Alien invasive insects such

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Emerald ash borer (Agrilus planipennis Fairmaire) (EAB), an alien invasive wood-boring buprestid beetle, is causing large-scale decline and mortality of the most widely distributed species of ash (Fraxinus spp.) trees endemic to eastern North America. We determined which arthropod species that are associated with ash may become threatened, endangered, and co-extinct with the demise of ash as a dominant tree species. A literature survey revealed that 43 native arthropod species in six taxonomic groups (Arachnida: Acari; Hexapoda: Coleoptera, Diptera, Hemiptera, Hymenoptera, and Lepidoptera) are known to be associated only with ash trees for either feeding or breeding purposes, and thus face high risk of endangerment. Most of these species are gall-formers followed by folivores, subcortical phloem/xylem feeders, sap feeders, and seed predators.Another 30 arthropod species are associated with 1-2 host plants in addition to ash, and herbivory on these hosts may increase as these arthropods shift from declining ash trees. Extirpation of arthropods dependent upon ash may unleash multiple extinctions of affiliated species with which they may be inextricably linked. The demise of North American ash species due to EAB is expected to lead to biotic loss with cascading ecological impacts and altered processes within forested ecosystems.

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a non-native, wood-boring beetle that has caused widespread mortality of ash (Fraxinus Linnaeus (Oleaceae)) in eastern North America. During 2004–2007, we determined whether forest community composition and structure of black (F. nigra Marshall), green (F. pennsylvanica Marshall), and white (F. americana Linnaeus) ash stands influenced their susceptibility to EAB invasion in southeast Michigan, United States of America. There was no relationship between EAB-induced ash decline or percentage mortality and any measure of community composition (tree species diversity, stand/ash density, total basal area, or relative dominance of ash). There was also no relationship between measures of EAB impact (density of EAB signs, ash decline rating, percentage ash mortality, or percentage infested ash) and forest attributes (ash/total stand density, basal area, ash importance, or stand diversity). Decline and mortality of black ash advanced more rapidly than that of white and green ash. Percentage mortality of ash increased from 51% to 93% during 2004–2007. Distance from the epicentre of the invasion was negatively correlated with ash mortality, but this relationship dissipated over time. Stand composition data suggests that ash will be replaced by Quercus Linnaeus (Fagaceae), Acer Linnaeus (Sapindaceae), and Tilia Linnaeus (Malvaceae); such vegetation changes will irreversibly alter the structure and function of these forests.

Field-based trapping experiments were conducted in Ohio in 2003, 2004, and 2008 to determine the influence of (-)-alpha-pinene on the attraction of exotic and native ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) to ethanol-baited traps. In 2003 and 2004, we determined the effect of adding an (-)-alpha-pinene ultrahigh release lure (UHR; 2 g/d at 20 degrees C) to traps baited with an ethanol UHR lure (0.39 g/d). FewerAnisandrus (Xyleborus) sayi (Hopkins) and Xyleborinus saxeseni (Ratzeburg) were collected in 2003 and 2004 from traps baited with ethanol UHR plus (-)-alpha-pinene UHR compared with ethanol UHR. (-)-alpha-Pinene also reduced the attraction of Xyloterinus politus (Say) to ethanol-baited traps in 2004. Total captures of Xylosandrus germanus (Blandford) in 2003 were higher in traps baited with ethanol UHR plus (-)-alpha-pinene UHR than in traps with ethanol UHR alone but not in 2004. In 2008, captures were compared among traps baited with eight combinations of ethanol and (-)-a-pinene at both UHR and low release (LR) rates. Release rates for ethanol LR and (-)-alpha-pinene LR were 0.027 and 0.0015 g/d, respectively. (-)-alpha-Pinene UHR and (-)-alpha-pinene LR reduced the attractiveness of ethanol UHR to A. sayi and X. saxeseni. Ethanol UHR was also more attractive than ethanol LR to A. sayi and X. germanus. These findings demonstrate traps baited with ethanol alone are more effective than ethanol plus (-)-alpha-pinene for monitoring ambrosia beetle flight activity in ornamental nurseries. Ethanol release rate is also an important consideration for monitoring purposes.

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Exotic herbivorous insects have drastically and irreversibly altered forest structure and composition of North American forests. For example, emerald ash borer (Agrilus planipennis Fairmaire) from Asia has caused wide-scale mortality of ash trees (Fraxinus spp.) in eastern United States and Canada. We studied the effects of forest changes resulting from emerald ash borer invasion on epigaeic or ground beetles (Coleoptera: Carabidae) along a gradient of ash dieback and gap sizes in southeastern Michigan. Ground beetles were sampled in hydric, mesic, and xeric habitats in which black (Fraxinus nigra Marshall), green (Fraxinus pennsylvanica Marshall), and white (Fraxinus americana L.) ash were the most common species, respectively. During 2006-2007, we trapped 2,545 adult ground beetles comprising 52 species. There was a negative correlation between percent ash tree mortality in 2006 and catches of all beetles. Catches of Agonum melanarium Dejean (in 2006) and Pterostichus mutus (Say) (in 2006-2007) were negatively correlated with tree mortality and gap size, respectively. However, catches of Pterostichus corvinus Dejean were positively correlated with gap size in 2006. As ash mortality and average gap size increased from 2006 to 2007, catches of all beetles as well as P. mutus and Pterostichus stygicus (Say) increased (1.3-3.9 times), while species diversity decreased, especially in mesic and xeric stands. Cluster analysis revealed that beetle assemblages in hydric and mesic stand diverged (25 and 40%, respectively) in their composition from 2006 to 2007, and that hydric stands had the most unique beetle assemblages. Overall, epigaeic beetle assemblages were altered in ash stands impacted by emerald ash borer; however, these impacts may dissipate as canopy gaps close.