It's been a while since my last post. Suffice to say, my life as a grad student is extremely busy!
I'm taking a course on biological control this semester. It's really fascinating! Biocontrol is the use of living organisms to control or suppress populations of undesirable organisms. One of our assignments was to research the parasitoids of an assigned pest. Parasitoids are similar to parasites, in that they require a host for survival. However, unlike parasites, parasitoids eventually kill their hosts. This attribute makes them important biocontrol agents. I've pasted my report on the waved sphinx moth and its parasitoids below:
The sphinx moth Ceratomia undulosa is a member of the Order Lepidoptera and the Family Sphingidae. The species was first described by Walker in 1856 and was originally placed in the genus Daremma9. C. undulata is widely distributed in North America. It is found as far north as Alberta and Maine and as far south as Texas and Florida. Its western range extends to the Rocky Mountains3,4. The species is most commonly found in deciduous forests.
C. undulosa is not considered to be a pest of any economic importance, although a closely related species, C. catalpae, is a pest of ornamental Catalpa plants2,5,6. The larvae of C. undulosa feed on deciduous trees including ash (Fraxinus spp.), privet (Ligustrum spp.), oak (Quercus spp.), hawthorn (Crataegus spp.), lilac (Syringa spp.) and fringe trees (Chionanthus spp,)3,4,6,8. Adult females lay approximately 200 pale green eggs on host plants; larvae typically emerge after eight days9. C. undulosa larvae are green with 7 white stripes and reddish spots on each side. The larvae are commonly known as hornworms due to a distinctive pinkish horn-like outgrowth from their last abdominal segment3. When the caterpillars reach their fifth instar, they drop from their host trees and burrow underground to pupate3,4,9. Interestingly, many larvae change from green to a rosy pink just prior to pupation9. After overwintering as pupae, the adults emerge in the spring. Two broods are produced in the south, and only one in the north4. The adults have no known food source and are not believed to feed4. Adult moths are gray and brown in coloring3,4,6,8. Their wings exhibit several distinct dark wavy lines, as suggested by their species name undulata. The wingspan is typically between 7.6 and 11 cm.4.
The larva stage of C. undulata is the most common stage attacked by parasitoid species3,8. The eggs are attacked by fewer species8. No Dipteran species are known to attack C. undulata. The Braconid wasp Cotesia congregata is a very common parasitoid of C. undulata and the closely related species C. catalpa. C. congregata is considered to be an effective natural enemy of C. catalpae, especially given its ability to overcome the toxic chemistry of the Catalpa leaves consumed by its host2,4. The adult female wasp attacks Ceratomia larvae during their second, third, and fourth instars. C. congregata larvae develop in the host hemocoel and emerge after two weeks2,4. The generalist parasitoid Trichogramma minutum attacks the eggs of C. undulosa. The adult female lays a single egg in each egg8.
Parasitoids of the waved sphinx, Ceratomia undulosa.
Parasitoid Host stage attacked
Cotesia congregata. (2, 3, 5) larva
Horismenus floridanus Ashmead (8) larva
Horismenus microgaster Ashmead (8) larva
Hypopteromalus tabacum Fitch (8) larva
Trichomalopsis viridascens Walsh (8) larva
Trichogramma minutum Riley (8) egg
1 Arnaud, P.H. 1978. A host-parasite catalogue of North American Tachinidae. USDA
Miscellaneos Publ. No. 1319, Washington, D.C. 860 pp.
2 Bowers, M. D. 2003. Hostplant suitability and defensice chemistry of the Catalpa Sphinx,
Ceratomia catalpae. Journal of Chemical Ecology, 29: 2359-2367.
3 BugGuide.net. 2011. Identification, images, and information for insects, spiders, and their
kin for the United States and Canada: Species Ceratomia undulosa-Waved Sphinx. Hosted by Iowa State University Entomology, Ames, IA. (http://bugguide.net/node/view/3749).
4 Butterflies and Moths of North America: Collecting and sharing data about Lepidoptera.
2012. Attributes of Ceratomia undulosa. (http://www.butterfliesandmoths.org/species/Ceratomia-undulosa).
5 Lampert, E.C., L.A. Dyer, and M.D. Bowers. 2010. Caterpillar chemical defense and
parasitoid success: Cotesia congregata parasitism of Ceratomia catalpae. Journal of
Chemical Ecology, 36: 992-998.
6 Kentucky Critter Files: Sphinx Moths. 2011.University of Kentucky Entomology
Cooperative Extension Service, Lexington, KY. (http://www.uky.edu/Ag/CritterFiles/casefile/insects/butterflies/sphinx/sphinx.htm#catalpa).
7 Krombein, K.V., et al. (eds.) 1979. Catalog of Hymentoptera in America North of Mexico.
Smithsonian Instit. Press, Washington, D.C. 2,735 pp. (3 volumes).
8 Natural History Museum. 2011. Universal Chalcidoidea Database. Chalcidoid associates
of named taxon: Ceratomia. (http://www.nhm.ac.uk/research-curation/research/projects/chalcidoids/database/namedHost.dsml?searchPageURL=indexNamedHost.dsml&HOSTFAMILY=Sphingidae&HOSGENUSqtype=equals&HOSGENUS=Ceratomia&HOSSPECIESqtype=equals&HOSSPECIES=)
9 Oehlke, Bill. 2011. Ceratomia undulosa, The Waved Sphinx.