Common Cockroach Species

The habitats of this species are quite variable. American cockroaches infest landfills, municipal sewage systems, storm drainage systems, septic tanks, crawl spaces beneath buildings, attics, tree holes, canopies of palm trees, voids in walls, ships, electronic equipment, caves, and mines. Studies conducted in Arizona indicated movement by a number of individuals several hundred meters through sewer systems and into neighboring homes. This species often can be seen at night on roofs and in air stacks or vents of sewage systems, through which they enter homes and commercial buildings. Entrance also is gained to homes through laundry vent pipes and unscreened or unfiltered attic ventilation systems. This cockroach is known to move from crawl spaces of hospitals via pipe chases into operating theaters, patients' rooms, storage facilities, and food preparation areas. Consequently, the potential of this cockroach for disseminating pathogenic microorganisms can be a significant concern for health care personnel.

Australian cockroach (Periplaneta. australasiae)

Adult body coloration is similar to that of the American cockroach, but with paler lateral markings on the upper edges of the tegmina (Fig. 3.5). The pronotum is ringed with similar coloration. Adults are slightly smaller than American cockroaches, measuring 32— 35 mm in length. Females mature in about 1 year and typically live for another 4—6 months. A female can produce 20—30 oothecae during her lifetime; the ootheca is about 11 mm long and contains about 24 embryos. Embryonic development requires about 40 days. Nymphs are strikingly mottled, distinguishing them from nymphs of other Periplaneta, species.

This peridomestic species requires somewhat warmer temperatures than the American cockroach and does not occur in temperate areas other than in greenhouses and

HGURE 3.5 Australian cockroach (Periplaneta australasiae), female. (Courtesy of the University of Florida/IFAS)
FIGURE 3.6 Brown cockroach (Periplaneta brarmea), female. (Courtesy of the University of Florida/IFAS)

other pseudotropical environs. In the United States, outdoor populations are well established in Florida and along the coastal areas of Louisiana, Mississippi, Alabama, and Georgia. It commonly is found in environments similar to those inhabited by the smoky brown cockroach. In situations where both species occur (e.g., tree holes, attics), the Australian cockroach tends to displace the smoky-brown. It can be a serious pest in greenhouses and other tropical environments in more temperate latitudes, where it can cause feeding damage to plants, notably seedlings.

Brown cockroach (Periplaneta brunnea)

The brown cockroach (Fig. 3.6) is smaller than the American cockroach (33-38 mm), and its pronotal markings are more muted. The most apparent diagnostic characteristic for separating these two species is the shape of the last segment of the cercus; in the brown cockroach, the length is about equal to the width, whereas in the American cockroach the length is about 3 times the width. The ootheca of the brown cockroach usually is larger (7—13 vs 8 mm) and contains more embryos (24 vs 16). The brown cockroach affixes its oothecae to substrates using salivary secretions. They give the ootheca a grayish hue not typical of other Periplaneta species that attach their oothecae with salivary secretions. This species is more subtropical than the American cockroach, occurring throughout the southeastern United States, where it infests homes and outbuildings. It is less frequently associated with sewage than is the American cockroach. Because of its similar appearance to the American cockroach, it is often misidentified and may be more widely distributed than is commonly recognized. In Florida, P. brunuea is commonly found in canopies of palm trees and attics. It also readily infests various natural cavities and those in human-associated structures. The oothecae can be useful in differentiating species infesting buildings. Most

FIGURE 3.7 Smokybrown cockroach (Periplaneta fuliginosa), female. (Courtesy of the University of Florida/IFAS)

cockroach oothecae persist in the environment after the nymphs have emerged and provide a history of infestation.

Smokybrown cockroach (Periplaneta fuliginosa) The smokybrown cockroach (Fig. 3.7) has become a major peridomestic pest throughout the southern United States, including southern California, and extends as far north as the Midwestern states. It can be differentiated from the American cockroach by its slightly smaller size (25-33 mm) and uniform dark coloration. Although developmental times are quite variable, individuals mature in about 10 months. Adults may jive for more than a year. Females produce several oothecae, which are 10-11 mm in length with 20 embryos, at 11-day intervals.

