Progress 11/20/02 to 09/30/08
Outputs
OUTPUTS: My lab assessed how insect defoliation of oaks affects tree growth and vigor. Root starch concentrations in defoliated trees were evaluated as an indication of tree vigor. I investiged ecological interactions and impacts associated with an exotic species, the Asian chestnut gall wasp. The gall wasp is expanding its North American distribution, recruiting native natural enemies and altering ecological interactions. Gall development on various chestnut species, and the role of plant signaling compounds in the defense response of chestnut, were evaluated. In collaboration with the Dept. of Forestry, we used remote sensing technology to evaluate the distribution of hemlock resources in Kentucky, and predicted how the hemlock woolly adelgid, an exotic invasive herbivore, could threaten those resources. My lab established long-term monitoring plots to assess the ecological effects of the adelgid. We assessed vegetative composition, forest structure, light penetration, soil characteristics, foliar characteristics, and effects on aquatic organisms in hemlock stands prior to arrival of the adelgid, and re-measured the same parameters as the adelgid became established. Forest composition and structure were correlated with topographic features to assess the combination of biotic and abiotic factors that put hemlocks most at risk for widespread mortality. We modeled how adelgid-induced loss of hemlocks might affect future forest structure and composition. Collectively our results are designed to provide land managers with a snapshot of how post-adelgid forests will appear, determine characteristics of hemlock stands most at risk of widespread mortality, and prioritize resources needed to save our hemlocks. We worked to perfect a hemlock woolly adelgid-specific monoclonal antibody, so as to assess the extent to which native predators influence adelgid populations. Focusing specifically on the spider community associated with hemlocks, we evaluated the extent that these predators utilize adelgid as prey. An understanding of the predator-prey relationships associated with the adelgid gives us additional tools to develop viable management options. The plant-insect interface was evaluated for the hemlock-hemlock woolly adelgid system. In collaboration with the Department of Materials Science, we evaluated species-specific differences in the micromechanical properties of the feeding site in hemlocks ranging from highly susceptible to highly resistant. My lab also evaluated nutritional differences among hemlock species. In an effort to better understand the relationships that exist between bats, nocturnal insects, and their forest environment, the Forest Entomology and Wildlife Ecology labs comprehensively surveyed these predator and prey groups in forests that vary in structure due to silvicultural treatments. We monitored insect activity and bat activity to evaluate trophic linkages in forests varying in structural complexity. We used a molecular approach to evaluate prey consumption by extracting and amplifying insect prey DNA from bat fecal samples. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Oak trees experiencing extensive defoliation have depleted starch reserves in their root systems. These effects are measurable 5 years following the defoliation event. This knowledge is useful to land managers in developing management plans to reduce the effects of insect outbreaks. Jasmonic acid (JA) induces production of defensive tannins in a species and tissue - specific manner. JA applied to American chestnut reduces suitability for Asian chestnut gall wasp, but does not affect adjacent foliage. JA applied to Chinese chestnut enhances suitability for the gall wasp, but also increases the defensive response in adjacent foliage. This work improves our understanding of defense responses in trees and the role of tannins in these defense responses, and also helps elucidate ecologically important differences in tannin induction and herbivore susceptibility in chestnut. Maps of eastern hemlock distribution were created using satellite imagery. The spread of HWA was assessed. Preliminary analysis indicates that replacement forests following hemlock woolly adelgid-induced hemlock mortality will be very different with respect to structure and composition. Few, large trees with a persistent canopy (hemlock) will be replaced with smaller, denser, deciduous trees, drastically changing species associations and the microclimate. Japanese hemlock, classified as adelgid-resistant, is micromechanically harder than its con-specifics tested.
Publications
- Coleman, T.W., J.R. Meeker, S.R. Clarke, and L.K. Rieske. 2008. Forest composition following overstory mortality from southern pine beetle and associated treatments. Canadian Journal of Forest Research 38, 1-13.
- Coleman, T.W., J.R. Meeker, S.R. Clarke, and L.K. Rieske. 2008. The suppression of Dendroctonus frontalis and subsequent wildfire have an impact on forest stand dynamics. Applied Vegetation Science 11, 231-242.
