Pj. Lester et Dr. Greenwood, PRETREATMENT INDUCED THERMOTOLERANCE IN LIGHTBROWN APPLE MOTH (LEPIDOPTERA, TORTRICIDAE) AND ASSOCIATED INDUCTION OF HEAT-SHOCK PROTEIN-SYNTHESIS, Journal of economic entomology, 90(1), 1997, pp. 199-204
The use of heat treatments for disinfestation purposes is becoming wid
espread. The efficacy of such treatments may be influenced by exposure
of insects to a range of temperatures in the environment before heat
treatment disinfestation. We exposed 5th-instar light brown apple moth
(Epiphyas postvittana Walker) to a range of temperatures and duration
s in hot air before treatment, and examined the effects of these condi
tions on mortality in a 43 degrees C hot-water treatment and on the in
duction of heat Shock protein synthesis. Insect thermotolerance increa
sed substantially with increased pretreatment temperature and duration
; the time until 99% mortality increased from 23.0 min with no pretrea
tment, to 37.4 min after 8 h at 35 degrees C. Long periods at temperat
ures before treatment as low as 28 degrees C increased thermotolerance
, and periods as short as 15 min increased thermotolerance at higher t
emperatures. Correlated with this increased thermotolerance was the de
novo synthesis of several proteins observed by radiolabeling with [S-
35] methionine. Commercially available monoclonal antibodies of broad
species cross reactivity to known heat shock proteins (HSP25, HSP60, H
SP70, and HSP90) bound to constitutive forms of these proteins in West
ern blots but were not induced as a result of heat pretreatment. A pro
tein of M(r) 78 kDa was the predominant protein synthesized, which is
in agreement with a recent report of a new class of heat shock protein
s in the Lepidoptera. These data indicated that thermal conditions exp
erienced by insects before disinfestation can greatly influence thermo
tolerance.