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Fitness costs of sublethal exposure to B acillus thuringiensis in H elicoverpa armigera : a carryover study on offspring
Author(s) -
Sedaratian A.,
Fathipour Y.,
TalaeiHassanloui R.,
JuratFuentes J. L.
Publication year - 2013
Publication title -
journal of applied entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 60
eISSN - 1439-0418
pISSN - 0931-2048
DOI - 10.1111/jen.12030
Subject(s) - biology , fecundity , bacillus thuringiensis , reproduction , toxicology , pest analysis , larva , zoology , offspring , population dynamics , andrology , botany , ecology , genetics , bacteria , pregnancy , population , demography , sociology , medicine
B acillus thuringiensis ( B t) is an efficient entomopathogen used for pest control. While B t pathogenesis has been thoroughly studied, less is known about the biological effects of sublethal B t exposure. To address this knowledge gap, we document sublethal effects of B acillus thuringiensis var. kurstaki ( B tk) on the biology and development of H elicoverpa armigera ( H übner) under laboratory conditions. The results obtained revealed that duration of the different life stages in treated neonates of H . armigera was significantly affected by sublethal treatments. Furthermore, fecundity was also negatively affected in female moths developed from B tk‐treated neonates, with the rate of egg hatchability reaching zero in the LC 25 . We also present data supporting that the effect of sublethal B tk concentrations could carry over to the next generation. Sublethal B tk concentrations reduced the net reproduction rate ( R 0 ), and there were also significant differences among the values of this parameter at all treatments tested when compared with controls. The intrinsic and finite rates of increase ( r m and λ , respectively) were significantly lower in insects treated with sublethal B tk concentrations compared with control insects. Consequent with the reduce rate of development observed for H . armigera treated with B tk, the mean generation time ( T ) and doubling time ( DT ) were significantly higher in insects exposed to any B tk concentration tested compared with control. Our data demonstrate significant fitness costs resulting from sublethal B tk exposure in H . armigera . These observations underline the importance of considering the role of sublethal effects when attempting to evaluate the impact of B t treatment on an insect pest population and its progeny.