 4-8 oothecae, but 9 may be produced in some field strains. Females produced 27.9 nymphs per ootheca in summer and 9.7 in winter. After ootheca 4, the number of eggs per ootheca declines, and by ootheca 7 and 8 the eggs per ootheca is about 75% of the initial number. Once formed, the ootheca is turned so the keel is directed sideways, to the right or left, and it is carried until egg development is complete. Eggs become desiccated if the ootheca is removed from the female prematurely. The end of the ootheca that is held by the female is not as sclerotized as the other end, and itis permeable to water. The ootheca is provided

Figure 4.5 Blattaria: Blattidae. (a) Blattella germanica male; (b) B. germanica male; (c) Ectobius sylvestris male; (d) B. vega, head anterior; (e) B. vega male, supraanal plate; (f) B. germanica male, supraanal plate; (g) E.pallidus male; (h) E. lapponicus male; (i) E. lapponicus female.

with water by the female and this is critical for development. A few days before hatching a green band of dark spots of condensed yolk develops along each side of the ootheca. The band intensifies as the time ofhatchingapproaches. Atthattime, the female deposits the eggcase, and hatching occurs within 24 h; hatching may occur while the female is carrying the eggcase. Development is 54-215 days at 24 °C, and 60 days for males and 65 days for females at 35 °C and 90-95% RH. Gregarious behavior of nymphs, which is encouraged by an aggregation pheromone, favors their growth and development. The number of nymph stages is 5-7 in males and 6-7 in females. Nymphs with relatively small bodies undergo six molts and those with large bodies have five molts. Adults mate 7-10 days after maturation. Males mate often; females in field populations mate once or twice. Adults live about 200 days at 21 °C. Survival without food or water at 27 °C is about 8 days for males and 12 days for females; survival with water is 10 days for males and 42 days for females.

Natural habitats for this species are probably moist leaf litter in forested areas; however there are not known natural populations. Related species in southern Asia occur in caves and in ground debris. In the urban environment this species lives only indoors. In tropical climates, it prefers indoor sites with high humidity, food, and harborage. Adults can move about in space 1.6 mm in width or depth, but they seem to prefer harborages that are 4.8 mm. The spatial distribution of adults and nymphs is influenced by the aggregation behavior induced by a pheromone. Occupied harborages are marked with the pheromones contained in the feces, and the behavior-manipulating substance remains active for atleast the period of one generation of B. germanica. The concentration of aggregation pheromone may regulate the density of individuals in local harborages. A repellent reaction occurs when the concentration of aggregation increases above a certain level, and individuals disperse rather than aggregate. Short migrations of a large number of individuals have been reported, but this behavior is not common. Distances covered by migrations range from 500 m to 1 km, and the migrating groups consist mainly of adult females.

Sexually mature male German cockroaches are generally capable of distinguishing between adult males and females, probably based on volatile and contact sex pheromones produced by the female. When a male B. germanica encounters another German cockroach, he investigates it with his antennae. If the other is a mature female he touches the female's body with his antennae. They then rub each other's antennae in a vibrating manner while in a head-to-head position. After a sideways motion of the abdomen, the male turns around and positions the tip of his abdomen close to the head of the female. At this time he extends his wings upward to nearly a right angle to its body. The factor responsible for eliciting the wing-raising behavior in males is a sex pheromone contained in the cuticle wax of fully developed virgin females. The raised wings expose the male abdomen, and the female palpates with her mouthparts the small glands on abdominal ter-gites 7 and 8, and she imbibes the material excreted from these tergal glands. After this the male moves his abdomen under the female, and extends his genitalia to contact the female's genitalia. Once joined, the male moves out from under the female, and they remain attached in a linear position for about 90 min.

The success of this cosmopolitan species as a domestic pest is linked to features of its biology and habits, and to some of the physical and environmental features common to human dwellings around the world. Adults and nymphs are relatively small and able to utilize the cracks and crevices common in households. Female fecundity and the number of eggs per ootheca are high, and the limited activity of gravid females increases the potential success of each ootheca.

