Biology Reference
In-Depth Information
5
Endosymbiosis in the Weevil
of the Genus
Sitophilus
:
Genetic, Physiological,
and Molecular Interactions
among Associated Genomes
Abdelaziz Heddi
CONTENTS
ssp. Symbiosis ......................................................................................68
Phylogenetic Characterization of SOPE and
Sitophilus
.................................................................70
Wolbachia
Induce Cytoplasmic Incompatibility in Weevils ....................................................73
Wolbachia
INTRODUCTION
InterspeciÝc associations are currently believed to take part in evolution either by improving a
partnerÔs Ýtness through integrated endosymbioses or by causing reproductive isolation and sub-
sequent host speciation, such as in the
Wolbachia
endosymbioses (Nardon and Grenier, 1991;
Margulis, 1993a; Bordenstein
et al., 2001). Most often, associations involve very distant species
like bacteria with invertebrates, but several examples are known where eukaryotes associate together
to form lichen or coral holobiont units (Rowan, 1997). Recently, an unusual symbiosis has been
discovered within the mealy bugs wherein a
h
-proteobacterium lives inside a
c
-proteobacterium
(von Dohlen
et al., 2001), which demonstrates that even among prokaryotes a tendency exists to
form tight associations among the genomes (Heddi
et al., 2001).
In insects of the order Coleoptera, a large array of symbioses occurs with three principal
types of association: ectosymbiosis with fungi in
beetles, intestinal lumen endosym-
biosis in Scarabaeidae, and intracellular endosymbiosis in Chrysomelidae, Scolytidae, and
Dryophthoridae (for review see Nardon and Grenier, 1989). The Dryophthoridae family (or
Ambrosia
