Kenneth W. McCravy

Assessing bee (Hymenoptera: Apoidea) diversity of an Illinois restored tallgrass prairie: methodology and conservation considerations

Bee species diversity and the effectiveness of four sampling methods were investigated in a west-central Illinois restored tallgrass prairie. Bees were sampled using malaise traps, ground-level pan traps, elevated pan traps, and vane traps. A total of 4,622 bees representing 31 genera and 111 species were collected. Malaise traps collected the greatest number of bees and species, and ground-level pan traps the least. Among the pan traps and vane traps, blue-colored traps collected the greatest abundance and species richness, and yellow traps the least. Chao1 estimator and rarefaction analyses showed that substantial increases in sample sizes would be necessary to achieve asymptotic species richness levels, particularly if ground-level pan traps alone were used. Elevated pan traps and vane traps collected relatively similar species composition. Different colored pan traps at the same height collected more similar species composition than did those at different heights, but species composition of blue ground-level pan traps was relatively similar to elevated pan traps, regardless of color. Indicator species analysis revealed 22 species that were significantly associated with a specific trap type, and 11 species that were associated with a particular pan trap color/elevation. Results of this study show that elevated traps can increase the effectiveness of bee surveys in tallgrass prairie, and that a combination of trap types gives a more complete picture of the bee fauna than does a single survey method. These results should be considered along with cost, ease of use, and goals when planning and designing bee inventories.

Carabid beetles (Coleoptera: Carabidae) of the Midwestern United States: a review and synthesis of recent research

Carabid beetles comprise a diverse and ubiquitous family of insects. Carabids are important in conservation biology and often have close associations with particular habitat types, making them useful biomonitoring organisms. Many carabids are also important biological control agents due to their predatory habits, but feeding habits within the family are quite diverse, and seed-eating or granivorous carabids can play an important role in shaping plant diversity and distributions. These qualities have particular relevance in the highly cultivated and fragmented landscape of the Midwestern U.S., and this region has become a very active one for carabid research in a variety of areas. In this paper, we review the state of carabid research in the Midwestern U.S., focusing on work published since the mid-1990s in carabid biogeography, conservation biology, biological control/pest management, feeding ecology and parasitism/health. Potentially productive directions for future research are discussed.

The nantucket pine tip moth (Lepidoptera: Torticidae): a literature review with management implications

The Nantucket pine tip moth, Rhyacionia frustrana (Comstock), an important pest of intensively-managed loblolly pine, Pinus taeda L., was first noted in the scientific literature in 1879. This pest gained notoriety with the establishment of loblolly pine monocultures throughout the southeastern United States during the 1950s. Current intensive forest management practices have led to increasing interest in managing this insect. Herein we review all Nantucket pine tip moth literature (1879-2002) by addressing the following subjects: biology and life history, natural enemies, sampling methodologies, site and stand influences, economic impact, and management strategies. Further, we provide management recommendations in the form of a decision chart that is based upon the best available information to date and our collective experience.

EFFECTS OF VEGETATION CONTROL ON PARASITOIDS OF THE NANTUCKET PINE TIP MOTH, RHYACIONIA FRUSTRANA (LEPIDOPTERA: TORTRICIDAE)

The Nantucket pine tip moth (Rhyacionia frustrana (Comstock)) is host to numerous parasitoid species that can cause substantial moth mortality. Little is known regarding the effects of forest management practices on these parasitoids. Abundance of parasitoids and parasitism rates, based on rearing of adult moths and parasitoids, were compared in herbicide-treated and untreated loblolly pine, Pinus taeda L., stands in the southeastern Georgia coastal plain. Three parasitoids, Lixophaga mediocris Aldrich, Eurytoma pini Bugbee, and Hyssopus rhyacioniae Gahan accounted for over 70% of total parasitism. Parasitism rates did not differ significantly between treated and untreated plots. Tip moth damage was higher in the untreated plots. Malaise trapping of parasitoids yielded no significant difference in numbers of tip moth parasitoids or total parasitoids captured in treated and untreated plots, suggesting a functional response of parasitoids to tip moth densities. Higher levels of naturally occurring vegetation did not improve tip moth control through increased parasitism rates.

