Author
![]() |
Smith, Michael |
![]() |
Tobin, Patrick |
![]() |
GUOHONG, LI - CHINESE ACAD OF FOREST |
![]() |
RUITONG, GAO - CHINESE ACAD OF FOREST |
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/20/2003 Publication Date: 4/20/2004 Citation: Smith, M.T., Tobin, P.C., Guohong, L., Ruitong, G. 2004. Dispersal and spatiotemporal dynamics of asian longhorned beetle (coleoptera: cerambycidae) in china. Environmental Entomology. 33(2):435-442. Interpretive Summary: Asian Longhorn Beetle (ALB) is native to China and Korea, where it is a serious pest of deciduous broadleaf tree species, particularly poplars, willows, elms and maples. It is widespread in China, found in parts of at least 25 provinces. ALB is thought to have been accidentally introduced into the U.S. in solid wood packing materials originating from China, with breeding populations discovered in New York City and Long Island (1996), Chicago, Illinois (1998) and Jersey City, NJ (2002). By September 1, 2002, 5,888 and 1,545 trees had been found infested, cut and removed in New York and Chicago, respectively. For the lumber, maple syrup, tourist and other forest-related industries, costs in survey, detection and management costs, and lost revenues could mount into the billions of dollars. Furthermore, a recent report projects that if ALB spreads to urban trees across North America, there could be a loss of 35% of total shade cover (1.2 billion trees) and a compensatory value loss of $669 billion. This is especially important for homeowners, because takedown costs for a dead tree can reach $1,000 or even more. Moreover, air conditioning costs can increase substantially due to shade loss. Eradication of ALB currently relies primarily upon: (1) detection of infested trees that are then cut and chipped, and (2) injection of trees with systemic insecticides that target adult beetles feeding on trees and/or larval feeding within infested trees. However, detection of infested trees relies solely on visual surveys, which are labor-intensive, costly, and only ca. 30-60% effective. Furthermore, use of systemic insecticides is labor-intensive and costly, and thought to be primarily effective against adult beetles. Since these surveys are the most expensive component of the eradication effort, optimization of these surveys would represent a major benefit to the Asian Longhorn Beetle Eradication Program, both in terms of cost saving and increased detection efficiency. Therefore, the objective of this research was to develop optimal sampling procedures based upon studies of the dispersal potential of ALB in both time and space under natural field conditions in China. We individually marked and released 39,960 beetles (1,538 known and 38,422 unknown aged) from 15 June to 30 September, 2000. Each week we then sampled 18-28 trees at each of 78 locations along 8 transects extending 1 km out in all directions from the central release site and recorded the number of ALB (marked and unmarked). A total of 395 marked beetles (147 females, 248 males) were recaptured during the duration of the study (2 June to 30 September), of which 18 were of known age. Results included the following: (1) With respect to how far ALB disperses, results showed that at distances > 295 m from a release point, the recapture rate was < 5%, while the median dispersal rate for all recaptured adults was 30 m/d. Male and female beetles (with eggs) dispersal was 2,394 and 2,644 m, respectively. This new information will allow Animal and Plant Health Insepection Service (APHIS) to know how far from known infested trees to survey for new infestations, as well as where to establish quarantine boundaries; (2) With respect to how to best design survey protocols, results showed that background populations exhibited local spatial autocorrelation during peak abundance, with ranges of spatial dependence of 229-543 m. In other words, because sampling points that are close to one another (229-543m) provide limited new information in reference to the presence of ALB, APHIS should design their survey protocols accordingly. This will result in tremendous savings to the APHIS survey program, as well as allow APHIS to focus survey resources at greater distances without sacrificing efficiency, thereby increasing the likelihood that isolated ALB infestations will be detected and elimina Technical Abstract: The cerambycid, Anoplophora glabripennis, is native to China and Korea, where it is a serious pest of deciduous broadleaf tree species, particularly Acer spp., Populus spp. Salix spp., and Ulmus spp. It is widespread in China, occurring in at least 25 provinces. ALB is thought to have been accidentally introduced into the U.S. in solid wood packing materials originating from China, with breeding populations discovered in New York City and Long Island (1996), Chicago, Illinois (1998) and Jersey City, NJ (2002). By September 1, 2002, 5,888 and 1,545 trees had been found infested, cut and removed in New York and Chicago, respectively. For the lumber, maple syrup, tourist and other forest-related industries, costs in survey, detection and management costs, and lost revenues could mount into the billions of dollars. Furthermore, a recent report projects that if ALB spreads to urban trees across North America, there could be a loss of 35% of total canopy cover (1.2 billion trees) and a compensatory value loss of $669 billion. Eradication of ALB currently relies primarily upon: (1) detection of infested trees that are then cut and chipped, and (2) injection of trees with systemic insecticides that target adult beetles should they feed on trees and/or larva feeding within infested trees. However, detection of infested trees relies solely on visual surveys, which are labor-intensive, costly, and only ca. 30-60% effective. Since these surveys are the most expensive component of the eradication effort, optimization of these surveys would represent a major benefit to the Asian Longhorn Beetle Eradication Program, both in terms of cost saving and increased detection efficiency. Therefore, the objective of this research was to develop optimal sampling procedures based upon investigations of the dispersal potential and spatiotemporal dynamics of ALB under natural field conditions in China, coupled with studies of the spatial and temporal distribution of the background population by modeling phenology and estimating spatial autocorrelation. We used mass mark-recapture methods and observed that at distances > 295 m from a release point, the recapture rate was < 5%, while the median dispersal rate for all recaptured adults was 30 m/d. Dispersal potential within the course of a season for males and gravid females was 2,394 and 2,644 m, respectively; however, more work is need to evaluate the potential of long distance dispersal events to initiate new colonies, which could be subject to the Allee effect and/or stochasticity, outside current U.S. quarantine boundary guidelines. We observed that tree size and number of existing emergence holes on a tree were significant positive predictors of new emergence holes, but we did not measure a significant effect of tree size, number of existing emergence holes, and number of new emergence holes on adult beetle abundance. Implications of these findings within the context of host quality are discussed, but more research is needed to identify key factors in the multiyear host colonization process. Peak population abundance of unmarked beetles (i.e., background populations) in both 1999 and 2000 occurred between 800-900 degree days (base threshold = 10 ºC) from 1 January. Background populations exhibited local spatial autocorrelation during peak abundance, with ranges of spatial dependence of 229-543 m. |