B. germanica has the unique capacity among cockroaches to develop physiological and behavioralresistance to insecticides. It seems to have the ability to acquire resistance to representatives of nearly all the major classes of chemical insecticides. The resistance-related mechanisms utilized by this cockroach include enhanced metabolic degradation, reduced rates of cuticular penetration, diminished target site sensitivity, and behavioral changes that enable avoidance of pesticide residues. In many cases, several of these resistance factors exist concurrently. High levels of resistance in this cockroach may be shortlived, but low-level resistance may persist in field populations.

Blattella nipponica Adults are 12-14 mm long and the body is brown to dark brown. It closely resembles B. germanica, except that the adults fly readily. The preferred habitat is under leaves in forested areas, and under decayed vegetation in cultivated areas in central Japan. The ootheca is about 6 mm long and contains 12-43 eggs. Hatching occurs in 17 (June) to 42 (September) days; fecundity is about five oothecae. Adults emerge in early June, and first-stage nymphs occur in July and September. There is one generation per year, and the adults live 5-6 months.

Field cockroach, Blattella vega (Fig. 4.5d, e) Adults are 10-12 mm long. The body is yellowish brown, and with a dark brown to black region between the eyes and extending to the mouthparts. Longitudinal stripes on the pronotum are blackish brown, widely separated and sharply defined. Nymphs are pale yellow, and have dark brown cerci; large nymphs are yellowish orange. The ootheca is 5-6 mm long, light brown, and with distinct indications of the egg compartments. The first three oothecae contain about 28 eggs, but the number of eggs per ootheca drops in the succeeding oothecae. The interval between oothecae is about 24 days. Hatching is in about 20 days; fecundity is 1-8 oothecae. Development takes 45-56 days at 30-36 °C; at 30 °C males develop in about 60 days and females in about 54 days. Newly hatched and small nymphs sometimes crawl on the back of females. Adults live 100-150 days. Adults mate 3-5 days after maturation, and an ootheca appears 2-3 days later.

Natural habitats include under stones, and in moist leaflitter where it feeds on decaying vegetation; it has been found in desert locations. Recent records from eastern Texas and southwestern Louisiana are from salt marsh or coastal habitats. In the agricultural environment, B. vega occurs in irrigated fields. In the urban environment, it occurs around the perimeter of buildings and moves indoors during dry weather. It is active during the day, but also occurs at streetlights at night. This species is probably native to semiarid regions of southern Asia; it occurs in Afghanistan, India, Pakistan, Sri Lanka, Mexico, and in southwestern USA. Itis frequently found in irrigated fields in southern Arizona and adjacentareas in southern California.

Other Blattella There are more than 40 species in this genus worldwide. Species are distributed from southern Asia, Japan, various Indo-Malaysian and Pacific islands, and Africa; and including several species from Africa, now placed in the genus Symploce. Most of these species occur outdoors and are not domiciliary pests. B. lituricollis occurs in Myanmar, China, Taiwan, Philippines, and on various islands north to Japan and east to Hawaii. It is occasionally a household pest, though it occurs mostly outdoors. It occurs in Hawaiian agricultural fields, and sometimes enters buildings. In Japan, it occurs around the outside ofbuildings, and indoors in kitchens.

Tawny cockroach, spotted Mediterranean cockroach, Ectobius pallidus (Fig. 4.5g) Adults are 8-9 mm long and uniformly pale brown. Wings extend to the tip of abdomen in both sexes; males and females are capable of flying. Front wings are wide and extend over the edges of the thorax and abdomen; there is a triangular area at the tip of the hind wings without veins and cross-veins. Nymphs are pale brown to dark brown. The ootheca is 2-3 mm long and dark brown; the ventral surface usually has a distinct longitudinal concavity (visible in ventral view) where the sides join. The keel has rounded teeth. The ootheca is turned on its side and carried by the female for 1-2 days. Oothecae are produced in fall and deposited in leaflitter, and hatching occurs the following spring. Nymphs develop through 5-6 instars during the spring and summer; nymphs overwinter and become adults the following spring. Natural habitats include wooded sites, but also grassy areas, heaths, and sand dunes. This species does not usually live in the urban environment, but they fly to lights atnight. It occurs in western, central, and southern Europe. In the USA, it has been found in Massachusetts and Michigan.

