Leptocybe invasa | |
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Female Leptocybe invasa inserting ovipositor into the petiole of Eucalyptus tree | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hymenoptera |
Family: | Eulophidae |
Genus: | Leptocybe |
Species: | L. invasa |
Binomial name | |
Leptocybe invasa Fisher & La Salle, 2004 | |
Leptocybe invasa, the blue gum chalcid wasp or eucalyptus gall wasp, is a chalcid wasp which is the only species in the monotypic genus Leptocybe in the subfamily Tetrastichinae, of the family Eulophidae. It is a gall wasp which causes the formation of galls on a number of species of Eucalyptus , it was described in 2004 after galls were found in river red gums (Eucalyptus camaldulensis) in the Mediterranean and Middle East and has since been found to be a widespread species where its host trees are planted. It is indigenous to Australia.
This tiny wasp is just over one millimeter in length. Its body is brown with a slight blue to green iridescence. Parts of the legs are yellowish in color. [1]
Leptocybe invasa is native to Queensland, Australia where its exact distribution has yet to be determined. It has now been found as an invasive species in eucalypts in northern, eastern and southern Africa, Asia, the Pacific Region, Europe as far north as the United Kingdom, southern Asia, southern South America, the Middle East, Mexico and the United States. It appears to be spreading. [2] [3] [4]
L. invasa was discovered in 2000 when river red gums in the Middle East and Mediterranean began developing disfiguring galls. The damage became severe enough to cause crop losses in tree plantations. Galls were collected and a previously undescribed species of chalcid wasp emerged. In 2004 it was described to science as Leptocybe invasa. [1]
The adult female injects a neat line of minute eggs in the epidermis of new leaf buds on eucalyptus trees. The leaf tissue may exude a whitish sap, which covers the oviposition site. Heavy wasp infestations can kill new buds on the trees. If the bud survives it develops a layer of corky tissue within one to two weeks of oviposition. This corky scar widens and becomes glossy in texture. It turns from green to pinkish to dark pink or red in color. It loses its glossy texture and turns dull brown or reddish. The chalcid wasp larva develops inside the gall and when it emerges as an adult insect the gall is spherical and up to 2.7 millimeters wide. During an infestation there are usually 3 to 6 galls per leaf, but up to 65 have been observed on a single leaf. [1] The adult wasps emerge from the galls after growing inside for 3–4 months. In temperate areas there may be 2-3 generations of adults in a year but in the tropics there can be as many as 6 generations. [5] The females can reproduce asexually by thelytokous reproduction and live for up to 7 days, [6] males are rare and the asexual reproduction allows L. invasa to rapidly increase its population size. [7]
Several eucalyptus species are susceptible to the wasp. Host species include bangalay (Eucalyptus botryoides), apple box (E. bridgesiana), Tasmanian blue gum (E. globulus), cider gum (E. gunnii), flooded gum (E. grandis), swamp mahogany (E. robusta), Sydney blue gum (E. saligna), forest red gum (E. tereticornis), and manna gum (E. viminalis). [1]
Possible biological agents for L. invasa have been actively searched for and numerous hymenopteran parasitoids of L. invasa were identified; in one study in China these were Quadrastichus mendeli , Aprostocetus causalis and Megastigmus viggianii , [8] and in another study in Israel these were Megastigmus zvimendeli , Megastigmus lawsoni , Selitrichodes kryceri and Quadrastichus mendeli . [9]
Quadrastichus mendeli has a short developmental time [10] and has proven to be an especially effective control agent in the Mediterranean Basin. [9] Selitrichodes neseri is another eulophid ectoparasitoid which is species specific to L. invasa and was discovered in its native Australian range in 2014 and show potential as a biological control agent on L. invasa. [11]
Chalcid wasps are insects within the superfamily Chalcidoidea, part of the order Hymenoptera. The superfamily contains some 22,500 known species, and an estimated total diversity of more than 500,000 species, meaning the vast majority have yet to be discovered and described. The name "chalcid" is often confused with the name "chalcidid", though the latter refers strictly to one constituent family, the Chalcididae, rather than the superfamily as a whole; accordingly, most recent publications (e.g.,) use the name "chalcidoid" when referring to members of the superfamily.
Galls or cecidia are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or warts in animals. They can be caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites. Plant galls are often highly organized structures so that the cause of the gall can often be determined without the actual agent being identified. This applies particularly to insect and mite plant galls. The study of plant galls is known as cecidology.
