Scientists & Staff
Nathan P. Havill
Ecology and Management of Invasive Species and Forest Ecosystems
E-mail: Contact Nathan P. Havill
51 Mill Pond Rd.
Hamden, CT 06514
With expertise in the ecology and evolution of multi-trophic interactions, I work to provide information about invasive pests, their natural enemies, and the impacted trees. Understanding the interactions among these trophic levels is critical to making sound management decisions to reduce the impact of invasive pests. Facets of my research objectives include investigating: 1) systematics and population genetics of invasive pests, especially hemlock woolly adelgid, balsam woolly adelgid, gypsy moth, and winter moth; 2) systematics and population genetics of predators and parasitoids being evaluated as biological control agents of invasive species, especially of hemlock woolly adelgid and emerald ash borer; and 3) systematics and biogeography of North American tree species and their relatives worldwide.
My goal is to help reconstruct the evolutionary history of multiple trophic levels of a pest system to guide management and mitigate the impact of invasive insect pests on forested ecosystems of the northeastern United States. I am especially concerned with research related to classical biological control to develop practical, cost effective tools used to evaluate the safety and efficacy of predators or parasites introduced as biological control agents.
Why This Research is Important
The exotic invasive pests that are the subject of this research originated in either Asia or Europe. Invasive insects in North America are not often pests in their region of origin due to resistant tree species and natural enemies that co-evolved with the pest over millions of years. The insect becomes a pest following introduction outside its native ranges when these bottom-up and/or top-down regulating factors are no long effective. The hemlock woolly adelgid, Adelges tsugae (Adelgidae), originated in Japan and causes the death and decline of eastern North American hemlock trees in 17 eastern states. The balsam woolly adelgid, Adelges piceae (Adelgidae), originated in Europe and has been killing fir trees throughout North America for over 100 years. The gypsy moth, Lymantria dispar (Lymantriidae), also was also introduced from Europe over 100 years ago. It is controlled to some extent by a pathogenic fungus in areas where it is well established, so management in the U. S. currently focuses on slowing its spread and on preventing invasion by more virulent strains from Asia. The winter moth, Operophtera brumata (Geometridae), is also from Europe and defoliates a broad range of tree species, including oaks and birches in southern New England, and is hybridizing with the native Bruce spanworm, O. bruceata. Finally, the emerald ash borer, Agrilus planipennis (Buprestidae) originated in Asia, was first discovered in the U.S. in Michigan in 2002, and has killed tens of millions of ash trees in at least 15 eastern states. Together, these pest species represent a diverse group of insects with very different feeding strategies, life cycles, host ranges, and natural enemy complexes.
- Yale University, Ph.D. Ecology & Evolutionary Biology, 2006
- Yale University, M.S. Ecology & Evolutionary Biology, 2003
- University of Wisconsin, Madison, M.S. Entomology, 1998
- College of William and Mary, B.S. Biology, 1996
- Society For The Study Of Evolution, Member (2012 - Current)
- Connecticut Entomological Society, Member (2001 - Current)
- Entomological Society of America, Member (1996 - Current)
Featured Publications & Products
- Havill, Nathan P.; Montgomery, Michael E.; Keena, Melody. 2011. Hemlock woolly adelgid and its hemlock hosts: A global perspective.
- Michael E., Montgomery; Shiyake, S.; Havill, Nathan P. . 2011. A new species of Laricobius (Coleoptera: Derodontidae) from Japan with phylogeny and a key for native and introduced congeners in North America.
- Havill, Nathan P.; Salom, Scott; Davis, Gina; Fischer, Melissa; Mausel, David; Onken, Bradley. 2011. The introduction of Laricobius nigrinus as a biological control agent for the hemlock woolly adelgid: Is there a threat to the native congener, L. rubidus?.
Publications & Products
- Havill, Nathan P.; Vieira, Ligia C.; Salom, Scott M. 2014. Biology and control of hemlock woolly adelgid.
- Fischer, Melissa J.; Havill, Nathan P.; Jubb, Carrie S.; Prosser, Sean W.; Opell, Brent D.; Salom, Scott M.; Kok, Loke T. 2014. Contamination delays the release of Laricobius osakensis for biological control of hemlock woolly adelgid: cryptic diversity in Japanese Laricobius spp.
