Academic journal article The American Midland Naturalist

A Field Study of Host Tree Associations of an Exotic Species, the Asiatic Oak Weevil [Cyrtepistomus Castaneus (Roelofs 1873), Coleoptera: Curculionidae]

Academic journal article The American Midland Naturalist

A Field Study of Host Tree Associations of an Exotic Species, the Asiatic Oak Weevil [Cyrtepistomus Castaneus (Roelofs 1873), Coleoptera: Curculionidae]

Article excerpt

ABSTRACT.-

The Asiatic oak weevil [Cyrtepistomus castaneus (Roelofs 1873), Coleoptera: Curculionidae] was detected in New Jersey in 1933 and is now abundant throughout deciduous forests in the Eastern and Midwestern United States. Laboratory feeding trials had suggested a broad range of acceptable hosts for C. castaneus, but field studies were needed to corroborate these findings. We quantified host tree associations of C. castaneus by comparing its abundance among crowns of 66 trees (representing six species) in forests of Ohio and Indiana. The 1827 individuals collected during the study were not equally distributed across tree species; mean proportional abundance was significantly higher on Quercus alba (white oak), Q. rubra (northern red oak) and Acer rubrum (red maple). The high abundance of C. castaneus on Quercus spp. is consistent with laboratory studies and natural history information. However, its presence on A. rubrum and Liriodendron tulipifera (tulip poplar) a Magnoliaceae - had not been documented in field studies. These results indicate that C. castaneus has broad host tree associations. We suggest that researchers conduct further field and experimental studies on C. castaneus to better understand its biology and potential for invading forested areas outside of its present geographic range.

INTRODUCTION

The Asiatic oak weevil [Cyrtepistomus castaneus (Roelofs 1873)] is native to Japan, where it is found primarily on Quercus spp. (oak) and Castanea spp. (chestnut) and is suspected to be regulated by natural enemies. It was detected in New Jersey in 1933 and spread westward to Ohio by 1960 and to Kansas by 1965 (Evans, 1959; Roling, 1979; Stanton, 1994).

The U.S. Forest Service classifies Cyrtepistomus castaneus as a minor defoliator (Solomon et al, 2003), although it has been recorded in high abundance in many different studies. For example, it accounted for 11% of all insect individuals in a partially cut (thinned to 53-63% of original stand) Ozarks (MO) forest area during the months of July and August (Linit et al., 1986). It also represented up to 60% of total beetle abundance on individual trees in southern Ohio that were sampled in August (Gering, 2001). During a 2 y study on insect diversity in the crowns of Quercus rubra (northern red oak), Stanton (1994) found that C. castaneus was the most common beetle species, accounting for 25% of the study-wide insect abundance.

Despite its abundance, the host-tree associations of Cyrtepistomus castaneus have not been compared outside laboratory settings. Stanton (1994), for example, sampled only from Quercus rubra and was not able to compare C. castaneus abundance across tree species. Ferguson et al. (1992) found that adult C. castaneus abundance was significantly and positively correlated with Quercus abundance in forests of central Missouri but did not report C. castaneus abundance from other tree genera.

In fact, most comparative information on Cyrtepistomus castaneus host tree associations comes from laboratory studies. In two-choice feeding experiments with ten tree species, Ferguson et al., (1991) found that C. castaneus preferred leaves of Quercus spp. over leaves from other tree genera, including Acer spp. (maple), Carya spp. (hickory) and Tilia spp. (basswood). The most complete list of purported host trees was presented by Triplehorn (1955), who found that C. castaneus fed on 44 plant species in laboratory trials. Unfortunately, the methods for feeding trials (e.g., frequency, replication, timing) were not provided.

Although laboratory studies have found considerable breadth in host tree preferences, these results would be strengthened by in situ field studies. In this study, we quantified host tree associations by analyzing Cyrtepistomus castaneus abundance from the crowns of 66 trees (representing six species) in forests of the Midwestern United States.

METHODS

SAMPLING DESIGN AND STUDY SITES

We collected beetles from six sites in southern Ohio and Indiana, USA: Hueston Woods State Park (Preble Co. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.