Evidence of gene flow between sympatric populations of the Middle East‐Asia Minor 1 and Mediterranean putative species of Bemisia tabaci

Bemisia tabaci is a complex of putative species that exhibit a strong geographical pattern. Crossing experiments have revealed various degrees of reproductive isolation between these nascent species, ranging between fertile first‐generation hybrids (F1) and no F1 at all. However, the relevance of these results under natural conditions is generally not known. The worldwide invasion of the putative species Middle East‐Asia Minor 1 (MEAM1) has caused secondary contacts between allopatric species, which in turn provide an opportunity to detect potential hybrids in nature. A total of 346 female B. tabaci were collected in 2003 and 2005 in the North East of Morocco and assigned to MEAM1 (119), Mediterranean (Med) (225) and a new putative species (2) using mitochondrial cytochrome oxidase (mtCOI) gene sequences. MEAM1 and Med individuals were characterized at seven microsatellite loci. MEAM1 and Med were found to be sympatric in 11 of 12 samples (6 fields/year). As previously reported from Spain, MEAM1 frequency decreased over time. The genetic data are consistent with a recent introduction of MEAM1. A Bayesian clustering analysis (Structure ) distinguished two groups, which were 100% consistent with the mtCOI groups. From several lines of evidence, two individuals were identified as hybrids. Assignment profiles using NewHybrids and allele composition indicated that they were not F1 hybrids. The results are discussed in relation to the secondary endosymbiont infection status determined on a sample of individuals, and the contrasting outcomes of the reported crossing experiments between MEAM1 and Med.     

Effect of host plant species of cotton whitefly Bemisia tabaci Middle East‐Asia Minor 1 (Hemiptera: Aleyrodidae) on the development,survival and reproduction of its predaceous ladybeetle Serangium japonicum (Coleoptera: Coccinellidae)

1. The ladybeetle Serangium japonicum has great potential to control the invasive pest Bemisia tabaci Gennadius Middle East‐Asia Minor 1 (MEAM1) in China. However, whether and how the host plant species of B. tabaci MEAM1 affect S. japonicum remains largely unexplored.
2. The present study investigated the influence of five host plant species of B. tabaci MEAM1, namely tobacco, cucumber, cotton, tomato and eggplant, on the pre‐imaginal development, survival of immature stages, adult weight, adult acquired rate and fecundity of S. japonicum under laboratory conditions.
3. The results obtained indicate that the developmental time from first instar to adult eclosion in S. japonicum was shortest when fed on B. tabaci MEAM1 reared on cotton and longest on cucumber. The survival rate of immature stages and the adult acquired rate were highest for cotton and tomato and lowest for tobacco. The fresh weight of adults and the number of eggs laid by S. japonicum were highest for cucumber and lowest for tobacco. The egg hatch rate was lowest for tobacco and highest for tomato.
4. These findings support suggest that host plant species should be factored into integrated pest management to maximize control efficiency when utilizing S. japonicum to control B. tabaci MEAM1.