Laricobius nigrinus | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Coleoptera |
Family: | Derodontidae |
Genus: | Laricobius |
Species: | L. nigrinus |
Binomial name | |
Laricobius nigrinus Fender, 1945 | |
Laricobius nigrinus is a species of tooth-necked fungus beetle in the family Derodontidae. [1] [2] It is native to western North America, and it is being studied as a biological control agent for the hemlock woolly adelgid. [3] It was first released in 2003 and continues to be reared and released across the Northeast to control infestations. [4]
Laricobius nigrinus was first described by Kenneth Fender in 1945 from specimens collected in Oregon. [5] Laricobius is one of four genera in Derodontidae. [6] The genus has a Holarctic distribution, with most species native to Asia. [6]
Adult beetles have a black body, clubbed antennae with eleven segments, and two ocelli. Their palps, antennae, and tarsi are dark brown to red. The head is partially visible from above. [7] They are usually 2.3-2.9 mm long, with no significant sex differences in size. [7] The species can be distinguished from other black Laricobius by its toothed pronotal margin. [6] Its eggs are yellow and oblong, usually laid in the ovisacs of A. tsugae. [7] The larvae have three segmented antennae, a well-developed head with twelve stemmata and hairy abdominal segments. [7] They are "oligopod type" larvae, with three pairs of thoracic legs, and no prolegs. The larvae start as yellow before darkening to yellow green/yellow brown with maturity. Pupae resemble the adult form, and individuals can be sexed in pupal form. [7]
All members of Laricobius feed on members of Adelgidae, and Laricobius nigrinus is specialized on the hemlock woolly adelgid. [7] The predatory life history of Laricobius is unique among the family as most derodontids are fungal feeders. [6] L. nigrinus is native to hemlock forests in the Pacific Northwest. It can be found throughout the western U.S. and Canada, and specimens in the U.S. Museum of Natural History have been collected as far north as the southeastern Yukon. [8] It has a univoltine life cycle, completing one generation per year. Eggs are laid in early spring, and its development is synchronized with the winter/spring generation of A. tsugae. [8] Females lay an average of 100 eggs during their lifetimes. [9] L. nigrinus goes through four larval instars, and the larvae use secretions to glue debris and adelgid wool to themselves as camouflage. [7] Fourth instar larvae drop to the ground as prepupae and complete their development in the soil before emerging as adults in the fall. Similar to its prey, L. nigrinus is dormant during the summer months, aestivating as a pupa. The adult beetles feed on adult adelgids, while the larvae feed on the eggs of the spring progrediens generation. [8] They have a temperature dependent development, and cannot complete development above 21 °C. [10] They are significantly more active during the day than at night. Their flight behavior is responsive to prey densities, and they will only fly when their food source is scarce. [11] They use scent to home in on adelgids at close range, and respond to the odors of the adelgid's native host tree, western hemlock as well as the odors of western white pine and white spruce. [12]
Due to its narrow prey specificity and geographic range, L. nigrinus was approved by USDA-APHIS for release as a biological control agent in 2000. [8] Field releases began in 2003, and populations have expanded to cover a wide range of A. tsugae infestation. [8] As of 2021 it has been released in 18 states, and has established in Pennsylvania, Maryland, New York, New Jersey, Virginia, Georgia, West Virginia, North Carolina, Tennessee, Connecticut, Massachusetts, Maine, and New Hampshire. Releases are continuing throughout the infestation range. [13] [4] It has been shown to strongly impact A. tsugae densities in experiments conducted in their native range, [14] and a recent study found that L. nigrinus has a significant impact on the mortality of A. tsugae eggs at caged release sites. [15] Studies are ongoing to determine the rate of hybridization between L. nigrinus and its native congener, Laricobius rubidus which feeds on pine bark adelgid. [16]
The Japanese beetle is a species of scarab beetle. The adult measures 15 mm (0.6 in) in length and 10 mm (0.4 in) in width, has iridescent copper-colored elytra, and a green thorax and head. Due to natural predators, the Japanese beetle is not considered a pest in Japan, but in North America and some regions of Europe, it is a noted pest to roughly 300 species of plants. Some of these plants include rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees, and others.
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.
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.
Adelges tsugae, 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.
Amara aenea is a ground beetle common in almost the whole of Europe and Northern Asia. Its range covers also parts of Northern Africa. It is known as the common sun beetle.
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.
Cyphocleonus achates is a species of true weevil known as the knapweed root weevil. It is native to southern Europe and the Mediterranean and is used as an agent of biological pest control against noxious knapweeds, especially spotted knapweed. It has recently been spotted in India.
Coccinellidae is a widespread family of small beetles. They are commonly known as ladybugs in North America and ladybirds in the United Kingdom; "lady" refers to mother Mary. Entomologists use the names ladybird beetles or lady beetles to avoid confusion with true bugs. The more than 6,000 described species have a global distribution and are found in a variety of habitats. They are oval beetles with a domed back and flat underside. Many of the species have conspicuous aposematic (warning) colours and patterns, such as red with black spots, that warn potential predators that they taste bad.
The hemlock moth, also known as the defoliating hemlock moth or poison hemlock moth, is a nocturnal moth species of the family Depressariidae. Of Palaearctic origin, it was first found in North America in 1973 when it was accidentally introduced. The moth is now widespread throughout the northern half of the United States, southern Canada, northern Europe, and, more recently, New Zealand and Australia. The larval form grows to around 10 mm, while the adults wingspan is between 17 mm and 19 mm.
Laricobius is a genus of beetles in the family Derodontidae, the tooth-necked fungus beetles.
Coleomegilla maculata, commonly known as the spotted lady beetle, pink spotted lady beetle or twelve-spotted lady beetle, is a large coccinellid beetle native to North America. The adults and larvae feed primarily on aphids and the species has been used as a biological control agent. Based on name connotation and to avoid confusion with other species also called "spotted ladybeetle", spotted pink ladybeetle is probably the most appropriate common name for this species.
Hylobius transversovittatus is a species of weevil in the family Curculionidae. It is native to the Old World where both adults and larvae feed on purple loosestrife. This plant is regarded as an invasive species in North America and the weevil has been introduced into both the United States and Canada in an effort to control the plant.
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.
Scymnus coniferarum, the conifer lady beetle, is a species of dusky lady beetle in the family Coccinellidae. It is found in western North America.
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.
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