- Cooper, W.R. and L.K. Rieske. 2008. Differential responses in American (Castanea dentata Marshall) and Chinese (C. mollissima Blume) chestnut (Fagales: Fagaceae) to foliar application of jasmonic acid. Chemoecology 18, 121-127.
- Dodd, L.E., M.J. Lacki, and L.K. Rieske. 2008. Variation in moth occurrence and implications for foraging habitat of Ozark big-eared bats. Forest Ecology and Management 255, 3866-3872.
- Lensing, J.R., L.K. Rieske, C.W. Harper, J.T. Collins, and J.J. Obrycki. 2008. A tale of success: Preventing establishment of the gypsy moth in Kentucky. American Entomologist 54, 138-143.
- McEwan R.W., L.K. Rieske, and M.A. Arthur. 2008. Potential for interactions between invasive woody shrubs and the gypsy moth (Lymantria dispar), an invasive insect herbivore. Biological Invasions DOI 10.1007/s10530-008-9316-0.
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Progress 01/01/07 to 12/31/07
Outputs
We are investigating ecological interactions associated with an exotic invasive species, the Asian chestnut gall wasp. Molecular techniques are being used for parasitoid identification, for detailed examination of the effects of natural enemies in regulating gall wasp populations, with the goal of managing expanding gall wasp populations. The role of jasmonic acid, a plant signaling compound, in the defense response of chestnut is being studied. Jasmonic acid induces the production of defensive tannins in a species- and tissue-specific manner. JA applied to American chestnut reduces suitability for Asian chestnut gall wasp, but does not affect adjacent foliage. JA applied to Chinese chestnut enhances suitability for the gall wasp, and increases the defensive response in adjacent foliage, affecting subsequent herbivores. This improves our understanding of tree defenses and the role of tannins, and helps elucidate ecologically important differences in tannin induction
and herbivore susceptibility in Castanea. Long term monitoring plots to assess the ecological effects of the hemlock woolly adelgid, an exotic invasive herbivore that kills hemlocks, have been established. We are assessing vegetative composition and structure, light penetration, and soil and foliar characteristics in hemlock stands prior to arrival of the adelgid. Headwater stream quality is being monitored over a two year period to assess effects on aquatic and riparian invertebrates, and stream chemical and physical characteristics. Forest composition and structure will be correlated with topographic features to assess what factors put hemlocks most at risk for widespread mortality. Results will show land managers how post-adelgid forests will appear, determine characteristics of hemlock stands most at risk of widespread mortality, and prioritize resources to save our hemlocks. Mechanisms of hemlock resistance to the hemlock woolly adelgid are being investigated. Physical,
mechanical and phenological differences of the highly susceptible eastern hemlock are being measured and compared to adelgid-resistant Asian and western hemlocks. Phenological differences, characteristics of the feeding site,sap viscosity and chemical composition are being assessed. A hemlock woolly adelgid-specific monoclonal antibody, coupled with an ELISA, is being used to assess the extent to which predators consume adelgids and potentially influence adelgid populations. Our research will help minimize the effects of this invasive species on hemlock resources. In an effort to better understand the relationships that exist between forest-dwelling bats, nocturnal insects, and their forest environment, the forest entomology and wildlife ecology labs are comprehensively surveying these predator/prey groups in forests that vary in structure. We are isolating prey DNA from bat fecal material to more accurately assess bat consumption of insects. Prey DNA has been successfully isolated
from bat feces, and selection of appropriate primers is underway to refine molecular identification. These results will help natural resource managers protect potentially endangered species.
