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Diversity of ground-dwelling insects in a mixed hardwood southern Appalachian forest in eastern Tennessee.

ABSTRACT--Insects were sampled using pitfall traps during a two-year study in four mixed hardwood forest sites (cove, slope, open, and tornado-damaged) to determine their diversity beneath three dominant tree species: white oak, Quercus alba L.; sugar maple, Acer saccharum Marsh; and tulip poplar, Liriodendvon tulipi/era L. From pitfall traps, 191 species were identified representing 69 families in 15 orders. Significantly greater numbers of insects were collected in the cove site than in the slope or tornado-damaged sites. Also, species diversity and evenness were significantly greater in the cove site. Beetles represented 65% of the species identified at the four sites. Beetle diversity and richness did not differ significantly among the four sites, although species evenness was significantly lower in the tornado-damaged site.

The natural beauty and biodiversity of southern Appalachian forests attract more than 14 million people to the region annually. As a result, tourism contributes over 12 billion dollars per year to Tennessee's economy (Travel Industry Association, 2006). The Great Smoky Mountains National Park attracts more than nine million visitors annually who contribute to the local economy. The southern Appalachian economy relies heavily on the resulting public service, retail sales, outdoor recreation and forestry practices generated (Travel Industry Association, 2006). About 87% of Tennessee forests are comprised of hardwoods, making Tennessee one of the nation's leading hardwood lumber manufacturers. Employment and income in the region have remained stable over the last 20 years due in large part to the tourism and wood products industries (Travel Industry Association, 2006; Southern Appalachian Man and Biosphere Cooperative, 1996) which annually create more than 225,000 jobs.

The Appalachian mountains of eastern Tennessee support a diverse array of flora and fauna and many species are unique to these forest ecosystems (Buck et al., 2005). These species contribute to the overall forest stability and health. Invasion and establishment of exotic pests are considered one of the primary causes for disruption of habitats, posing significant threats to native insect species and the forests in which they occur. For example, population outbreaks of the gypsy moth, Lymantria dispar (L.), have caused defoliation of millions of hectares of forests, resulting in millions of dollars of damage (Ghent, 1994; Grace, 1986). Since its introduction into the United States, the gypsy moth has become established in most of the northeastern and midwestern states and the District of Columbia (USDA, 1996). The movement of the gypsy moth front, currently located near Roanoke, Virginia, has been reduced from 10.9 to 4.8 km per year by the "Slow the Spread Program". This slower movement has delayed the predicted time this pest will significantly impact forests in eastern Tennessee (Sharov et al., 2002). However, isolated infestations have been reported in the Great Smoky Mountains National Park, as well as in 71 counties in Tennessee (Strohmeier, 2006).

The gypsy moth is capable of repeated defoliation of trees over vast regions, resulting in major changes in flora, fauna and leaf litter composition, the quality of streams and rivers draining affected marshlands, and food availability for species residing in forest habitats. Understanding the ground-dwelling insect species composition of this hardwood forest may help to determine the impact of the gypsy moth, once established, on the insect composition and on the health of native southern Appalachian hardwood forests in eastern Tennessee. To date, no comprehensive study on the diversity of ground-dwelling insects in hardwood forests in eastern Tennessee has been conducted. Insect data collected prior to the anticipated gypsy moth invasion will be useful to assess the impact of the gypsy moth on native species inhabiting southern Appalachian hardwood forests. Such information also may be useful in identifying potential natural enemies of this exotic pest and provide a better understanding of the importance of species composition, seasonality, abundance, and diversity in southern Appalachian forest habitats. Over the past two decades, several exotic pests, such as the balsam woolly adelgid, Adelges piceae (Rathzeburg), beech scale, Cryptococcus fagisuga Lind., elongate hemlock scale, Fiorinia externa Ferris, and hemlock woolly adelgid, Adelges isugae (Annand), have become established in Tennessee and have the potential to dramatically change the composition of the fauna and flora within the area (Hughes, 1993; Lambdin et al., 2005; Vance, 1995). These data will be useful as a standard for comparing the impact of such invasive pests on insect diversity. Therefore, a study was initiated in 1997 to: 1) determine the overall diversity of ground-dwelling insects associated with three dominant tree species, and 2) determine the size of the ground-dwelling beetle populations within the area.


