Cabbage white ichneumon wasp

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Cabbage white ichneumon wasp
Cabbage white parasitic wasp pupae

Cabbage white parasitic wasp pupae
Systematics
Class : Insects (Insecta)
Order : Hymenoptera (Hymenoptera)
Family : Brackish wasps (Braconidae)
Subfamily : Microgastrinae
Genre : Cotesia
Type : Cabbage white ichneumon wasp
Scientific name
Cotesia glomerata
( Linnaeus , 1758)

The cabbage white ichneumon wasp , actually more correct cabbage white brackish wasp ( Cotesia glomerata , in older works also Apanteles glomeratus ) is a parasitic hymenoptera species from the braconid family (Braconidae).

features

Microgastrinae are small, mostly black or black and yellow marked species. The subfamily got its name from the strikingly short free abdomen (metasoma). The species-rich group includes numerous very similar and difficult to distinguish species. Cotesia glomerata is about 2.5 to 3 millimeters long in both sexes, with antennae that are slightly longer than the length of the body. The body is black, the legs reddish yellow to yellow. A determination is possible with suitable means.

Sex determination

The species is bisexual and has a complex mode of sex determination. As is typical for hymenoptera, males develop from unfertilized eggs (arrhenotoke parthenogenesis ). Fertilized eggs develop into females if they carry different alleles in a sex-determining gene segment , i.e. are heterozygous . With the same alleles, males develop here too. Through this mechanism, the proportion of males increases with increasing inbreeding . Nevertheless, no discrimination against related individuals as partners was proven in mating attempts. Diploid males produce just as much offspring as haploid, but with a slightly shifted gender ratio in favor of the males. An excess of females (about two-thirds females) is commonly observed in free-range populations of the species.

Ecology and way of life

Cotesia glomerata is considered to be the main parasitoid of the great cabbage white butterfly ( Pieris brassicae ) in many parts of the population, but it can also infect other butterfly species. However, the high number of (up to 75) possible host species is probably due in part to incorrect determinations or rare incorrect hosts. Reliable information is mainly available for the butterfly genera Pieris and Aporia ( i.e. white flies in the broad sense ). Pieris brassicae is clearly preferred. This is partly because the caterpillars of the great cabbage white butterfly occur in gregarious clusters, while the other species live individually, the ichneumon wasp is adapted in its search strategy. In addition, Cotesia glomerata finds its hosts partly through the food plant, which is recognized through the smell. As a result, butterfly caterpillars that do not live on cruciferous vegetables are hardly affected.

Parasitization rates of cabbage white caterpillars were given in various studies between 5% and 95% of the caterpillars, in one study in Germany even 100% of the white caterpillars were parasitized. The small cabbage white butterfly ( Pieris rapae ) is also attacked, but less often. This species also has its own specialist, Cotesia rubecula , which is superior to the competition when it occurs together. The parasitization can therefore greatly reduce the population density of the butterfly host, which is considered an agricultural pest. However, the parasitization no longer affects the feeding of existing white caterpillars on a plant. Butterfly caterpillars on the upper leaves of a cabbage plant are attacked by the parasite far more frequently than those on the middle or lower leaves.

The host caterpillars are preferably pricked in the first larval stage; if necessary, caterpillars are accepted up to the third stage with decreasing preference. Older caterpillars defend themselves with violent movements and also use a defense fluid. Numerous eggs are deposited in each caterpillar (" fermented " parasitoid ), around 20 (to 30) wasp larvae develop synchronously per caterpillar. Occasionally, however, a caterpillar is parasitized by more than one female parasitic wasp. The larvae feed on their host's hemolymph without attacking the organs. The presence of the parasitoid larvae slows down their development by about 3 days (from 16 to 19 days). There are three larval stages. The wasp larvae develop within the caterpillars until they are about to pupate and then emerge synchronously through the skin.