In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation.
Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" (petiole) formed between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host or in a nest cell provisioned by their mothers.
Wiliwili is a species of tree in the pea family, Fabaceae, that is endemic to the Hawaiian Islands. It is the only species of Erythrina that naturally occurs there. It is typically found in Hawaiian tropical dry forests on leeward island slopes up to an elevation of 600 m (2,000 ft).
Trichogramma is a genus of minute polyphagous wasps that are endoparasitoids of insect eggs. Trichogramma is one of around 80 genera from the family Trichogrammatidae, with over 200 species worldwide.
A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as bees and ants are deeply nested within the wasps, having evolved from wasp ancestors. Wasps that are members of the clade Aculeata can sting their prey.
Quadrastichus is a genus of hymenopteran insects of the family Eulophidae.
Phytomyza ilicis, the holly leaf miner, is a leaf mining fly in the family Agromyzidae, whose larvae burrow into leaves of the holly tree leaving characteristic pale trails or leaf mines.
Ophelimus maskelli is a species of chalcid wasp about 1mm long, known as the eucalyptus gall wasp, indigenous to Australia and New Zealand, and invasive in the Mediterranean, the Middle East, North Africa, South Africa, tropical Asia, and the United States (California). It is considered a plant pest as females lay eggs on immature eucalyptus leaves; the larvae produce galls on the leaves. Heavy infestations induce much galling which causes widespread defoliation and loss of growth. Wasps may emerge in large numbers in the spring, forming clouds which are a nuisance to humans.
Evania appendigaster, also known as the blue-eyed ensign wasp, is a species of wasp in the family Evaniidae. Its native range is not known, but it likely originated in Asia. Today it occurs throughout the tropics and subtropics and in many temperate regions. As with the rest of its family, the blue-eyed ensign wasp is a parasitoid known for specializing on cockroach eggs.
Sycophila is a genus of wasp that associates with figs and galls of various insects such as gall wasps and gall midges. They have a cosmopolitan distribution.
Cotesia urabae is a small wasp, having a black body with yellow-brown legs, characterized by a solitary larval endoparasitoid stage. It is part of a large complex of 11 primary parasitoids of Uraba lugens Walker, many of which are polyphagous. The female inserts its ovipositor into the a U. lugens larva, depositing its eggs there, and it has been found that one female may carry up to 400 eggs. While C. urabae females are able to attack the same larva several times; only one single parasitoid completes its development in each larva.
Quadrastichus erythrinae Kim, 2004, is a small parasitoid wasp belonging to the family Eulophidae, but also a secondary phytophage by way of inducing galls on the leaves, stems, petioles and young shoots of various Erythrina species.
Anaphes nitens is a species of fairyfly, a chalcid wasp in the family Mymaridae. Native to Australia, it is an egg parasitoid of the gum tree snout beetle, a pest of Eucalyptus trees, and has been used in biological pest control of that species.
Tetrastichinae is a subfamily of the chalcid wasp family Eulophidae. It is one of the largest subfamilies of the Eulophidae containing over 100 genera and nearly 3,000 species. The species of the family Tetrastichinae are found in almost any type of terrestrial habitat and have a worldwide distribution, except Antarctica. They show a varied biology and hosts for Tetrastichinae wasps have been identified from over 100 different insect families, across 10 different orders and they have also been recorded as being parasitoids on nematodes, mites and spiders' eggs. Some species are even phytophagous, while others are inquilines and yet others are gall formers.
Euderus set, the crypt-keeper wasp, is a tiny chalcid wasp from the family Eulophidae from the United States, described in 2017 as a parasitoid of the gall wasp Bassettia pallida. The description of its life cycle has attracted widespread publicity.
Selitrichodes is a genus of hymenopteran insects of the family Eulophidae, most of which are parasitoids associated with gall producing insects on Eucalyptus.
Bassettia pallida is a species of gall wasp found in the Southern United States. This species was described by American entomologist William Harris Ashmead in 1896. B. pallida reproduces asexually in galls it induces on oak trees. The parasite Euderus set, a eulophid wasp, has B. pallida as a host and manipulates its behavior.
Oomyzus gallerucae is a species of chalcid wasp in the family Eulophidae. It is a parasitoid of the elm leaf beetle. The adults and larvae eat the eggs of the beetle.