Critter Catalog

What do they look like?

Emerald ash borers are long, thin, metallic green beetles. Their bodies are coppery-red underneath their wings. They can grow to be 7.5 to 15 mm long and 3 mm wide. Males are covered in setae, which are like hair. Females don't have as much, but their bodies are larger than males. Adult females lay eggs that are 1 mm in diameter on the bark of ash trees. Eggs are white at first, and then turn amber as they develop. The eggs hatch into flat larvae with segments. They chew their way through the bark of the tree and tunnel into the layer underneath. Larvae can reach 23 to 26 mm long. (Bauer, et al., 2003; Haack, et al., 2002; Wang, et al., 2010)

• Other Physical Features
• heterothermic

• Sexual Dimorphism
• female larger

• Range length

  7.5 to 15 mm

  0.30 to 0.59 in

Where do they live?

Emerald ash borers are beetles from Eurasia that are invasive in North America. In the United States, they were first found in Michigan in 2002. Since then, they have spread to Ohio, Indiana, Illinois, Maryland, and Ontario, Canada. Emerald ash borers spread mostly by human transportation, because they can only spread 1.1 km per year by themselves. (Anulewicz, et al., 2007; Kovacs, et al., 2010; Liu, et al., 2003; Wang, et al., 2010)

• Biogeographic Regions
• nearctic
  • introduced
• palearctic
  • native

What kind of habitat do they need?

Emerald ash borers need to use ash trees to live and eat. Adult females lay their eggs on the bark of ash trees. When the eggs hatch, the larvae chew their way through the bark layer into the cambium, which is the part of the tree just underneath the bark. Emerald ash borer larvae stay in this layer until they come out from the tree as adult beetles. Ash trees are often planted by humans for shade or to stop wind on a farm. Emerald ash borers feed on the leaves and reproduce inside the tree. (Kovacs, et al., 2010; Wang, et al., 2010)

• These animals are found in the following types of habitat
• terrestrial

• Terrestrial Biomes
• forest

• Other Habitat Features
• urban
• suburban
• agricultural

How do they grow?

Female emerald ash borers lay eggs on the bark of ash trees. The eggs are white at first, and then turn amber in color as they develop. They are about 1 mm across. In 15 days, they hatch into larvae. The larvae are flat with segments. They chew through the bark into the inner layers of the tree, disrupting the transportation of nutrients. Emerald ash borers stay as larvae for 300 days, usually from June to April of the next spring. During this time, the larvae go through four different stages, and can grow to be 23 to 26 mm long. In late summer and early fall, larvae in their final stage tunnel into the bark and make a chamber where they spend the winter. Their bodies have special chemicals that help them survive the cold winter. They finish developing in the chambers in the next summer, sometime between mid-May in July. Then they chew their way out of the tree, leaving behind a hole shaped like a D. They can fly when they come out of the tree. (Bauer, et al., 2003; Crosthwaite, et al., 2011; Haack, et al., 2002; Poland, 2007; Wang, et al., 2010)

• Development - Life Cycle
• metamorphosis

How do they reproduce?

Males generally come out of trees as adults before females. Then, they grow for 5 to 7 more days before they can reproduce. Males find females using chemicals called pheromones as well as by sight. Both males and females have multiple mates. (Rutledge and Keena, 2012)

• Mating System
• polygynandrous (promiscuous)

Males find females to mate with, and then drop out of the air to mate. Females start laying eggs 7 to 10 days later, and keep laying eggs for 4 to 6 weeks. They have a special body part called an ovipositor which they use to lay eggs in the cracks of bark. They usually lay 70 eggs, but can lay anywhere from 50 to 200. Females place eggs individually, and the eggs hatch within 2 weeks. (Poland, 2007; Rutledge and Keena, 2012; Wang, et al., 2010)

• Key Reproductive Features
• seasonal breeding
• sexual
• fertilization
  • internal
• oviparous

• How often does reproduction occur?

  Emerald ash borers mate for the duration of their adult lives.

• Breeding season

  Both males and females begin to mate 5 to 7 days after emerging from their host tree. Females lay their eggs 7 to 10 days after mating.

