Sex Determination in Insects - Insect Molecular Genetics - page 444

could be increased. Experiments have been conducted to determine whether it
is possible to artificially transfer thelytoky-inducing strains of Wolbachia from
one Trichogramma species to another so that the new strain could be improved
by increasing the proportion of female progeny ( Grenier et al. 1998 ). Wolbachia
isolated from an infected species, Trichogramma pretiosum , was transferred
by microinjection into the pupae of an uninfected species, T. dendrolimi . The
Wolbachia were found in the recipient species 26 generations after the transfer,
but only a partial level of thelytoky was observed, perhaps because the density
of symbionts was too low or because symbiont-host interactions interfered with
the expression of the thelytoky phenotype.
10.15 Conclusion
Gempe and Bey (2010) reviewed sex-determination systems in insects and
concluded:
“One common theme from these studies is that evolved mechanisms produce
activities in either males or females to control a shared gene switch that
regulates sexual development. Only a few small-scale changes in existing
and duplicated genes are sufficient to generate large differences in sex
determination systems.”
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