''Nezara viridula'', commonly known as the southern green stink bug (USA), southern green shield bug (UK) or green vegetable bug (Australia and New Zealand), is a plant-feeding stink bug. Believed to have originated in

Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the Er ...

, it can now be found around the world.Squitier J.M. (1997, updated 2007)
Southern green stink bug»
Featured creatures, University of Florida Institute of Food and Agricultural services. Because of its preference for certain species of

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock fo ...

s, such as

bean A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes thr ...

s and

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu ...

s, it is an economically important pest on such crops.

Description

The adult males can reach a body length (from front to elytral apex) of about , while females are bigger, reaching a size of about . The body is usually bright green and shield-shaped and the eyes are usually reddish, but they may also be black. There is a row of three white spots on the scutellum. They differ from the similar green stink bug (''Chinavia hilare'') by the shape of their scent

gland In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream ( endocrine gland) or into cavities inside the body or its outer surface ( exocrine gland). Structure ...

openings, which are short and wide in ''N. viridula'', and narrow and long in the green stink bug.

Color morphs

Several distinct morphs can be distinguished by the pattern of their

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton ( endoskeleton) in for example, a human. In usage, some of the ...

coloration. The most common morph is predominantly green (''Nezara viridula'' f. ''smaragdula''), a less common morph is green with white or yellowish front margins on the head and the

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

(''Nezara viridula'' f. ''torquata'' Fabricius, 1775) and a very rare morph has a uniformly orange or yellow (occasionally pink) coloration (''Nezara viridula'' ''f. aurantiaca'').Mary Golden and Peter A. Follet
First report of Nezara viridula f. aurantiaca in Hawai
/ref>

Life history

''Nezara viridula'' reproduces throughout the year in

tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referre ...

. In

temperate zone In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges througho ...

s this species presents a reproductive winter diapause, associated with a reversible change of body colouration from green to brown or russet.Musolin, Dmitry (2012)
Surviving winter: diapause syndrome in the southern green stink bug Nezara viridula
Physiological Entomology - Volume 37, Issue 4, pages 309–322 When ready to mate ''N.viridula'' sound 100 Hz vibration with a "tymbal" composed of a fused first and second terga (not to be confused with

tymbal The tymbal (or timbal) is the corrugated exoskeletal structure used to produce sounds in insects. In male cicadas, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect. In tiger moths, the t ...

of cicadas) that allow bi-directional communication to any ''Nezara'' standing on the same plant so they could find each other. The female lays 30 to 130 eggs at a time, in the form of an egg mass glued firmly to the bottom of a

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...

. The eggs are barrel-shaped, with an opening on the top. The eggs take between 5 and 21 days to develop, depending on the temperature. The newborn larvae gather near the empty eggs and do not feed until three days later, after the first

moult In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

. They moult five times before reaching maturity, increasing in size each time. Each

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 as ...

stage lasts about a week, except for the last one before the

metamorphosis Metamorphosis is a biological process by which an animal physically developmental biology, develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell cell growth#Cell ...

, which is a day longer. Up to four generations can develop in one year, with eggs developing into adults in as few as 35 days in mid-summer. Up until their third moult the larvae aggregate together on the host plant, the purpose of this aggregation is probably pooling of chemical defenses against

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill t ...

s, for example ants.

Gallery

File: Nezara viridula13.jpg , Eggs File: Nezara viridula12.jpg , First instar File: Nezara viridula11.jpg, Second instar File: Pentatomidae - Nezara viridula-003.JPG , Third instar File: Nezara viridula instar 4 on back.jpg , Fourth instar File: Pentatomidae - Nezara viridula-005.JPG , Fifth instar File: Pentatomidae - Nezara viridula-004.JPG , Adult, winter color pattern

Ecology

It is a highly polyphagous herbivore, able to feed on

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae ex ...

s from over 30

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...

, both

monocot Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of t ...

s and

dicot The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, t ...

s.Todd J.W. (1989). «Ecology and behavior of ''Nezara viridula»''. ''Annu. Rev. Entomol.'' 34: 273-292. It has a preference for legumes, preferring to feed on plants that are fruiting or forming pods. The most important factor limiting the

population Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...

s is winter cold. Mortality of overwintering individuals is between 30 and 80%, and the population cannot survive in areas where the average mid-winter temperature is below 5 °C.Musolin D.L. (2005).
The Southern Green Shield Bug Nezara viridula (L.) expands its distribution range, not only in the U.K.»
''Het News'' - Newsletter of the Heteroptera Recording Schemes. Retrieved on 2008-10-14. Females are more likely to survive the winter than males, as are larger individuals and those that develop reddish-brown coloration. In recent decades, the species seems to be expanding its range towards the north in the northern hemisphere, possibly because of

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

.Yukava J. et al. (2007).
Distribution range shift of two allied species, Nezara viridula and N. antennata (Hemiptera: Pentatomidae), in Japan, possibly due to global warming
�. ''Applied Entomology and Zoology'' 42(2): 205-215 The animal's ability to survive the winter also depends on the timely onset of

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 ...

Origin and range

''Nezara viridula'' is a cosmopolitan species, living in tropical and subtropical regions of Americas, Africa, Asia, Australasia and Europe between 45 degrees north and 45 degrees south. Its exact origin is unknown, but it is believed to have originated from the Ethiopia region of East Africa, from where it has spread around the world thanks to its strong flight and human trade routes.

References

External links

*
''Nezara viridula'' pheromones
in Pherobase.
Fauna Europaea

video of Nezara viridula
{{Taxonbar, from=Q600498 Nezarini Cosmopolitan arthropods Agricultural pest insects Bugs described in 1758 Insects of Ethiopia Taxa named by Carl Linnaeus Insect pests of millets