Insects associated with yellow-poplar, Liriodendron tulipifera L., in a mixed hardwood forest and a plantation in eastern Tennessee

A total oil,229 specimens representing 13 orders, 146 families, and some 727 species were collected from May 1999 to June 2000 from yellow-poplar trees located in an Arboretum (mixed hardwood forest) and a Plantation using four sampling methods (canopy fogging, direct sampling. Malaise and pan flight intercept trapping). Currently, 373 of the approximate 727 types are identified to species and an additional 122 are identified to genus. Species and family richness and specimen abundance was greater at the Arboretum than at the Plantation and greater in the lower canopy than in the higher canopy at both sites. Species and family diversity calculated using the Shannon-Wiener Diversity Index was higher at the Arboretum than at the Plantation. Species evenness and diversity was not significantly different (p<0.05) between canopy layers. The Coleoptera contained the most species (n=301) at both sites, and the most specimens (n=l,330) at the Plantation. However, the Hymenoptera was the most abundant group collected at the Arboretum. Nearly 60% of the families were shared by the sites. Several uncommon to rare families and species were collected. Each site contained a distinct assemblage of insect species with only 16% species overlap.

The numbers of species and specimens collected by the different sampling methods used differed between the sites. Malaise and pan flight intercept trapping was more productive at the Arboretum than at the Plantation, while direct sampling and canopy fogging was more productive at the Plantation than at the Arboretum. The direct sampling method measured greatest in species diversity (H'= 4.12 (Arboretum) and 3.79 (Plantation)) and evenness (H'/Hmax = 0.88 (Arboretum) and 0.79 (Plantation)) and the lower pan traps measured the lowest at both sites.

Thirteen species were identified as exotic, 10 of which are considered to be pest species and three that are considered to be beneficial biological control agents. The exotic pest species were most abundant at the Arboretum, while the beneficial exotic species were more abundant at the Plantation. Also, 28 species representing three orders and 10 families were directly collected on yellow-poplar flowers. Species of Halictidae, Andrenidae, and Cantharidae were the most abundant. In addition, 19 beetle species collected may represent new state records for Tennessee with four representing new southern range limits in the United States. Finally, pest and beneficial species occurrence, abundance, and their potential effects on yellow-poplar are discussed.