Neriidae is a relatively small family of true flies (Diptera)
with long, stilt-like legs. Most species are found in the
tropics. Neriids have very interesting behaviours, and many
species are strikingly sexually dimorphic, with males having
much longer legs, heads and/or antennae than females. Like
piophilid flies, neriid larvae have the ability to leap during
the stage just before pupation when they migrate from the larval
feeding substrate to the pupation site. Very little research has
been done on this interesting group of flies.
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Telostylinus angusticollis female. |
Telostylinus angusticollis male. |
Two neriid species
are known in Australia:
Telostylinus
angusticollis is native to NSW and south Queensland.
These large flies (up to 2 cm in length) aggregate and
breed on rotting trunks of Acacia longifolia.
They are a particularly fascinating system for research
on environmental effects on body size and shape (i.e.,
phenotypic plasticity and condition dependence). I have
found that flies reared on low-quality larval medium
exhibit little or no sexual dimorphism in body size or
shape, whereas males reared on rich larval medium
exhibit extreme elongation of legs, head and antennae
relative to females.
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Telostylinus angusticollis aggregate on
rotting Acacia trunks. |
Males vary
enormously in body size. |
Females feed
on resin, and oviposit into the bark. |
T. angusticollis is
particularly interesting because it exhibits extreme
condition dependence (phenotypic plasticity) of body size
and shape. The four flies pictured below are full-siblings
(males on the left, females on the right) that were reared
on larval diets of varying quality.
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Telostylinus
lineolatus inhabits tropical north Queensland, where
it aggregates on flowers and rotting fruit. These flies
are much smaller than T. angusticollis, and much
less sexually dimorphic, particularly in head shape.
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Telostylinus lineolatus breeds on rotting
fruit and dense flowers in tropical north
Queensland. |
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Neriids can be reared
in the lab on an artificial medium consisting of
molasses, malt and soy protein mixed with hydrated
'cocopeat' (shavings from coconut husks). The have a
generation time of about 30 days at 26 C.
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