Site Description--Four collection sites (cove: 36[degrees]00'49"N, 84[degrees]11'20"W, slope: 36[degrees]00'10 N, 84[degrees]12'34"W, open: 36[degrees]00'02"N, 84[degrees]12'26"W, and tornado-damaged: 35[degrees]59'57"N, 84[degrees]12'27"W) within a mixed hardwood forest were selected in the University of Tennessee Forestry Experiment Station and Arboretum located in Oak Ridge, Tennessee. At each site (30.5 [m.sup.2]), one tree from each of three host tree species (white oak, Quercus alba L.; sugar maple, Acer saccharum Marsh; and tulip Poplar,Liriodendron tulipifera L.) was selected. These trees were chosen based on their demonstrated susceptibility to the gypsy moth as determined by Montgomery (1990) and Twery (1990). All four sites contain a Fullerton series soil type consisting of deep, well-drained cherty soils that formed in dolomite. Sites were located on ridges and hills with a range in slope from 5 to 45[degrees]. Overstory and understory vegetation present within the sites was reported by Gibbs et al. (2003).

Collection of Insect Specimens--Four pitfall traps were placed under the canopy (one in each cardinal direction near drip line) of each of three trees in each site in mid-June 1997. Two pitfall samples were alternately collected weekly from each tree from 26 June to 21 November 1997 and from 26 March to 26 August 1998. In late November 1997, pitfall traps were removed from the sites and returned to the same location in early March 1998. Each pitfall trap consisted of a metal receptacle (450 ml) with holes in the bottom for drainage, and a specimen container (120 ml) filled with 20 ml of a 50/50 composition of propylene glycol and water. A plastic funnel was nested within the container to direct specimens into the unit. Receptacles were buried to a depth of 10.5 cm with the top of the receptacle flush with the ground. Wooden covers (30.5 cm by 30.5 cm) supported by four baffles (each 40.6 cm long) were painted brown for camouflage and water-proofing. These covers were placed over the pitfall traps to help direct insects into the containers and prevent entry of rain or debris.

Insect specimens were taken to the laboratory, poured onto a pore sieve (250 [micro]m) with a collection pan below to collect the propylene glycol, rinsed with tap water to remove excess propylene glycol, and placed in vials containing 20 ml of 70% ethyl alcohol. Each vial was labeled with collection date, site number, tree number, and trap number. Specimens were later removed from the alcohol vials and pinned, identified to species, labeled (family and species name, locality, collector, determiner), and systematically arranged into Cornell drawers for incorporation into the insect museum of The University of Tennessee.

Data Analyses--Data were incorporated into Excel[R] and Biota[R] databases (Colwell, 1996). The overall insect and tree species diversity for each site was determined with the Shannon diversity index (Newell, 1997; Smith, 1992). This index considers the number of species as well as their relative abundance to define species richness. A separate Shannon evenness measurement was calculated. Species evenness values range from 0 to 1, with one representing the most even value. Mean estimates were calculated separately using Proc GLM (SAS Institute, 1997) for overall abundance of species. Data were analyzed using SAS procedures (SAS Institute, 1997, 1989) with analysis of variance (ANOVA) used to determine significant differences (P < 0.05) in species diversity, species richness, and species evenness, as well as differences among beetle species, among sites and tree species.


