Author
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BLACKMER, JACQUELYN |
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BYRNE, DAVID - UNIV OF AZ, TUCSON, AZ |
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Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/29/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Phloem amino acids of honeydew melon were measured to determine whether changes in nitrogen availability could influence life-history traits and flight activity of Bemisia tabaci. During plant development, 23 amino acids were identified, which varied both quantitatively and qualitatively over time. Factor analysis was used to generate a reduced number of amino acid groups. Individual amino acids that were correlated, but largely independent of other subsets of amino acids were combined to create new variables or factors: (1) predominantly the essential amino acids, was the most important predictor of whitefly weight and developmental time, as well as one of the most important predictors for emergence rate; (2) (predominantly serine and glutamine/glutamic acid) and (3) (predominantly histidine and ornithine), also had significant positive effects on developmental time. Higher concentrations of alanine and methionine (4) were associated with a decrease in female weight, while citrulline (5) was associated with increase in female weight. High concentrations of aspartic acid (6) had a negative impact on all life-history traits of B. tabaci. Flight durations were always skewed toward short flights; however, the frequency of long-duration flights increased as melon plants began to senesce. Whiteflies from all plant-age categories were capable of flying for more than 2 h with fully developed eggs, but the presence of more than four mature eggs was associated with flights of reduced duration. Technical Abstract: Phloem amino acids were measured in Cucumis melo L. to determine whether changes in nitrogen availability might affect life-history traits and flight activity of Bemisia tabaci. During plant development, 23 amino acids were identified which varied quantitatively and qualitatively over time. Factor analysis was used to generate a reduced number of amino acid groups. .Individual amino acids were correlated, but largely independent of other subset of amino acids were combined to create new variables or factors. Males and females, factor 1 (predominantly essential amino acids) was the single most important predictor of adult weight. As relative concentrations of essential amino acids decreased, whitefly weights decreased. Factors 1 and 3 (predominantly histidine and ornithine) were the most important predictors of developmental time. As amino acids decreased in relative concentration, developmental time increased. Percent emergence was positively associated with factor 1 and negatively associate with factor 6 (predominantly aspartic acid). Distributions of flight duration for whiteflies emerging from young, mature and senescing melon plants were compared and were always skewed towards short flights; frequency of long-duration flights increased when melon plants began to senesce. Whiteflies from all plant-age categories were capable of flying for more than 2 h with fully developed eggs, but presence of more than four mature eggs was associated with flights of reduced duration. |