When the larvae emerge, the caterpillar is lethargic and does not react to disturbances. The parasitic wasp larvae molt when they emerge to the third larval stage and leave their larval skin behind in the exit wound so that it closes the wound. They pupate right next to the caterpillar. Often the caterpillar even spins a protective web over the cocoons of its parasite. This can possibly continue to live for some time (days to weeks), but can no longer complete its life cycle, but remains close to the parasite pupae. If it is disturbed there, it reacts with violent beating of the head and thereby defends the wasp larvae against predators.

The wasp cocoons have a striking lemon-yellow to orange color. The pupal period lasts until the slip of Imagines 7 to 11 days ago. The lifespan of the adults is a maximum of about 30 days.

Depending on the season and the host species, Cotesia glomerata overwinters either as an old larva ready to pupate ("prepupa") in the pupa cocoon or as a larva within the host caterpillar.

The species, although parasitoids itself, has its own parasitoids (hyperparasitism). These wasp species also lay their eggs in the caterpillar. However, the hatching larva then searches for the parasitoid larva, penetrates it and develops in it. Hyperparasitiode of Cotesia glomerata are z. B. Mesochorus gemellus ( Ichneumonidae ) and Tetrastichus sinope ( Eulophidae ).

Neozoa

Cotesia glomerata was introduced to North America for biological pest control of the small cabbage white butterfly introduced there, the species is naturalized here today and is not uncommon. This introduction, however, has led to a sharp decline in a related whitefly subspecies indigenous to the region, the green vein whitefly Pieris napi subsp. oleracea , which is also host of the parasitoid. A similar influence on Pieris virginiensis is feared.

In the Canary Islands, the wasp species, which is believed to have been introduced there for pest control, poses a serious threat to the endemic white whale Pieris cheiranthi .

Piers brassicae has also been introduced into Japan . However, Cotesia glomerata was already present here, its host species was the small cabbage white butterfly Pieris rapae . After the introduction, the parasitic wasp quickly passed on to the great cabbage white butterfly as the preferred host.

Phylogeny

In an investigation of the large and almost worldwide distributed genus Cotesia by means of homologous DNA sequences (molecular phylogeny), Cotesia plutellae and Cotesia melitaearum were identified as the closest related species. These results contradict traditional groups of species based on morphological characteristics. Many species of the subfamily Microgastrinae have been sequenced barcoding for determination by means of DNA and have thus become easier to determine.

