James L. Hanula

Efficiency of Malaise traps and colored pan traps for collecting flower visiting insects from three forested ecosystems

Pan and Malaise traps have been used widely to sample insect abundance and diversity, but no studies have compared their performance for sampling pollinators in forested ecosystems. Malaise trap design and color of pan traps are important parameters that influence insect pollinator catches. We compared pan trap (blue, yellow, white, and red) and Malaise trap catches from forests in three physiographic provinces (Piedmont, Coastal Plain, and Blue Ridge) of the southeastern United States. Similarities in trap performance between sites were observed with blue pan traps being most effective overall. Our results showed that various pollinator groups preferred certain pan trap colors and that adding color to Malaise traps influenced insect pollinator catches. However, pan traps generally caught more pollinators than Malaise traps. Because of their low cost and simplicity, using several colors of pan traps is an effective way to sample relative abundance and species richness of flower-visiting insects.

Biology and host associations of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae), exotic vector of laurel wilt killing redbay trees in the Southeastern United States

Abstract The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), and its fungal symbiont, Raffaelea sp., are new introductions to the southeastern United States responsible for the wilt of mature redbay, Persea borbonia (L.) Spreng., trees. In 2006 and 2007, we investigated the seasonal flight activity of X. glabratus, its host associations, and population levels at eight locations in South Carolina and Georgia where infestations ranged from very recent to at least several years old. Adults were active throughout the year with peak activity in early September. Brood development seems to take 50–60 d. Wood infested with beetles and infected with the Raffaelea sp. was similar in attraction to uninfested redbay wood, whereas both were more attractive than a nonhost species. Sassafras, Sassafras albidium (Nutt.) Nees, another species of Lauraceae, was not attractive to X. glabratus and very few beetle entrance holes were found in sassafras wood compared with redbay. Conversely, avocado, Persea americana Mill., was as attractive to X. glabratus as swampbay, P. palustris (Raf.) Sarg., and both were more attractive than the nonhost red maple, Acer rubrum L. However, avocado had relatively few entrance holes in the wood. In 2007, we compared X. glabratus populations in areas where all mature redbay have died to areas where infestations were very active and more recent. Trap catches of X. glabratus and numbers of entrance holes in trap bolts of redbay were correlated with the number of dead trees with leaves attached. Older infestations where mature host trees had been eliminated by the wilt had low numbers of beetles resulting in trap catches ranging from 0.04 to 0.12 beetles per trap per d compared with 4–7 beetles per trap per d in areas with numerous recently dead trees. Our results indicate beetle populations drop dramatically after suitable host material is gone and provide hope that management strategies can be developed to restore redbay trees. The lack of attraction of X. glabratus to sassafras suggests that spread of X. glabratus may slow once it is outside the range of redbay.

A comparison of the Beetle (Coleoptera) Fauna Captured at two heights above the ground in a North American temperate deciduous forest

ABSTRACT We compared the beetle fauna captured in 12 pairs of flight intercept traps suspended at two different heights above the ground (≥15 m and 0.5 m) in a temperate deciduous forest in the southeastern United States to better understand how the abundance, species richness, diversity and composition of insect communities differ among forest strata. A total of 15,012 beetle specimens were collected representing 73 families and 558 morphospecies. Shannons diversity and evenness were both higher near the ground than in the canopy, but no differences in total abundance or species richness between the two layers were observed. There were many differences at the family level, however, and species composition differed considerably between the two layers. About 29% and 31% of species were captured exclusively in the canopy or near the ground, respectively. The canopy traps were more similar to one another than they were to those near the ground and vice-versa based on both Sorensens quotient of similarity and Raabes percentage of similarity. The canopy and ground trap locations were quite distinct based on nonmetric multidimensional scaling. The degree to which species composition was similar (i.e., Sorensens quotient of similarity) between pairs of traps decreased significantly with inter-trap distance for the traps in the canopy, but not for those near the ground, suggesting a more uniform community near the ground. Of the 41 families or subfamilies represented by more than 40 individuals, 12 were more abundant in the canopy and 14 were more abundant near the ground. Similarly, of the 16 families or subfamilies represented by more than 10 species, five were more species rich in the canopy and four were more species rich near the ground. Three families (Cerambycidae, Cleridae and Coccinellidae) were both more abundant and species rich in the canopy, whereas four other groups (Carabidae, Pselaphinae (Staphylinidae), Scolytinae (Curculionidae) and other Staphylinidae) were both more abundant and species rich near the ground. In addition to differing considerably among families, the vertical distribution patterns varied within many families as well. The distribution patterns for several groups are discussed in some detail with respect to known life history information.

