Braconidae

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Braconidae
Temporal range: Cretaceous–Present
Atanycolus sp.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Superfamily: Ichneumonoidea
Family: Braconidae
Latreille
, 1829
Subfamilies

47, see text

Synonyms

Stenophasmidae Benoit, 1949

The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed.[1] One analysis estimated a total between 30,000 and 50,000, and another provided a narrower estimate between 42,000 and 43,000 species.[1]

A female tropical braconid ovipositing into dead wood

Classification

The Braconidae are currently divided into about 47 subfamilies and over 1000 genera,

Bracon, Cenocoelius, Chaenusa, Chorebus, Cotesia, Dacnusa, Diachasma, Microgaster, Opius, Parapanteles, Phaenocarpa, Spathius, and Syntretus
.

These fall into two major groups, informally called the cyclostomes and noncyclostomes. In cyclostome braconids, the

monophyletic whereas noncyclostomes can be divided formally into microgastroids, sigalphoids, helconoids, and euphoroids.[4]

Subfamilies

Head of a cyclostome braconid showing circular opening above mandibles.
Head of a noncyclostome braconid.

Morphology

The morphological variation among braconids is notable. They are often black-brown (sometimes with reddish markings), though some species exhibit striking coloration and patterns, being parts of

trochanters
have two segments.

Females often have long

Coleoptera larvae in tree trunks.[5]

Life history

Cotesia ruficrus illustrated by Des Helmore

The larvae of most braconids are internal or external

Embiidina. Most species kill their hosts, though some cause the hosts to become sterile and less active. Parasitoidy on adult insects (particularly on Hemiptera and Coleoptera) also occurs. Members of two subfamilies, the Mesostoinae and Doryctinae are known to form galls on plants.[6][7] Braconids are often used as biological pest control agents, especially against aphids.[8]

Examples of hosts

Thousands of species of insects are used as hosts by braconid wasps. A few notable examples are detailed here.

Some species of braconids are parasitoids of Ostrinia furnacalis (the Asian corn borer, a lepidopteran moth known for being a pest of maize in East Asia), the African sugarcane borer (a moth commonly found in sub-Saharan Africa),[9] the butterfly Danaus chrysippus in Ghana,[10] and Liriomyza trifolii (the American serpentine leafminer) and Manduca quinquemaculata (the tomato hornworm) in North America.[11] Braconids often will prey on fruit fly larvae like Anastrepha suspensa as well.[12]

Polydnaviruses

Main article:
Polydnavirus

Endoparasitoid species often display elaborate physiological adaptations to enhance larval survival within the host, such as the co-option of endosymbiotic viruses for compromising host immune defenses. These bracoviruses are often used by the wasps instead of, or in addition to, a venom cocktail. The DNA of the wasp actually contains portions that are the templates for the components of the viral particles and they are assembled in an organ in the female's abdomen known as the calyx.[13] A 2009 study has traced the origins of these templates to a 100-million-year-old viral infection whose alterations to its host DNA provided the necessary basis for these virus-like "templates".[14]

These viruses suppress the immune system and allow the parasitoid to grow inside the host undetected. The exact function and evolutionary history of these viruses are unknown. Sequences of polydnavirus genes show the possibility that venom-like proteins are expressed inside the host caterpillar. Through the evolutionary history of being used by the wasps, these viruses apparently have become so modified, they appear unlike any other known viruses today. Because of this highly modified system of host immunosuppression, a high level of parasitoid-host specificity is not surprising.

Evolutionary history

The family seems to date from early Cretaceous (provided that Eobracon is properly assigned to this family). It underwent extensive diversification from mid or late Cretaceous to early Cenozoic, correlating with the radiation of flowering plants and associated insect herbivores, the main hosts of braconids.

Differentiation from Ichneumonidae

Ichneumonidae wing morphology
Braconidae wing morphology

Braconids are distinguished from their

Apozyx penyai – this vein is present in 95% of Ichneumonidae. Vein 1/Rs+M of the forewing is 85% present in Braconidae, but absent in all Ichneumonidae. Vein 1r-m of the hind wing is in 95% of Braconidae basal to the separation of R1 and Rs (it is opposite or apical in Ichneumonidae). In Braconidae, metasomal tergum 2 is fused with tergum 3, (secondarily flexible in Aphidiinae) – 90% of Ichneumonidae have a flexible suture.[15]

Other characteristics

The species

explosives detection.[16]

At least some braconids appear to be very resistant to

rads can kill an average human, a dose of 180,000 rads was required to kill a braconid of genus Habrobracon in an experiment.[17]

Gallery

References

  1. ^
    S2CID 86775770
    .
  2. ^ Beyarslan, A. and M. Aydogdu. (2013). Additions to the rare species of Braconidae fauna (Hymenoptera: Braconidae) from Turkey. Mun Ent Zool 8(1) 369-74.
  3. ^ Wharton, R. M. (2000). "Can braconid classification be restructured to facilitate portrayal of relationships?". In Austin, A. D.; Dowton, M. (eds.). Hymenoptera: evolution, biodiversity, and biological control. 4th. Vol. International Hymenopterists Conference. Collingwood, Victoria, Australia: Commonwealth Scientific and Industrial Research Organisation (CSIRO). pp. 143–153.
    ISBN 978-0-643-06610-6
    .
  4. S2CID 52986629
    .
  5. ISSN 0033-2615
    – via Santa Clara University Scholar Commons.
  6. S2CID 85057439
    .
  7. ISSN 0022-2933
    .
  8. ^ Mahr, S. (February 1998). "Know Your Friends: Aphidius Wasps". Midwest Biological Control News Online. University of Wisconsin–Madison. Archived from the original on 2 January 2013. Retrieved 25 March 2013.
  9. hdl:10520/AJA00128789_2538
    .
  10. ISSN 0024-4082
    .
  11. ^ Gray, Betty. "Beneficial insects in the garden: #04 Braconid Wasp on Hornworm (Cotesia congregatus)". aggie-horticulture.tamu.edu. Retrieved 2017-11-14.
  12. OCLC 9311697
    .
  13. Greenwood Press
    .
  14. S2CID 6538583
    .
  15. ^ Sharkey, M. J. Family Braconidae. pp. 362–94 In: Goulet, H. and J. Huber (eds.) Hymenoptera of the World, an Identification Guide to Families. Agriculture Canada Research Branch Monograph No. 1894E. 1993.
  16. ^ Hall, M. Scientists recruit wasps for war on terror. USA Today December 26, 2005. Accessed June 19, 2012.
  17. ^ Cockroaches and radiation. ABC Science. February 23, 2006.

Further reading

  • Achterberg, C. van (1990): Illustrated key to the subfamilies of the Holarctic Braconidae (Hymenoptera: Ichneumonoidea) Zoologische Mededelingen Vol. 64 p.  1–20 PDF
  • Achterberg, C. van (1993): Illustrated key to the subfamilies of the Braconidae (Hymenoptera: Ichneumonoidea) Zoologische Verhandelingen Vol. 283 p.  1–189 PDF

External links

Wikimedia Commons has media related to Braconidae.
Wikispecies has information related to Braconidae.
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