Impacts
Research on natural enemy recruitment by expanding populations of the exotic Asian chestnut gall wasp could lead to potential biological control of the gall wasp, minimizing its impact in commercial chestnut production and restoration efforts for the American chestnut. Herbivore susceptibility in chestnut has not been fully investigated. Our work on jasmonic acid-dependent defenses and the role of tannins in these defense responses enhances our understanding of chestnut-herbivore interactions and woody plant defenses, and also helps elucidate ecologically important species-specific and tissue-specific differences in tannin induction. The effects of invasion by an exotic insect on an ecologically unique forest ecosystem are being evaluated. Long term monitoring plots to assess the effects of the exotic invasive hemlock wooly adelgid will help determine the characteristics of hemlock forests most at risk of widespread mortality, and help prioritize resources needed to
save our hemlocks. Mechanisms of hemlock resistance to the invasive hemlock woolly adelgid are being investigated with the hope of employing some of these resistance mechanisms to save the eastern hemlock. Understanding the extent to which native natural enemies are able to exploit exotic invaders will provide additional tools for the development of viable management options, potentially minimizing the hemlock woolly adelgid's impact. Our research will help minimize the effects of this invasive species on our hemlock resources. Evaluating the distribution and occurrence of insect prey of forest dwelling bats, and how this prey base varies with forest disturbance, is an essential step in bat conservation. This work has implications with respect to forest stewardship and will help natural resource managers protect potentially endangered species.
Publications
- Rieske, L.K. 2007. Success of an exotic gallmaker, Dryocosmus kuriphilus, on chestnut in the USA: a historical account. Invited submission for the Bulletin of the European and Mediterranean Plant Protection Organization. EPPO Bulletin 37, 172-174.
- Rieske, L.K. and Dillaway, D.N. 2008. Response of two oak species to extensive defoliation: Tree growth and vigor, phytochemistry, and herbivore suitability. Forest Ecology and Management (Submitted).
- Cooper, W.R. and Rieske, L.K. 2007. Community associates of an exotic gallmaker, Dryocosmus kuriphilus, (Hymenoptera: Cynipidae) in eastern North America. Annals of the Entomological Society of America 100. 236-244.
- Dillaway, D.N., Stringer, J.W., and Rieske, L.K. 2007. Light availability influences root carbohydrates, and potentially vigor, in white oak seedlings. Forest Ecology and Management 250, 227-233.
- Dillaway, D.N., Stringer, J.W., and Rieske, L.K. 2008. Regenerative status of white oak (Quercus alba L.) advance regeneration affects response to increased light availability. Forest Ecology and Management (Submitted).
- Dodd, L.E., Lacki, M.J., and Rieske, L.K. 2008. Variation in moth occurrence and the implications for foraging habitat of the Ozark big-eared bat. Forest Ecology and Management (Under revision).
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Progress 01/01/06 to 12/31/06
Outputs
The Forest Entomology lab has been investigating ecological interactions associated with an exotic invasive species, the Asian chestnut gall wasp. Expanding populations of the exotic gall wasp are recruiting native and introduced natural enemies in North America. Consequences of this recruitment are being investigated in consideration of ecological interactions leading to potential biological control of the gall wasp, which could play a role in commercial chestnut production and restoration efforts for the American chestnut. The role of the plant signaling compound, jasmonic acid, in the defense response of chestnut is being studied. Jasmonic acid induces the production of tannins in a species and tissue - specific manner. JA applied to American chestnut reduces suitability for Asian chestnut gall wasp, but does not affect adjacent foliage. JA applied to Chinese chestnut enhances suitability for the gall wasp, but also increases the defensive response in adjacent
foliage. This improves our understanding of JA-dependent defenses in trees and the role of tannins in these defense responses, and also helps elucidate ecologically important differences in tannin induction and herbivore susceptibility in Castanea. We are establishing long term monitoring plots to assess the ecological effects of the hemlock wooly adelgid, an exotic invasive herbivore that kills hemlocks and was first reported in Kentucky in 2006. We are assessing vegetative composition, forest structure, light penetration, soil characteristics, foliar characteristics, and effects on aquatic organisms in hemlock stands prior to arrival of the adelgid. The same parameters will be re-measured as the adelgid moves through our hemlock forests. Forest composition and structure will be correlated with topographic features to assess the combination of biotic and abiotic factors that puts hemlocks most at risk for widespread mortality. Our results will provide land managers with a snapshot of
how post-adelgid forests will appear, determine characteristics of hemlock stands most at risk of widespread mortality, and prioritize resources needed to save our hemlocks. We are developing a hemlock wooly adelgid-specific monoclonal antibody, so we can assess the extent to which native predators influence adelgid populations. An understanding of the predator-prey relationships associated with the adelgid will give us additional tools for the development of viable management options, potentially minimizing the adelgid's impact. As the adelgid becomes established in Kentucky, it is expected to cause widespread hemlock mortality. Our research will help minimize the effects of this invasive species on our hemlock resources. In an effort to better understand the relationships that exist between bats, nocturnal insects, and their forest environment, the Forest Entomology and Wildlife Ecology labs are comprehensively surveying these predator and prey groups in forest systems that vary in
structure as a consequence of silvicultural treatments. Results have implications with respect to forest stewardship, and will help natural resource managers protect potentially endangered species.