The Biology and Preliminary Host Range of Megacopta cribraria (Heteroptera: Plataspidae) and Its Impact on Kudzu Growth

ABSTRACT The bean plataspid, Megacopta cribraria (F.), recently was discovered in the United States feeding on kudzu, Pueraria montana Lour. (Merr.) variety lobata (Willd.), an economically important invasive vine. We studied its biology on kudzu and its impact on kudzu growth. We also tested its ability to use other common forest legumes for oviposition and development. Flight intercept traps operated from 17 May 2010 to 31 May 2011 in a kudzu field near Athens, GA showed three peaks of adult flight activity suggesting there are two generations per year on kudzu. Vine samples examined for eggs from April 2010 to April 2011 and June to October 2011 showed two periods of oviposition activity in 2010, which coincided with the peaks in adult activity. In 2011, the second period of oviposition began on or before 24 June and then egg abundance declined gradually thereafter until late August when we recovered <2 eggs/0.5 m of vine. Samples of the five nymphal instars and adults on vines did not show similar trends in abundance. Adults did not lay eggs on the various legume species tested in 2010 in a no-choice test possibly because the cages were too small. In the 2011 field host range experiments conducted in a kudzu field by using 12 legume species, M. cribraria preferentially oviposited on kudzu over soybean, Glycine max Merrill, but they still laid 320 eggs per plant on soybean. Lespedeza hirta (L.) Hornem. and Lespedeza cuneata (Dum. Cours.) G. Don had 122.2 and 108.4 eggs per plant, respectively. Kudzu and soybean were the only species M. cribraria completed development on. Plots protected from M. cribraria feeding by biweekly insecticide applications had 32.8% more kudzu biomass than unprotected plots. Our results show that M. cribraria has a significant impact on kudzu growth and could help suppress this pest weed.

Manuka oil and phoebe oil are attractive baits for Xyleborus glabratus (Coleoptera: Scolytinae), the vector of laurel wilt.

Abstract Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a native of Southeast Asia recently established in coastal forests of Georgia, SC and Florida. It vectors a wilt fungus, Raffaelea sp., lethal to redbay trees, Persea borbonia L. Spreng, and certain other Lauraceae. No practical monitoring system exists for this beetle so we conducted studies to identify host attractants and develop lures. Volatiles were collected from redbay wood and bark by steam distillation, direct solvent extraction, and dynamic headspace sampling with a Poropak Q cartridge. Steam, methanol, and pentane extracts were tested as baits in trapping trials but were not attractive to X. glabratus. Major constituents in Poropak aerations identified by gas chromatography-mass spectrometry included α-pinene, β-pinene, δ-3-carene, eucalyptol, p-cymene, α-copaene, terpinene-4-ol, linalool, calamenene, and nonanoic acid. We assayed several of these compounds (including eucalyptol, p-cymene, terpinene-4-ol, linalool, nonanoic acid, and caryophyllene oxide) both individually and in combination, but none were attractive at tested doses. Two other redbay odor components, α-copaene and calamenene, were unavailable in sufficient quantities commercially so we substituted manuka oil, the essential oil extracted from Leptospermum scoparium Forst. and Forst., which contains high proportions of both compounds. Manuka oil was equally attractive as redbay wood to X. glabratus, but increasing release rates >10-fold did not enhance its activity. Phoebe oil, an extract of Brazilian walnut (Phoebe porosa Mez.), which contains significant quantities of α-copaene and calamenene, was also attractive. Fractions of manuka oil were not more attractive than the whole oil. Manuka and phoebe oil are readily available and are good alternatives to redbay wood as a trap bait for monitoring X. glabratus distribution and population trends.

