B. tabaci
not annotated - annotated - LINNAEUS only
21521136
Host plant effects on alkaline phosphatase activity in the whiteflies, Bemisia tabaci Biotype B and Trialeurodes vaporariorum.
Bemisia tabaci (Gennadius) B-biotype and Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) often coexist on greenhouse-grown vegetable crops in northern China. The recent spread of B. tabaci B-biotype has largely replaced T. vaporariorum, and B-biotype now overlaps with T. vaporariorum where common hosts occur in most invaded areas. The impact of the B-biotype on the agro eco system appears to be widespread, and involves the ability to compete with and perhaps replace other phytophages like T. vaporariorum. An emerging hypothesis is that the B-biotype is physiologically superior due at least in part to an improved ability to metabolically utilize the alkaline phosphatase pathway. To test this hypothesis, alkaline phosphatase activity was studied in the B-biotype and T. vaporariorum after feeding on a number of different hosts for a range of durations, with and without host switching. Alkaline phosphatase activity in T. vaporariorum was 1.45 to 2.53-fold higher than that of the B-biotype when fed on tomato for 4 and 24 h, or switched from tomato to cotton and cabbage for the same durations. However, alkaline phosphatase activity in the B-biotype was 1.40 to 3.35-fold higher than that of T. vaporariorum when the host switching time was -72 and -120 h on the same plant. Both short-term (4 h) and long-term (72 h) switching of plant hosts can significantly affect the alkaline phosphatase activity in the two species. After -120 h, feeding on tomato and cotton alkaline phosphatase activity in the B-biotype was significantly higher than that of T. vaporariorum. It was shown that alkaline phosphatase aids the species feeding on different plant species, and that the B-biotype is physiologically superior to T. vaporariorum in utilizing the enzyme compared to T. vaporariorum over longer periods of feeding.
22182622
Rapid Cold Hardening and Expression of Heat Shock Protein Genes in the B-Biotype Bemisia tabaci.
This paper describes the rapid cold hardening processes of the sweetpotato whitefly, Bemisia tabaci (Gennadius). It was found that all developmental stages of B. tabaci have the capacity of rapid cold hardening and the length of time required to induce maximal cold hardiness at 0^0C varies with stage. There was only 18.3% survival when adult whiteflies were transferred directly from 26^0C to -8.5^0C for 2 h. However, exposure to 0^0C for 1 h before transfer to -8.5^0C increased the survival to 81.2%. The whiteflies show "prefreeze" mortality when they were exposed to temperatures above the supercooling point (SCP), although the range of SCP of whiteflies is -26^0C to -29^0C. The rapid cold hardening had no effect on SCP and reduced the lower lethal temperature of adults from -9^0C to -11^0C. Rapid cold-hardened adults had a similar lifespan as the control group but deposited fewer eggs than nonhardened individuals. The expression profiles during cold hardening and recovery from this process revealed that HSP90 did not respond to cold stress. However, HSP70 and HSP20 were significantly induced by cold with different temporal expression patterns. These results suggest that the rapid cold hardening response is possibly advantageous to whiteflies that are often exposed to drastic temperature fluctuations in spring or autumn in northern China, and the expression of HSP70 and HSP20 may be associated with the cold tolerance of B. tabaci.
22182623
Interspecific Interactions Between Bemisia tabaci Biotype B and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae).
Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) are invasive whitefly species that often co-occur on greenhouse-grown vegetables in northern China. Although B. tabaci biotype B has been present in China for a relatively short period of time, it has become dominant over T. vaporariorum. We studied the interspecific competitive interactions between the two species in single or mixed cultures at 24 +/- 1^0C, 40 +/- 5% RH, and L14:D10 h photoperiod. Female longevity on tomato was not significantly different between species, but B. tabaci reproduced 4.3 to 4.9 fold more progeny. The ratio of female to male progeny in both instances was greater for B. tabaci. When cultured on tomato, cotton, and tobacco, B. tabaci developed 0.8, 3.3, and 4.7 d earlier in single culture, and 1.8, 3.9, and 4.3 d earlier in mixed culture. B. tabaci displaced T. vaporariorum in four, five and six generations when the initial ratios of B. tabaci to T. vaporariorum were 15:15, 20:10, or 10:20 on tomato. Populations of B. tabaci were 2.3 fold higher than that of T. vaporariorum on tomato plants for seven consecutive generations in single culture. B. tabaci performed better in development, survival, fecundity, and female ratio. We conclude that B. tabaci could displace T. vaporariorum in as short as four generations in a controlled greenhouse environment when they start at equal proportions. Warmer greenhouse conditions and an increase in total greenhouse area could be contributing factors in the recent dominance of B. tabaci.