Saiful Islam
A Faculty Member of the Department of Zoology, University of Rajshahi, Bangladesh, engaged in teaching and research since 1983.
Phone: +88-0721-750451
Address: Department of Zoology
University of Rajshaji
Rajshahi, Bangladesh
Phone: +88-0721-750451
Address: Department of Zoology
University of Rajshaji
Rajshahi, Bangladesh
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Papers by Saiful Islam
Schistocerca gregaria were examined in a series of
experiments to determine the means by which phase
characteristics are passed between generations. Both
crowding of solitary-reared females at the time of
oviposition and high egg pod densities promoted
behavioural gregarization, although the former appeared
to be a rather more potent factor. In contrast, egg pod
density alone appeared to promote the development of
hatchlings with dark patterns characteristic of the
gregarious phase. The phase characteristics of hatchlings
were unaffected when sand previously used for oviposition
was used to collect further egg pods. Early separation of
presumptive gregarious eggs from egg pods laid by crowdreared
females led to solitarization of the hatchlings,
indicating that a factor, either in or around the eggs,
removed by early separation promoted gregarization.
Both the eggs and foam plugs of egg pods from crowdreared,
gregarious females appeared to be a source of this
gregarizing factor. In contrast, there was no evidence for
a solitarization factor in egg pods from solitary-reared S.
gregaria. Saline extracts of egg pod foam plugs produced
an active factor which promoted gregarization both in
eggs from solitary-reared females and in eggs from
gregarious females which were separated and washed to
removed the factor. Solitary eggs were influenced by the
gregarizing factor in foam plug extracts for up to 1 day
after oviposition. Saline extracts of foam plug retained
their activity for up to 1 day. Initial studies on the
properties of this factor were made. We conclude that the
foam plugs of egg pods from crowd-reared, gregarious
locusts contain a small (<3 kDa), hydrophilic gregarizing
factor which is produced at the time of oviposition and
which predisposes hatchlings to attain characteristics of
the gregarious phase.
Schistocerca gregaria were examined in a series of
experiments to determine the means by which phase
characteristics are passed between generations. Both
crowding of solitary-reared females at the time of
oviposition and high egg pod densities promoted
behavioural gregarization, although the former appeared
to be a rather more potent factor. In contrast, egg pod
density alone appeared to promote the development of
hatchlings with dark patterns characteristic of the
gregarious phase. The phase characteristics of hatchlings
were unaffected when sand previously used for oviposition
was used to collect further egg pods. Early separation of
presumptive gregarious eggs from egg pods laid by crowdreared
females led to solitarization of the hatchlings,
indicating that a factor, either in or around the eggs,
removed by early separation promoted gregarization.
Both the eggs and foam plugs of egg pods from crowdreared,
gregarious females appeared to be a source of this
gregarizing factor. In contrast, there was no evidence for
a solitarization factor in egg pods from solitary-reared S.
gregaria. Saline extracts of egg pod foam plugs produced
an active factor which promoted gregarization both in
eggs from solitary-reared females and in eggs from
gregarious females which were separated and washed to
removed the factor. Solitary eggs were influenced by the
gregarizing factor in foam plug extracts for up to 1 day
after oviposition. Saline extracts of foam plug retained
their activity for up to 1 day. Initial studies on the
properties of this factor were made. We conclude that the
foam plugs of egg pods from crowd-reared, gregarious
locusts contain a small (<3 kDa), hydrophilic gregarizing
factor which is produced at the time of oviposition and
which predisposes hatchlings to attain characteristics of
the gregarious phase.