- Mayfield, Albert E., III.; Reynolds, Barbara C.; Coots, Carla I.; Havill, Nathan P.; Brownie, Cavell; Tait, Andrew R.; Hanula, James L.; Joseph, Shimat V.; Galloway, Ashley B. 2014. Establishment, hybridization and impact of Laricobius predators on insecticide-treated hemlocks: Exploring integrated management of the hemlock woolly adelgid.
- Havill, Nathan P.; Vieira, Ligia C.; Salom, Scott M. 2014. Hemlock woolly adelgid: a threat to eastern forests.
- Ravn, H.P.; Havill, N.P.; Akbulut, S.; Foottit, R.G.; Serin, M.; Erdem, M.; Mutun, S.; Kenis, M. 2013. Dreyfusia nordmannianae in Northern and Central Europe: potential for biological control and comments on its taxonomy.
- Havill, N.P.; Davis, Gina; Mausel, David; Klein, Joanne; McDonald, Richard; Jones, Cera; Fischer, Melissa; Salom, Scott; Caccone, Adelgisa. 2012. Hybridization between a native and introduced predator of Adelgidae: An unintended result of classical biological control.
- Davis, G.A.; Havill, N.P.; Adelman, Z.N.; Caccone, A.; Kok, L.T.; Salom, S.M. 2011. DNA barcodes and molecular diagnostics to distinguish an introduced and native Laricobius (Coleoptera: Derodontidae) species in eastern North America.
- Havill, Nathan P.; Davis, Gina; Klein, Joanne; Caccone, Adalgisa; Salom, Scott. 2011. Hemlock woolly adelgid biological control: molecular methods to distinguish Laricobius nigrinus, L. rubidus, and their hybrids.
- Sano, Masakazu; Havill, Nathan P.; Ozaki, Kenichi. 2011. Taxonomic identity of a galling adelgid (Hemiptera: Adelgidae) from three spruce species in central Japan.
- Yang, Zi-xiang; Chen, Xiao-ming; Havill, Nathan P.; Feng, Ying; Chen, Hang. 2010. Phylogeny of Rhus gall aphids (Hemiptera:Pemphigidae) based on combined molecular analysis of nuclear EF1α and mitochondrial COII genes.
- Havill, Nathan P.; Klein, Joanne; Keena, Melody A.; Caccone, Adalgisa. 2009. Characterization of microsatellite loci for Laricobius nigrinus and L rubidus, predators of adelgids in North America.
- Foottit, R.G.; Maw, H.E.L.; Havill, N.P.; Ahern, R.G.; Montgomery, M.E. 2009. DNA barcodes to identify species and explore diversity in the Adelgidae (Insecta: Hemiptera: Aphidoidea).
- Havill, Nathan P.; Montgomery, Michael; Shiyake, Shigehiko; Lamb, Ashley; Keena, Melody A.; Caccone, Adalgisa. 2009. Hemlock woolly adelgid population genetics.
- Havill, Nathan P.; Montgomery, Michael E. 2008. The role of arboreta in studying the evolution of host resistance to the hemlock woolly adelgid.
- Butin, Elizabeth; Elkinton, Joseph; Havill, Nathan; Montgomery, Michael. 2003. Comparative impact of Scymnus ningshanensis and Pseudoscymnus tsugae (Coleoptera: Coccinellidae) on the hemlock woolly adelgid.
- Montgomery, Michael; Havill, Nathan; Cheah, Carole; McClure, Mark; Zilahi-Balogh, Gabriella; Lamb, Ashley; Salom, Scott. 2003. Hemlock woolly adelgid biological control research.
- Montgomery, Michael; Wang, Hongbin; Yao, Defu; Lu, Wenhau; Havill, Nathan; Li, Guangwu. 2002. Biology of Scymnus ningshanensis (Coleoptera: Coccinellidae): A predator of Adelges tsugae (Homoptera: Adelgidae).
- Butin, Elizabeth; Montgomery, Montgomery; Havill, Nathan; Elkinton, Joseph. 2002. Pre-release host range assessment for classical biological controls: experience with predators for the hemlock woolly adelgid.