Fitness comparison inPhytoseiulus persimilis strains resistant and susceptible to methidathion

The effect of selection for methidathion resistance on fitness components of aP. persimilis strain was analysed by different means. The resistant strain was compared with the susceptible one from which it was selected. The life history and some parameters essential to the successful use of this species in biological control (voracity, resistance to starvation and drought) were analysed. Methidathion resistance was followed for 6 months under rearing conditions free of insecticide in the resistant and in a mixed strain. The investigations showed that the fitness of resistant mites did not seem altered by methidathion selection. It thus appears possible to increase pesticide resistance in beneficial arthropods without adversely affecting their main fitness components.     

Current data on the exploration and the evaluation of clinical pain]

Pain is a complex, multidimensional and multifactorial neuropsychological phenomenon with sensory-discriminative, affective, cognitive and behavioral components. Issues on pain assessment are related to the objective evaluation of a subjective phenomenon. Different levels of evaluation are to be considered. Some methods like visual analogue scale, numerical scale and verbal permit a global pain estimation. The aim of other methods like the McGill Pain Questionnaire is a quantitative and qualitative evaluation of the sensory and affective pain components. The measure of objective behavioral changes is an interesting approach, but at the present time there is no valid, simple and commonly used method. There is also a need for methods permitting a better exploration of a pain, and in particular a selective evaluation of organic and functional factors. The limits of psychological factors evaluation are reported.