Tamarixia radiata

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Tamarixia radiata
Tamarixia radiata.png
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Eulophidae
Genus: Tamarixia
Species:
T. radiata
Binomial name
Tamarixia radiata
(Waterston, 1922)
Synonyms [1]
  • Tetrastichus indicusKhan & Shafee, 1981
  • Tetrastichus radiatusWaterston, 1922

Tamarixia radiata, the Asian citrus psyllid parasitoid, is a parasitoid wasp from the family Eulophidae which was discovered in the 1920s in the area of northwestern India (Punjab), now Pakistan. It is a parasitoid of the Asian citrus psyllid ( Diaphorina citri ), an economically important pest of citrus crops around the world and a vector for Citrus greening disease.

Contents

Description

The adults of Tamarixia radiata are small, 0.92 to 1.04 mm long, black wasps. They have widely separated eyes, which are red in newly emerged adults, [2] on a head which is slightly wider than its length, and transparent wings with pale yellow veins. There is marked sexual dimorphism, with the male antennae being one and a half times the length of female antennae. [3] The antennae of the males have long and slightly curved setae while female antennae have short setae. [4] The males are also slightly smaller than females in length and have smaller wings and darker abdomens. [2] On the females, the ovipositor barely protrudes. [3] In both males and females the head and thorax are shiny black and the posterior dorsal and lateral portions of the gastric segments are black and the vent and a patch on the anterior dorsal gaster are pale, sometime yellow. [4] The legs are off white in colour. [2]

Distribution

Tamarixia radiata was initially described as Tetrastichus radiatus in 1922 by the British entomologist James Waterston from specimens collected in 1921 from part of the Punjab which is now in Pakistan. [5] The natural range of T. radiata extends from Yemen and Saudi Arabia in the west to China and Indonesia in the east. [6] When it was reported that this species was a highly efficient parasitoid of Diaphorina citri on the French Mascarene island of Réunion, [7] it was spread around the world to control its host. T. radiata has since been introduced or spread to Argentina, Brazil, Colombia, Guadeloupe, Mauritius, Mexico, Philippines, Taiwan, Vietnam, Puerto Rico and the United States. [3] [6]

Biology

Tamarixia radiata is an idiobiont ectoparasitoid of Diaphorina citri. [6] The female wasp lays one or occasionally two eggs on the underside of a nymph of its host, between the third pair of legs. [6] Even if two eggs are laid beneath a nymph, only one adult wasp will result, so T. radiata is a solitary parasitoid. One adult female T. radiata can lay up to 300 eggs in her life. On hatching the larvae attach themselves to the host and begin to feed on its haemolymph which eventually results in the death of the host. The newly hatched larvae are about 0.28mm long and 0.11mm wide. Larvae go through four instars and reach 0.14 mm long and 0.59 mm wide in their fourth instar. [3] In the later stages of its growth, the larval T. radiata will have totally excavated the body cavity of the host nymph. [8] The nymph's body turns a dark brown colour and becomes "mummified". [9] The T radiata pupa extrudes silk which is used to adhere the excavated host's body to the twig where the nymph was feeding and sometimes the silk can be seen around a nymph with a T. radiata pupa within [8] The larvae then pupates within the remains of the host and the adult wasp emerges through a hole, visible to the naked eye, in the nymph's thorax or head. The wasps will parasitise any age of host nymph but prefer the fifth instar nymphs. Under laboratory conditions, the development time from oviposition to the emergence of the adult from the host can take 11.4 days. [3]

Tamarixia radiata emergence hole in mummified host nymph Tamarixia radiata hole in host nymph cuticle.png.jpg
Tamarixia radiata emergence hole in mummified host nymph

Adult female T. radiata live on average for 23.6 days while the shorter-lived males have an average longevity of 11.4 days. The males are polygynous but the females normally mate once and mating does not affect longevity. The females mate on emergence, or at least within a day, and most mate only once. [2] There are normally 1.8 females for every 3.2 males, but the sex ratio varies depending on the origin of the colony and conditions the wasps are reared under. As well as parasitizing the nymphs of its host adult female T. radiata are known to obtain protein for egg laying by feeding on the haemolymph of D. citri nymphs which they obtain by puncturing the nymph's skin with their ovipositor. It is thought that one female T. radiata may kill up to 500 nymphs of D. citri in her lifetime by a combination of parasitism and predation. [3] Both the male and the female wasps have also been recorded feeding on the honeydew excreted by D. citri. Although adults of T. radiata are attracted to fluorescent lights it is thought that the females detect host through olfactory cues. [3] Experiments having shown that female wasps are attracted to the volatile chemicals emitted by the nymphs of D. citri while males are attracted to the volatiles emitted by female T. radiata. It has also been found that female T. radiata avoid laying eggs in nymphs which have already been parasitized, unless there is a shortage of nymphs in which case superparasitism may occur. [2]