From 6,504 insect specimens collected from pitfall traps during 1997 and 1998, 191 species were determined from 69 families representing 15 orders (Table 1). The highest number of species was in the orders Coleoptera (123 species). Hymenoptera (24 species) and Diptera (15 species). Significantly (P [<] 0.05) greater numbers of insect species (species richness) were collected in the cove site (44) than in the slope (38) or tornado-damaged sites (38), while the open site (41) did not differ significantly (P > 0.05) from the other sites (Table 2). The higher number of insects associated with the cove site may be the result of most ground-dwelling insects requiring habitats in sheltered forested areas with high moisture levels. Species diversity (1.75) and species evenness (0.67) was highest among insects collected in the cove site, possibly as a result of a denser canopy cover and a more open forest floor. In the winter of 1997, a neighboring forest stand was clear-cut, and this disturbance may have caused more insects to move into the cove site. Also, after heavy rains, a portion of the cove site retains water. The associated increase in overall soil moisture content may benefit many insects inhabiting the cove site by helping them avoid desiccation during the dry summer months. Diversity indices suggest the four sites are generally species diverse with an even representation of the species inhabiting this mixed hardwood ecosystem.
TABLE 1. Total number of insect species collected using pitfall
traps at four mixed hardwood sites in The University of Tennessee
Forestry Experiment Station and Arboretum in 1997 and 1998.

Order Family Genus Species

Diplura Japygidae Undet. sp.

Microcoryphia Machilidae Thermobia domestica

Thysanura Lepismatidae Lespisma saccharina

Orthoptera Gryllacrididae Ceuthophilus sp.

Orthoptera Gryllidae Gryllus sp.

Orthoptera Nemobiidae Nemobius sp.

Orthoptera Tettigoniidae Atlanticus sp.

Blattaria Blattellidae Ischnoptera deropeltiformis

Blattaria Blattellidae Parcoblatta bolliana

Isoptera Rhinotermitidae Undet. sp.

Plecoptera Undet. Undet. sp.

Psocoptera Psocidae Indiopsocus sp.

Psocoptera Psocidae Undet. sp.

Hemiptera Undet. Undet. sp. 1

Hemiptera Undet. Undet. sp. 2

Hemiptera Undet. Undet. sp. 3

Hemiptera Aphididae Undet. sp.

Hemiptera Cleadellidae Undet. sp. 1

Hemiptera Cleadellidae Undet. sp. 2

Hemiptera Cixiidae Undet. sp.

Thysanoptera Thripidae Undet. sp.

Neuroptera Chrysopidae Chrysopa sp.

Neuroptera Myrmeleontidae Ascaloptynx appendiculance

Coleoptera Agyrtidae Necrophilus pettiti

Coleoptera Anobiidae Tricorynus sp.

Coleoptera Anthicidae Tomoderus sp.

Coleoptera Carabidae Chlaenius emarginatus

Coleoptera Carabidae Cyclotrachelus conviva

Coleoptera Carabidae Cyclotrachelus freilagi

Coleoptera Carabidae Cyclotrachelus fucatus

Coleoptera Carabidae Cyclotrachelus Sigillata

Coleoptera Carabidae Cyclotrachelus sodalis

Coleoptera Carabidae Dicaelus ambiguus

Coleoptera Carabidae Dicaelus dilatatus

Coleoptera Carabidae Dicaelus politus

Coleoptera Carabidae Dicaelus teter

Coleoptera Carabidae Galerita bicolor

Coleoptera Carabidae Galerita sp.

Coleoptera Carabidae Harpalus fulgens

Coleoptera Carabidae Melanius caudicalis

Coleoptera Carabidae Nolobia sp.

Coleoptera Carabidae Notiophilus novemstrlatus

Coleoptera Carabidae Platynus decetis

Coleoptera Carabidae Pterostichus coracinus

Coleoptera Carabidae Scaphinotus andrewsi

Coleoptera Carabidae Selenophorus opalinus

Coleoptera Carabidae Sphaeroderus lecontei

Coleoptera Carabidae Sphaeroderus stenostomus

Coleoptera Carabidae Stenolophus sp.

Coleoptera Chrysomelidae Demotina modesta

Coloptera Chrysomelidae Lupraea pieta

Coleoptera Chrysomelidae Undet. Alticinae sp.

