The diversity of phytoseiid mite communities in the Maghreb comparisons with the fauna of one of the Canary Islands.

Phytoseiid mite diversity was surveyed on wild and cultivated plants in Morocco and Tunisia from 1994 to 2003. Results were associated with those obtained in previous surveys conducted by other authors in Algeria and in one of the Canary Islands (Gran Canaria). They showed, 21 species are known from Tunisia (1 was known before), 53 from Algeria, 41 from Morocco (15 were known before) and 23 from the Canary Island. Eight were known from all these islands before the data published in 2003 concerning only Gran Canaria, which represent a very small area compared to the three large countries, above all to Algeria. Ten species were common to all the four countries, 4 to Morocco, Algeria and Tunisia, 1 to Algeria and Tunisia. One species was in Tunisia and Morocco, suggesting that this species might also be present in Algeria, 1 was present in Morocco, Algeria and in the Canary Island. Nine species were found in Algeria and Morocco and one species in Algeria and the Canary Island. The authors detected a new genus and a new species in Tunisia, 8 new species in Morocco, and published data mentioned 6 new species in the Canary Island. The considerations on biogeography were also given.

Factors affecting abundance and diversity of phytoseiid mite communities in two arboreta in the South of France.

Phytoseiid mite densities and diversity were surveyed on 16 plant species in two arboreta in the South of France. Samplings in these two arboreta were carried out on 5 trees of the same plant species twice a month during 4 months. Within the same arbouretum, densities were not significantly different within the same plant between the 5 replicated realised. However, differences in phytoseiid mite densities and diversity were seen between the plants species within each of the two arboreta. In order to determine the factors affecting these differences, foliar characteristics (trichome and domatia densities, domatia structure, pilosity of the vein axils, leaf surface) were evaluated. Multi-factorial analysis shows relationships between some of these parameters, especially domatia density and structure and pilosity on vein axils, and phytoseiid mite densities. These results are different from previous observations, as they minimise the importance of leaf trichomes on limb. This could be due to phytoseiid mite species considered, and especially to their size, larger phytoseiids being probably less able to colonise high pilose leaves. Mite densities and diversity were also different for same plants located in the 2 arboreta. Kampimo-dromus aberrans was the main species occurring in the aboretum 2 and is absent in the first one while Typhlodromus exhilaratus was the main species in the arboretum 1 but not in arboretum 2. Different factors, as ecological factors like surrounding vegetation and environment, plant community successions, soil characteristics affecting plant communities and plant physiology, could have determined abundance and diversity of phytoseiid mites.