SURVEY AND POPULATION STUDIES OF INSECTS ASSOCIATED WITH ORNAMENTAL PLANTS BY USING SWEEPING NETS AND PITFALL TRAPS AT RIYADH METROPOLIS, SAUDI ARABIA

A survey along with some studies on the population densities and relative abundance of insects associated with ornamental plants were conducted using sweeping nets and pitfall traps in Riyadh metropolis, Saudi Arabia, for a full year from December, 2006 to November, 2007. A total number of 2411 individuals, included thirty three species belonging to thirty genera, fifteen families and five orders, i.e. Coleoptera, Homoptera, Hemiptera, Hymenoptera and Orthoptera, were collected by the two methods. The largest numbers were observed during May, June and April. Also the largest number of species was belonging to the order Coleoptera (16 species), followed by the hymenopterans (7 species). Other orders were represented by varying number of species. The coleopterans were found to be the most abundant and dominant, constituting the majority of the catch (961 specimens, representing 39.9% of the total catch), followed by hymenopteran individuals (939 specimens, constituting 38.9% of the total catch). Insects of other orders were less abundant and were represented by small numbers of individuals, with the hemipterans constituting the minority of catch (4 specimens of two species).
Fifteen species belonging to fourteen genera, ten families and five orders were obtained throughout the year by using sweeping nets. While nineteen species belonging seventeen genera, six families and three orders were collected by pitfall trap.