Agriculture Reference
In-Depth Information
Chapter 1
I
NFLUENCE OF THE
S
OYBEAN
S
EED
C
OAT UPON
S
EED
I
NFESTATION AND
D
EVELOPMENT OF
THE
I
NSECT
C
ALLOSOBRUCHUS
M
ACULATUS
Antonia Elenir A. Oliveira, Kátia V. S. Fernandes
*
,
Amanda J. Souza and Patrícia O. Santos
Laboratório de Química e Função de Proteínas e Peptídeos LQFPP, Centro de
Biociências e Biotecnologia - CBB, Universidade Estadual do Norte Fluminense Darcy
Ribeiro - UENF, Campos dos Goytacazes - RJ, Brazil
A
BSTRACT
Seed coats represent the first tissue contacted by bruchids on host or non-host species
suggesting its participation in the evolutionary adaptation of bruchids to legume seeds.
On the cowpea (
Vigna unguiculata
)
host seeds the oviposition and egg hatching phases of
Callosobruchus maculatus
are completed in about 6 days, eclosion occurs within the
seed, and adult beetles emerge some 25-30 days after oviposition. Before the larva
reaches the cotyledons, where it completes its life cycle, it is necessary to cross the seed
coat, what may represent a critical event when infesting non-host seeds, because of
physical and toxicity characteristics of this tissue. In the present chapter we present data
on the influence of seed coat from several soybean (
Glycine max
) cultivars over the
C.
maculatus
larvae capacity to penetrate, develop and survive on these seeds. Seed coat
effects were evaluated by exposing the insects to different systems: natural soybeans;
cowpea-based artificial seeds supplemented by soybean seed coat flour; or artificial
cowpea seeds covered with natural soybean seed coats. Natural soybeans reduced both
female oviposition, ranging from 100% (Tucunaré cultivar) to 35% (UFUS 2005) and
larval eclosion (82.5% - Conquista cultivar - to 25% - commercial line). Major effects of
natural soybeans were observed in respect to adult emergency, since no adult has
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