• Range number of offspring

  50 to 200

• Average number of offspring

  70

• Range age at sexual or reproductive maturity (female)

  5 to 7 days

• Range age at sexual or reproductive maturity (male)

  5 to 7 days

Females are careful to find and use cracks in the bark for their eggs that protect them from bad weather. Emerald ash borers don't care for the eggs after they are laid. (Wang, et al., 2010)

• Parental Investment
• female parental care
• pre-fertilization
  • provisioning

How long do they live?

Emerald ash borers spend about 300 days as larvae, which is most of their lives. After coming out of the tree as adults, they live for 3 to 6 more weeks. (Poland, 2007; Wang, et al., 2010)

• Average lifespan
  Status: wild

  1 years

How do they behave?

Emerald ash borers are not social beetles. They are able to fly up to 2.8 km per day at a speed of 3 mph. Females that have already mated fly twice as far as those that haven't, probably to find new trees. The maximum distance flown by an emerald ash borer is about 10 km. (Crosthwaite, et al., 2011; Taylor, et al., 2006)

• Key Behaviors
• arboreal
• flies
• parasite
• motile
• sedentary
• solitary

Home Range

Emerald ash borers are capable of flying 5.2 km in 40 hours. If there is an ash tree nearby, they are more likely to fly less than 100 km. Other ash trees within 0.5 mile radius of an infected tree can also get infected. (Cipollini, et al., 2011; Kovacs, et al., 2010; Poland, 2007)

How do they communicate with each other?

Emerald ash borers communicate using sight and chemicals. For example, adults are attracted purple traps. They have organs on their antennae that they can use to smell, and others on their mouth and legs used for taste. Males have more sensory receptors than females, so they are probably used to recognize mates. Other kinds of beetles have organs used for hearing as well. (Crook, et al., 2008a; Crook, et al., 2008b; Forrest, et al., 1997)

• Communication Channels
• visual
• acoustic
• chemical

• Perception Channels
• visual
• acoustic
• chemical

What do they eat?

Emerald ash borers feed on ash trees. Adults eat leaves, and larvae eat wood and bark. Adults leave visible ridges on the leaves after they eat. Once the larvae hatch from eggs, they chew into the tree and feed on the tissues of the tree. (Chen, et al., 2011)

• Primary Diet
• herbivore
  • folivore
  • lignivore

• Plant Foods
• leaves
• wood, bark, or stems

What eats them and how do they avoid being eaten?

In China where emerald ash borers are native, they are eaten by different kinds of woodpeckers like great spotted woodpeckers and grey-headed woodpeckers. Woodpeckers find emerald ash borer larvae by seeing holes in the bark and sensing vibrations. (Chen, et al., 2011; Ulyshen, et al., 2012; Wang, et al., 2010)

• Known Predators

  • grey-headed woodpeckers (Pica canus)
  • great spotted woodpeckers (Dendrocopos major)

What roles do they have in the ecosystem?

On average, healthy ash trees die after 3 years of infestation. In the first year, there is no visible detection to suggest an attack. During this year, eggs are laid inside bark cracks and upon hatching feeding under the bark begins. During the second year, the tree begins to develop less foliage. If the bark is removed, the feeding paths of the larvae can be observed. In the final year of infestation, branches begin to die and bark starts to split and break off. Exit holes where recently hatched adults have emerged become apparent. (Haack, et al., 2002)

Emerald ash borer larvae feed on ash trees. They feed in a zigzag pattern up and down the tree, eating the layers or wood under the bark that transport nutrients. Affected trees usually die in 2 to 3 years. In the first year, the tree doesn't show the infection from the outside. In the second year, it has less leaves, and the tunnels made by larvae can be seen underneath the bark. In the third year, branches start to die, the bark starts to fall off, and holes where the beetles came out are visible. (Haack, et al., 2002; Wang, et al., 2010)

Emerald ash borer eggs get one kind of non-stinging wasps as a parasite, and larvae get two others. Their scientific names are Spathius agrili and Tetrastichus planipennisi. In some places, these wasps are being introduced to try to control the spread of emerald ash borers. (Chen, et al., 2011; Ulyshen, et al., 2012; Wang, et al., 2010)

• Ecosystem Impact
• parasite

Do they cause problems?

