Dinocampus coccinellae

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Dinocampus coccinellae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Braconidae
Subfamily: Euphorinae
Genus: Dinocampus
Species: D. coccinellae
Binomial name
Dinocampus coccinellae
(Schrank, 1802)[1]
Synonyms [2]
  • Ichneumon coccinellae
  • Bracon terminatus
  • Perilitus terminatus
  • Dinocampus terminatus
  • Euphorus sculptus
  • Perilitus americanus

Dinocampus coccinellae is a braconid wasp parasite of coccinellid beetles, including the spotted lady beetle, Coleomegilla maculata. D. coccinellae has been described as turning its ladybird host into a temporary "zombie" guarding the wasp cocoon. About 25% of ladybirds recover after the cocoon they are guarding matures.

Description[edit]

In 1802, Schrank first described a female adult of this species as "Lady-bird killer 2155. Deep black, eyes green; head, front legs, and apex of the petiolate abdomen mussel-brown."[2] (A petiolate abdomen is one whose basal segment is stalk-like, that is, long and slender.) Nearly all D. coccinellae are female offspring of unfertilized eggs, although males are also occasionally found.[3] The male, when observed, has no ovipositor and is slimmer and darker than females.[4]

Biology[edit]

The mature female wasp seeks out adult female ladybirds, although they will sometimes oviposit into a male adult or larval instar.[3][5] One egg is planted in the host's soft underbelly. The wasp larva hatches after 5–7 days into a first instar larva with large mandibles and proceeds to remove any other eggs or larvae before beginning to feed on the ladybird's fat bodies and gonads.[6]

The wasp larva inside the ladybird goes through four larval instars in 18–27 days.[6] Meanwhile, the ladybird continues to forage and feed until the wasp larva, when it is ready to emerge, paralyzes the ladybird before tunneling out.[7] It pupates in a cocoon attached to the leg of the living ladybird, whose brightly colored body and occasional twitching reduce predation.[8] A growing D. coccinellae wasp nestled in its cocoon is extremely vulnerable, and other insects will devour it. If one of these predators tries to eat it, the ladybug retaliates, scaring it off. The ladybug becomes the parasites bodyguard, by protecting it from predators.[9] However, wasp cocoons protected in this way develop into adults that produce fewer eggs, due to the energy demands of maintaining a living protector.[10]

Ladybirds paralyzed, twitching, and attached to the cocoon of D. coccinellae have been compared to zombies by many writers.[10][11][12] After 6–9 days, the wasp emerges from the cocoon.[6] Remarkably, some 25% of ladybirds revive and emerge from paralysis once the cocoon has been emptied.[10] The paralytic effect has been proposed to be associated with an RNA virus, Dinocampus coccinellae paralysis virus.[13][14]

Ecology[edit]

Dinocampus coccinellae can itself be parasitised by Gelis agilis, a hyperparasite that is known for its mimicry of ants. The wingless females of G. agilis oviposit into D. coccinellae cocoons; the egg immediately hatches and consumes the developing wasp. Cocoons hosting G. agilis usually take twice as long to emerge.[citation needed]

Dinocampus coccinellae larva exiting Ladybug
Dinocampus coccinellae larva forming cocoon next to paralyzed ladybug

Economic importance[edit]

Because one ladybird can consume up to 5,500 aphids in a year, any ladybird parasite represents a potential threat to agriculture.[6] In Britain, at least, the infestatation of seven-spotted ladybirds (Coccinella septempunctata) with D. coccinellae rose significantly during the 1990s, from about 20% to more than 70%, threatening to have a serious economic impact on British farmers.[15]

References[edit]

  1. ^ "Dinocampus coccinellae (Schrank 1802)". Fauna Europaea. Retrieved 23 June 2011. 
  2. ^ a b Cushman, R. A. (1922). "The identity of Ichneumon coccinellae Schrank (Hym.)". Proceedings of the Entomological Society of Washington. 24 (9): 241–242. 
  3. ^ a b Davis, Dexter S.; Sarah L. Stewart; Andrea Manica; Michael E. N. Majerus (2006). "Adaptive preferential selection of female coccinellid hosts by the parasitoid wasp Dinocampus coccinellae (Hymenoptera: Braconidae)" (PDF). European Journal of Entomology. 103 (1): 41–45. doi:10.14411/eje.2006.006. Archived from the original (PDF) on 2012-03-11. 
  4. ^ Geoghegan, Irene E.; Tamsin M. O. Majerus; Michael E. N. Majerus (1998). "A record of a rare male of the parthenogenetic parasitoid Dinocampus coccinellae (Schrank) (Hym.:Braconidae)". The Entomologist's Record and Journal of Variation. 110 (5–6): 171–172. 
  5. ^ Shaw, Scott Richard (1988). "A new Mexican genus and species of Dinocampini with serrate antennae (Hymenoptera; Braconidae; Euphorinae)" (PDF). Psyche. 95 (3–4): 289–298. doi:10.1155/1988/98545. 
  6. ^ a b c d Bruce, Anne. "Parasitoid wasp threatens Scottish Seven Spot ladybird". Microscopy UK. Retrieved 23 June 2011. 
  7. ^ "'Save our ladybirds' plea". BBC News. 17 January 2000. Retrieved 24 June 2011. 
  8. ^ Fanny Maure; Jacques Brodeur; Nicolas Ponlet; Josée Doyon; Annabelle Firlej; Éric Elguero; Frédéric Thomas (2011). "The cost of a bodyguard". Biology Letters. 7 (6): 843–846. doi:10.1098/rsbl.2011.0415. PMC 3210670Freely accessible. PMID 21697162. Archived from the original (PDF) on 2014-08-08. 
  9. ^ Zimmerm, Carl (November 2014). "Meet Natures Nightmare Mindsuckers". National Geographic. 
  10. ^ a b c "Ladybird made into 'zombie' bodyguard by parasitic wasp". BBC News. 23 June 2011. Retrieved 23 June 2011. 
  11. ^ Braconnier, Deborah. "A real-life zombie story in the life of bugs". PhysOrg. Retrieved 25 June 2011. 
  12. ^ Pappas, Stephanie (21 June 2011). "The case of the wasp and the zombie ladybug". MSNBC. Retrieved 25 June 2011. 
  13. ^ Dheilly NM, Maure F, Ravallec M, et al., "Who is the puppet master? Replication of a parasitic wasp-associated virus correlates with host behaviour manipulation", Proceedings of the Royal Society B, 282: 20142773, doi:10.1098/rspb.2014.2773, PMC 4345448Freely accessible, PMID 25673681 
  14. ^ Anonymous, "Wasp virus turns ladybugs into zombie babysitters", Science, doi:10.1126/science.aaa7844 
  15. ^ Connor, Steve (5 August 1998). "Ladybirds being wiped out by parasitic wasps". The Independent. Retrieved 24 June 2011. 

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