Coleoptera Chrysomelidae Undet. sp.

Coleoptera Cicindellidae Cicindela unipunctata

Coleoptera Coocinellidae Undet. sp.

Coleoptera Corylophidae Bathona. sp.

Coleoptera Cryptophagidae Cryptophagus sp.

Coleoptera Cryptophagidae Cryptophagus sp.

Coleoptera Curculionidae Conotrachelus elegams

Coleoptera Curculionidae Conotrachelus posticatus

Coleoptera Curculionidae Cyrtepistonums castaneus

Coleoptera Curculionidae Dryophthorus americanus

Coleoptera Curculionidae Odontopus calceatus

Coleoptera Elateridae Hemicrepidus memmonius

Coleoptera Elateridae Melamotus sp.

Coleoptera Elateridae undet. sp.1

Coleoptera Elateridae undet. sp.2

Coleoptera Eucinetidae Eucinetus Striglosus

Coleoptera Geotrupidae Geotrupes htackburnill

Coleoptera Geotrupidae Geotrupes splendidus

Coleoptera Histeridae Euspilotus sp.

Coleoptera Histeridae Hister sp.

Coleoptera Histeridae Onthophilus pleuricostatus

Coleoptera Hydrophiltidae Cereyon sp. 1

Coleoptera Hydrophilidae Cercyon sp. 2

Coleoptera Leiodidae Anisotoma sp.

Coleoptera Leiodidae Catops simplex

Coleoptera Leiodidae Catops sp.

Coleoptera Leiodidae Colon sp. 1

Coleoptera Leiodidae Colon sp. 2

Coleoptera Leiodidae Dissochaetus oblitus

Coleoptera Leiodidae Geomysaprinus posthumus

Coleoptera Leiodidae Geomysaprinus sp.

Coleoptera Leiodidae Nemadus sp.

Coleoptera Leiodidae Prionochaeta opaca

Coleoptera Leiodidae Ptomophagus sp.

Coleoptera Leptinidae Leptinus testaceous

Coleoptera Leptodiridae Namadus sp.

Coleoptera Mordellidae Mordellistena pubescens

Coleoptera Nitidulidae Colopterus truncata

Coleoptera Nitidulidae Epuraea sp.

Coleoptera Nitidulidae Pallodes palidus

Coleoptera Nitidulidae Phenolia grossa

Coleoptera Nitidulidae Stelidota octomaculatu

Coleoptera Nitidulidae Undet. sp.

Coleoptera Orthoperidae Sericoderus lateralis

Coleoptera Ptiliidae Acrotrichis sp.

Coleoptera Ptiliidae Nephanes sp.

Coleoptera Ptiliidae Undet. sp.

Coleoptera Ptilodactylida Ptiloductyla sp.

Coleoptera Physodidae Clinidium sculptile

Coleoptera Scaphidiidae Scaphidium quadrigutiatum

Coleoptera Scaphidiidae Undet. sp.

Coleoptera Scarabacidac Aphodius sp.

Coleoptera Scarabaeidac Ateuchus histeroides

Coleoptera Scarabaeidae Canthon hudsonias

Coleoptera Scarabaeidae Canthon viridis

Coleoptera Scarabaeidae Copris minutus

Coleoptera Scarabaeidae Deltochilum gibbosus

Coleoptera Scarabaeidae Glaphyrocanihon viridis

Coleoptera Scarabaeidae Onthophagus hecate

Coleoptera Scarabaeidae Onthophagus janus

Coleoptera Scarabaeidac Onthophagus pennsylvanicus

Coleoptera Scarabaeidae Onthophagus strialulus

Coleoptera Scarabaeidae Phyllophaga hirticula

Coleoptera Scarabaeidae Phyllophaga ilicis

Coleoptera Scolytidae Dendrouctonus fromalis

Coleoptera Scolytidae Undet. sp.

Coleoptera Seydmaenidae Noctophus sp.

