''Melanostoma fasciatum'' is a species of

hoverfly Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while ...

found in

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, where it is common in agricultural fields and gardens. Locally dense populations of this hoverfly species might effectively reduce pest infestation. Hence, they are perhaps an effective natural and non-toxic

bioagent A biological agent (also called bio-agent, biological threat agent, biological warfare agent, biological weapon, or bioweapon) is a bacterium, virus, protozoan, parasite, fungus, or toxin that can be used purposefully as a weapon in bioterro ...

that may control and reduce

aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...

and small caterpillar populations. __TOC__

Taxonomy

''Melanostoma fasciatum'' was first described in 1850 by

Pierre-Justin-Marie Macquart Pierre-Justin-Marie Macquart (8 April 1778 – 25 November 1855) was a French entomologist specialising in the study of Diptera. He worked on world species as well as European and described many new species. Biography Early years Macquart was ...

as ''Plesia fasciata''. In 1860, ''Plesia'' was recognized as a synonym of ''

Melanostoma ''Melanostoma '' is a large genus of hoverfly, hoverflies. Little is known of their biology, but they are suspected to be general predators of small insects in leaf litter. Species"Melanostoma". Encyclopedia of Life, available from http://eol.o ...

''. ''Plesia fasciata'' was then renamed as ''Melanostoma fasciatum''. In 1901, ''Melanostoma apertum'' was described from a single specimen from

Christchurch Christchurch ( ; mi, Ōtautahi) is the largest city in the South Island of New Zealand and the seat of the Canterbury Region. Christchurch lies on the South Island's east coast, just north of Banks Peninsula on Pegasus Bay. The Avon River / ...

. This was later recognized to be a synonym of ''M. fasciatum''.

Description

The adults have a similar appearance to that of '' Melangyna novaezelandiae'', another endemic hoverfly of New Zealand. The body is glossy black but the abdomen has three pairs of yellow patches on three segments. While stationary, the wings are folded over the abdomen. The compound eyes are relatively large and are coloured dark red. Larvae are legless and are initially pale after hatching from their egg, but will darken as they undergo molts. The rear end of the body has a projections that acts as a breathing tube for the larva. The eggs are white and may be laid singly or in clusters.

Distribution/habitat

''Melanostoma fasciatum'' is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to New Zealand where it is widespread, but appears to be more abundant in the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

. They are known to occur in grasslands, gardens and other habitat types that have low growing vegetation, especially in agricultural settings.

Diet

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. The ...

e, ''Melanostoma fasciatum'' is predatory and is known to prey on aphids and small caterpillars. Due to this choice of diet, these flies are considered a useful bioagent for managing aphid and caterpillar pests on crops. Adults of this species feed on pollen grains from

anemophilous Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plan ...

species of plant. Pollen grains up to 50μm have been observed in the gut of ''M. fasciatum'' adults. '' Plantago lanceolota'' and ''

Taraxacum ''Taraxacum'' () is a large genus of flowering plants in the family Asteraceae, which consists of species commonly known as dandelions. The scientific and hobby study of the genus is known as taraxacology. The genus is native to Eurasia and Nor ...

'' pollen grains have been recorded in the gut of ''M. fasciatum''. The flies will usually eat pollen out of the

anther The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

of the plant. The adults also feed on nectar from a range of species (such as ''

Leptospermum ''Leptospermum'' is a genus of shrubs and small trees in the myrtle family Myrtaceae commonly known as tea trees, although this name is sometimes also used for some species of ''Melaleuca''. Most species are endemic to Australia, with the greate ...

'' and ''

Daucus ''Daucus'' is a worldwide genus of herbaceous plants of the celery family Apiaceae of which the best-known species is the cultivated carrot. ''Daucus'' has about 25 species. The oldest carrot fossil is 1.3 Ma, and was found on the island of Made ...

''), but they will generally not feed on pollen from these plants.

Biocontrol

Because of their predatory diet as larvae, ''Melanostoma fasciatum'' may be a useful biocontrol agent. In New Zealand, potato crops may be damaged by ''

Bactericera cockerelli ''Bactericera cockerelli'', also known as the potato psyllid, is a species of Psylloidea, psyllid native to southern North America. Its range extends from Central America north to the American Pacific Northwest and parts of Manitoba, in Canad ...

'', which acts as a

vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...

for pathogens that may cause

zebra chip Zebra chip, also known as ''papa manchada'' and ''papa rayada'', is a disease in potatoes putatively caused by an alphaproteobacteria "''Candidatus'' Liberibacter solanacearum", which is vectored by the potato psyllid. When fried, potato tubers f ...

disease in potatoes. It has been proposed that ''M. fasciatum'' may be useful for controlling populations of ''B. cockerelli'', which could thereby reduce zebra chip disease. Similarly, it has been suggested that planting ''

Coriandrum sativum Coriander (;

'' near cabbage may attract ''M. fasciatum'' and thereby give the cabbage some measure of protection from infestation. However, more research may be needed to confirm how effective this is.

References

{{Taxonbar, from=Q14514075 Syrphinae Diptera of New Zealand Insects described in 1850 Taxa named by Pierre-Justin-Marie Macquart Endemic fauna of New Zealand Endemic insects of New Zealand