demographic parameters of the ladybeetle, serangium montazerii fursch feeding on citrus whitefly, dialeurodes citri ashmead were determined on two host plants, page tangerine and thompson navel orange. this study was carried out under laboratory conditions (25 ± 1 °c and rh of 60 ± 5% and a photoperiod of 16: 8 h (l: d). total pre-adult periods of the lady beetle were 20.84 ± 0.302, 19.27 ± 0.2...

Using an identity for effective resistances, we find a relationship between the arithmetic-geometric index and the global ciclicity index. Also, with the help of majorization, we find tight upper and lower bounds for the arithmetic-geometric index.