Use as a biological control

Tamarixia radiata is an obligate ectoparasitoid of the Asian citrus psyllid (Diophorina citri) which is a pest of citrus crops, the type specimen was collected from D. citri attacking lemon leaves. [5] D. citri is one of the main vectors for the transmission of the bacterial infection citrus greening disease to citrus trees, a disease which can devastate citrus orchards and which had been known in China since the 19th Century. In the early part of the 20th century it began to be recorded in new areas in Asia and Africa and in the 1950s psyllids were shown to be vectors of the disease. In the early 2000s the disease was found in Brazil and Florida. [7] In the early 1960s both T. radiata and the encyrtid Diaphorencyrtus aligarhensis , another parasitoid of D. cirti were introduced to Réunion where they successfully controlled populations of their host and reduced the impact of the disease. [9] In a survey conducted on Réunion showed that T. radiata had parasitized up to about 70% of the potential host nymphs, while D. aligarhensis had parasitized less than 20%. [6]

Once the disease appeared in Florida colonies of T. radiata were imported from Taiwan and Vietnam and released between 1999 and 2001 and it appears to have been at least partially successful at establishing itself. It has also been recorded in Puerto Rico and Texas where no known deliberate releases have taken place. Its effectiveness in suppressing its host populations in Florida has been variable. This is probably due to the differences in climate from their places of origin and predation by coccinellid beetles on psyllids (consuming many that were playing host to T. radiata). [9]

In California colonies of T. radiata were bred from specimens captured in the Punjab as the climate there was thought to be closest to that of southern California. [10] The wasps have been recovered some months after the initial release suggesting that they have bred in the wild and are capable of forming self sustaining populations. The wasps have also been found up to 65 miles from the release sites showing that they will disperse. The project is run by University of California Riverside and the insects bred by them show wider genetic variability than T. radiata elsewhere, reflecting the careful sourcing and selection of the founder specimens. [8]

The release of Tamarixia radiata for biological control of D. citri in California has potentially been affected by ants, especially the Argentine ant. Ants guard the nymphs of various bugs in return for a reward of honeydew. Ants have been observed to capture and consume Tamarixia wasps they encounter among clumps of D. citri nymphs as well as chasing the wasps away from the nymphs if they were unable to catch them. When D. citri populations are tended by ants then control of the ants may be necessary if the parasitoids are to control the psyllids. [8] In addition, it is possible that the use of insecticides could affect the populations and rates of parasitism of D. citri by T. radiata so an effective integrated pest management program would involve the use of selective insecticides or pesticides harmful to the adult wasps, as long as the adult are not part of a self sustaining population or that the application of the pesticide does not coincide with releases of adult wasps. [11]

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The Strepsiptera are an order of insects with eleven extant families that include about 600 described species. They are endoparasites of other insects, such as bees, wasps, leafhoppers, silverfish, and cockroaches. Females of most species never emerge from the host after entering its body, finally dying inside it. The early-stage larvae do emerge because they must find an unoccupied living host, and the short-lived males must emerge to seek a receptive female in her host. They are believed to be most closely related to beetles, from which they diverged 300–350 million years ago, but do not appear in the fossil record until the mid-Cretaceous around 100 million years ago.

<span class="mw-page-title-main">Parasitoid</span> Organism that lives with its host and kills it

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.

<span class="mw-page-title-main">Psyllid</span> Family of true bugs

Psyllidae, the jumping plant lice or psyllids, are a family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closely related plants (oligophagous). Together with aphids, phylloxerans, scale insects and whiteflies, they form the group called Sternorrhyncha, which is considered to be the most "primitive" group within the true bugs (Hemiptera). They have traditionally been considered a single family, Psyllidae, but recent classifications divide the group into a total of seven families; the present restricted definition still includes more than 70 genera in the Psyllidae. Psyllid fossils have been found from the Early Permian before the flowering plants evolved. The explosive diversification of the flowering plants in the Cretaceous was paralleled by a massive diversification of associated insects, and many of the morphological and metabolic characters that the flowering plants exhibit may have evolved as defenses against herbivorous insects.

<span class="mw-page-title-main">Parasitoid wasp</span> Group of wasps

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<span class="mw-page-title-main">Eucharitidae</span> Family of wasps

The Eucharitidae are a family of parasitic wasps. Eucharitid wasps are members of the superfamily Chalcidoidea and consist of four subfamilies: Akapalinae, Eucharitinae, Gollumiellinae, and Oraseminae. Most of the 42 genera and >400 species of Eucharitidae are members of the subfamilies Oraseminae and Eucharitinae, and are found in tropical regions of the world.