Diversity of Ground Beetles (Coleoptera: Carabidae) in Relation to Habitat Type in West-Central Illinois

Abstract The diversity of ground beetles in relation to habitat type was investigated in west-central Illinois from May to Oct. 2005 and 2006 using pitfall traps in six habitats: (1) prairie burned in 2004, (2) prairie burned in 2005, (3) early successional forest, (4) oak-hickory forest burned in 2004, (5) oak-hickory forest burned in 2005 and (6) oak-hickory forest burned in 2006. A total of 2712 ground beetles representing 28 genera and 54 species were collected. A multi-response permutation procedure showed significant differences in ground beetle assemblages among habitat types. Nonmetric multidimensional scaling and analysis of similarity supported the findings of MRPP. Indicator species analysis found significant habitat associations for seven species of carabids in 2005 and eight species in 2006. Forest habitats generally had lower species richness than expected based on rarefaction. The effects of fire on prairie carabid assemblages and detrimental effects on individual species appeared to be short-lived. There was little difference in carabid faunas inhabiting oak-hickory stands with different burn histories, but early successional hardwood forest fragments harbored several carabid indicator species.

Malaise Trap Sampling Efficiency for Bees (Hymenoptera: Apoidea) in a Restored Tallgrass Prairie

Summary Effective assessment of bee (Hymenoptera: Apoidea) diversity is essential for informed bee conservation policies. In this study, the effectiveness of Malaise traps in assessing bee species richness in a westcentral Illinois restored prairie was examined using the Chao1 nonparametric richness estimator. Individual traps varied greatly in abundance and species richness of bees collected, and substantially greater trapping effort would have been needed to achieve Chao1 estimates. Malaise traps provide a potentially effective means of augmenting bowl trap inventories, but more studies on Malaise trap performance and comparisons with bowl traps are needed, particularly in heterogeneous environments.

Diversity, Seasonal Activity and Habitat Associations of Robber Flies (Diptera: Asilidae) in West-Central Illinois

Abstract Robber fly diversity, seasonal activity and habitat associations were studied in prairie and forest habitats in west-central Illinois from May to Oct. 2005. The greatest numbers of individuals and species were collected in recently burned prairie and forest habitats, although richness in the recently burned prairie was lower than expected based on rarefaction. Six of the eight most abundant species had primarily mid-season or earlier flight activity patterns; the other two species were mid- to late or late season fliers. There was significant variation in robber fly species composition among habitats. Forest habitats had greater within-habitat variation in species composition than did prairie habitats. Three indicator species (Cerotainia macrocera Say, Nerax aestuans (L.) and Promachus hinei Bromley) were found, all for prairie habitats. Two species (Ommatius ouachitensis Bullington & Lavigne and P. hinei) showed significant sex-related variation in habitat associations. These results show that significant variation in robber fly assemblages can occur over relatively small geographic areas and that fire may affect robber fly abundance and diversity.

Parasitoids of the Nantucket pine tip moth (Lepidoptera: Tortricidae) in the coastal plain of Georgia.

Parasitism of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), was studied for four consecutive generations in the Georgia coastal plain by collecting tip moth-infested shoots and rear...

An Analysis of Malaise-Trap Effectiveness in Assessing Robber Fly (Diptera: Asilidae) Species Richness

Abstract Little quantitative information is available on the effectiveness of Malaise traps in estimating insect species richness. I used the Chao1 nonparametric species richness estimator to evaluate the effectiveness of Malaise traps in assessing species richness of robber flies in west-central Illinois burned and unburned deciduous forest and tallgrass prairie habitats. Two of 12 traps yielded asymptotic species richness values, with remaining traps requiring fold increases ranging from 3.1 to 20.9 to reach asymptotic richness. Overall, observed species richness was over 85% of estimated species richness, but a 3.9-fold sample-size increase would have been required to reach asymptotic species richness. For individual habitats, estimated fold increases in sample size ranging from 1.9 to 9.7 would have been needed to reach asymptotic species richness. These results show that Malaise traps are effective in sampling robber flies, but asymptotic species richness would be difficult to achieve. Lower target coverage levels may be practical in terms of sampling effort and cost, and use of complementary sampling methods could improve the completeness of inventories.

Variation in Developmental Synchrony of the Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) with Implications for Chemical Control

Regional variation in developmental phenology of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), was studied at four locations in southeastern Virginia and northeastern North Carolina...