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<drosophi.htm> [For educational
purposes only] Glossary <Principal Natural Enemy Groups > <Citations> <Home> |
DIPTERA, Drosophilidae -- <Images> & <Juveniles> Please refer also
to the following links for details on this group: Drosophilidae = Link 1 The majority of species of Drosophilidae develop in decaying
fungi, fruits and similar materials, but there is a small number which are
predaceous or parasitic in habit.
Larvae of genera Acletoxenus,
Gitona and Gitonides are predaceous on Homoptera, and Titanochaeta ichneumon
Knab was reared from spider egg sacs (Knab 1914). Gitonides perspicax Knab is a predator on
mealybugs in Hawaii and Asia, and Pseudiastata
brasiliensis C.L. attacks Pseudococcus in South America. Rhinoleucophenga
obesa Lw. is predaceous in egg sacs
of Aclerda campinensis Hemp. in Brazil, and an undetermined species is found
in those of Orthesia in
Brazil. Acletoxenus seems restricted in its host preferences to
Aleyrodidae, and a short account of the habits of A. indica Malloch was
given by Clausen & Berry 1932).
In some parts of Java it is the dominant predator attacking Aleurocanthus spp. The eggs are somewhat oblong, measuring
0.4 X 0.2 mm., and are covered with a white waxy incrustation. They are laid singly on the leaf surface
adjacent to mature host larvae or pupae.
The larva is at first translucent white, but later becomes distinctly
greenish. It is very sluggish and
never moves from the leaf on which the egg was laid. A single host cluster provides ample food
for its development. The larva in its
later stages secretes an adhesive substance of the body which attaches
various extraneous matter, including host exuviae, to it. Pupation occurs in situ on the leaf
surface, and the developing fly can be readily seen through the
semitransparent puparial wall. Empty
puparia are noticeable among host colonies by their white color. The life cycle takes ca. 2 weeks (Clausen
1940/62). The dominant genus Drosophila
contains several species of questionable parasitic or predaceous habit. Bonnamour (1921) reared D. rubrostriata
Beck. from caterpillars of Pieris brassicae L. confined with gravid
females. Host larvae probably die by
oviposition of the fly. Liquefaction
of the body contents is rapid, and the larvae then feed mostly as
scavengers. Drosophila paradoxa
Lamb and D. inversa Wlk. have been found to attack nymphs of the cercopid
genus Clastoptera in tropical
America. Clausen (1940) noted that
there is some question as to the role of the larvae attacking this host, as
some researchers consider that they are inquilines, feeding mostly if not
entirely on the spittle surrounding them.
However, Lamb (1918) noted that half the masses contained D. paradoxa
larvae, with their heads embedded in the bodies of the host nymphs. In D.
inversa Baerg (1920) found that the
larvae usually lie diagonally across the host's dorsum, with mandibles
embedded in the 4th or 5th abdominal segment. He did not consider this species to be a true parasitoid but
rather that it fed only on spittle.
The fact that the larvae have a fixed position and embed the mandibles
or even the entire head in the host body suggests a closer relationship than
would be necessary for a scavenger (Clausen 1940/62). The larval habits and host relationships
recall those of epipyropid larvae that are associated with Fulgoridae and
related families (Clausen 1940/62). References: Please refer to <biology.ref.htm>, [Additional references
may be found at: MELVYL
Library] |