Sphaerularia bombi - Misplaced Pages

Species of roundworm

Sphaerularia bombi

Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Nematoda
Class:	Secernentea
Order:	Tylenchida
Family:	Sphaerulariidae
Genus:	Sphaerularia
Species:	S. bombi
Binomial name
*Sphaerularia bombi* Dufour, 1837

Sphaerularia bombi is an entomopathogenic nematode. It is parasite of bumblebees. It infects and sterilizes gynes or potential queens of bumblebees.

Life Cycle

Sphaerularia bombi is a nematode that infects hibernating bumblebees. Bumblebees start seeking out a hibernation site for the winter season during fall and autumn. S. bombi would cause the infected bee multiple fail attempts to burrow into the ground, and with each fail attempt hundreds of 3rd stage larvae would be discharged from the bee's anal opening. The larvae would eventually develop into the 4th larvae stage, this is the period where the infected bee dies. When a healthy bee finds its hibernation site, the 3rd stage larvae would infect the bee by penetrating it. The bee emerges to the surface during the spring season, and by that time the nematodes has developed into a mature female producing eggs within the bumblebee; 1st larvae stage. The eggs then hatches and molts into the 2nd larvae stage, which then rapidly molts into the 3rd larvae; the 3rd larvae stage is the infective stage for S. bombi. These 3rd stage larvae would be in the bee's hemocoel, midgut, and hindgut.

Morphology

Once in the host, the uterus and other related reproductive counterparts of the female S. bombi turn inside out, allowing for the uterine cells to stretch out and expand into a sac. The sac, also known as a prolapsed uterus, is composed of an ovary, oviduct, and sperm, and is found all over the body of the parasite. These “bumps” on the parasite's body bulge into bigger sacs to create a larger surface area for absorbing nutrients from the host via pinocytosis. Once absorbed, the nutrients are digested and delivered through the ovary-oviduct to the eggs. Developing eggs from the uterine sac develop into third-stage juveniles once they disperse into the host's hemocoel. Although the eggs develop, there is no apparent growth of the parasite that initially produced the eggs. At this stage, the nematode is nothing but an enormous uterus filled with eggs, with a tiny appendix containing the remaining organs.

Distribution

Canada, France, Germany, Netherlands, New Zealand, Norway, Sweden, USA, Argentina

References

K. Sayama; H. Kosaka & S. Makino (2007). "The first record of infection and sterilization by the nematode Sphaerularia in hornets (Hymenoptera, Vespidae, Vespa)". Insectes Sociaux. 54 (1): 53–55. doi:10.1007/s00040-007-0912-2.
"Sphaerularia bombi". smartsite.ucdavis.edu. Retrieved 26 November 2013.
Johnstone, Colin (January 24, 2000). "The Nematodes". cal.vet.upenn.edu. University of Pennsylvania. Retrieved 26 November 2013.
"Sphaerularia bombi". smartsite.ucdavis.edu. Retrieved 26 November 2013.
G. Poinar Jr. & R. Hess (1972). "Food Uptake by the Insect-parasitic Nematode, Sphaerularia bombi (Tylenchida)". Journal of Nematology. 4 (4): 270–277 http://journals.fcla.edu/jon/article/view/64738/62406.
Combes, Claude (2001). Parasitism: The Ecology and Evolution of Intimate Interactions. University of Chicago Press. p. 218. ISBN 978-0-226-11446-0.
Plischuk, Santiago; Lange, Carlos E. (2012). "Sphaerularia bombi (Nematoda: Sphaerulariidae) parasitizing Bombus atratus (Hymenoptera: Apidae) in southern South America". Parasitology Research. 111 (2): 947–50. doi:10.1007/s00436-012-2853-6. hdl:11336/11303.

Life Cycle

Morphology

Distribution

References

Further reading