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 Coccinellidae 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]

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 the ladybird's own eggs and larvae before beginning to feed on its 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]

Ladybirds paralyzed, twitching, and attached to the cocoon of D. coccinellae have been compared to zombies by many writers.[9][10][11] 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.[9]

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 infection 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.[12]

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)". European Journal of Entomology 103 (1): 41–45. doi:10.14411/eje.2006.006. 
  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" (PDF). Biology Letters 7 (6): 843–846. doi:10.1098/rsbl.2011.0415. PMID 21697162. 
  9. ^ a b "Ladybird made into 'zombie' bodyguard by parasitic wasp". BBC News. 23 June 2011. Retrieved 23 June 2011. 
  10. ^ Braconnier, Deborah. "A real-life zombie story in the life of bugs". PhysOrg. Retrieved 25 June 2011. 
  11. ^ Pappas, Stephanie (21 June 2011). "The case of the wasp and the zombie ladybug". MSNBC. Retrieved 25 June 2011. 
  12. ^ Connor, Steve (5 August 1998). "Ladybirds being wiped out by parasitic wasps". The Independent. Retrieved 24 June 2011. 

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