Dinocampus coccinellae

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

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]

Economic importance

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 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

1. ^ "Dinocampus coccinellae (Schrank 1802)". Fauna Europaea. http://www.faunaeur.org/full_results.php?id=338557. 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. http://books.google.com/books?id=Do4UAAAAYAAJ&pg=PA242&lpg=PA242&dq=dinocampus+coccinellae+ichneumon&source=bl&ots=b__MxjylU9&sig=buihkL6VwR1kstMIz0Fpi6T9ilA&hl=en&ei=-1cDTsP0FIvpgQfZ3tT8DQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCgQ6AEwAg#v=onepage&q=dinocampus%20coccinellae%20ichneumon&f=false. Retrieved 23 June 2011. 
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: 41–45. http://katz.entu.cas.cz/pdfarticles/1077/eje_103_1_041_Davis.pdf. Retrieved 23 June 2011. 
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: 171–172. http://www.biodiversitylibrary.org/page/30013421. Retrieved 24 June 2011. 
5. ^ Shaw, Scott Richard (1988). "A new Mexican genus and species of Dinocampini with serrate antennae (Hymenoptera; Braconidae; Euphorinae)". Psyche 95: 289–298. http://psyche.entclub.org/pdf/95/95-289.pdf. Retrieved 23 June 2011. 
6. ^ ^{a b c d} Bruce, Anne. "Parasitoid wasp threatens Scottish Seven Spot ladybird". Microscopy UK. http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/art98/ladybird.html. Retrieved 23 June 2011. 
7. ^ "'Save our ladybirds' plea". BBC News. 17 January 2000. http://news.bbc.co.uk/2/hi/uk_news/scotland/607064.stm. 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 (in press). doi:10.1098/rsbl.2011.0415. 
9. ^ ^{a b} "Ladybird made into 'zombie' bodyguard by parasitic wasp". BBC News. 23 June 2011. http://www.bbc.co.uk/news/science-environment-13860891. Retrieved 23 June 2011. 
10. ^ Braconnier, Deborah. "A real-life zombie story in the life of bugs". Physorg.com. http://www.physorg.com/news/2011-06-real-life-zombie-story-life-bugs.html. Retrieved 25 June 2011. 
11. ^ Pappas, Stephanie (21 June 2011). "The case of the wasp and the zombie ladybug". MSNBC. http://www.msnbc.msn.com/id/43487686/ns/technology_and_science-science/. Retrieved 25 June 2011. 
12. ^ Connor, Steve (5 August 1998). "Ladybirds being wiped out by parasitic wasps". The Independent. http://www.independent.co.uk/news/ladybirds-being-wiped-out-by-parasitic-wasps-1169691.html. Retrieved 24 June 2011.