Other Ectobius These cockroaches live outdoors and only occasionally enter structures. E. lapponicus (Fig. 4.5h, i) adults are about 10 mm long; the males are dark brown and the females are pale brown. Wings of the female do not cover the abdomen. The male has long wings, is capable of flight, and may occur indoors. This species occurs in Europe, including southern UK. E. panzeri adults are 5-7 mm long and pale brown to dark brown. The male wings extend to the tip of the abdomen; the female has short wings. This species occurs primarily in coastal regions ofEurope. E. syluestris (Fig. 4.5c), the forest cockroach, is closely related to E. pallidus and may occur indoors.

Nicaraguan cockroach, Ischnoptera bergrothi Adults are 15-18 mm long. The body is reddish brown dorsally and black ventrally; the pronotum has two distinct spots. Wings cover the body; both sexes are strong flyers. Nymphs are similar to adults. This species is native to Central America, from Panama to Nicaragua, but also occurs in outdoor populations along the Gulf and lower Atlantic coastal plain from Texas to Georgia and Florida. Indoor infestations are not common, but they fly to lights at night and occur around the outside of structures. A related species, I. nox, is primarily tropical and is currently known from Panama and Florida. In Fort Lauderdale, Florida, populations occur on extensively landscaped grounds of resorts.

Pennsylvania woods cockroach, Parcoblatta pennsylvanica (Fig. 4.6b, c) Adult males are 22-30 mm and females are 13-20 mm long. Males and females are light brown, and the thorax and front wings have pale brown margins. Wings of the male extend to the tip of the abdomen; female wings are usually small pads and of variable length; only the males fly. Nymphs are dark brown. The ootheca is 10-12 mm long and yellowish brown, ithas a distinctkeel, and there are indications of the egg compartments. The ootheca contains 32-36 eggs, and about 26 eggs hatch in 32-36 days at 24-27 °C. Oothecae are produced every 5-9 days and they are carried for 1-3 days; fecundity is about 30 oothecae. Nymphs hatch in summer and usually overwinter and complete development in the spring of the following year. Under unfavorable conditions, development is completed later in the second year.

Natural habitats include moist leaflitter and under the bark of decaying logs in hardwood and pine forests of eastern USA, and in undisturbed areas. In the urban environment this species occurs around the perimeter of buildings, in woodpiles and accumulated forest debris. They live around outbuildings in suburban areas. Males have long wings and are capable of flights over 30 m. This species is attracted to lights at night. Males occur around the outside of structures and indoors in May and June; females are abundant in July. Females and nymphs may be carried indoors with firewood or other material. These cockroaches rarely persist indoors, perhaps because of their high humidity requirements and food preferences. Nymphs remain active throughout the year, even at 0 ° C.

Figure 4.6 Blattaria: Blattellidae. (a) Parcoblatta virginica male; (b) P. pennsylvanica male; (c) P. pennsylvanica female; (d) Supella longi-palpa male; (e) S. longipalpa female.

P. pennsylvanica is widely distributed in the eastern and southern USA, and it occurs in southeastern Canada.

Other Parcoblatta Species in this genus are common in wooded areas in North America. They are found in decaying logs, under the bark of dead or down trees, and in woodpiles. These cockroaches are often attracted to lights atnight. Adults and oothecae (Fig. 4.ig) can be accidentally carried indoors with firewood. There are 12 described Parcoblatta species, but aside from P. pennsylvanica, only a few are known to be associated with buildings or occur indoors. P. americana occurs in Mexico and southwestern USA and it is occasionally reported near buildings and at lights. P. áivisa occurs in southeastern USA and west to Texas and Kansas. It is sometimes reported invading houses built in wooded areas. P. lata and P. virginica (Fig. 4.6a) occur in eastern USA and have been reported indoors, at lights, and under wooden signs on trees.

New Zealand black cockroach, kokoroihi, Platyzosteria novae-seelandiae (= P. novae-zealandiae) This species is uniformly blackish brown, and brachypterous. Adults and nymphs occur under loose bark of trees and down logs, or among stones on the ground; they are sometimes carried indoors. They are predaceous on other insects. This species occurs in New Zealand.

