''Cotesia rubecula'' is a

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

wasp from the large wasp family

Braconidae The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...

Description

Black in adulthood with a body less than 1/4 of an inch long, ''C. rubecula'' has long, extending antenna about the same size as its body.

Distribution and habitat

''Cotesia rubecula'' is not common, established in only a few areas of the world. Originally native to

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, the parasite has been introduced as

biological pest control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...

in North America, specifically in

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...

. The population dies down during winter months with a population bubble in late summer related to the growth of its host species.

Reproduction and lifecycle

The mating system of ''C. rubecula'' is

polygynous Polygyny (; from Neoclassical Greek πολυγυνία (); ) is the most common and accepted form of polygamy around the world, entailing the marriage of a man with several women. Incidence Polygyny is more widespread in Africa than in any ...

. Mate-guarding, a process in which a member of a species prevents another member of the same species from mating with their partner, is seen in ''C. rubecula''. Males are attracted to females through pheromones and they induce females to mate through vibrations, to which the female responds by assuming a specific position. When a male who has copulated with a female sees another male trying to court her, he will often adopt the female receptive position. Post-copulatory female mimicry by the male offers an advantage by acting as a mate-guarding mechanism. If a second male arrives soon enough after the female copulates with the first male, the second male may be able to induce a second copulation which will compete with the first one. However, if the first male who copulated with her mimics the female, it distracts the second male long enough that the female becomes unreceptive. ''Cotesia rubecula'' parasitizes the cabbage worm caterpillar, generally in the stage of 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 ...

, with the female wasp stinging and laying between 20 and 50 eggs within the host instar. The defense mechanism of the caterpillars can sometimes kill the eggs. If they do not, the caterpillar does not die until the larvae of the wasp emerge. The impact on the host population can vary greatly, from a small percentage to up to 75% of the caterpillars in a given habitat.

References

*P.J. Cameron and G.P. Walker. New Zealand Institute for Crop & Food Research *http://web.entomology.cornell.edu/shelton/diamondback-moth/pdf/1996papers/1996DBM47.pdf *http://www.uky.edu/~mjshar0/genera/Cotesia/rubecula.html *http://www.entomology.wisc.edu/mbcn/kyf303.html * *http://entnemdept.ufl.edu/creatures/veg/leaf/imported_cabbageworm.htm *http://cnho.files.wordpress.com/2012/05/cotesia-glomerata-rubecula.png?w=595 *http://www.missouribotanicalgarden.org/Portals/0/Gardening/Gardening%20Help/images/Pests/Imported_Cabbageworm1194.jpg *http://www.discoverlife.org/IM/I_JP/0042/320/Cotesia_congregata,I_JP4229.jpg {{Taxonbar, from=Q2669579 Microgastrinae Insects described in 1885