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<spala1.ima.htm> [For
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Immature
Stages of Pteromalidae: Spalangiinae
Detailed information on
immature stages of Pteromalidae (Spalangiinae) is being acquired.
However, Clausen (1940) noted that the 1st instar larva is very active
and capable of extended movement over the surface of the body of the host
pupa. This is for the purpose of
finding a suitable point for feeding, which varies, but usually is around the
dorsum or dorsolateral areas of the abdomen.
The skin of the pupa is much thinner at these points and more easily
punctured than elsewhere. The 2nd and
3rd instar larvae have a fixed feeding position. The eggs of Spalangia muscidarum and S.
nigra are elongate‑ovate
in outline and broader at the anterior end, which bears a nipple‑like
protuberance. That of Cerocephala is of similar form
except that the anterior protuberance is lacking. Please
CLICK on
picture to view details: The first‑instar
larvae are hymenopteriform and elongate‑oval in outline and have a relatively
large head. In S. nigra
(Parker, 1924), each body segment bears a band of minute setae at the
anterior margin. An open tracheal
system is found in S. nigra with the spiracles
occurring on the second thoracic segment, or on the membrane between the
first and second, and on the first three abdominal segments (Fig. 58 A). Richardson emphasized that not only does
the first‑instar larva of S.
muscidarum lack spiracles,
but the intermediate and mature larvae are likewise apneustic. The number of larval
instars in the family is uncertain, with only three mentioned for S. muscidarum and four for S. nigra. The second‑ (Fig. 68) and third‑instar larvae of the
latter species bear nine pairs of spiracles, situated on the second and third
thoracic and the first seven abdominal segments. The mature larvae of the
genus Spalangia (Fig. 58C)
are distinguished by the possession of distinct conical protuberances or
tubercles at each dorsolateral margin of the first eight abdominal
segments. A minute pair is found on
the first thoracic segment. These
tubercles have not been noted upon larvae of other genera. They are considered by Richardson to have
neither an ambulatory nor sensory function, but appear to relate to prepupal
growth. The mature larva of C. cornigera is more elongated than that of Spalangia, and each body
segment bears four pairs of setae, those of the last segment being longest. References: Please refer to <biology.ref.htm> [Additional references may be found at: MELVYL Library] |