This thesis project documented the diversity and abundance of the insect population supported by the Arroyo Willow (Salix lasiolepis) at the Madrona Marsh Preserve in Torrance, California, and the Willows Wetland Preserve in Gardena, California. The purpose was to provide information for future wetland conservation. A total of 15 samples were collected from September 2004 until August 2005 with a total sample size (n=3030) being comprised of 9 orders and 54 families of insects. Ten families made up 87% of the total population. Insect assemblage differences were discovered, as only 52% percent of the families were found at both sites. The remaining 26 families were not concurrent with 14 identified from Madrona Marsh and 12 being unique to The Willows Wetland. Insect population size was found to be much greater during the spring and summer months than the fall. These results suggest that Salix lasiolepis supports a site specific high diversity with a wide range of relative abundances.