Emerald ash borers are invasive beetles that have killed over 15 million ash trees in Michigan. It is hard to know if a tree is infected because it is often too late to save the tree by the time you can see it is infected. The total cost of emerald ash borers on farming, forestry, and fisheries is around $134 million per year. It would cost about $1 million dollars a year to take out infested trees and replace them. Experiments trying to prevent further infections by taking trees out haven't worked, and have cost millions of dollars. There are efforts to prevent their spread by checking all wood crossing the Mackinac Bridge in Michigan. Quarantines like this are expensive for the timber industry. (Hausman, et al., 2010; Kovacs, et al., 2010; Poland, 2007)

• Ways that these animals might be a problem for humans
• crop pest

How do they interact with us?

Emerald ash borers have no known positive impacts on humans.

Are they endangered?

Emerald ash borers are not endangered.

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Contributors

Ashley Fooy (author), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.

References

Anulewicz, A., D. McCullough, D. Cappaert. 2007. Emerald Ash Borer (Agrilus planipennis) Density and Canopy Dieback in Three North American Ash Species. Arboriculture & urban Forestry, 33/5: 338-349. Accessed May 05, 2012 at https://docs.google.com/viewer?a=v&q=cache:mq_-kzl6MVwJ:joa.isa-arbor.com/request.asp?JournalID%3D1%26ArticleID%3D3011%26Type%3D2+emerald+ash+borer+density+and+canopy&hl=en&gl=us&pid=bl&srcid=ADGEEShpv8YLa6sDKYcZBNUmZlukfZdaHm7O7ddFHanmIB_7QR8XkHAsUNrsSod9JgN3Ghl9gyh4DoKt8wxRXVx-Y0LC3ARGkodZ0aY3coFb6iNEswEuyt6i6CpPLldO759xqStYk_Fm&sig=AHIEtbS7U-17Iw1R9gRRx-V9tqD4f15oSA&pli=1.

Bauer, L., R. Haack, D. Miller, T. Petrice, H. Liu. 2003. "Emerald Ash Borer Life Cycle" (On-line pdf). Accessed February 02, 2012 at http://nrs.fs.fed.us/pubs/jrnl/2003/nc_2003_bauer_001.pdf.

Chen, Y., T. Ciaramitaro, T. Poland. 2011. Moisture content and nutrition as selection forces for emerald ash borer larval feeding behavior. Ecological Entolomolgy, 36: 344-354. Accessed February 12, 2012 at http://onlinelibrary.wiley.com.proxy.lib.umich.edu/doi/10.1111/j.1365-2311.2011.01278.x/full.

Cipollini, D., Q. Wang, J. Whitehill, J. Powell, P. Bonello, D. Herms. 2011. Distinguishing defensive characteristics in the phloem of ash species resistant and susceptible to Emerald Ash Borer. Journal of Chemical Ecology, 37/5: 450-459. Accessed February 13, 2012 at http://www.springerlink.com.proxy.lib.umich.edu/content/ul8046nv608661n6/fulltext.pdf.

Crook, D., L. Keer, V. Mastro. 2008. Distribution and Fine Structure of Antennal Sensilla in Emerald Ash Borer (Coleoptera: Buprestidae). Annals of the Entomological Society of America, 101/6: 1103-1111. Accessed May 05, 2012 at http://ddr.nal.usda.gov/bitstream/10113/21493/1/IND44126924.pdf.

Crook, D., A. Khrimian, J. Francese, I. Fraser, T. Poland, A. Sawyer, V. Mastro. 2008. Development of a Host-Based Semiochemical Lure for Trapping Emerald Ash Borer Agrilus planipennis (Coleoptera: Buprestidae). Entomological Society of America, 37/2: 356-365. Accessed February 29, 2012 at http://ddr.nal.usda.gov/bitstream/10113/15553/1/IND44053185.pdf.

Crosthwaite, J., S. Sobek, B. Lyons, M. Bernards, B. Sinclair. 2011. The overwintering physiology of the emerald ash borer, Agrilus planipennis Farmaire (Coleoptera:Buprestidae). Journal of Insect Physiology, 57: 166-173. Accessed February 12, 2012 at http://pdn.sciencedirect.com.proxy.lib.umich.edu/science?_ob=MiamiImageURL&_cid=271905&_user=99318&_pii=S0022191010003021&_check=y&_origin=article&_zone=toolbar&_coverDate=31-Jan-2011&view=c&originContentFamily=serial&wchp=dGLbVlk-zSkWA&md5=471a57d7382801fa24fa3a056c30bbb4/1-s2.0-S0022191010003021-main.pdf.

