of Anoplophora glabripennis (Cerambycidae) (PDF)
Dispersal Potential of Anoplophora glabripennis Motsch.
Modeling Dispersal of the Asian Longhorned Beetle (PDF)
Acoustic Detection of Anoplophora glabripennis and Native Woodborers (Coleoptera:Cerambycidae)
Semiochemicals of Anoplophora glabripennis, the Asian longhorned beetle (Coleoptera:Cerambycidae)
Aggregation Pheromone for the Asian Longhorned Beetle, Anoplophora glabripennis (Coleoptera: Cerambycidae)
Dispersal Potential of Anoplophora glabripennis Motsch.
Michael T. Smith1, Jay Bancroft1, Ruitong Gao2, and Guohong, Li2
1USDA Agricultural Research Service, Beneficial Insects Introduction Research Lab 501 S. Chapel Street, Newark, DE 19713
2Institute of Forest Protection, Chinese Academy of Forestry Beijing, CHINA 100091
The Asian longhorned beetle (ALB), Anoplophora glabripennis Motsch., is native to China and Korea. As a recent invader, ALB is a candidate for eradication because infestations are currently thought to be limited in size and scope. The aim of eradication is the elimination of all reproductively viable ALB from North America. Intensive survey for infested trees, followed by felling, removal and chipping, is the currently the only available method of population suppression. Effective surveys require establishment of boundaries around infestations (referred to as eradication survey and delimitation survey boundaries), inside of which surveys are conducted. Current guidelines for the eradication surveys, as per USDA Animal Plant Health Inspection Service (APHIS), are 1/2 mile from the closest known infested tree. These guidelines are based upon rate of detection of infested trees. However, delineation of boundaries should be based upon the dispersal potential of ALB, likely the most important factor for invasion by exotic species (Higgins et al. 1996). Therefore, the objective of these studies was to determine the dispersal potential of adult ALB, thereby providing a basis for the delineation of the quarantine boundaries, and the concentration of survey and detection efforts. In turn, this should lower the detection threshold for incipient populations, vastly improve the operational cost:benefit ratio of APHIS’s eradication program, and greatly enhance the potential for successful eradication.
Because the release of ALB is justifiable prohibited in North America, mass mark recapture (MMR) field experiments were conducted in Gansu Province, China, in order to estimate ALB dispersal characteristics. In the event that ALB becomes uncontainable in the U.S., this research, when coupled with other current investigations (i.e. colonization behavior, host preference, natural enemies), will provide estimates of ALB dispersal parameters that are applicable in other landscapes at risk (i.e. urban and forests) in North America. In so doing, therefore, this proactive approach will form the basis for development of adaptive management strategies for this and other invasive species.
Materials and Methods
These studies were conducted 1 km west of the town of Liu Hua, bordering the Yellow River in Gansu Province, north central China. This field site was selected because it possessed landscape characteristics similar to those of the urban infestations in the U.S., particularly site-specific factors that are thought to most likely influence dispersal distance. The general landscape is composed of both host (72.3%) and non-host (27.7%) tree species of mixed age classes. Known ALB hosts are dominated by Populus nigra L. var. thevestina (Dode) Bean, comprising ca. 87% of the ALB hosts, followed by Salix sp. and Ulmus sp., at 9% and 4%, respectively. The study site was composed of isolated trees and trees planted along paths amid dwellings, such as homes and greenhouses, as well as trees planted as wind-rows (generally 2 m spacing within rows and 50 m spacing among rows) bordering agricultural fields. Greenhouses and small dwellings were also commonly found within or adjoining agricultural fields.
ALB used in these studies were marked and released from the center of the study areas. Of these ALB, those that had emerged from logs were released daily, while those that were collected outside the study areas were released weekly. Transects radiated from the center release site in 8 directions: north, northeast, east, southeast, south, southwest, west and northwest. Recapture locations lay along each transect at 50, 100, 150, 200, 250, 300, 400, 500, and 600m intervals in the 1999 study, and at 100m intervals from 100-1,000m in the 2000 study. However, landscape heterogeneity (presence of obstacles), sometimes required that recapture positions be modified accordingly. Each recapture location was composed of a fixed group of poplar trees (average of 12 trees per location). Trees at each recapture location were sampled weekly for adult A. glabripennis by shaking. This passive recapture method was preferred since it did not influence the dispersal behavior of ALB (as is common where pheromone traps are used to recapture insects in MMR studies). In addition to recapturing beetles along the transects mentioned above, beetles were also sampled weekly at random positions beyond the 600 m and 1,000, m radius in the 1999 and 2000 studies, respectively. Each marked ALB recaptured was preserved, and the location, release date, and body length and width recorded. In addition, marked female ALB were dissected and the number of mature eggs recorded. Unmarked adult ALB collected were recorded and released.