<i>Brachygastra mellifica</i> Species of wasp

Brachygastra mellifica, commonly known as the Mexican honey wasp, is a neotropical social wasp. It can be found in North America. B. mellifica is one of few wasp species that produces honey. It is also considered a delicacy in some cultures in Mexico. This wasp species is of use to humans because it can be used to control pest species and to pollinate avocados.

<span class="mw-page-title-main">Wasp</span> Group of insects

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<i>Leptocybe invasa</i> Species of wasp

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<i>Tamarixia</i> Genus of wasps

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<i>Encarsia perplexa</i> Species of wasp

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<i>Amitus hesperidum</i> Species of wasp

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<i>Diaphorina citri</i> Species of true bug

Diaphorina citri, the Asian citrus psyllid, is a sap-sucking, hemipteran bug now in the taxonomic family Psyllidae. It is one of two confirmed vectors of citrus greening disease. It has a wide distribution in southern Asia and has spread to other citrus growing regions.

<i>Trioza erytreae</i> Species of true bug

Trioza erytreae, the African citrus psyllid, is a sap-sucking insect, a hemipteran bug in the family Triozidae. It is an important pest of citrus, being one of only two known vectors of the serious citrus disease, huanglongbing or citrus greening disease. It is widely distributed in Africa. The other vector is the Asian citrus psyllid, Diaphorina citri.

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<i>Planococcus ficus</i> Species of mealybug

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<i>Orchamoplatus citri</i> Species of whitefly

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References

  1. "Tamarixia radiata (Waterston, 1922)". GBIF.org. Retrieved 2 June 2017.
  2. 1 2 3 4 5 Xulin Chen; Philip Stansly (2014). "Biology of Tamarixia radiata (Hymenoptera: Eulophidae), Parasitoid of the Citrus Greening Disease Vector Diaphorina citri (Hemiptera: Psylloidea): A Mini Review". Florida Entomologist. 97 (4): 1404–1413. doi: 10.1653/024.097.0415 .
  3. 1 2 3 4 5 6 7 Rajinder S. Mann; Lukasz L. Stelinski (2010). Jennifer L. Gillett-Kaufman (ed.). "common name: an Asian citrus psyllid parasitoid scientific name: Tamarixia radiata (Waterston) (Insecta: Hymenoptera: Eulophidae)". Featured Creatures. University of Florida . Retrieved 11 July 2017.
  4. 1 2 Jawwad A. Qureshi; Philip A. Stansly. Anthony Shelton (ed.). "Tamarixia radiata Waterston [Hymenoptera: Eulophidae], an ectoparasitoid of Diaphorina citri Kuwayama [Hemiptera: Psyllidae]". Biological Control: A Guide to Natural Enemies in North America. Cornell University College of Agriculture and Life Sciences. Retrieved 11 July 2017.
  5. 1 2 James Waterston (1922). "On the chalcid parasites of psyllids (Homoptera)" (PDF). Bulletin of Entomological Research. 13 (1): 55. doi:10.1017/s0007485300045235.
  6. 1 2 3 4 5 Jose´ Roberto Postali Parra; Gustavo Rodrigues Alves; Alexandre Jose´ Ferreira Diniz; Jaci Mendes Vieira (2016). "Tamarixia radiata (Hymenoptera: Eulophidae) X Diaphorina citri (Hemiptera: Liviidae): Mass Rearing and Potential Use of the Parasitoid in Brazil" (PDF). Journal of Integrated Pest Management. 7 (1): 1–11. doi: 10.1093/jipm/pmw003 .
  7. 1 2 Timothy R. Gottwald; John V Da Graca; R. B. Bassanezi (2007). "Citrus Huanglongbing: The Pathogen and Its Impact". Plant Health Progress. 8: 31. doi: 10.1094/PHP-2007-0906-01-RV .
  8. 1 2 3 4 Mark Hoddle (2012-07-19). "Has the Asian Citrus Psyllid Parasitoid, Tamarixia radiata, Established in California?". Center for Invasive Species Research Blog. Regents of the University of California. Retrieved 11 July 2017.
  9. 1 2 3 Marjorie A. Hoy; Ru Nguyen; A. Jeyaprakash (2017). "Classical Biological Control of Asian Citrus Psylla - Update on Tamarixia radiata releases and first releases of Diaphorencyrtus aligarhensis". Integrated Pest management. University of Florida. Retrieved 11 July 2017.
  10. "Can Parasitic Wasps Help Save America's Citrus?". National Geographic Society. Archived from the original on June 24, 2014. Retrieved 11 July 2017.
  11. Vitor Hugo Beloti; Gustavo Rodrigues Alves; Diogo Feliciano Dias Araujo; et al. (2015). "Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata". PLOS ONE. 10 (7: e0132128): e0132128. Bibcode:2015PLoSO..1032128B. doi: 10.1371/journal.pone.0132128 . PMC   4488444 . PMID   26132327.