Bt Research 2015, Vol.6, No.5, 1-10
1
Research Article
Open Access
Interactions between
Bacillus thuringiensis
proteins,
Spodoptera frugiperda
(Lepidoptera: Noctuidae) and
Campoletis flavicincta
(Hymenoptera: Ichneumonidae)
Salles S.M.D. , Pinto L.M.N., Pavani F., Machado V., Fiuza L.M.
Programa de Pós-Graduação em Biologia, Laboratório de Microbiologia e Toxicologia, Ciências da Saúde, Universidade do Vale do Rio dos Sinos
(UNISINOS), CEP: 93001-970 Caixa Postal 275. São Leopoldo, RS, Brasil
Corresponding author email
Bt Research, 2015, Vol.6, No.5
doi: 10.5376/bt.2015.06.0005
Received: 21 May, 2015
Accepted: 23 Jun., 2015
Published: 05 Aug., 2015
Copyright
©
2015
Salles et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Salles et al., 2015, Interactions between
Bacillus thuringiensis
proteins,
Spodoptera frugiperda
(Lepidoptera: Noctuidae) and
Campoletis flavicincta
(Hymenoptera: Ichneumonidae), Bt Research, Vol.6, No.5 1
-
10 (doi
Abstract
Plant expression of the entomopathogenic bacteria
Bacillus thuringiensis cry
gene hás reduced the damage created by
insect pests in several economically important cultures. The commercialization of
Bt
plants for insect management has revolutionized
agriculture and become a major tool for integrated pest management (IPM) programs. Among the parasitoids of the pest species
Spodoptera frugiperda Campoletis flavicincta
(Ashmead) is a major parasitoid of larvae. In this context, this study aimed to
investigate the interactions of the
Bt
proteins (from strains of
B. thuringiensis
, rice and
Bt
corn) on the parasitoid
C. flavicincta
and
the armyworm
S. frugiperda
. To evaluate this interaction,
S. frugiperda
larvae were exposed to four different assays: (T1) without
parasitism or exposure to the
Bt
proteins (control); (T2) exposure only to
Bt
proteins (
Bt
plants or monogenic strains); (T3) exposure
only to parasitism by
C. flavicincta
; and (T4) exposure to both parasitism and
Bt
proteins (
Bt
plants or monogenic strains). In each
treatment, 30 larvae and three replications were included, for a total of 360 larvae. In general, the treatments T4 (
Bt
proteins and
C.
flavicincta
) were more effective in controlling
S. frugiperda
thus indicating a potential to be used for the pest control in an integrated
pest management system.The biological characteristics of
C. flavicincta
that developed into larvae under the action of
Bt
thuringiensis
differed from parasitoids that emerged from healthy larvae (control). Therefore, the results in this laboratory system
may significantly differ from what would be seen in the Field.
Keywords
Parasitoids; Biotech crops; Cry proteins; Integrated pest management; Rice; Corn
Background
Some methods, solely or together, get the satisfactory
control of
Spodoptera frugiperda
(J.E Smith). Among
the entomopathogenic agents used in biological control of
lepidopterous pests the
Bacillus thuringiensis
Berliner
bacterium (
Bt
) has gained special attention as an
alternative method (Höfte and Whiteley, 1978; Alves
et al., 1998).
The cultivars transformed with
cry
genes, present several
advantages over
Bacillus thuringiensis
formulations, as
they do not require foliar spraying for insect control
because the toxin is expressed by the plant itself. The
commercialization of
Bt
plants for insect management
has revolutionized agriculture and become a major tool
for integrated pest management (IPM) programs
(Shelton et al., 2002; Romeis et al., 2008).
The responses of resistant and susceptible insects to
Bt toxins maybe useful for understanding, monitoring,
and managing evolution of pest resistance to Bt crops
(Shikano and Cory, 2014
ª
) Several
Bt
rice genotypes
showing high resistance against lepidopteran pests
have been developed since 1993 (Cohen et al., 2008).
While rice is the most important human food in China,
corn is the essential grain for farm animals. More than
35 million acres of corn are grown in China (James,
2014).
However, a major concern related to
Bt
plants is their
potential effects on non-target organisms, especially on
natural enemies that help control pest populations, in
addition to the ability of pest insects to develop
resistance to
Bt
proteins (Gould, 1998; Onstad, 2008;
Tabashnik et al., 2013; Shikano and Cory, 2014 ).
The inclusion of non-
Bt
refuges among plants may be
an alternative for suppressing the evolution of resistance,
through maintaining the
Bt
protein-susceptible alleles
in the population (Tabashnik et al., 2009; Huang et al.,