Coleoptera Silphidae Nicrophorus orbicolis

Coleoptera Silphidae Nicrophorus pustulantus

Coleoptera Staphylinidae Bryoporus rufescens

Coleoptera Staphylinidae Dasycerus sp.

Coleoptera Staphylinidae Hoplandria laeviventris

Coleoptera Staphylinidae Hoplandria sp.

Coleoptera Staphylinidae Lobrathium collare

Coleoptera Staphylinidae Oxytelus exiguus

Coleoptera Staphylinidae Philonthus blandus

Coleoptera Staphylinidae Philonthus cyanipennis

Coleoptera Staphylinidae Philonthus sp.

Coleoptera Staphylinidae Platydracus fossator

Coleoptera Staphylinidae Platydracus maculosus

Coleoptera Staphylinidae Tachinus fimbriams

Coleoptera Staphylinidae Undet. sp. 1

Coleoptera Staphylinidae Undet. sp. 2

Coleoptera Staphylinidae Undet. sp. 3

Coleoptera Staphylinidae Undet. sp. 4

Coleoptera Staphylinidae Undet. sp. 5

Coleoptera Staphylinidae Undet. sp. 6

Coleoptera Staphylinidae Undet. sp. 7

Coleoptera Staphylinidae Undet. sp. 8

Coleoptera Staphylinidae Undet. sp. 9

Coleoptera Staphylinidae Undet. sp. 10

Coleoptera Staphylinidae Undet. sp. 11

Coleoptera Tenebrionidae Anaedus brunneus

Coleoptera Troginae Trox variolatus

Siphonaptcra Ctenophthalmidae Ctenophthalmus sp.

Diptera Calliphoridae Undet. sp.

Diptera Cecidomyiidae Undet. sp.

Diptera Chironomidae Undet. sp.

Diptera Chloropidae Undet. sp.

Diptera Drosophilidae Undet. sp.

Diptera Muscidae Undet. sp.

Diptera Otitidae Undet. sp.

Diptera Phoridae Undet. sp.

Diptera Psychodidae Undet. sp.

Diptera Rhagionidae Undet. sp.

Diptera Sarcophagidae Undet. sp.

Diptera Sciaridae Undet. sp.

Diptera Sphacroceridae Undet. sp.

Diptera Tachinidae Undet. sp.

Diptera Tipulidae Undet. sp.

Hymenoptera Eulophidae Undet. sp.

Hymenoptera Formicidae Amblyopone pallips

Hymenoptera Formicidae Aphaenogaster lamellidens

Hymenoptera Formicidae Aphaenogaster tennesseensis

Hymenoptera Formicidae Aphaenogaster texana var.

