CONICET | Buscador de Institutos y Recursos Humanos

Neoseiulus californicus (McGregor) is a phytoseiid that can provide biological control of Tetranychus urticae Koch. The effectiveness of phytoseiids for biological control depends on different attributes including their ability to survive conditions of food shortage. Newly N. californicus copulated females were singly introduced into an arena for 10 days and were either provided with or deprived of food (all stages of T. urticae) during the first 48 or 96h. Food deprivation reduced adult survival (control: 100%, 48h: 83% and 96h: 62.5%) and the proportion of reproducing females, while the pre reproductive period increased with increasing starvation. The number of offspring produced by females of age x that effectively laid eggs after the periods of starvation was not significantly different from the control in all cases they levelled at approximately 2.9 eggs per reproducing female. Expressing the mean number of eggs laid per female in physiological age (days after starvation), differences were observed in the second and third days denoting the effect of starvation in the fecundity recovery period. The net reproduction rate during the first 10 days of adulthood was 18.22, 8.91 and 1.95 female eggs/female/10 days, for the control, the 48 and the 96h starvation treatments, respectively. The overall effect of food deprivation was mainly due to a reduction in adult survivorship and in the proportion of reproducing females. The negative effect on the net reproductive rate during the first 10 days of adulthood could reduce the capacity of N. californicus to prevent population increases of T. urticae in the short term. Notwithstanding, this effect would be mitigated because this predator is capable of feeding on alternate food sources such as pollen, different mites and insect eggs.

enviar mensaje