''Melanostoma fasciatum'' is a species of

hoverfly Hoverflies, also called flower flies or syrphids, 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 the l ...

found in New Zealand, 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 Biological agents, also known as biological weapons or bioweapons, are pathogens used as weapons. In addition to these living or replicating pathogens, toxins and Toxin#Biotoxins, biotoxins are also included among the bio-agents. More than 1,2 ...

that may control and reduce

aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white Eriosomatinae, woolly ...

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 Fly, flies. He worked on world species as well as European and described many new species. Biography Early life Macquart wa ...

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

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

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

Christchurch Christchurch (; ) is the largest city in the South Island and the List of cities in New Zealand, second-largest city by urban area population in New Zealand. Christchurch has an urban population of , and a metropolitan population of over hal ...

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

Description

The adults have a similar appearance to that of ''

Melangyna novaezelandiae ''Melangyna novaezelandiae'' (commonly referred to as the "large hoverfly") is a hoverfly Endemism, endemic to New Zealand.Parkinson, Brian (2007). ''A Photographic Guide To The Insects Of New Zealand''. New Holland Publishers (NZ) Ltd. . It is ...

'', 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 only 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 foun ...

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

North Island The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...

. 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 (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

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 pla ...

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 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 has a near-cosmopolitan distribu ...

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

anther The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

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 45 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 Canada ...

'', which acts as a

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

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 alphaproteobacterium "''Candidatus'' Liberibacter solanacearum", which is vectored by the potato psyllid. When fried, potato tubers ...

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 (), whose leaves are known as cilantro () in the U.S. and parts of Canada, and dhania in parts of South Asia and Africa, is an annual herb (''Coriandrum sativum'') in the family Apiaceae. Most people perceive the leaves as ha ...

'' 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 bacchini 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