Forrest, T., M. Read, H. Farris, R. Hoy. 1997. A Tympanal Hearing Organ in Scarab Beetles. The Journal of Experimental Biology, 200: 601-606. Accessed May 05, 2012 at http://jeb.biologists.org/content/200/3/601.full.pdf.

Haack, R., E. Jendek, H. Lui, K. Marchant, T. Petrice, T. Poland, H. Ye. 2002. "The Emerald Ash Borer: A New Exotic Pest in North America" (On-line). Michigan Entomological Society Newsletter Volume 47. Accessed February 02, 2012 at http://www.ncrs.fs.fed.us/pubs/jrnl/2002/nc_2002_Haack_001.pdf.

Hausman, C., J. Jaeger, O. Rocha. 2010. Impacts of the emerald ash borer (EAB) eradication and tree mortality: potential for a secondary spread of invasive plant species. Biological Invasions, 12: 2013-2023. Accessed February 23, 2012 at http://www.springerlink.com.proxy.lib.umich.edu/content/y2545n254l34673k/fulltext.pdf.

Kovacs, K., R. Haight, D. McCullough, R. Mercader, N. Siegert, A. Liebhold. 2010. Cost of potential emerald ash borer damage in U.S. communities, 2009-2019. Ecological Economics, 69: 569-578. Accessed February 13, 2012 at http://pdn.sciencedirect.com.proxy.lib.umich.edu/science?_ob=MiamiImageURL&_cid=271867&_user=99318&_pii=S0921800909003681&_check=y&_origin=article&_zone=toolbar&_coverDate=15-Jan-2010&view=c&originContentFamily=serial&wchp=dGLzVlt-zSkWb&md5=61e37ebfdd50257435b075522b159eaf/1-s2.0-S0921800909003681-main.pdf.

Liu, H., L. Bauer, R. Gao, T. Zhao, T. Petrice, R. Haack. 2003. Exploratory Survey for the Emerald Ash Borer, Agrilus planipennis (Coleoptera, Buprestidae), and its Natural Enemies in China. The Great Lakes Entomologist, 36/3&4: 191-204. Accessed February 02, 2012 at http://nrs.fs.fed.us/pubs/jrnl/2003/nc_2003_liu_001.pdf.

Poland, T. 2007. "Twenty Million Ash Trees Later: Current Status of Emerald Ash Borer in Michigan" (On-line pdf). Accessed February 02, 2012 at http://www.nrs.fs.fed.us/pubs/jrnl/2007/nrs_2007_poland_001.pdf.

Rutledge, C., M. Keena. 2012. Mating Frequency and Fecundity in the Emerald Ash Borer Agrilus planipennis (Coleoptera: Buprestidae). Arthropod Biology, 105/1: 66-72.

Taylor, R., T. Poland, L. Bauer, K. Windell, J. Kautz. 2006. Emerald Ash Borer Flight Estimates Revised. Emerald Ash Borer and Asian Longhorned Beetle Research and Development Review Meeting: 10-12. Accessed May 05, 2012 at http://www.emeraldashborer.info/files/2007.EAB.flight.revised.Abs.Cinc.pdf.

Ulyshen, M., J. Duan, L. Bauer. 2012. Interactions between Spathius agrili (Hymenoptera: Braconidae) and Tetrastichus planipennisi (Hymenoptera: Eulophidae), larval parasitoids of Agrilus planipennis (Coleoptera: Buprestidae). Biological Control, 52: 188-193. Accessed February 29, 2012 at http://ddr.nal.usda.gov/dspace/bitstream/10113/38545/1/IND44302685.pdf.

Wang, X., Z. Yang, J. Gould, G. Liu, E. Liu, Y. Zhang. 2010. The biology and ecology of the emerald ash borer, Agrilus planipennis, in China. Journal of Insect Science, 10/128: 1-23. Accessed February 02, 2012 at http://www.bioone.org/doi/pdf/10.1673/031.010.12801.