Impacts
The work on jasmonic acid-dependent defenses in trees and the role of tannins in these defense responses enhances our understanding of woody plant defenses, and also helps elucidate ecologically important differences in tannin induction and herbivore susceptibility in Castanea. Research on the exotic Asian chestnut gall wasp natural enemy recruitment could lead to potential biological control of the gall wasp, minimizing its impact in commercial chestnut production and restoration efforts for the American chestnut. Long term monitoring plots to assess the ecological effects of the exotic invasive hemlock wooly adelgid will help determine the characteristics of hemlock stands most at risk of widespread mortality, and help prioritize resources needed to save our hemlocks. A more complete understanding of the predator-prey relationships associated with the adelgid will give us additional tools for the development of viable management options, potentially minimizing the
adelgid's impact. Our research will help minimize the effects of this invasive species on our hemlock resources. Forest Entomology and Wildlife Ecology labs are comprehensively surveying the insect prey and bat predator groups in forest systems that vary in structure as a consequence of silvicultural treatments. Our work has implications with respect to forest stewardship, and will help natural resource managers protect potentially endangered species.
Publications
- Coleman, T.W. and L.K. Rieske. 2006. Arthropod response to prescription burning at the soil-litter interface in oak-pine forests. Forest Ecology and Management 233, 52-60.
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Progress 01/01/05 to 12/31/05
Outputs
We are investigating the relationship between herbivory and disease resistance in chestnut, focusing on plant response to an exotic gallmaking insect. Activation of the plant signaling compound, jasmonic acid, produces a systemic response that increases total tannin production in foliage. Chestnut blight-susceptible American chestnut and blight-resistant Chinese chestnuts infested with the Asian chestnut gall wasp respond differently to topical applications of jasmonic acid. American chestnut shoots treated with jasmonic acid produced smaller galls with higher gall wasp mortality, but with no affect on associated foliage. Chinese chestnut shoots treated with jasmonic acid produced larger galls and experienced lower larval mortality, and foliar tannins increase. Gall abortion due to pathogen growth was decreased by jasmonic acid treatment on Chinese chestnut, but not on American chestnut. Leaf and gall tannin concentration is negatively correlated. Carbon and nitrogen
content are positively correlated in leaves directly attached to galls, but there is no correlation between carbon and nitrogen in the galls themselves, suggesting manipulation by the gall wasp. We are also monitoring the natural enemy complex associated with invading populations of the gall wasp. Six parasitoids have been identified, including one introduced species. Following catastrophic pine mortality from southern pine beetle in southeastern Kentucky, we assessed the effects of a prescribed fire management regime on shortleaf pine regeneration, arthropod herbivory, and the soil/ litter arthropod community. Prescription burning is accomplishing its management goal of manipulating vegetation. Naturally regenerating pine seedlings grew more, but suffer greater mortality, in burned stands. Insect herbivory played a role in growth and survival of seedlings, and their activity is affected by fire. Weevil and tip moth activity was greater, but pine sawfly abundance was less, in burned
stands. Herbivore pressure did not impact growth of naturally regenerating seedlings. Prescribed fire had no negative impact on large, mobile ground-dwelling arthropods, but mites and collembolans were devastated. Diversity and richness of the litter arthropod community was unaffected by fire, and arthropod community evenness increased. A prescribed burn rotation of greater than two years may be suitable to allow accumulation of the leaf litter, with minimal effects to the leaf-litter arthropod community. We modeled succession in loblolly pine stands killed by southern pine beetle in the southern US. Forest modeling predicts that subsequent disturbance from wildfire maintains forest composition relative to a single disturbance from southern pine beetle and management alone. Following disturbance from beetles and wildfire, natural regeneration of loblolly pine is predicted to produce stands moderately susceptible to future beetle outbreaks. Predators are the primary mortality factor
for young eastern tent caterpillars, whereas parasites and pathogens affect older caterpillars. Our research suggests that these natural enemies could be enhanced through manipulation of fencerow vegetation.