Results and Discussion
Distances at which marked beetles were recaptured during 1999 and 2000 are shown in Figures 1 and 2, respectively. In 1999, the average distance that ALB dispersed was 266m, while the maximum distance was 1,450 m. Analysis showed that the 98% recapture radius was 560 m. (n=188 recaptured beetles). In 2000, the average distance that ALB dispersed was 498.02 m, while the maximum distance was 2,664 m (n=401 recaptured beetles). Among these recaptured ALB, 20 (10.6% of the recaptured ALB in 1999) and 76 (19.0% of the recaptured ALB in 2000) were recaptured beyond 600 m and 1,000 m in 1999 and 2000, respectively.
Distances at which marked female ALB dispersed with eggs during 1999 and 2000 are shown in Figures 3 and 4, respectively. Surprisingly, there was no significant correlation in eggs remaining in females as distance increased. One explanation is that ALB emerge from trees with their full complement of eggs, disperse, settle and then begin to oviposit. However, female ALB held no more than 25 eggs at recapture, but are capable of producing as many as 80 eggs (Gao, per. Comm.; Smith, unpublished data). Therefore, this may indicate that female ALB develop eggs continuously or in batches. Thus, mated females may disperse great distances (1,442 m and 2,664 m in 1999 and 2000, respectively) and then deposit eggs. We suspect that the distribution in Figure 4 shows evidence for serial oogenesis.
Previous studies have generally reported lower ALB dispersal distances than were found in the study reported here. These differences may be based upon a variety of factors. First, recapture sampling at high frequency over an extensive area may trap out dispersing individuals (Turchin 1997). This may have contributed, in part, to the lower average dispersal distance of 106 m reported from the mark recapture study by Wen et al (1998), in which they recaptured ALB daily or every other day. Weekly recapture sampling was used in the study reported here. Secondly, recapture sampling duration, both in terms of the entire life-span of an insect, as well as across an entire season, provides a more accurate measure of population dispersal. Wen et al (1998) used unknown-aged ALB, and extrapolated dispersal distance from the first 28 days of recapture. As many insects are known to decrease movement behavior with age, this may account, in part, for their shorter dispersal distance. Both life-time (use of newly emerged ALB) and season-long (recaptured for ca. 100 d) ALB dispersal potential were ascertained in the study reported here. Finally, landscape heterogeneity, especially variation in size and arrangement of tree species, is likely to have strong effects on ALB dispersal. This too may account, at least in part, for the lower ALB dispersal distance (generally within 200 m, but not more than 300 m) reported by Huang (1991), where they conducted their experiment in a homogeneous young poplar plantation (3 by 5 m tree spacing). ALB dispersal distance may tend to be relatively low in plantations where preferred host trees are proximal, but greater where preferred host trees are more widely spaced. Our field site (described above) contained heterogeneity in key features that are likely to be important to ALB dispersal. Our future studies will strengthen the understanding of host tree interaction and dispersal in response to landscape elements.
Most important for eradication of ALB is that the maximum dispersal distance recorded was 2,664 m (1.5 miles), which was a female ALB carrying mature eggs. It must be assumed that ALB can disperse at least 2,664 m in the U.S. Therefore, surveying or treatment of trees should extend to this distance so that incipient colonies do not prevent eradication. Current APHIS detection and survey guidelines are as follows: (1) each year, all host trees within 0.5 miles from an infested tree are inspected; (2) each year, 50% of all host trees that are between 0.5 miles to 1.5 miles from an infested host tree are inspected; and (3) over a three year period, 18 host trees/square mile (2 host trees at each of 9 inspection points, within each 1 by 1 mile grid) that are between 1.5 miles and 25 miles from each infested host tree are inspected.
