Flea-Phylogeny

Siphonaptera (fleas) is a highly-specialized holometabolous insect order, currently comprised of 243 genera and 2,574 described species. Fleas are laterally compressed, wingless insects that range from 1-10 mm in length. The head is usually small and shield or helmet shaped, compound eyes are absent, and mouthparts are specialized for piercing and sucking. Fleas are entirely ectoparasitic, with ~100 species as parasites of birds and the remaining species as parasites of mammals . Flea distribution extends to all continents including Antarctica, and fleas inhabit a range of habitats and hosts from equatorial deserts, through tropical rainforests, to the arctic tundra. Fleas are of tremendous economic importance as vectors of several diseases important to human health including bubonic plague, murine typhus, and tularemia.

The majority of fleas species are associated with mammal hosts, with about 74% of described species recorded from rodents. Only 8% of fleas are known from Insectivora, 5% each from Marsupalia and Chiroptera, followed by a mere 3% from Carnivora and Lagomorpha. The mammalian orders Monotremata, Xenarthra, Pholidota, Hyracoidea and Artiodactyla harbor together only one percent of the flea fauna, whereas 6% of the total diversity is ornithophilic.

The main goals of this study are to: (1) use molecular data from multiple loci and a broad sampling of taxa to provide the first formal estimate of flea phylogeny; (2) decipher which extant taxa or taxon is sister group to the remaining fleas (i.e., is the most basal extant flea lineage); and (3) use the phylogenetic reconstruction as a framework to infer divergence times, broad scale biogeographic patterns, and the history of host associations. This work will focus on molecular data as the underlying source of information on flea phylogeny.

Our taxon sampling includes 128 flea taxa comprised of 125 species representing a wide diversity of flea groups. Taxonomically, these exemplars represent 13 of 15 families, 25 of 30 described subfamilies, 26 of 43 described tribes, and 83 of 242 described genera. Four genes were targeted for amplification and sequencing: small subunit nuclear ribosomal RNA (18S, ~2000bp), large subunit nuclear ribosomal RNA (28S, ~2400 bp), Elongation Factor-1 (EF-1, 1065 bp, and mitochondrial Cytochrome Oxidase II (COII, ~612 bp). To analyze this dataset we applied three approaches, Maximum Parsimony and Maximum Likelihood as implemented in POY (POY-MP) and Maximum Likelihood based on a MUSCLE alignment.

The final data are currently in the process of being published (as of October 2006). Upon release of the publication, additional information will be available on this site.

Recent Publications related to this project:

Bitam I, Parola P, Dittmar K, Matsumoto K, Baziz B, Rolain JM, Belkaid M, Raoult D. (2006). First molecular detection of Rickettsia felis in fleas from Algeria. Journal of the American Society of Tropical Medicine and Hygiene. 74(4): 532-535.

Taylor S, Dittmar K, Porter M, Whiting MF (2005). Characterization of the long wavelength opsin from Mecoptera and Siphonaptera: Does a flea see? Molecular Biology and Evolution 22(5): 1165-1174.

Dittmar K, Whiting MF (2004): New Wolbachia sp. and their phylogeny from Siphonaptera throughout the Nearctic and Neotropical Region. Journal of Parasitology 90(5): 953-957.

Dittmar K, Whiting MF (2003): Genetic and phylogeographic structure of populations of Pulex simulans (Siphonaptera) from domesticated guinea pigs (Cavia aperea f. porcellus) in Peru inferred from two genes (Cyt B and Co II). Parasitology Research, 91(1): 55-60.

Dittmar K, Worschech K (2002): Siphonapteran fauna of Myoxus glis, Linnaeus 1766 of the Altenburg Region, Germany. Säugetierkundliche Information 19: 22-24.