SIPHONAPTERA - SIPHONAPTERA - Fleas

SYNAPOMORPHIES

• Adult apterous, bilaterally compressed, ectoparasites on and birds • Compound eyes small or absent; ocelli absent • Antennae short, in cranial grooves (Male antennae serve as accessory clasping organs) • Sucking mouthparts with labral (“epipharynx”) and lacinial stylets; mandibles absent • Thorax greatly specialized (abdominal terga overlap the sclerotized sterna; metepimeron enlarged accommodating leaping muscles) • Larvae legless • (Long labial palps [up to five segments in some species]) SIPHONAPTERA - Fleas Diagnostic characteristics • Heavily sclerotized • Laterally compressed (only laterally compressed ectoparasitic ) • Eyes absent or nearly so; ocelli absent • Antennae short, 9 flat flagellomeres, lie in grooves - scrobes • Wing absent and thorax reduced • Ctenidia - well developed stiff setae on body that point backwards • Sensilium (pygidium) of tergite IX (detects air movement, vibrations, temp gradients) • Large tarsal claws • Large hind coxae (with pads of resilin at base) SIPHONAPTERA - Fleas Mouthparts & Feeding • Mandibles absent • Labrum (“epipharynx”) and paired, serrated maxillary laciniae pierce skin and suck blood • Food channel formed by epipharynx, salivary channel by laciniae • Palps long and prominent • Both sexes feed; water absorbed in rectum • Proventricular acanthae prevent backflow of blood (also clog bacteria) • Feces and undigested blood released as black drops that dry SIPHONAPTERA - Fleas Habitat & Habits

• Adults feed on blood of host, primarily the Rodentia • Only 6% of species on birds, 75% on rodents; none on humans as primary host, none on marine mammals • Exhibit wide range of host specificity - highly host specific, habitat specific, or broadly host specific; , felis, occurs on 8 orders of mammals and lizards; bird flea, Ceratophyllis gallinae, on over 100 species • Co-speciation not as prevalent as is Phthiraptera • Habitat requirements of larvae probably most important in determining host and geographic distributions SIPHONAPTERA - Fleas Habitat & Habits

• Female lays in den or nest of host or on host while in nest; eggs sticky • Larvae are free-living in nest or den of host; feed on debris, feces of host, dried secretions, and dried, bloody feces of adults • Larvae legless, eyeless, with long, stiff setae; well developed mouthparts; 3 larval instars; final one spins a silken pupal cocoon • Adult emerges in cocoon and may stay inside for long period waiting for host to return

(stimulated by CO2 of host) SIPHONAPTERA - Fleas Medical Importance • Three species in the flea genus Xenopsylla () transmit plague, but especially X. cheopis • Causative agent is a bacterium, Yersinia pestis, a disease of flea, harbored in rodents, principally the brown rat, Rattus rattus • “Black Death” - Originated in China and followed Silk Road to Europe • Rural famine, resulted in over crowding in cities in Europe in the mid-1300s with resultant unsanitary conditions and explosion of rat populations • As rats became infected and died, fleas sought out other hosts - humans • Millions of people died (est. 30-60% of population!); took 200 years for populations to recover; other important outbreaks over the centuries. China lost half its population! • Only in 1914 was causative agent discovered by British-Indian Plague Commission and independently by a Japanese researcher SIPHONAPTERA - Fleas Medical Importance

• As flea feeds on infected host, the bacteria multiply in midgut, causing partial or complete blockage of proventriculus • Fleas with blocked proventriculi feel starved, so they feed even more frequently, and more indiscriminately • The blocking causes fleas to regurgitate blood, causing even more infection. Fleas eventually dies from starvation. • Even fleas without blocked guts can spread plague via their mouthparts • Scratching feces or ingesting flea will also spread disease; sneezing, coughing, contact • Infection causes blackish swellings at bites, called “buboes,” hence “bubonic plague”

SIPHONAPTERA - Fleas Additional Medical (and Veterinary) Importance

• Virus: myxomatosis of rabbits

• Bacteria: tularemia, murine typhus, Q fever, sylvatic typhus, salmonellosis, staphylococcal infection, plague; mammals

• Protozoa: murine and rabbit trypanosomiasis

• Nematoda: canine filariasis

• (as intermediate hosts): several , cat, rodent, and human tapeworms SIPHONAPTERA - Fleas Diversity and Distribution 2,500 species in 15 families well known due to the medical importance of fleas, the major transmitters of plague Major series of works by Hopkins & Rothschild (1953-1971) of the British Museum Dame Miriam Rothschild, world’s foremost authority (1904-2005) SIPHONAPTERA - Fleas Diversity and Distribution

Stephanocircidae - helmet fleas, head very reduced, dominated by genal combs; southern South America (rodents, some marsupials and insectivores) and Australia (marsupials) Pulicidae, Tunginae - Tunga penetrans, chigger,chigoe flea, bicho do pé, SE Asia, Africa, American tropics; females burrows in skin under toenail, between toes; only anus and gonopore exposed, feeds and expands to 1000X her original size; releases 1000 of eggs; site becomes infected and very painful; common around pigs SIPHONAPTERA - Fleas Diversity and Distribution Ceratophyllidae - largest family, several subfamilies; some show high host specificity; on ground squirrels, pocket gophers, etc. Ischnopsyllidae - exclusively on bats Leptopsyllidae - small rodents, house mouse, mountain beaver Ctenophthalmidae - small rodents, flying squirrels, , woodrats, deermice, etc, and shrews, moles; also on the mountain beaver Hystrichopsyllidae - small rodents, insectivores Rhopalopsyllidae - armadillos, possums, small rodents SIPHONAPTERA - Fleas Diversity and Distribution Pulicidae - includes the (Ctenosephalides felis) and dog flea (C. canis), both not native to North America. Cat fleas very common and with wide host range; dog flea intermediate host of dog tapeworm. Includes “sticktight” flea of domestic poultry and Pulex irritans L., on a broad range of hosts and sometimes associated with human habitations; other pulicids of birds, rabbits, and the infamous Xenopsylla cheopis, associated with plague.

Vermipsyllidae - carnivores (racoons, foxes, , bears) SIPHONAPTERA - Fleas

Collecting and Preserving • Collect from host and from their nests, dens, bedding, etc. • Collect nest themselves and bring into lab. Observe in white pan over several days-weeks and pick off fleas with small, wet brush • In areas of high numbers of adults, walk around with white clothing and collect fleas as they jump on you! • Preserve in formalin free alcohol and later clear and mount on microscope slides • Record identity of host! • Chaetotaxy important in taxonomy