The Japanese cockroach (''Periplaneta japonica''), also known as the Yamato cockroach, is a

cockroach Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as ...

native to Japan, adapted to cooler northern climates. It has a flexible univoltine or semivoltine (one- or two-year) lifecycle, depending on the timing of its hatching, and is unusual in being able to spend two winters as

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...

before reaching maturity.

Description

Initial first-

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

nymphs are dark brown, with white or brownish white tips of the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

ry and labial

palps Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") a ...

. Adults measure in length, and have a shiny, uniformly black to blackish-brown body, with brown tarsi and maxillary and labial palps. The adult male's wings extend slightly beyond the body's length, while the female's wings are around half the body's length. Unlike most cockroaches, the major

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

in ''P. japonica''’s cuticular lipids is . Males have significant amounts of not found on females, as do '' P. australasiae'' and '' P. fuliginosa'' males and females.

Glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

myo-inositol Inositol, or more precisely ''myo''-inositol, is a carbocyclic sugar that is abundant in the brain and other mammalian tissues; it mediates cell signal transduction in response to a variety of hormones, neurotransmitters, and growth factors and ...

scyllo-inositol ''scyllo''-Inositol is one of the stereoisomers of inositol. It is also known as scyllitol, cocositol, quercinitol, and 1,3,5/2,4,6-hexahydroxycyclohexane. ''scyllo''-Inositol is a naturally occurring plant sugar alcohol found most abundantly in ...

and

trehalose Trehalose (from Turkish '' tıgala'' – a sugar derived from insect cocoons + -ose) is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it ...

were found in overwintering nymphs and are thought to be a factor in their freeze tolerance.

Freeze tolerance

Nymphs have been observed in the wild hibernating in subfreezing temperatures during winter in snow-covered habitats. Overwintering nymphs were able to survive laboratory supercooling experiments in the temperature range, enduring 12 hours of tissue freezing, as well as recover from burial in ice. The ability to walk on ice was also found to be unique among several cockroach species tested.

Habitat

Primarily an outdoors species, populations are adaptable to living indoors in houses and buildings where food is stored, prepared, or served.

Defense

A ''P. japonica'' nymph alone or in sparse populations accumulates a viscous secretion along its rear dorsal surface, droplets of which it can be splashed some distance toward a threat through a shaking action. The presence of an aggressive species of ant, ''

Formica exsecta ''Formica exsecta'' (the narrow-headed ant or excised wood ant) is a species of ant found from Western Europe to Asia. A rare formicine ant with a deeply excised head, ''F. exsecta'' forms small mounds up to around a foot in height consisting ...

'', triggered this defensive response, rendering the ants helpless.

Presence as an introduced species

Originally from Japan, ''P. japonica'' has spread to China, Korea and far eastern Russia, though it is considered a common pest primarily in central and northern Japan. The species was found in New York City in 2013 by Evangelista ''et al.'', . . . the first time the species was found in the United States. It was found by an exterminator beneath plantings in

High Line The High Line is a elevated park, elevated linear park, greenway (landscape), greenway and rail trail created on a former New York Central Railroad spur on the West Side (Manhattan), west side of Manhattan in New York City. The High Line's ...

, a

Manhattan Manhattan (), known regionally as the City, is the most densely populated and geographically smallest of the five boroughs of New York City. The borough is also coextensive with New York County, one of the original counties of the U.S. state ...

park, and was able to survive over a cold winter. Scientists who confirmed the identity of the species through genetic testing theorize that it may have been imported in the soil of ornamental plants used in the park. This identification demonstrates the use of

DNA barcoding DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections (also called "sequences"), an indiv ...

for urban pest control.

References

{{Taxonbar, from=Q10623970 Cockroaches Insects described in 1908