The data reported here show that 89.4% and 81.0% of ALB dispersed less than 600 m (0.37 miles) and 1,000 m (0.62 miles) in 1999 and 2000, respectively, suggesting that most beetles occur close to previously infested trees. On the other hand, the data also show that 10.6% and 19.0% of ALB dispersed beyond 600 m (0.37 miles) and 1,000 m (0.62 miles), and that 0.53% and 0.25% of ALB dispersed 1,450 m (0.9 miles) and 2,664 m (1.6 miles) in 1999 and 2000, respectively. Collectively these beetles represent long dispersers that may initiate new infestations. For eradication to be successful, ALB near previous infestations must obviously be killed. However, one must also detect and kill rare, newly founded, infestations resulting from the long dispersers as well. Therefore, one of the greatest challenges facing eradication will be to effectively partition finite resources between efforts to kill all beetles in local infestations, with efforts to detect and kill the more rare distant infestations that represent foci for potential future breeding populations. Spatially explicit models being developed here at BIIR, using data from a number of complementary studies will provide a detailed understanding and prediction of ALB spread within landscapes at risk in the U.S.
Higgins, S. I., D. M. Richardson and R. M. Cowling. 1996. Modeling invasive plant spread: The role of
plant-environment interactions and model structure. Ecol. 77:2043-2054.
Huang, J. 1991. Current status and problems in the control of poplar wood-boring insect pests. J. For. Dis. Ins.
Pests. 1: 52-56.
Turchin, P. 1997. Quantitative analysis of movement: measuring and modeling population redistribution in animals
and plants. Sinauer Associates. New York, NY.
Wen, J., Y. Li, N. Xia, and Y. Luo. 1998. Study on dispersal pattern of Anoplophora glabripennis adults in
poplars. ACTA Ecol. Sin. 18: 269- 277.
Acoustic Detection of Anoplophora glabripennis and Native Woodborers
Robert A. Haack1, Therese M. Poland1, Toby R. Petrice1, Cyrus Smith2, Dale Treece2, and Glen Allgood2
Wood-infesting insect larvae generate acoustic signals as they feed and tunnel in trees. Studies on acoustic detection of Anoplophora glabripennis (Motschulsky) (Cerambycidae) larvae were conducted in 1999 and 2000. In the U.S., we have recorded acoustic data from A. glabripennis and several native cerambycid larvae including cottonwood borer, Plectrodera scalator (Fabricius); linden borer, Saperda vestita Say; locust borer, Megacyllene robiniae (Forster); whitespotted sawyer, Monochamus scutellatus (Say); red oak borer, Enaphalodes rufulus (Haldeman); and sugar maple borer, Glycobius speciosus (Say). In China, we have recorded acoustic data from A. glabripennis-infested elm, poplar and willow trees. The specific objectives of this study are to determine how vibration data varies by insect species, tree species, larval instar, wood moisture content, and distance between the larva and the sensor. The goal of this work is to develop a field-portable acoustic detector that can identify trees infested with A. glabripennis.
Scientists at the Oak Ridge National Laboratory conducted extensive sound analyses on the vibration data and developed a mathematical algorithm that would recognize the acoustic signature produced by A. glabripennis larvae feeding in wood. The algorithm has been successfully tested on a variety of infested materials, including infested log samples and standing trees in both the U.S. and China. The algorithm is a real time filter that is optimized to respond to vibrations that match closely with pre-selected data sets of actual larval feeding vibrations. Incoming data first passes through the algorithm (filter). If the output is a close match to the pre-selected data set then a high amplitude response is generated and a “bite” is recorded. On the other hand, if there is no match between the input data and the pre-selected data set then no “bite” is recorded.
The detection algorithm has been incorporated into a data collection and analysis system that has been installed on a laptop computer. The system is fully portable. Data analysis is completed in real time. An indication of infestation (number of beetle “bites” detected) is displayed on the computer screen in real time. All components utilized in this system can be miniaturized and integrated into a smaller package.
