''Euaresta aequalis'' is a species of fruit fly in the genus '' Euaresta'' of the family

Tephritidae The Tephritidae are one of two fly families referred to as fruit flies, the other family being the Drosophilidae. The family Tephritidae does not include the biological model organisms of the genus ''Drosophila'' (in the family Drosophilidae), ...

Description

''E. aequalis'' has elaborate markings on its wings, characteristic of the family

, and brilliant green eyes. The diagnostic characters for this species are a tan or yellow body with a clear round spot on the wing in cell r4+5, separated from the wing margin by distinct brown band. All North American species of the genus '' Euaresta'' except ''E. aequalis'' and ''festiva'' have a base color of dark brown to black. This species is generally the largest of the North American '' Euaresta''. It is commonly known as the burr-seed fly.

Distribution

''E. aequalis'' is distributed widely across the United States and southern Canada. The species was first observed in Mexico in 1969, in

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

. It was introduced to Australia in the 1930s in an attempt to control invasive cocklebur.Cullen, J., Julien, M., & McFadyen, R. (2012). ''Biological Control of Weeds in Australia''. Collingwood: CSIRO Publishing.

Behavior

''E. aequalis'' is a specialist—its only known host is the common or rough cocklebur, ''

Xanthium strumarium ''Xanthium strumarium'' (rough cocklebur, clotbur, common cocklebur, large cocklebur, woolgarie bur) is a species of annual plants of the family Asteraceae. Some sources claim it originates in southern Europe and Asia, but has been extensively na ...

''.Jackson, M. D., Marshall, S. A., Hanner, R., & Norrbom, A. L. (2011, May 24). Euaresta aequalis (Loew). Retrieved from https://cjai.biologicalsurvey.ca/jmhn_15/teph98.htm Females of this species have large ovipositors for laying eggs inside the hard burr capsule, which is protected by spines.Currie, G. A. (1932). Oviposition Stimuli of the Burr-seed Fly, Euaresta aequalis, Loew (Dipt. Trypetidae). Bulletin of Entomological Research,23(02), 191. Retrieved from https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0007485300004089. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

develops inside this capsule, feeding on one of the two seeds found in each burr. ''E. aequalis'' is

univoltine Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. The term is most often applied to insects, and is particularly in use in sericulture, where silkworm varieties vary in their voltinism. ...

, and its flight period is generally from mid-July to mid-August.

Use in biological control

A variety of ''

Xanthium ''Xanthium'' (cocklebur) is a genus of flowering plants in the tribe Heliantheae within the family Asteraceae, native to the Americas and eastern Asia and some parts of south Asia . Description Cockleburs are coarse, herbaceous annual plants ...

'' known as Noogoora burr was introduced to Australia in the 1920s, likely imported from the southern United States. It quickly became a widespread problem, especially for the wool industry. The burrs would get stuck on sheep as they grazed and were very hard to remove. ''E. aequalis'' was identified as a possible candidate for

biological 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 i ...

, along with two stem-boring beetles and a tortricid moth. ''E. aequalis'' was first released in

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

in 1932. It was established at low levels and was not effective in controlling the burr, because the larvae typically only attack one of the two seeds in each fruit. Noogoora burr was eventually controlled by an accidentally introduced

rust fungus Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales (previously known as Uredinales). An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus ''Puccinia'', are currently ...

References

Tephritinae Insects described in 1862 Diptera of North America {{tephritinae-stub