Vertical stratification of Coleoptera assemblages in pecan (Carya illinoensis) canopies

Plant canopies in large tree systems can host diverse arthropod assemblages. However, much is still being discovered about their role in supporting arthropod diversity in perennial tree agroecosystems; in addition, how vertical stratification sorts or distributes species needs to be understood to predict functional changes of these potentially diverse communities. This study aimed to (1) characterize the assemblages of the predominant Coleoptera taxa across a vertical canopy gradient within mature pecan trees, (2) determine seasonal patterns of assemblage composition, and (3) estimate changes in diversity (functional and taxonomic) in relation to pesticide use. Pecan trees were sampled over a two-year period with a suction sampler in conjunction with an aerial lift along three strata (lower canopy, middle canopy, and upper canopy) from summer to early fall. In total, 1,333 individuals constituting ~22 families and over ~50 genera were collected. The two most common taxa were Lady beetles (Coleoptera: Coccinellidae) followed by minute brown scavenger beetles (Coleoptera: Latridiidae). Our preliminary analysis suggests a potential abundance gradient with the highest number of beetles captured from the upper canopy and fewest in lower canopy. These data show a genera rich Coleoptera community in a pecan system with Coleoptera assemblages displaying vertical stratification. Further analyses will help clarify the changes in relative abundance of different taxa within the canopies and potential relationship to pesticides used in the system.