Hymenoptera Formicidae Brachymyremx heeri depilis

Hymenoptera Formicidae Camponotus caryae

Hymenoptera Formicidae Camponotus chromaiodes

Hymenoptera Formicidae Camponotus herculeans

Hymenoptera Formicidae Crematogaster lineolata

Hymenoptera Formicidae Formica fusca

Hymenoptera Formicidae Formica fusca var. subsericea

Hymenoptera Formicidae Formica pallide-fulva

 schafussi var. dolosa

Hymenoptera Formicidae Leptothorax pergandei

Hymenoptera Formicidae Leptothorax tennesseensis

Hymenoptera Formicidae Myrmecina graminicola americana

Hymenoptera Formicidae Neivamyrmex nigresens

Hymenoptera Formicidae Paratrechina terricola

Hymenoptera Formicidae pheidole dentata

Hymenoptera Formicidae Ponera pennsylvanica

Hymenoptera Formicidae Prenolepis imparis

Hymenoptera Formicidae Prenolepis imparis var. pumila

Hymenoptera Formicidae Prenolepis imparis var. testacea

Hymenoptera Formicidae Pyramica pergandei

Order Author No. Collected

Diplura 1

Microcoryphia (Pack.) 1

Thysanura (L.) 2

Orthoptera 5

Orthoptera 1

Orthoptera 3

Orthoptera 1

Blattaria (Brunner) 4

Blattaria (Saussure and Zehntner) 1

Isoptera 1

Plecoptera 1

Psocoptera 1

Psocoptera 2

Hemiptera 1

Hemiptera 1

Hemiptera 1

Hemiptera 1

Hemiptera 1

Hemiptera 1

Hemiptera 1

Thysanoptera 1

Neuroptera 1

Neuroptera (F.) 1

Coleoptera Horn 4

Coleoptera 1

Coleoptera 1

Coleoptera Say 2

Coleoptera LeConte 5

Coleoptera Bousquet 12

Coleoptera Freitag 15

Coleoptera (Say) 4

Coleoptera (LeConte) 4

Coleoptera Laferte 1

Coleoptera Say 4

Coleoptera Dejean 12

Coleoptera Bonelli 10

Coleoptera Drury 136

Coleoptera 1

Coleoptera Csiki 2

Coleoptera 1

Coleoptera 36

Coleoptera LeConte 1

Coleoptera (Say) 2

Coleoptera Newman 1

Coleoptera L. 1

Coleoptera LeConte 2

Coleoptera Dejean 17

Coleoptera Weber 5

Coleoptera 1

Coleoptera Baly 1

Coloptera (Say) 1

Coleoptera 1

Coleoptera 1

Coleoptera F. 1

Coleoptera 1

Coleoptera 1

Coleoptera 1

Coleoptera 1

Coleoptera (Say) 12

Coleoptera Boheman 2

Coleoptera (Roelofs) 7

Coleoptera Bedel 1

Coleoptera (Say) 3

Coleoptera (Herbst) 2

Coleoptera 1

Coleoptera 1

Coleoptera 1

Coleoptera LeConte 1

Coleoptera Say 3

Coleoptera (F.) 15

Coleoptera 9

Coleoptera 1

Coleoptera LeConte 1

Coleoptera 20

Coleoptera 1

Coleoptera 19

Coleoptera Say 1

Coleoptera 5

Coleoptera 1

Coleoptera 1

Coleoptera (LeConte) 6

Coleoptera (Marseul) 2

Coleoptera 3

Coleoptera 1

Coleoptera (Say) 1

Coleoptera 48

Coleoptera Meuller 1

Coleoptera 73

Coleoptera (F.) 1

Coleoptera (Randall) 18

Coleoptera 1

Coleoptera (Beauvois) 5

Coleoptera (F.) 2

Coleoptera (Say) 206

Coleoptera 1

Coleoptera (Gyllenhal) 1

Coleoptera 1

Coleoptera 54

Coleoptera 8

Coleoptera 3

Coleoptera (Newman) 7

Coleoptera Melsheimer 3

Coleoptera 1

Coleoptera 10

Coleoptera Weber 29

Coleoptera Forster 2

Coleoptera (Palisot de Beauvios) 87

Coleoptera (Drury) 23

Coleoptera (F.) 21

Coleoptera (Beauvois) 159

Coleoptera Panzer 5

Coleoptera 56

Coleoptera Harris 2

Coleoptera (Beauvois) 135

Coleoptera (Knoch) 1

Coleoptera (Knoch) 1

Coleoptera Zimmermann 9

Coleoptera 1

Coleoptera 2

Coleoptera Say 10

Coleoptera Herschel 1

Coleoptera LeConte 2

Coleoptera 1

Coleoptera Casey 64

Coleoptera 197

Coleoptera Erichson 218

Coleoptera Erichson 381