Impacts
Chestnut blight-susceptible American chestnut and blight-resistant Chinese chestnut infested with the exotic Asian chestnut gall wasp respond differently to topical applications of jasmonic acid, a plant signaling compound. American chestnut shoots treated with jasmonic acid produced smaller galls and experienced higher gall wasp mortality, but with no affect on associated foliage. Chinese chestnut shoots treated with jasmonic acid produced larger galls and experienced lower larval mortality, and foliar tannins increase. The natural enemy complex associated with invading populations of the Asian chestnut gall wasp include six parasitoids, of which one is an introduced species. Naturally regenerating shortleaf pine suffers greater mortality, but grows larger in burned stands. Insect herbivores play a role in seedling growth and survival, and their activity is affected by fire. Prescribed fire has no negative impact on larger, relatively mobile arthropods, but mites and
collembolans are devastated by fire. Forest modeling predicts that subsequent disturbance from wildfire maintains forest composition relative to a single disturbance from southern pine beetle and management alone. Following disturbance from beetles and wildfire, natural regeneration of loblolly pine is predicted to produce stands moderately susceptible to future beetle outbreaks. Predators cause mortality of young eastern tent caterpillars, whereas parasites and pathogens affect older caterpillars. These natural enemies could be enhanced through manipulation of vegetation.
Publications
- Kellogg, S.K. and Rieske, L.K. 2005. Resistance to a fungal pathogen influences resistance to generalist herbivores. Entomologia experimentalis et applicata 117, 209-219.
- Rieske, L.K. and Townsend, L.H. 2005. Orientation and dispersal patterns of the eastern tent caterpillar, Malacosoma americanum F. (Lepidoptera: Lasiocampidae). Journal of Insect Behavior 18, 193-207.
- Choate, B.A. and Rieske, L.K. 2005. Life history and age-specific mortality of the eastern tent caterpillar, Malacosoma americanum Fabricius (Lepidoptera: Lasiocampidae). Annals of the Entomological Society of America 98(4), 496-502.
- Choate, B.A. and Rieske, L.K. 2005. Sympiesis fragariae (Hymenoptera: Eulophidae) parasitizes Malacosoma americanum (Lepidoptera: Lasiocampidae) in Kentucky: Host and geographic records. Entomological News 116(3), 183-185.
