A Page Dedicated to Scientific Research and Student Training in
Flea Systematics, Taxonomy, Phylogeny and Evolution
(fleas) is a highly-specialized holometabolous insect order
with 2,380 described species placed in 15 families and 238
genera (Lewis and Lewis, 1985). Fleas are laterally compressed,
wingless insects; the head is shield or helmet shaped, compound
eyes are absent, and mouthparts are specialized for piercing
and sucking (Dunnet and Mardon, 1991). Fleas are of tremendous
medical and economic importance as vectors of several diseases
important to human health including bubonic plague, murine
typhus, and tularemia (Traub and Starcke, 1980).
a phylogenetic standpoint, fleas are perhaps the most neglected
of all insect orders. While we have a reasonable knowledge
about the taxonomy at the species and subspecific level, phylogenetic
relationships among fleas at any level have remained virtually
unexplored. The major obstacle in flea phylogenetics has been
their extreme morphological specializations associated with
ectoparasitism, and the inability to adequately homologize
morphological characters across taxa. The majority of characters
used for species diagnoses are based on the shape and structure
of their extraordinarily complex genitalia, and the presence
and distribution of setae, spines and ctenidia (Traub and
Starcke, 1980; Dunnet and Mardon, 1991).
are entirely ectoparasitic, and while it has been generally
assumed that fleas originally exploited mammals as hosts with
a subsequent shift to birds (Holland, 1964), this has never
been formally investigated. There are 137 flea species representing
22 genera and 6 families that have birds as hosts, 5 species
that are found on both bird and mammal hosts, and the remainder
of the species are mammal specific. It is not clear how many
times fleas have host shifted, the polarity of the shift (bird
to mammal or vice versa), or whether any of these shifts correlate
with morphological radiation.
majority of flea specialists are retired and there exists
a dire need to train new specialists in flea systematics.
Moreover, many aspects of flea evolution are virtually unexplored
and fleas may serve as interesting research organisms for
understanding host shifts, coevolution, gross morphological
specialization, and molecular evolution.
page is regulary updated by Katharina Dittmar de la
Cruz. For any questions or suggestions please write
This material is based upon work supported by National
Science Foundation under grant 9983195.
Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s)
and do not necessarily reflect the views of the National