| Lebia grandis | |
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| L. grandis inside pitcher plant | |
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| Species: | L. grandis |
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| Lebia grandis Say, 1823 | |
Lebia grandis is a ground beetle in the family Carabidae found in North America. It is a specialist predator on the eggs and larvae of Colorado potato beetles, and its larvae are obligate parasitoids of Colorado potato beetle pupae. [1]
Lebia grandis is the largest species in its genus found in North America. It is about one centimetre long with a rusty orange head, thorax and legs, a black abdomen and an iridescent blue or purple lustre to the dark coloured elytra. [2] These are wide but rather shorter than the abdomen which protrudes posteriorly. [3]
Adult Lebia grandis ground beetles overwinter in soil in or near potato fields. In the spring Colorado potato beetles emerge from hibernation. By the time Lebia grandis beetles emerge a few weeks later, there are eggs and young larvae of their prey for them to eat and suitable pupae will soon be available for their larvae to attack. An adult beetle can eat about twenty three eggs or three third instar larvae of the Colorado potato beetle each day. [4] After mating, the females lay eggs singly in the soil near potato plants. A glandular secretion causes soil granules to stick to the eggs which serves to camouflage them. Each female can lay up to 1300 eggs over the course of a few months. [2]
The eggs hatch after about two weeks and the first instar larvae search out Colorado potato beetle larvae that are about to pupate. They may follow an odour trail left behind by the burrowing larvae and they need to reach the pupation chamber before it is sealed. They sink their mandibles into the integument of their hosts and start feeding, killing the host in the process. After moulting they cease feeding and soon metamorphose into the pupal stage. Adult ground beetles emerge about three weeks after the eggs were hatched. [2]
The significance of Lebia grandis in keeping Colorado Potato Beetle under control was not originally fully appreciated because of the largely nocturnal habits of the adult beetles and the subterranean existence of the larvae. [5] In fact it was about a hundred years after its first description as a species that the larvae were discovered to have a parasitoid habit. [6]
Because it specifically targets Colorado potato beetles and is native to North America, Lebia grandis shows promise as a biological control species in the United States. However it does not usually occur in sufficient numbers to effect complete control. Populations may need to be augmented by releasing adult beetles but rearing these in bulk presents certain difficulties that have not yet been overcome. [2] Other predators such as the spotted lady beetle ( Coleomegilla maculata ) also prey on Colorado potato beetles but Lebia grandis is constrained by its chrysomelid larval host to habituate potato fields while other predators may disperse to other sources of food. [4]
The historical records for Lebia grandis show that it was present in areas where Leptinotarsa decemlineata was not found. This would seem to imply that at one time it parasitized a different species. [7]
The original host plant of the Colorado potato beetle, Leptinotarsa decemlineata was the buffalo bur, Solanum rostratum , in Mexico. No association has been found between Lebia grandis and Leptinotarsa 'decemlineata on this host plant. In the 1850s, Leptinotarsa decemlineata began to feed on the potato plant and spread rapidly eastwards on potato crops. Lebia grandis may have had a relationship prior to this with the false potato beetle, Leptinotarsa juncta which feeds on horsenettle, Solanum carolinense . [8] Another closely related chrysomid beetle, Leptinotarsa haldemani is recorded from Texas, Oklahoma, Arizona and Mexico, where it lives on wild species of Physalis and Solanum douglasii , but its range does not overlap with Lebia grandis except possibly in Texas.
In an attempt to find the original species associated with Lebia grandis, research was undertaken examining its prey preferences and the suitability of the three chrysomelid species, L. decemlineata, L. juncta and L. haldemani as hosts for its larvae.
Adult Lebia grandis beetles were offered suitable sized larvae of these three chrysomelid species and the number of larvae of each species that were eaten was noted. A similar experiment was performed using the eggs of the three chrysomelid species. The Lebia grandis adults showed no significant difference in the number of larvae of each prey species they chose to eat, but they did differentiate between their eggs. L. juncta egg consumption averaged nearly twice as high as L. decemlineata egg consumption, with L. haldemani being in an intermediate position. [4]
In another experiment, a first instar larva of Lebia grandis was placed in close proximity to a 4th instar chrysomelid larva that was about to pupate. The success rate of parasitism in each of the three prey species was noted. Successful development of Lebia grandis from first instar larva to adult occurred with each of the three species of Leptinotarsa. However the success rate recorded for L. juncta was about 43% as compared to 12% for the other two species. [4]
These studies would seem to support the view that Lebia grandis was originally exclusively a parasitoid of L. juncta, but that the opportunity afforded by its encounter with L. decemlineata less than 150 years ago enabled it to exploit this new and abundant food source. [4]
The Colorado potato beetle, also known as the Colorado beetle, the ten-striped spearman, the ten-lined potato beetle, or the potato bug, is a major pest of potato crops. It is about 10 mm long, with a bright yellow/orange body and five bold brown stripes along the length of each of its elytra. Native to the Rocky Mountains, it spread rapidly in potato crops across America and then Europe from 1859 onwards.