Individual evidence

  1. ↑ J. Papp (1987): A survey of the European species of Apanteles Först. (Hymenoptera, Braconidae: Microgastrinae), X. The glomeratus group 2 and the cultellatus group. Annales historico-naturales Musei Nationalis Hungarici 79: 207-258.
  2. ↑ Y. Zhou, H. Gu, S. Dorn (2006): Single-locus sex determination in the parasitoid wasp Cotesia glomerata (Hymenoptera: Braconidae). Heredity 96: 487-492. doi : 10.1038 / sj.hdy.6800829
  3. ^ Daniel Ruf, Dominique Mazzi, Silvia Dorn (2010): No kin discrimination in female mate choice of a parasitoid with complementary sex determination. Behavioral Ecology 21 (6): 1301-1307. doi : 10.1093 / beheco / arq148
  4. ↑ J. Elias, D. Mazzi, S. Dorn (2009): No Need to Discriminate? Reproductive Diploid Males in a Parasitoid with Complementary Sex Determination. PLoS ONE 4 (6): e6024. doi : 10.1371 / journal.pone.0006024
  5. ^ J. Papp (1990): A survey of the European species of Apanteles Först (Hymenoptera, Braconidae: Microgastrinae) XII. Supplement to the key of the glomeratus group. Parasitoid / host list 2. Annales historico-naturales Musei Nationalis Hungarici 81: 159-203.
  6. ↑ JSC Wiskerke & LEM Vet (1994): Foraging for solitarily and gregariously feeding caterpillars: A comparison of two related parasitoid species (Hymenoptera: Braconidae). Journal of Insect Behavior Volume 7, Issue 5: 585-603.
  7. ↑ Betty Benrey, Robert F. Denno, Laure Kaiser (1997): The influence of plant species on attraction and host acceptance in Cotesia glomerata (Hymenoptera: Braconidae). Journal of Insect Behavior Volume 10, Issue 5: 619-630.
  8. ^ A b John Feltwell: Large White Butterfly: The Biology, Biochemistry and Physiology of Pieris brassicae (Linnaeus). Series Entomologica, Vol. 18. Springer Verlag, 1981. ISBN 978-90-6193-128-7
  9. ^ OW Richards (1940): The biology of the Small White butterfly (Pieris rapae) with special reference to the factors controlling its abundance. Journal of Animal Ecology Vol.9 No.2: 243-288.
  10. ^ RA Coleman, AM Barker, M. Fenner (1999): Parasitism of the herbivore Pieris brassicae L. (Lep., Pieridae) by Cotesia glomerata L. (Hym., Braconidae) does not benefit the host plant by reduction of herbivory. Journal of Applied Entomology, 123: 171-177. doi : 10.1046 / j.1439-0418.1999.00334.x
  11. ^ RA Coleman, AM Barker, M. Fenner, FC King (1997): Relative effect of different host feeding site on long-range host location and electroantennogram response in the parasitoid Cotesia glomerata (Hym., Braconidae). Journal of Applied Entomology Volume 121, Issue 1-5: 487-494. doi : 10.1111 / j.1439-0418.1997.tb01438.x
  12. ↑ a b Jacques Brodeur & Louise EM Vet (1994): Usurpation of host behavior by a paraitic wasp. Animal behavior 48: 187-192.
  13. ^ Roy van Driesche: Introductions of parasitoids to control the imported cabbageworm. In C. Vincent & G. Lazarovits (editors): Biological Control: A Global Perspective. CABI 2007
  14. ↑ J. Benson, RG Van Driesch, A. Pasquale, J. Elkinton (2003): Introduced braconid parasitoids and range reduction of a native butterfly in New England. Biological Control Volume 28, Issue 2: 197-213. doi : 10.1016 / S1049-9644 (03) 00058-6
  15. ↑ Jessica Benson, Andy Pasquale, Roy Van Driesche, Joseph Elkinton (2003): Assessment of risk posed by introduced braconid wasps to Pieris virginiensis, a native woodland butterfly in New England. Biological Control Volume 26, Issue 1: 83-93. doi : 10.1016 / S1049-9644 (02) 00119-6
  16. ↑ Aurel I. Lozan, Michael T. Monaghan, Karel Spitzer, Josef Jaros, Martina Zurovcova, Vaclav Broz (2008): DNA-based confirmation that the parasitic wasp Cotesia glomerata (Braconidae, Hymenoptera) is a new threat to endemic butterflies of the Canary Islands. Conservation Genetics 9: 1431-1437. doi : 10.1007 / s10592-007-9470-4
  17. ↑ Tanaka, S., Nishida, T. and Ohsaki, N. (2007), Sequential rapid adaptation of indigenous parasitoid wasps to the invasive butterfly Pieris brassicae Evolution 61: 1791-1802. doi : 10.1111 / j.1558-5646.2007.00165.x
  18. ↑ Alice Michel-Salzat & James B. Whitfield (2004): Preliminary evolutionary relationships within the parasitoid wasp genus Cotesia (Hymenoptera: Braconidae: Microgastrinae): combined analysis of four genes. Systematic Entomology 29: 371-382.
  19. ↑ Alex Smith, M., Fernández-Triana, JL, Eveleigh, E., Gómez, J., Guclu, C., Hallwachs, W., Hebert, PDN, Hrcek, J., Huber, JT, Janzen, D. , Mason, PG, Miller, S., Quicke, DLJ, Rodriguez, JJ, Rougerie, R., Shaw, MR, Várkonyi, G., Ward, DF, Whitfield, JB, Zaldívar-Riverón, A. (2013): DNA barcoding and the taxonomy of Microgastrinae wasps (Hymenoptera, Braconidae): impacts after 8 years and nearly 20,000 sequences. Molecular Ecology Resources 13: 168-176. doi : 10.1111 / 1755-0998.12038

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