ISSN 10674136, Russian Journal of Ecology, 2010, Vol. 41, No. 3, pp. 264–268. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © G.V. Ben’kovskaya, M.P. Sokolyanskaya, 2010, published in Ekologiya, 2010, No. 3, pp. 227–231.
The role of the intensity and duration of stress
inducing exposure in the development of the protec
tive response remains an open question. The thresh
olds of the exposure intensity above which the
homeostasis of an individual or population is irre
versibly disturbed have been determined for many
animal species and a number of factors. Such studies
on insects are especially numerous. Toxicological
parameters, namely lethal and effective doses of insec
ticides of all chemical classes currently available, have
been estimated for a number of economically impor
tant species (Thacker, 2002; Sukhoruchenko, 2005).
These characteristics, which have a genetically deter
mined basis, allow us to judge on the reaction norm for
the response to stressors in a species as a whole and to
detect differences between and within populations.
They make it possible to determine the exposure
thresholds above which stress response is developed as
an adaptive process accompanied by corresponding
rearrangements (or, more precisely, readjustments) of
vital activity ranging from the expression of the genes
controlling adaptive characters to complex structural
transformations of populations and groups of both
lower and higher ranks.
Irrespective of specific action mechanisms, the fac
tors affecting an insect population may evoke several
types of responses: (1) an increased survival rate at the
preimaginal stage or during some periods of this stage;
(2) an increased fertility, which is determined by a
number of parameters (the activity of reproductive
behavior, including the search for a partner and mat
ing; the number of eggs laid; the frequency of egglay
ing; and the duration of the reproductive period); and
(3) an increased life span at the adult stage. These
types of changes in the population demographic char
acteristics may be observed simultaneously or sepa
rately. In the case of longterm stress, all these param
eters may decrease (Raushenbakh, 1990).
In this study, we estimated the parameters of sur
vival at the preimaginal developmental stages and the
fertility and life span of adult insects in laboratory pop
ulations (lines) of houseflies selected for the resistance
to stress factors of different types and durations.
MATERIAL AND METHODS
Laboratory lines of the housefly (
L.) were selected from the original Cooper line (line S)
kindly provided by Dr. Roslavtseva. The larvae and
adult flies were kept according to the standard proto
col (Roslavtseva, 1978; Sokolyanskaya, 2007). Selec
tion was performed on early instar III larvae over 25
generations (Sokolyanskaya et al., 2005). The selec
tion differential was 25–30%. The following selection
factors were used:
(1) A high or low temperature; specifically, a single
exposure of larvae (in the nutrient medium) to tem
for 30 min
(the Rh line) or from
30 min (the Rc line).
(2) A single addition of Bitoxibacillin (BTB), a
bacterial preparation based on
to the nutrient medium for larval development at con
centrations from 0.01% in
to 0.17% in
line) or Malathion (Carbophos), an organophospho
rous insecticide, at concentrations from 0.003% in
to 0.17% in
(the Rm line).
The Adaptive Role of Resistance to Stressors of Different Types
Formed in Laboratory Housefly Populations
G. V. Ben’kovskaya and M. P. Sokolyanskaya
Institute of Biochemistry and Genetics, Ufa Research Center, Russian Academy of Sciences,
Ufa, 450054 Republic of Bashkortostan, Russia
Received July 2, 2008
—The adaptive role of resistance formed in housefly larvae exposed to different stress factors,
namely Bitoxibacillin, Malathion, and high and low temperatures, has been estimated. Comparison of biotic
parameters in the original line and in all selected (derivative) lines indicates that the resistance to stress factors
formed in the derivative lines due to selection over 25 generations does not always coincide with the improve
ment of their adaptation potential.
: adaptation, housefly, biotic characteristics, resistance, stress response.