Oropsylla montanablokha

Geographic Range

Oropsylla montana can be found in North America, west of the Rocky Mountains in the United States and Mexico (Hubbard, 1968; Lawson, 1982; Pan American Health Organization, 1965). More specifically, it can be found in the Pacific Coastal and Rocky Mountain region along with Colorado, Utah, Arizona, New Mexico and also south to Michoacan and Edo. de Mexico, Mexico (Traub, 1983).


Oropsylla montana usually lives in the nests of ground squirrels located in a non-urban setting (Young, 1982) and is rarely found feeding on other rodents (Hubbard 1968). Nests inhabited by fleas may include twigs and leaves or even cotton or upholstery stuffing (Beard, 1992).

Physical Description

This is a dark brown flea. Adults are medium-sized compared to most fleas. This species has particularly long palps (Ebeling, 2002).

Male and female O. montana are sexually dimorphic with males having a rounded clasper that is pushed ventrally. There are two long, strong bristles and four weak bristles near the finger and clasper. The finger of O. montana forms a curved blade-like shape, which has 11 bristles. In females, the spermatheca has a bit of a bulging body and a crooked tail (Hubbard, 1968). The spermatheca also shows a ventral contriction between the bulga and hilla. The anal stylet normally has one long ventral seta and no dorsal seta. In males, sternum VIII is without setae (Traub et al., 1983). (Hubbard, 1968; Traub, et al., 1983)

Eggs are large (around 0.5 mm). Larvae are white, legless, eyeless and are sensitive to humidity. Pupae spin silk cocoons. (Roberts and Janovy, Jr., 2000)

  • Sexual Dimorphism
  • female larger


Fleas have holometabolous metamorphosis (larval, pupal, and adult stages). (Roberts and Janovy, Jr., 2000)


Oropsylla montana was found to be most abundant on ground squirrels at lower than 18.44°C temperatures. (Lang, 1996). The hosts (squirrels) may become infected with plague from the flea after hibernation and after returning to burrows. (Lang, 1996)

Fleas are nidicolus parasites; they get on the host and immediately feed and then quickly get off. Their ability to quickly get on and off the host is aided by their impressive jumping mechanism. (Roberts, 2000) (Lang, 1996; Roberts and Janovy, Jr., 2000)

Food Habits

Oropsylla montana is a parasite that feeds mainly on the blood from ground squirrels in the genus Spermophilus (Hubbard, 1968). Some specific examples of ground squirrels carrying O. montana are the California ground squirrel, Spermophilus beecheyi (Lang, 1996) and S. variegatus (Traub et al., 1983). Oropsylla montana has a proventriculus that facilitates the break down of the rodent blood meal injested by the flea. If the flea is infected by the plague-causing bacteria, Yersinia pestis, the bacteria will multiply and block the proventriculus. When the flea tries to feed, the host blood can not pass through the proventriculus and a blood and bacteria mixture go back into the host causing the host to become infected with the plague bacteria. Even though fleas can survive long periods of time without food, they will eventually die from starvation because the flea can no longer feed (Roberts & Janovy 2000). (Hubbard, 1968; Roberts and Janovy, Jr., 2000; Traub, et al., 1983)

Ecosystem Roles

These fleas are ectoparasites on their hosts, feeding on blood. They sometimes transfer diseases to their hosts as well.

Species Used as Host

Economic Importance for Humans: Negative

Oropsylla montana is one of the North American vectors for the pathogen Yersinia pestis, the plague bacillus. Other flea species can transmit the disease as well. Plague is mainly a disease of rodents, but humans may also become infected through a bite from an infected flea. Oropsylla montana is a vector for the spread of campestral plague ("plague in the countryside," as opposed to plague in cities) in the western United States. D. montanus has been shown to be only a moderately effective vector, which is not very likely to transmit the bacteria even if it bites a human.

Many people are unaware that bubonic plague still exists in the United States, but every year a few Americans become infected with the bacteria, which now can be treated with antibiotic drugs. Y. pestis infections are more common in particular regions of the world, such as certain parts of the western U.S., where the right combinations of climate, rodents, and fleas allow the disease to persist in wild rodent populations. While this disease does not currently pose a major threat to North American populations, it remains present, and public health agencies in parts of the continent where it exists do monitor it to prevent epidemics. (Lang, 1996; Roberts and Janovy, Jr., 2000; Russel, 1913; Weniger, et al., 1984)

  • Negative Impacts
  • injures humans
    • bites or stings
    • carries human disease

Conservation Status

This species is fairly abundant in its range, and is not believed to be in need of conservation.


George Hammond (editor), Animal Diversity Web.

Linda Hemeyer (author), University of Michigan-Ann Arbor, Solomon David (editor), University of Michigan-Ann Arbor.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.


This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.


an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death


specialized for leaping or bounding locomotion; jumps or hops.


an animal that mainly eats blood

scrub forest

scrub forests develop in areas that experience dry seasons.


remains in the same area


lives alone


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


Pan American Health Organization. Plague in the Americas. Scientific Publication #115. Washington, District of Columbia, USA: 1965.

Beard, M., G. Maupin, R. Craven, C. Montman, A. Barnes. 1992. Laboratory and field trials of permethrin-treated cotton used as nesting material to control fleas (insecta: Siphonaptera) on cricetid rodents. Journal of Medical Entomology, 29(2): 338-342.

Ebeling, W. 2002. "Urban Entomology" (On-line). Accessed December 03, 2004 at http://www.entomology.ucr.edu/ebeling/.

Hubbard, C. 1968. Fleas of Western North America. NY: Hafner Publishing Co..

Lang, J. 1996. Factors affecting the seasonal abundance of ground squirrel and wood rat fleas (Siphonaptera) in San Diego County, California. Journal of Entomological Society of America, 33(5): 790-804.

Roberts, L., J. Janovy, Jr.. 2000. Foundations of Parasitology. McGraw-Hill Higher Education.

Russel, H. 1913. The Flea. London: Cambridge University Press.

Rutledge, L., M. Lawson, L. Young. 1982. Tests of repellents against *Diamanus montanus* (Siphonaptera: Ceratophyllidae). Journal of Medical Entomology, 19: 361-365.

Traub, R., M. Rothschild, J. Haddow. 1983. The Rothschild Collection of Fleas. The Ceratophyllidae: Key to genera and host relationships. London: Academic Press Inc..

Weniger, B., J. Warren, V. Forseth, G. Shipps, T. Creelman. 1984. Human bubonic plague transmitted by a domestic cat scratch. Journal of the American Medical Association, 251: 927-929.