Australian woods cockroach, Shawella couloniana Adult males are 15-18 mm long and females are 20-22 mm long; both sexes are shiny and uniformly dark brown. Wings of the male cover about half of the abdominal segments, while wings of the female cover the basal 2-3 abdominal segments. Nymphs are shining, dark brown. The ootheca is 6-8 mm long, brown, and contains about 20 eggs. This species is limited to sites in Australia and New Zealand. It is an outdoor species, but occasionally occurs indoors.

Brownbanded cockroach, Supella longipalpa (Fig. 4.1h; 4.6d, e) Adult males are 13-14.5 mm long and females are 11-12 mm long; the body is brown to yellowish brown, and with distinct pale brown banding. Nymphs and adults have long palps. Wings of the male cover the abdomen, but rarely reach the tip of the abdomen in the female. Adult males fly readily when disturbed, but females do not fly. Pronotum lateral edges are translucent, the remainder is dark; the pronotum often has a pale area in the center. The common name is derived from two dark brown, transverse bands on the mesonotum and abdominal tergites. Nymphs are banded light and dark brown; one band is across the posterior margin of the mesonotum, the other across abdominal segment one, and extends dorsolater-ally along the next few segments.

The ootheca is about 4 mm long, brown to reddish brown, and has a prominent keel; it is curved and there are indentations showing the position of the eggs. The ootheca contains 14-18 eggs; hatching occurs in about 96 days at 23 °C, 74 days at 25 °C, 43 days at 27.5 °C, and 37 days at 30 °C. The number of eggs per ootheca remains nearly unchanged during the life of the female. Fecundity is 10-20 oothecae. The ootheca is deposited 24-36 hafter development, and the female glues it to the substrate. Many females often deposit oothecae at the same location. In large, household infestations, there may be clusters of large numbers of oothecae. Nymph development in isolation in the laboratory at 30 °C includes eightinstars and lasts aboutii4 days for males, and sixinstars and about 69 days for females. Development in groups of nymphs is about 54 days for males and about 56 days for females. Nymph development is about i6i days for males and 162 days for females at 23 °C, and at 29 °C it is 90 days for males and 95 days for females. Optimum development is above 27 °C. Adult life span is about 115 days for males and 90 days for females. Adults mate 3-5 days after maturation, and the first ootheca appears in 7-10 days. Survival without food or water at 27 °Cis about9 days for males and 12 days for females; survival with water is 10 days for males and 14 days for females.

Natural habitats are probably leaf litter in nonforested regions of Africa north of the Equator. In the urban environment, it occurs outdoors and indoors; in warm climates, it is abundant year-round. In infested buildings and houses it often inhabits all rooms, and is common on furniture and in drawers of chests, and this habit has earned it the commonnameoffurniturecockroach (supellex, Latinforhouse-hold goods and furniture). It seems to prefer locations high on the walls of heated rooms, and favored oviposition sites include behind picture frames. Males often fly around lights in houses, and they have been observed flying outdoors during the day.

This cockroach was described as Blatta longipalpa in 1798 from eastern India. It was described again in 1838 as Blatta supellectilum from specimens collected in Mauritius. Evidence from related species and early records of B. longipalpa indicates that it is native to Africa. It was in Cuba in i862, and introduced into North America (Florida) in about 1903; it spread to nearly all the contiguous states by i967. It was first recorded in Australia in 1924, and in the UK after i960.

Symploce pollens (= Symploce lita) Adults are 13-16 mm long and uniformly brown. Wings of the male extend to the tip of the abdomen, and female wings extend to a third of the abdomen. Male abdominal segment 6 has a setose and slightly sculptured area. This species is distributed in the tropical regions of the world, and is a pest in Malaysia and other southeastern Asian countries; it is also known from the USA. It occurs in structures in Key West, Florida.

Other Blattellidae Cariblatta lutea is known from Cuba and southeastern USA. It has been found around houses and disturbed areas, particularly in lawns and in leaf litter. Euthlasto-blatta gemma occurs in the Bahamas and southeastern USA. It occurs in arboreal habitats, such as behind wooden signs on trees, and in and around houses in southern Georgia. Latiblat-tella rehni occurs in the Bahamas, Cuba, and northern Florida, where it has been found in house attics. Lupparia vilis adults are i0-i2 mm long, brown, and distinctly flattened. It occurs in Iwo Jima, China, Thailand, Malaysia, and Indonesia; it has been reported as a household pest in Iwo Jima.

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