Primary foci for this peridomestic species in the southeastern United States are tree holes, canopies of palm trees, loose mulches such as pine straw or pine bark, and firewood piles. Within structures, P. fuliginosa seeks the ecological equivalent of tree holes—areas characterized as dark, warm, protective, and moist, with little air flow and near food resources. These include die soffits (eves) of underventilated attics, behind wall panels, the interstices of block walls, false ceilings, pantries, and storage areas. From these harborages, individuals forage for food and water, generally returning to the same refugia. Mark-release-recapture studies using baited live traps have shown that the median distance traveled between successive recaptures is less than 1 m but that some adults may forage at distances of more than 30 m.

Florida woods cockroach (Eurycotis floridana)

This cockroach is restricted to a relatively small area of the United States along the Gulf of Mexico from

FIGURE 3.8 Florida woods cockroach (Eurycotisfloridana), female.

(Courtesy of the University of Florida/IFAS)

FIGURE 3.8 Florida woods cockroach (Eurycotisfloridana), female.

(Courtesy of the University of Florida/IFAS)

eastern Louisiana to southeastern Georgia. It is mentioned here only because of its defensive capabilities. It is a large, dark-reddish brown to black cockroach (Fig. 3.8), 30-40mm long. Akhough small wing pads are evident, adults are apterous and are relatively slow moving. Oothecae are 13—16 mm long and contain about 22 embryos. E. floridana occurs in firewood piles, mulches, tree holes, attics, wall voids, and outbuildings. Last-instar nymphs and adults, if alarmed, can spray a noxious mix of aliphatic compounds that are both odoriferous and caustic. If this is sprayed into the eyes or onto soft tissues, a temporary burning sensation is experienced. Domestic dogs and cats quickly learn to avoid this species. Among its common names are the Florida cockroach, the Florida woods roach, the Florida stinkroach, and palmettobug. The last term also is commonly used for other Periplaneta species.

Brownbanded cockroach (Supslla longipalpa)

Like the German cockroach, this domestic species probably originated in tropical Africa, where it occurs both indoors and outdoors. In North America and Europe it is confined almost exclusively to indoor environments of heated structures. In warm climates, infestations occur particularly in apartments without air conditioning and in business establishments with relatively high ambient temperatures, such as pet stores and animal-care facilities. Adults are similar in size to the those of the German cockroach (13—14.5 mm long) but lack pronotal stripes. Adults have two dark bands of horizontal stripes on the wings {Fig. 3.9), whereas nymphs have two prominent bands running across the mesonotum and first abdominal segment. The brown-banded cockroach derives its name from these bands.

FIGURE 3.9 Brown banded cockroach (Supella longipalpa), female. (Courtesy of the University of Florida/IFAS)

Populations tend to occur in the nonfood areas of homes, such as bedrooms, living rooms, and closets. Male brownbanded cockroaches occasionally fly and are attracted to lights. Members of this species seek harborage higher within rooms than do German cockroaches. The ootheca is small, only 5 mm long, with an average of 18 embryos and an incubation time of 35—80 days. Females deposit their oothecae by affixing them to furniture, in closets, on or behind picture frames, and in bedding. Transporting S. longipalpa with furniture to new locales is common. Although this species occurs with other cockroaches in homes, the German cockroach often outcompetes it within a few months.

German cockroach (Blattellagermanica)

This cockroach also is known as the steamfly in Great Britain. It is believed to have originated in northern or eastern Africa, or Asia, and has spread from there via commerce. The German cockroach is considered to be the most important domestic pest species throughout the developed world. Adults are about 16 mm long, with two dark, longitudinal bands on the pronotum (Fig. 3.10). It requires warm (optimally 30-33°C), moist conditions near adequate food resources. It primarily inhabits kitchens and pantries, with secondary foci in bathrooms, bedrooms, and other living spaces in heavily infested structures. Although this species is nocturnal, like most other cockroaches, some individuals may be seen moving about on walls and in cupboards during the daylight hours where infestations are heavy. Their wing musculature is vestigial, making them unable to fly except for short, gliding, downward movements. B. germanica does not readily move between buildings; however, it does occur in garbage collection containers and outbuildings near heavily infested structures.

FIGURE 3.10 German cockroach (Bíattelia germanictt), female. (Courtesy of die University of Florida/IFAS)

The German cockroach has a high reproductive potential. Females produce an ootheca (6—9 mm) containing about 30 embryos within 7-10 days after molting to the adult, or about 2—3 days after mating. The female carries the egg case until a few hours before hatching of the nymphs, preventing access of any oothecal parasitoids or predators. Oothecae are produced at intervals of 20— 25 days, with a female producing 4—8 oothecae during her lifetime. Nymphs complete their development in 7— 12 weeks.

