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File: <torym1.ima.htm> [For educational purposes only] Terminology Glossary <Principal Natural
Enemy Groups > <Citations> |
Immature Stages of Torymidae
Immature stages of Torymidae were discussed in detail by Clausen
(1940) under Callimomidae, as follows: The normal egg form in the Torymidae is elongate-oval to
kidney-shaped, with the anterior end broadest and terminating in a short,
rounded protuberance (Clausen 1940, noted as Callimodidae). The posterior end is somewhat attenuated,
and in occasional instances it terminates in a sharp point. The egg of Epimegastigmus brevivalvus
described by Noble is markedly different, for it possesses a slender stalk
about 2X the length of the egg body.
The illustrations of eggs of this species in different stages of
embryonic development show the had of the larva at the end of the egg
opposite the stalk, and the latter must thus be posterior, as opposed to its
anterior position in the normal stalked egg of the superfamily. In this species and in Callimome cyanimum, the chorion is unsculptured and glistening,
while in Ditropinotus aureoviridis (Fig. 87A), Monodontomerus aereus, Eridontomerus isosomatis,
and Callimome abbreviatus it is densely
clothed with minute papillae except, in some species, for a small area at the
posterior end. These papillae often
give the egg a grayish color. Please CLICK on picture to view
details:
The stalked type of egg described above for Epimegastigmus is of general occurrence among the
phytophagous members of the family, although the stalk is normally at the
anterior end. The 1st instar larvae are hymenopteriform, with 13 distinct body
segments, and bear rather large, cylindrical antennae and sensory setae on
the head, heavy and long sensory setae on the body segments, particularly the
thorax, which may equal the length of several segments, and spiracles on the
2nd thoracic and 1st 3 abdominal segments.
Each body segment also bears a band of short integumentary setae. Several species show departures in one or more characters from
the above. The larva of Epimegastigmus brevivalvus is very stout, is
devoid of sensory and integumentary setae, and has no spiracles or internal
tracheal system. In D. aureoviridis, there are thought to be 5 pairs of
spiracles, the additional pair being on the metathorax, and there are
indications of this pair in Eridontomerus
isosomatis, also. Five larval instars have been observed and described in D. aureoviridis, E.
isosomatis, M. aereus, and Epimegastigmus
brevivalvus. In the first two species, the 2nd instar
larvae are readily distinguished from the first by the reduction in size of
the sensory setae and the absence of the bands of integumentary setae. The sensory setae then become progressively
larger and the integumentary setae more abundant in the following
instars. The full complement of
spiracles appears on the 2nd instar larva, situated on the last two thoracic
and the first seven abdominal segments.
In E. brevivalvus, the internal
tracheal system is first evident in the 3rd instar, but open spiracles do not
occur until the 5th. The mature larva of most species bears heavy and long sensory
setae and one or more rows of long integumentary setae in a band encircling
each segment, giving it a distinctly hairy appearance. In D.
aureoviridis (Fig. 87B) and Eridontomerus isosomatis,
the head is also densely clothed with setae and spines of varying
length. The larva of Epimegastigmus brevivalvus bears a closer
resemblance to those of the phytophagous members of the family, the
integument being smooth and shining except for a transverse row of very
minute setae on each segment. That of
P. pachymerum is distinguished by a heavy band of minute
setae, set upon tubercles, on each segment. In a considerable number of species, the mandibles of the 5th
instar are simple, as are those of the earlier instars, but in E. brevivalvus they are tridentate, and in Megastigmus dorsalis F. and Epibootania nonvitta Gir. they are
4-dentate. References: Please refer to <biology.ref.htm>, [Additional references may be found at: MELVYL Library ] |