Influence of long-term dormant-season burning and fire exclusion on ground-dwelling arthropod populations in longleaf pine flatwoods ecosystems

Abstract Frequent dormant-season prescribed burns were applied at 1-, 2- and 4-year intervals to longleaf pine stands, Pinus palustris , for over 40 years on the Osceola National Forest in Baker County, Florida. Control plots were unburned for the same period of time. Pitfall traps were operated from November 1994 to October 1999 to measure the short- and long-term effects of prescribed burning frequency on the relative abundance and diversity of ground-dwelling macroarthropods. We also measured dead and live plant biomass to determine how long-term frequent fires affected the structure of the forest floor. The average total dead plus live plant biomass was significantly higher on plots where fire had been excluded. Annual and biennial burning resulted in about the same amount of total plant biomass (dead and live plant material combined) which was significantly less than the quadrennially burned plots. Shannon diversity ( H ′) and evenness of ground-dwelling arthropods were reduced by burning. Annually burned plots had the lowest diversity and evenness while biennially and quadrennially burned plots also were significantly lower than unburned control plots. Dormant-season burning did not increase the number of rare genera regardless of frequency. Percent similarity of arthropod communities was highest for comparisons between plots that had been burned (60–68%) and lowest for the comparison of annually burned plots to unburned controls (37%). Examination of diversity and similarity through time showed that changes were due to short-term effects caused by the application of fire and not long-term changes in the ground-dwelling arthropod community. Burning significantly reduced the numbers of predators regardless of fire frequency and resulted in an increased number of detritivores. A total of 42 genera were reduced by prescribed burning; 32 genera were captured in greater numbers on annually burned plots, and 11 genera had higher numbers in one or both of the intermediate burn frequencies (biennial or quadrennial). Twenty-six genera were captured in equal numbers on quadrennially and annually burned plots, but in significantly lower numbers than on unburned plots, demonstrating that 4 years was insufficient time for their populations to recover from mild dormant-season fires. Arthropod response to burning appeared to be species specific so attempts to generalize how arthropods will respond based on a few species or groups should be avoided. The slow recovery rate of so many species suggests that management oriented toward conservation of biodiversity in longleaf pine flatwoods should include areas of fire exclusion.

Chinese Privet (Ligustrum sinense) Removal and its Effect on Native Plant Communities of Riparian Forests

Abstract Chinese privet is a major invasive shrub within riparian zones throughout the southeastern United States. We removed privet shrubs from four riparian forests in October 2005 with a Gyrotrac® mulching machine or by hand-felling with chainsaws and machetes to determine how well these treatments controlled privet and how they affected plant community recovery. One year after shrub removal a foliar application of 2% glyphosate was applied to privet remaining in the herbaceous layer. Three “desired-future-condition” plots were also measured to assess how well treatments shifted plant communities toward a desirable outcome. Both methods completely removed privet from the shrub layer without reducing nonprivet shrub cover and diversity below levels on the untreated control plots. Nonprivet plant cover on the mulched plots was > 60% by 2007, similar to the desired-future-condition plots and higher than the hand-felling plots. Both treatments resulted in higher nonprivet plant cover than the untreated controls. Ordination showed that after 2 yr privet removal plots were tightly grouped, suggesting that the two removal techniques resulted in the same plant communities, which were distinctly different from both the untreated controls and the desired-future-condition. Both treatments created open streamside forests usable for recreation and other human activities. However, much longer periods of time or active management of the understory plant communities, or both, will be required to change the forests to typical mature forest plant communities. Nomenclature: Glyphosate; Chinese privet, Ligustrum sinense Lour.