Coleoptera Erichson 2

Coleoptera (F.) 1

Coleoptera 1

Coleoptera Gravenhorst 22

Coleoptera Gravenhorst 20

Coleoptera Gravenhorst 33

Coleoptera 86

Coleoptera 6

Coleoptera 2

Coleoptera 17

Coleoptera 1

Coleoptera 9

Coleoptera 1

Coleoptera 1

Coleoptera 5

Coleoptera 8

Coleoptera 1

Coleoptera (Ziegler) 5

Coleoptera Melsheimer 1

Siphonaptcra 1

Diptera 1

Diptera 1

Diptera 1

Diptera 4

Diptera 1

Diptera 1

Diptera 1

Diptera 221

Diptera 5

Diptera 1

Diptera 2

Diptera 1

Diptera 1

Diptera 2

Diptera 1

Hymenoptera 1

Hymenoptera (Halderman) 3

Hymenoptera Mayr 695

Hymenoptera Mayr) 71

Hymenoptera Wheeler 2

Hymenoptera Emery 26

Hymenoptera (Fitch) 77

Hymenoptera Bolton 288

Hymenoptera DeGeer 741

Hymenoptera (Say) 16

Hymenoptera L. 28

Hymenoptera Say 90

Hymenoptera Wheeler 15

Hymenoptera Emery 1

Hymenoptera Cole 1

Hymenoptera Emery 25

Hymenoptera (Cresson) 87

Hymenoptera (Buckley) 63

Hymenoptera Mayr 1

Hymenoptera Buckley 9

Hymenoptera (Say) 36

Hymenoptera Wheeler 29

Hymenoptera Emery 1424

Hymenoptera (Emery) 5

TABLE 2. Mean ([+or-] SE) diversity indices for species collected
at each site in The University of Tennessee Forestry Experiment
Station and Arboretum(a), 1997 and 1998.

 Species Diversity (b) Species Richness

Cove 1.75 [+ or -] 0.05 a 44.14 [+ or -]0.52 a
Slope 1.44 [+ or -]0.05 b 38.68 [+ or -] 0.56 b
Open 1.56 [+ or -] 0.05 b 40.64 [+ or -] 0.55 ab
Tornado-damaged 1.51 [+ or -] 0.05 b 38.82 [+ or -] 0.54 b

 Species Evenness

Cove 0.67 [+ or -] 0.02 a
Slope 0.59 [+ or -] 0.02 b
Open 0.62 [+ or -] 0.02 b
Tornado-damaged 0.61 [+ or -] 0.02 b

(a) Data represent 22 collection dates from 26 June to 21 November 1997
and from 26 March to 26 August 1998. Means followed by the same letters
are not significantly different (LSD Test; P > 0.05).
(b) Shannon diversity index (H = - [contains as member of]
([p.sub.i]In[p.sub.i], where In = natural log and [p.sub.i] =
the proportion of
individuals of the total sample belonging to the [] species)
(Newell, 1997; Smith, 1992). Evenness (J) was determined by
J = H/[H.sub.max] using [H.sub.max] = InS where S = number of species
(Smith, 1992).

Thirty-two families of beetles were collected with 84% of the specimens collected in four families: Staphylinidae (43%), Scarabaeidae (21%), Carabidae (11%) and Nitidulidae (9%). Beetle species diversity and richness did not differ among the four sites. However, species evenness was significantly (P < 0.05) lower in the tornado-damaged site (0.89) when compared to the open site (0.95) (Table 3). The increased availability of habitats and food may have contributed to the lower species evenness value throughout the open site compared to the tornado-damaged site.
TABLE 3. Mean (+or- SE) diversity indices of beetle species collected
in pitfall traps at each site in The University of Tennessee Forestry
Experiment Station and Arboretum(a), 1997 and 1998.

 Species Diversity (b) Beetles Species Richness

Cove 0.94 [+ or -] 0.07 a 12.22+or- 0.30 a
Slope 0.81 [+ or -] 0.07 a 11.17 [+ or -] 0.33 a
Open 0.98 [+ or -] 0.07 a 11.29 [+ or -]0.31 a
Tornado-damaged 0.95 [+ or -] 0.07 a 10.96 [+ or -] 0.30 a

 Species Evenness

Cove 0.92 [+ or -] 0.01 ab
Slope 0.92 [+ or -] 0.02 ab
Open 0.95 [+ or -] 0.01 a
Tornado-damaged 0.89 [+ or -] 0.01 b

