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Nathan Havill | |
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Born | 1972 |
Nationality | American |
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Nathan Peterson Havill (born 1972) is an American entomologist and evolutionary biologist. Havill is a Research Entomologist with the United States Forest Service in Hamden, Connecticut and is internationally recognized on the phylogeny of Adelgidae.
Since 1996 Havill has been a member of the Entomological Society of America. Since 2001, he has been a member of the Connecticut Entomological Society. Since 2012, he has been a member of the Society for the Study of Evolution. [1]
His research focuses on the ecology and evolution of multi-trophic interactions and, in particular invasive pests, their natural enemies, and the impacted trees. [1]
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A typical life cycle involves flightless females giving live birth to female nymphs—who may also be already pregnant, an adaptation scientists call telescoping generations—without the involvement of males. Maturing rapidly, females breed profusely so that the number of these insects multiplies quickly. Winged females may develop later in the season, allowing the insects to colonize new plants. In temperate regions, a phase of sexual reproduction occurs in the autumn, with the insects often overwintering as eggs.
Tsuga is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The common name hemlock is derived from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock. Unlike the latter, Tsuga species are not poisonous.
Tsuga canadensis, also known as eastern hemlock, eastern hemlock-spruce, or Canadian hemlock, and in the French-speaking regions of Canada as pruche du Canada, is a coniferous tree native to eastern North America. It is the state tree of Pennsylvania. Eastern hemlocks are widespread throughout much of the Great Lakes region, the Appalachian Mountains, the Northeastern United States, and Maritime Canada. They have been introduced in the United Kingdom and mainland Europe, where they are used as ornamental trees.
The winter moth is a moth of the family Geometridae. It is an abundant species in Europe and the Near East and a famous study organism for evaluating insect population dynamics. It is one of very few lepidopterans of temperate regions in which adults are active in late autumn and early winter. The adults use endothermy for movement in these cold temperatures. The females of this species are virtually wingless and cannot fly, but the males are fully winged and fly strongly. After the initial frosts of late fall, the females emerge from their pupae, walk to and up trees and emit pheromones in the evening to attract males. After fertilization, they ascend to lay, on average, around 100 eggs each. Typically, the larger the female moth is, the more eggs she lays.
Derodontidae is a family of beetles, in its own superfamily, Derodontoidea, sometimes known as the tooth-necked fungus beetles. Beetles of this family are small, between 2 and 6 mm in length, typically with spiny margins on their pronotum that give them their name, though the genus Laricobius lacks these spines. Unusual among beetles, they have two ocelli on the top of their heads.
Tsuga caroliniana, the Carolina hemlock, is a species of hemlock endemic to the United States. As of 2023, it is under review for listing under the Endangered Species Act of 1973.
The hemlock woolly adelgid, or HWA, is an insect of the order Hemiptera native to East Asia. It feeds by sucking sap from hemlock and spruce trees. In its native range, HWA is not a serious pest because populations are managed by natural predators and parasitoids and by host resistance. In eastern North America it is a destructive pest that threatens the eastern hemlock and the Carolina hemlock. HWA is also found in western North America, where it has likely been present for thousands of years. In western North America, it primarily attacks western hemlock Tsuga heterophylla and has only caused minor damage due to natural predators and host resistance. Accidentally introduced to North America from Japan, HWA was first found in the eastern United States near Richmond, Virginia, in 1951. The pest is now found from northern Georgia to coastal Maine and southwestern Nova Scotia. As of 2015, 90% of the geographic range of eastern hemlock in North America has been affected by HWA.
The gall adelgid is an adelgid species that produces galls in spruce trees. They infect the new buds of native spruce trees in the foothills of the Rocky Mountains in the spring. They also attack blue spruce to a lesser degree. The insects complete two generations within the year. They require two different trees for its life cycle, the second being the Rocky Mountain Douglas-fir. They may also attack Sitka, Engelmann, or white spruce. The many different species of adelgids produce different galls on different spruce species.
The Adelgidae are a small family of the Hemiptera closely related to the aphids, and often included in the Aphidoidea with the Phylloxeridae or placed within the superfamily Phylloxeroidea as a sister of the Aphidoidea within the infraorder Aphidomorpha. The family is composed of species associated with pine, spruce, or other conifers, known respectively as "pine aphids" or "spruce aphids". This family includes the former family Chermesidae, or "Chermidae", the name of which was declared invalid by the ICZN in 1955. There is still considerable debate as to the number of genera within the family, and the classification is still unstable and inconsistent among competing authors.
Operophtera bruceata, the Bruce spanworm, hunter's moth, or native winter moth is a moth of the family Geometridae. The species was first described by George Duryea Hulst in 1886. It is found from coast to coast in southern Canada and the northern parts of the United States.
Laricobius is a genus of beetles in the family Derodontidae, the tooth-necked fungus beetles.
The pineapple gall adelgid is a species of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids are pear-shaped, soft-bodied green insects with long antennae, closely related to the aphid. Adelges lays up to one hundred eggs at a time, one on each needle. Adelges abietis is one of the most common species; synonyms are A. gallarum-abietis, Chermes abietis and Sacciphantes abietis.
Phylloxeridae is a small family of plant-parasitic hemipterans closely related to aphids with only 75 described species. This group comprises two subfamilies and 11 genera with one that is fossil. The genus type is Phylloxera. The Phylloxeridae species are usually called phylloxerans or phylloxerids.
Laricobius osakensis is a species of Derodontid beetle native to Japan. Described in 2011, it feeds exclusively on hemlock woolly adelgid, an invasive insect species that is destroying huge numbers of hemlock trees in eastern North America. It has shown promise as a biological control agent in field trials.
Trunk injection or endotherapy also known as vegetative endotherapy,—is a method of targeting a precise application of pesticides, plant resistance activators, or fertilizers into the xylem vascular tissue of a tree with the purpose of protecting the tree from pests, or to inject nutrients to correct for nutrient deficiencies. This method largely relies on harnessing the tree's vascular system to translocate and distribute the active compounds into the wood, canopy and roots where protection or nutrition is needed.
Chelonoidis niger donfaustoi, known as the eastern Santa Cruz tortoise, is a subspecies of Galápagos tortoise living on Santa Cruz Island, within the Galápagos. Until 2015, C. n. donfaustoi was classified as part of another subspecies, Chelonoidis porteri.
Grylloprociphilus is a genus of woolly and gall-making aphids in the family Aphididae. There is at least one described species in Grylloprociphilus, G. imbricator. G. imbricator feeds on American beech.
Laricobius nigrinus is a species of tooth-necked fungus beetle in the family Derodontidae. It is native to western North America, and it is being studied as a biological control agent for the hemlock woolly adelgid. It was first released in 2003 and continues to be reared and released across the Northeast to control infestations.
Laricobius rubidus is a species of tooth-necked fungus beetle in the family Derodontidae. It is found in North America. Studies are ongoing to determine the rate of hybridization between L. rubidus, which feeds on pine bark adelgid, and its native congener, Laricobius nigrinus, which is being studied as a biological control agent for the hemlock woolly adelgid.
Sasajiscymnus tsugae, formerly Pseudoscymnus tsugae, is a species of insect in the family Coccinellidae. It feeds on the hemlock woolly adelgid.