Cockroache; Ecology, behavior & history - W.J. Bell

Fig. 8.5 Perisphaerus sp. from the Philippines. (A) Ventral view of adult female from Mt. Galintan;
arrows indicate orifices between coxae. (B) Orifices (arrows) between coxae. (C) Head of
probable first instar that was attached to an adult female. (D) Head of probable second instar that
was attached to an adult female. From Roth (1981b); photos by L.M. Roth.
on the maxillae and labium, suggesting that they feed on
a liquid diet. Midguts of young instars are filled with a
pink material rather than the leaf chips they eat when
older (Reuben, 1988). Jayakumar et al. (1994) and Bhoopathy
(1998), however, suggest that young instars of this
species may use a long, sharp mandibular tooth to pierce
the tergites of the female and withdraw nourishment.
First-instar nymphs removed from the mother do not
live. Second-instar nymphs begin to make short forays
from their maternal dome home to feed on dry leaves,
and will survive if removed from their mother.
Among the Perisphaeriinae there are two recorded
cases of nymphs clinging to the ventral surface of the
mother for protection and nutrition. Nymphs of Perisphaerus
cling to the female for at least two instars (Roth,
1981b). There are 17 species in this genus, but they are
known almost exclusively from the study of museum
specimens. First-instar nymphs are eyeless and have an
elongate head and specialized galeae that suggest the intake
of liquid food from the mother. There are four distinct
orifices on the ventral surface of the female, with one
pair occurring between the coxae of both the middle and
hind legs (Fig. 8.5). Females have been collected with the
mouthparts of a nymph inserted into one of these
orifices; the “proboscis” of nymphs is 0.3 mm wide, about
the same width as the intercoxal opening. The food of the
nymphs may be glandular secretions or possibly hemolymph.
The female can roll up into a ball with her
144 COCKROACHES