(a) Data represent 22 collection dates from 26 June to 21 November
1997 and from 26 March to 26 August 1998. Means followed by the
same letter do not differ significantly (LSD Test; P > 0.05)
(b) Shannon diversity index (H-_[contains as member](p.sub.i],
where In = natural log and [p.sub.i] = the proportion of individuals
of the total sample belonging to the []species) (Newell, 1997
Smith, 1992). Evenness (J) was determined by J = H/[H.sub.max] using
[H.sub.max] = InS where S = number of species (Smith, 1992).

No significant differences were noted for the number of insect species collected from underneath the canopy of sugar maple, tulip popular, or white oak. Differences were found, however, for beetles in relation to host tree. Significantly (P< = 0.05) greater numbers of beetles were collected under sugar maple and fewer under tulip poplar. However, the number of beetles collected under white oak did not differ significantly (P< 0.05) from that obtained under sugar maple or tulip poplar trees. The higher number of beetle specimens collected under sugar maple may suggest that many species are attracted to its sugary sap when exposed on the surface (or to other insects that feed on these sugars). Sugar maple and white oak are generally shorter but have sparser and wider canopies than tulip poplar (Little, 1996). The large, dense canopy of sugar maple may provide more shelter for these ground-dwelling insects. White oak also has many wide-spreading branches and a rounded crown. Conversely, the tulip poplar has a long, straight trunk and a narrow crown occurring high above the forest floor (Little, 1996). This tree may not provide as much shelter for ground dwellers and may be the reason fewer beetles were collected in pitfall traps associated with this tree species.


The higher species diversity and evenness in the cove site was most likely a result of the site's sheltered location and higher moisture levels compared to the other three sites. Beetle species diversity and richness did not differ significantly (P >0.05) among the four sites, although species evenness was significantly (P <0.05) higher in the open site and lower in the tornado-damaged site. Also, more beetles were collected in pitfall traps placed under sugar maple, and significantly fewer were collected under tulip poplar. Pitfall traps placed under white oak did not yield significantly different numbers of beetles in comparison to the other two tree species.

These forest habitats provide a stable community with many different guilds represented. Although various arthropod sampling techniques exist, the use of pitfall traps is an effective and uniform means of collecting ground-dwelling arthropods (Topping and Sunderland, 1992). For example, the carabid beetle, Calosoma sycophanta L., is a gypsy moth predator that has successfully colonized in North America (Leonard, 1981). Calosoma sycophanta was imported into the United States from central Europe between 1906 and 1926 (Spieles and Horn, 1998) and released in New England as a biological control agent for the gypsy moth. Since its introduction, it has been helpful in reducing gypsy moth outbreaks (Bess, 1961; Weseloh, 1985, 1990), but it has a substantial impact on gypsy moth populations beginning two or more years after the initial outbreak (Spieles and Horn, 1998). Ward et al. (2001) demonstrated that widely spacing pitfall traps at the sample site provided a more effective means of sampling some insects, such as beetles. Similar analyses performed on data collected after the gypsy moth is established in eastern Tennessee will better quantify the impact of this invasive, introduced pest on native southern Appalachian forests as well as the impact of potential biological control agents on this important pest species.


We are grateful to R. Evans and M. Young at The University of Tennessee Forestry Experiment Station and Arboretum for providing research sites and assisting throughout this research.


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North Carolina State University, Center for Integrated Pest Management, Raleigh. NC 27606 (MMG) The University of Tennessee. Department of Entomology and Plant Pathology. Knoxville, TN 37996 (PLL, JFG) The University of Tennesse, Departnent of Animal Science, Knoxville, TN 37996 (AS)
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Author:Gibbs, M. M.; Lambdin, P. L.; Grant, J. F.; Saxton, A. M.
Publication:Journal of the Tennessee Academy of Science
Article Type:Report
Geographic Code:1U6TN
Date:Jul 1, 2007
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