Biology Reference
In-Depth Information
Family EPHYDRIDAE
Family DROSOPHILIDAE
Very small to small flies, found mainly near water or in
damp situations.
Very small to small flies, much attracted to fermenting
juices and often called 'vinegar flies'. Compound eyes
bright red; arista of the antennae generally plumose,
with a bifid tip. Larvae of a few species are leaf miners,
but most feed in rotting plant tissue, or act as predators
or parasitoids.
Scatella spp.
Glasshouse wing-spot flies
Two species, Scatella stagnalis and S. tenuicosta , of
these small ( c. 3 mm long), black-bodied flies are
commonly present in greenhouses and other protected
sites, where they are associated with algal growths in
nutrient-film troughs and on potting composts,
rockwool growing-media and so forth. They are often
mistaken for sciarid flies (p. 173) and, when present in
large numbers, may cause concern. Although of little
significance, they contaminate plants with specks of
faecal material and also aid the spread of fungal
diseases. Unlike the larvae of sciarids, those of Scatella
are harmless; they do not attack plant roots, cuttings or
seedlings. The adults are characterized by their twice-
broken costal veins, and by the slightly darkened wings
which have several small, clear patches in the
membrane; differences between species are slight.
Scaptomyza flava (Fallén) ( 428 )
syn. S. apicalis Hardy
A widely distributed, often abundant leaf miner which
attacks various brassicaceous plants, including
ornamentals; nasturtium ( Tropaeolum ) is also a host. In
severe cases infested leaves are killed, but any effect on
plant growth is unimportant. There are several
overlapping generations each year, and adults occur
from April to September. The larvae feed within the leaf
blades, forming conspicuous whitish mines that vary
from simple blotches to irregular, branched galleries
which often follow the major veins. Fully fed larvae are
3-4 mm long, white and translucent, with four
prominent tubercles at the hind end. They pupate
externally on the ground, each in an elongate
(3.0-3.5 mm long) reddish-brown puparium. Adults
(wings 2.5 mm long) are pale yellow, with grey
markings and red eyes.
428
428 Mines of Scaptomyza flava in leaves of Tropaeolum .
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