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Progress 01/01/04 to 12/31/04
Outputs
Herbivore susceptibility of several chestnuts varying in susceptibility to the introduced chestnut blight fungus was investigated. Blight-susceptible American chestnut and blight-resistant Chinese chestnut were compared with hybrid crosses of intermediate resistance for susceptibility to herbivory. Blight resistance had little effect on herbivore performance or foliar chemistry. When the parent trees and backcross groups were compared however, significant differences in performance of the gypsy moth, a leaf consumer, and consumption by Japanese beetle, a leaf skeletonizer, were evident. Most foliar characteristics measured differed among chestnut types at some point, and all varied seasonally. Herbivore susceptibility may be guild-specific, since herbivores with different modes of feeding vary in their ability to exploit these chestnut hosts. Mechanisms of herbivore resistance factors in chestnut are also being investigated. Foliar tannins in American and Chinese
chestnut increase following artificial induction of the signaling compound jasmonic acid. This may lead to induced resistance that renders plants less susceptible to herbivores. These results have implications with respect to woody plant response to multiple stresses, interactions among stressing agents, and to forest restoration. The recovery of southern pine beetle (SPB) devastated forest stands is under investigation. Regeneration insects, including reproduction weevils and tip moths, are common in recovering stands. Prescription burning, used to enhance seedling regeneration, appears to have little effect on the abundance of insects impacting regeneration. Vegetation abundance, richness, and diversity were greater in forest stands disturbed by SPB and associated cut and leave management when compared to non-disturbed stands. There were no differences between SPB alone and SPB with management. Wildfire enhances plant richness and abundance. Nearly all of collected burr, pin, and
red oak acorns suffer damage from either biotic or abiotic forces. Squirrels are the primary vertebrate predator in the Bluegrass Region, and are present throughout the period of acorn production. Weevils are the primary insect predator, and are most prevalent late in the acorn season. The eastern tent caterpillar is associated with Mare Reproductive Loss Syndrome. Caterpillar life history characteristics and age-specific mortality was assessed in the Bluegrass Region. Predators impact early instar caterpillars, whereas parasites and pathogens impact late instar caterpillar survival. Caterpillar tents in the lower canopy suffer greater parasitization, and decreased vegetative cover in fencerows enhances parasitization. The larval parasitoid, Hyposoter fugitivus, is the most common. The pupal parasitoid Sympiesis fragariae had not been reported from eastern tent caterpillar, nor had it been reported from Kentucky prior to this study. Tent caterpillar dispersal depends on caterpillar
age and the presence or absence of a tent, which may function as an orientation point. Late instar caterpillars are predicted to move easterly greater than 5 m. Our data support this prediction.
Impacts
There is considerable variability in herbivore susceptibility among chestnuts, but chestnut blight resistance appears to have little effect on herbivore performance or foliar chemistry. Foliar tannins in American and Chinese chestnut increase following artificial induction of the signaling compound jasmonic acid, perhaps leading to induced resistance that renders plants less susceptible to herbivory. These results have implications with respect to woody plant response to multiple stresses, interactions among stressing agents, and to chestnut restoration efforts. Vegetation abundance, richness, and diversity are greater in forest stands disturbed by SPB and associated management when compared to non-disturbed stands. Regeneration insects, including reproduction weevils and tip moths, are common in recovering stands. Prescription burning, used to enhance seedling regeneration, appears to have little effect on the abundance of insects impacting regeneration. Eastern tent
caterpillar life history characteristics and age-specific mortality was assessed in the Bluegrass. Predators impact early instar caterpillars, whereas parasites and pathogens impact late instar caterpillar survival. Caterpillar tents in the lower canopy suffer greater parasitization, and decreased vegetative cover in fencerows enhances parasitization. Tent caterpillar dispersal depends on caterpillar age and the presence or absence of a tent, which may function as an orientation point. Late instar caterpillars are predicted to move easterly greater than 5 m. Our data support this prediction.
Publications
- Rieske, L.K. and Townsend, L.H. 2005. Orientation and dispersal patterns of the eastern tent caterpillar, Malacosoma americanum F. (Lepidoptera: Lasiocampidae). Journal of Insect Behavior 18: 193-207.
- Foss, L.J. and Rieske, L.K. 2004. Stem galls impact oak foliage with potential consequences for herbivory. Ecological Entomology 29: 273-280.
- Rieske, L.K. 2004. Age-specific host utilization in the eastern tent caterpillar (Lepidoptera: Lasiocampidae). Journal of Entomological Science 39: 94-100.
- Rieske, L.K. 2004. Prescription burning to promote oak regeneration: Do the herbivores care? Proceedings: Enhancing the southern Appalachian forest resources NC State Univ Forestry Educational Outreach Program (cd). www.ncsu.edu/feop.
- Kellogg, S.K. 2004. Blight resistance and gall wasp attack influence foliar properties and herbivore susceptibility of chestnut trees. M.S. Thesis.