Source, distribution and abundance of macroarthropods on the bark of longleaf pine: potential prey of the red-cockaded woodpecker

Abstract Arthropod diversity, abundance and biomass on 50–70-year-old longleaf pine (Pinus plalustris) tree boles were examined to determine the origin of the prey available to the endangered red-cockaded woodpecker (Picoides borealis) and the variability of this prey over time. Traps designed to capture arthropods crawling on the bark (crawl traps), alighting on the bark (flight traps), and crawling on the ground (pitfall traps) were operated continuously for 12 months. Flight and crawl traps were placed at different heights. One-half of the trees with crawl traps were fitted with a barrier to prevent arthropods from crawling up from the ground. Arthropods were identified to genus from one weekly sample per month and subsamples were oven-dried and weighed to estimate biomass. The arthropod community on the bark included over 400 genera. Crawl trap captures were the most similar to the prey of P. borealis. Arthropod fauna captured in crawl traps had a 58% similarity to pitfall trap captures and a 60% similarity with flight trap captures. Flight and pitfall trap captures had a 10% similarity. Barriers to arthropod movement up the tree reduced the arthropod biomass on the bole of the trees by 40–70%. Arthropod biomass was relatively evenly distributed over the tree, but varied seasonally with the highest biomass captured in the fall of the year. In general, the study showed that little of the arthropod biomass on the bark is in the form of arthropods that live exclusively in that habitat and that a large portion of the biomass is crawling up from the soil/litter layer.

Responses of Arthropods to large scale manipulations of dead wood in loblolly pine stands of the southeastern United States

ABSTRACT Large-scale experimental manipulations of dead wood are needed to better understand its importance to animal communities in managed forests. In this experiment, we compared the abundance, species richness, diversity, and composition of arthropods in 9.3-ha plots in which either (1) all coarse woody debris was removed, (2) a large number of logs were added, (3) a large number of snags were added, or (4) no coarse woody debris was added or removed. The target taxa were ground-dwelling arthropods, sampled by pitfall traps, and saproxylic beetles (i.e., dependent on dead wood), sampled by flight intercept traps and emergence traps. There were no differences in total ground-dwelling arthropod abundance, richness, diversity, or composition among treatments. Only the results for ground beetles (Carabidae), which were more species rich and diverse in log input plots, supported our prediction that ground-dwelling arthropods would benefit from additions of dead wood. There were also no differences in saproxylic beetle abundance, richness, diversity, or composition among treatments. The findings from this study are encouraging in that arthropods seem less sensitive than expected to manipulations of dead wood in managed pine forests of the southeastern United States. Based on our results, we cannot recommend inputting large amounts of dead wood for conservation purposes, given the expense of such measures. However, the persistence of saproxylic beetles requires that an adequate amount of dead wood is available in the landscape, and we recommend that dead wood be retained whenever possible in managed pine forests.

Longleaf pine characteristics associated with arthropods available for Red-Cockaded Woodpeckers

Red-cockaded woodpeckers (Picoides borealis) forage on the boles of living pine trees for a variety of arthropods. To assess the availability of prey under differing stand conditions, we sampled arthropods that crawled up the boles of 300 living longleaf pine trees (Pinus palustris) ranging in age from 20-100 years with passive traps over a 1-year period. We identified, counted, ovendried, and weighed >50.000 arthropods in 22 orders and 470 genera. The most diverse orders were the Coleoptera (beetles), Araneae (spiders), and Hymenoptera (ants, wasps and bees). The most abundant orders were the Homoptera with large numbers of aphids (Aphididac) and the Hymenoptera with large numbers of ants (Formicidae) The Coleoptera and Araneae accomted for the greatest available biomass. Overall, arthropod biomass/tree increased with increasing stand age up to approximately 65-70 years. Init arthropod biomass/ha was highest in the youngest stands Abundance and biomass of arthropods on each tree bole were positively correlated with bark thickness and tree diameter, and negatively correlated with basal area (m 2 /ha). Arthropod biomass differed among seasons. with the highest arthropod biomass occurring in winter and spring. We found no correlation of diversity. abandance, or biomass of arthropods on the tree bole with site index. the numbers of herbaceous plant genera in the understory, the number of herbaceous plant stems, or the percentage of ground covered by herbs. Stand characteristics, such as average bark thickness and diameter, associated with increased arthropod abundance and biomass on the bark are positively correlated to tree age, but these relationships would change with management practices that either accelerated or slowed tree growth.