Initial results confirm that larval feeding in wood produces detectable vibrations. The vibrations from A. glabripennis and other cerambycids are similar, although there are some unique acoustic features of A. glabripennis feeding. Vibrations are larger in amplitude for larval feeding in wood compared with larval feeding in inner bark.
Preliminary studies were conducted in 2000 to compare feeding vibrations among different sized larvae, different wood species, and different insect species. More detailed studies will be conducted in each of these areas in 2001. In addition, more detailed studies will be conducted in 2001 to (a) compare acoustic signals of larvae in live trees compared with infested crating, (b) determine how feeding vibrations vary with air temperature, and (c) determine over what distance feeding vibrations can be detected in trees. We are currently using trunks of cottonwood trees, 7-8 m long, into which we have inserted P. scalator larvae. In this way, we can vary the distance between the sensor and the larvae. We also hope to field test a prototype acoustic detector in 2001 on actual infested trees in the U.S.
*An abstract prepared for the USDA Interagency Research Forum on Gypsy Moth and Other Invasive Species
(January 16-19, 2001 Annopolis, Maryland)
1USDA Forest Service, North Central Research Station, 1407 S. Harrison Rd., Rm. 220, East Lansing, MI 48823
2Oak Ridge National Laboratory, Instrumentation and Controls Division, 1 Bethel Valley Road, Oak Ridge, TN 37831-6010
Semiochemicals of Anoplophora glabripennis, the Asian longhorned beetle
Joseph A. Francese1, Michael J. Bohne2, Michael J. Domingue3, Jennifer L. Lund3, Victor C. Mastro1, Stephen A. Teale3
The objective of our study is to identify semiochemical attractants for use in the survey and detection of Anoplophora glabripennis (Coleoptera: Cerambycidae). In the absence of other means, detection of trees infested with A. glabripennis has been limited to visual inspection of the stem and branch surfaces. Evidence, of a possible female or host attractant for A. glabripennis, exists in the literature. We collected volatiles from male beetles, female beetles and host material. These volatiles were analyzed using gas chromatography coupled with mass spectrometry (GC-MS) and gas chromatography coupled with an electroantennographic detector (GC-EAD). It was revealed that male beetles can antenally detect at least 22 of the compounds that were collected. Multivariate discriminant analysis revealed that two compounds might encode information about hosts and beetles producing them. One of these compounds, along with an unknown compound, may also encode information about sex and age of the beetles producing them. Laboratory bioassays of several of the compounds that have been identified were inconclusive. Field testing of these compounds in China has also been inconclusive.
*An abstract prepared for the Entomological Society of America Annual Meeting
(December 3-6, 2000 Montreal, Quebec, Canada)
1USDA APHIS PPQ, Otis Plant Protection Laboratory Bldg 1398, Otis ANGB, MA 02542-5008
2University of Vermont, Entomology Research Lab P.O. Box 53400, Burlington, VT 05405-3400
3SUNY College of Environmental Science and Forestry Department of Environmental and Forest Biology
133 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210
Aggregation Pheromone for the Asian Longhorned Beetle, Anoplophora glabripennis
Aijun Zhang, James E. Oliver, and Jeffrey R. Aldrich
PROGRESS: Isolated, identified and synthesized two male-specific compounds from the Asian longhorned beetle (ALB). July 1999 field tests in China failed to demonstrate attraction of flying beetles to these compounds, with or without a mixture of six host volatiles. However, Y-tube olfactometer tests conducted during the 2000 season showed that the synthetic alkyl ethers are significantly attractive to walking ALB females and males. A patent has been granted for the use of these heretofore unknown compounds (4-(n-heptyloxy)butanal and 4-(n-heptyloxy)-1-butanol) to assist in trapping the beetles. Negotiations are ongoing with potential licensees/CRADA partners to develop the technology. Traps are being designed to catch beetles walking on host trees; these new traps, baited with the male-specific dialkyl ethers, will be tested in China by CAIBL scientists during the 2001 season. In addition, past laboratory and field observations indicated that ALB males are territorial and that males recognize females upon antennal contact. Therefore, we plan to chemically identify the ALB female contact recognition pheromone since, for example, these chemicals may also be useful in inducing beetles to enter traps.
Chemicals Affecting Insect Behavior Laboratory, Agricultural Research Center-West, Beltsville, Maryland, USA 20705