This species is the main cockroach pest in most households and apartment complexes. Control is difficult, in part because of their movement between apartments through plumbing chases in shared or adjacent walls. Researchers studying over 1,000 apartments in Florida concluded that the median number of cockroaches per apartment was >13,000. This high biotic potential makes this species a major nuisance, as well as a pest with implications for human health.

Asian cockroach (Blandía asahinai)

The Asian cockroach is closely related to the German cockroach, from which it is difficult to distinguish morphologically. In fact, Asian and German cockroaches are capable of hybridizing and producing fertile offspring, which further complicates their identifications. Techniques have been developed to differentiate these two species and their hybrids based on cuticular hydrocarbons in the waxy layer of the integument.

Despite their morphological similarity, B. asahinai differs from B. germánica in several aspects of its behavior and ecology. It is both a feral and a peridomestic species. Nymphs of the Asian cockroach commonly occur, sometimes in large numbers, in leaf litter and in areas of rich ground cover or well-maintained lawns. Unlike the German cockroach, the adults fly readily and are most active beginning at sunset, when they fly to light-colored walls or brightly lit areas. This behavior can make invasion a nightly occurrence in homes near heavily infested areas. Flight does not occur when temperatures at sunset are below 21°C.

Like those of the German cockroach, Asian cockroach females carry their oothecae until shortly before they are ready to hatch. The ootheca is similar in size and contains the same number of embryos as does that of the German cockroach (38—44). Nymphs are smaller than their B. germaniea counterparts and are somewhat pater in appearance. Development from egg to adult requires about 65 days, with females producing up to six oothecae during their life span. Adults also are slightly smaller than those of B. germanica (average of 13 vs 16mm).

The Asian cockroach was first described in 1981 from specimens collected in sugar-cane fields on the Japanese island of Okinawa. When it was first discovered in the United States in 1986, the Asian cockroach was found only locally in three counties in Florida, from Tampa to Lakeland; populations already had become established, with densities as high as 250,000 per hectare. By 1993, this species had spread to at least 30 Florida counties and had infested citrus groves throughout the central part of the state. It feeds on succulent early growth of citrus nursery stock, tassels of sweet corn, strawberries, cabbage, tomatoes, and other agricultural products, although there has been no evidence of significant economic damage.

Infestations of apartments by B. nsabinni have become common in central Florida. This cockroach also has become an increasing problem in warehouses, department stores, hotels, fast-food establishments, automobile dealerships, and other businesses with hours of operation that extend beyond dusk.

Surinam cockroach (Pycnoscelus surinamensis) This species is believed to have originated in the Indo-Malayan region. It commonly occurs in the southeastern United States from North Carolina to Texas. The adults are fairly stout, 18—25 mm in length, with shiny brown wings and a black body (Fig. 3.11). Nymphs characteristically have shiny black anterior abdominal segments, whereas the posterior segments are dull black and roughened. In North America this species is unusual in that it is parthenogenetic, producing only female offspring; elsewhere both males and females are found. The ootheca is 12—15 mm long, is poorly scle-rotized, and contains about 26 embryos. Oothecae are retained inside the genital chamber, from which the nymphs emerge in about 35 days. Females produce an average of three oothecae and live about 10 months in the laboratory. This cockroach commonly burrows into compost piles and the thatch of lawns. Transfer

FIGURE 3.11 Surinam cockroach (Pycnoscelus surinamensis). (Courtesy of the University of Florida/IFAS)

Cuban cockroach (Panchlora. nivm)

This medium-sized cockroach (22—24 mm in length) is unusual in that the adults are pale green. The nymphs are dark brown and are found in leaf litter and decaying wood piles. Adults are strong fliers and are attracted to lights. Panchlora nirea is believed to be native to the Caribbean basin, Mexico, Central America, and northern South America. In the United States it occurs commonly in Florida and coastal Louisiana and Texas. This cockroach often is seen in the evening, resting on windows and glass patio doors, apparently drawn to the brightness of indoor lighting.

Cockroaches infesting human dwellings and workplaces represent a more intimate and chronic association than do most other pests of medical/veterinary importance. High populations of any cockroach species may adversely affect human health in several ways. These include contamination of food with their excrement, dissemination

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