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Progress 01/01/03 to 12/31/03
Outputs
Herbivore susceptibility of several chestnuts varying in susceptibility to the introduced chestnut blight fungus was investigated. The blight-susceptible American chestnut and the blight-resistant Chinese chestnut were compared with hybrid crosses of intermediate blight resistance for susceptibility to herbivory. We used the gypsy moth, a leaf consumer, and the Japanese beetle, a leaf skeletonizer, as our generalist herbivores. Foliar suitability varied between and within chestnut species for both herbivores. This variability did not necessarily correlate with blight resistance, nor was it consistent between herbivores. Herbivore susceptibility may be guild-specific, since herbivores with different modes of feeding vary in their ability to exploit these chestnut hosts. These results have implications with respect to interactions among stressing agents, and to forest restoration. Species composition and relative abundance of arthropod acorn predators in oak-dominated
eastern forests was assessed, and related to prescribed fire regime. Plots were established on burned and non-burned sites to determine the species composition of the herbivores responsible for acorn predation, assess the extent to which these predators impact acorn germination, and to assess potential fire-induced, species-specific differences in acorn phytochemistry (specifically tannins and carbohydrates) which could influence susceptibility to predation. This project will provide information to allow a better understanding of the impact of seed predators on oak regeneration in the region. Arthropod abundance and diversity was assessed in forests plots subjected to prescription burning. Prescription burning altered understory vegetation, and these vegetative changes coincided with changes in arthropod abundance. Leaf litter arthropod abundance, diversity and richness were significantly reduced by burning, and this persisted for two years. More mobile ground dwelling arthropods
showed a transitory decrease in diversity, richness, and evenness due to burning, but abundance was not affected. The effects of prescribed fire on the foliar chemistry of several common forest trees, including chestnut oak, red maple, and sassafras, and the impacts on herbivore fitness, were measured. Gypsy moth caterpillars fed foliage from chestnut oak grew larger and developed more quickly than did those fed red maple foliage. Caterpillars fed foliage from burned forests grew larger, but not faster, than those fed foliage from non-burned forests. The eastern tent caterpillar is associated with Mare Reproductive Loss Syndrome. Caterpillar life history characteristics and age-specific mortality was assessed in the Bluegrass Region. From egg to adult, caterpillar development and mortality factors were monitored. Approximately 20% of the eggs failed to develop; 14% were parasitized. Tent formation, caterpillar development, and predation and parasitization rates were affected by
site.
Impacts
Chestnuts varying in susceptibility to the introduced chestnut blight fungus were assessed for susceptibility to gypsy moth and Japanese beetle herbivory. Suitability of foliage varied between and within chestnut species for both herbivores. This variability did not necessarily correlate with chestnut blight resistance, nor was it consistent between herbivores, suggesting that blight resistance and herbivore resistance may operate independently in the chestnut system. These results may impact forest restoration efforts and management approaches. Prescription burning for forest stand management alters understory vegetation, and these vegetative changes coincide with changes in arthropod abundance. Burning significantly reduced leaf litter arthropod abundance, diversity and richness for two years. Ground dwelling arthropods showed a transitory decrease in diversity, richness, and evenness due to burning, but abundance was not affected. These results demonstrate that
forest floor arthropods are impacted by fire, suggesting that arthropods should be considered when developing prescriptions for stand management.
Publications
- Foss, L.J. and L.K. Rieske. 2003. Species-specific differences in oak foliage affect gypsy moth preference and performance. Entomologia Experimentalis et Applicata 108 (2), 87-94.
- Rieske, L.K., C. Rhoades, and S.P. Miller. 2003. Foliar chemistry and gypsy moth herbivory on pure American chestnut, Castanea dentata (Fam: Fagaceae), and a disease-resistant hybrid. Environmental Entomology 32 (2), 359-365.
- Adams, A.S. and L.K. Rieske. 2003. Prescribed fire affects white oak seedling phytochemistry: Implications for insect herbivory. Forest Ecology and Management 176 (1 3), 37 47.
- Rieske, L.K. and K.F. Raffa. 2003. Evaluation of visual and olfactory cues for sampling three thrips species (Thysanoptera: Thripidae) in northern deciduous forests. Journal of Economic Entomology 96 (3), 777-782.
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