The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle families. Numerous subfamilies are recognized, but the precise taxonomy and systematics are likely to change with ongoing research.
The Tansy beetle is a species of leaf beetle. The common name derives from its main foodplant, Tansy, but it can also use other wetland plants such as Gypsywort and Water Mint. It measures 7.7–10.5 mm in length and has a characteristic bright metallic green colouration, with pitted elytra and a coppery tinge. In addition to the nominotypical subspecies, which repeats the specific name, C. graminis graminis, there are five further distinct subspecies of Tansy beetle, which, collectively, have a Palearctic distribution, although in the majority of countries where it is found the species is declining. In the United Kingdom it is designated as 'Nationally Rare'. The UK's stronghold population is located along the banks of the river Ouse in York, North Yorkshire,. Other, small fenland populations exist at Woodwalton Fen and at Welney Wildfowl and Wetlands Trust (WWT) reserve.
The false potato beetle is a beetle found primarily in the Mid-Atlantic and Southeastern United States. Its distribution extends to Maine.
The scarlet lily beetle, red lily beetle, or lily leaf beetle, is a leaf beetle that eats the leaves, stem, buds, and flowers, of lilies, fritillaries and other members of the family Liliaceae. It lays its eggs most often on Lilium and Fritillaria species. In the absence of Lilium and Fritillaria species, there are fewer eggs laid and the survival rate of eggs and larvae is reduced. It is now a pest in most temperate climates where lilies are cultivated.
Leptinotarsa is a genus of leaf beetles.
Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.
The Chrysomelinae are a subfamily of leaf beetles (Chrysomelidae), commonly known as broad-bodied leaf beetles or broad-shouldered leaf beetles. It includes some 3,000 species around the world.
Delphastus pusillus is a small ladybird beetle which preys on all species and stages of whitefly, but prefers eggs and nymphs. The adults are small, shiny, black beetles. Newly emerged adults are pale-brown to almost white. They eventually turn black with a brown head. The eggs are 0.2 mm long, clear and twice as long as they are wide. The elongate larvae are pale yellow.
Anthonomus eugenii is known as the pepper weevil. This beetle feeds and lays eggs on plants in the genus Capsicum and a few species in the genus Solanum. A. eugenii is native to Mexico, however, it is an important pest of Capsicum in Florida, Puerto Rico, and Central America.
Acherontia lachesis, the greater death's head hawkmoth or bee robber, is a large sphingid moth found in India, Sri Lanka and much of the Oriental region. It is one of the three species of death's-head hawkmoth genus, Acherontia. The species was first described by Johan Christian Fabricius in 1798. It is nocturnal and very fond of honey; they can mimic the scent of honey bees so that they can enter a hive unharmed to get honey. Their tongue, which is stout and very strong, enables them to pierce the wax cells and suck the honey out. This species occurs throughout almost the entire Oriental region, from India, Pakistan and Nepal to the Philippines, and from southern Japan and the southern Russian Far East to Indonesia, where it attacks colonies of several different honey bee species. It has recently become established on the Hawaiian Islands.
Diamphidia, or Bushman arrow-poison beetle, is an African genus of flea beetles, in the family Chrysomelidae.
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.
Leptinotarsa haldemani, commonly known as Haldeman's green potato beetle, is a glossy green-colored species of beetle in the leaf beetle family Chrysomelidae. It was named in honour of Samuel Stehman Haldeman, a 19th-century American entomologist who collected insect specimens in Texas.
Diabrotica balteata is a species of cucumber beetle in the family Chrysomelidae known commonly as the banded cucumber beetle. It occurs in the Americas, where its distribution extends from the United States to Colombia and Venezuela in South America. It is also present in Cuba. It is a pest of a variety of agricultural crops.
Gratiana boliviana is a species of beetle in the leaf beetle family, Chrysomelidae. Its common name is tropical soda apple leaf beetle. It is native to South America, where its distribution includes Argentina, Brazil, and Paraguay. It specializes on tropical soda apple, an invasive plant species. It has been released as an agent of biological pest control against the weedy plant in Florida and other parts of the United States.
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Perillus bioculatus, the two-spotted stink bug or double-eyed soldier bug, is a species of insect in the family Pentatomidae. They are native to North America but have been introduced to Eastern Europe and North India. Both the larval and adult stages are specialized predators of eggs and larvae of the Colorado potato beetle. However, the first instar larvae feed by sucking the juices out of potato stems.
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