D3107: Survey of insect floral visitation to landscape crape myrtle trees across a rural-urban gradient

Crepe myrtle trees (Lagerstroemia spp.) are ornamental staples in the southeastern U.S. Crepe myrtle trees commonly have pest infestations and systemic pesticide applications are a standard treatment for insect pest control. Systemic pesticide uses on crepe myrtle trees can pose a threat to non-target insect species. However, few studies have defined the floral visitors to crepe myrtle in a landscape context, and none across the rural-urban gradient. This study aimed to survey the diversity and abundance of insect species visiting the flowers of crepe myrtle trees across a rural – urban gradient in Alabama. Trees for this study were selected based on cultivar (Lagerstroemia x ‘Natchez’) and location. Three levels of urbanization were established by calculating the percentage of impervious surfaces surrounding the trees within a 50-meter radius, using ArcGIS software. Levels of urbanization established included urban (51-100% impervious surfaces), suburban (31-50% impervious surfaces), and rural (≤ 30% impervious surfaces). For each level of urbanization, three sites were selected. Within each site, three trees were surveyed to total nine trees per level of urbanization and twenty-seven trees total for all sites. Surveys were conducted between July 1 and August 18, 2020 (period of full bloom for trees). A 30-second observation was taken at each tree and insects visiting the flowers were counted and identified, in-field, to family level. Following this count, insects visiting flowers were collected with an aerial net for 10 minutes. Specimens were identified to determine the abundance and diversity. The results and implications will be discussed.