Evolution journalière du sex-ratio dans une population de Mononychellus tanajoa Bondar (Acari: Tetranychidae) en laboratoire, paramètres de la dynamique des populations

Sex-ratio Daily Evolution in a Population of Mononychellus tanajoa Bondar (Acari: Tetranychidae) in the Laboratory, Population Dynamics Parameters. The sex-ratio (100.males/females) of offsprings laid by fertilized female parents of Mononychellus tanajoa Bondar and its daily evolution was studied in the laboratory. The highest sex-ratio value 900 (90.0% male offsprings) was obtained on the first day of the oviposition and the lowest value 7.2 (6.7% male offsprings) on the 16th day of the oviposition period which lasted 38.1 ± 4.9 days (mean ± standard deviation). From a total number of 118.0 ± 10.9 offsprings, 94.0 ± 10.5 (on the average 79.7%) were ''laid'' during the first half of the oviposition period. The results also show that from a total number of 88.0 ± 8.3 female offsprings, 74.0 ± 8.0 (84.1%) were ''laid'' during the first half of the oviposition period whereas from a total number of 30.0 ± 2.7 male offsprings, 20.0 ± 2.5 (66.7%) were ''laid'' within the same period. The sex-ratio of each fertilized female parent was 31.9 ± 1.7 (24.2% ± 1.0% male offsprings) and the sex-ratio within the population was 34.0 ± 0.0 (25.4% ± 0.1% male offsprings). The intrinsic rate of increase, and the rate of multiplication in one generation were 0.1380 and 79.23 respectively.