Hs. Costa et al., REGIONAL DISTRIBUTION, INSECTICIDE RESISTANCE, AND RECIPROCAL CROSSESBETWEEN THE A-BIOTYPE AND B-BIOTYPE OF BEMISIA-TABACI, Insect science and its application, 14(2), 1993, pp. 255-266
Populations of the whitefly, Bemisia tabaci collected from the America
s and the Caribbean Basin were examined for non-specific esterases and
for the ability to induce characteristic phytotoxic disorders in key
assay species as a means of investigating biogeographic diversity. Est
erase markers were used to detect polymorphisms among regional B. taba
ci populations and to establish the present distribution of B. tabaci
biotypes in the region. The A biotype occurred only in contiguous loca
les in northern Mexico and the southwestern US, while the B biotype wa
s present throughout much of the Caribbean Basin and the US, and in Br
azil. Distinct C and D type esterase markers were observed for Costa R
ican and Nicaraguan B. tabaci populations, respectively. The 0 or null
type population was collected only from Jatropha gossypifolia (L.) in
Puerto Rico. Laboratory colonies of the A and the B biotypes were alm
ost equally sensitive to an organophosphate, profenofos. The B biotype
was more resistant to a pyrethroid, permethrin, suggesting the existe
nce of a biotype of B. tabaci, with a history of exposure to pesticide
s with a pyrethroid-based chemistry. In mating studies involving recip
rocal crosses between the A and the B biotypes, very few F1 female pro
geny were produced, indicating either minimal or non-existent reproduc
tive compatibility between these haplo-diploid B. tabaci populations,
presently considered to be the same species. Evidence is presented for
the recent and widespread introduction, and subsequent spread of the
B biotype throughout the US, the Caribbean Basin, and other proximal l
ocations.