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Tricholipeurus lipeuroides

By Gayle Soskolne

Geographic Range

Though the primary host of Tricholipeurus lipeuroides, the white-tailed deer, is found throughout the United States, extending into Canada and Mexico, this parasite is primarily found on the deer that reside in the southern states, such as Mississippi and Texas (Watson and Anderson, 1974). However, this species has also been found in three provinces in Canada, as well as seventeen other states in southern United States (Price and Graham, 1997). (Price and Graham, July 1997; Watson and Anderson, 1975)

Habitat

Tricholipeurus lipeuroides is found on Odocoileus virginianus subspecies (Watson and Anderson, 1975). Odocoileus hemionus, the mule deer, is also a known host (Price and Graham, 1997). These lice prefer deer that reside in relatively warm temperate areas. (Price and Graham, July 1997; Watson and Anderson, 1975)

Physical Description

Many researchers believe that lice descended from insects in the order Psocoptera, a very similar looking, though not parasitic, group of insects. Unlike their believed ancestor, all lice are adapted to a parasitic lifestyle in their loss of ancestral wings, as well as being dorsoventrally flattened (Plane and Crosskey, 1993). The head of all lice in the suborder Ischnocera is wider than the neck, and all lice in the order Mallophaga have manidbles adapted for chewing. Tricholipeurus lipeuroides is no exception.

Adults of this species range from 2.5 to 2.75 mm long (Price and Graham, 1997). The basal plate of the male's genitalia extends to the fifth abdominal segment, in contrast to the basal plate of the female's genitalia, which is found only on the last abdominal segment (Price and Graham, 1997).

The antennae are consistent with the rest of the suborder Ischnocera in their filiform (thin and linear) structure. Each antenna is made up of three to five segments, with a style at the tip. The male's antennae are modified as holding structures used during reproduction (Lane and Crosskey, 1993). (Lane and Crosskey, 1993; Price and Graham, July 1997)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    2.5 to 2.75 mm
    0.10 to 0.11 in

Development

Tricholipeurus lipeuroides is a hemimetabolous species, exhibiting three life stages: egg, nymph, and adult. The time it takes the eggs to hatch depends on body temperature of the host, and external environmental conditions. Once the eggs hatch, the nymphs go through approximately three instars (the length and number also depending on external conditions). The mature adult that develops is ready for reproduction.

Reproduction

No information is available on the mating system of these lice.

Female lice lay up to 100 eggs throughout their lifetime. Each is stuck to the hair of the host using a special glue secreted directly before secreting the egg, also known as a "nit." Eggs are very resistant to removal, desiccation, or destruction.

The exact life cycle of T. lipeuroides is unknown (Price and Graham, 1997). The density of this species on its host dramatically changes with the seasons. Adult T. lipeuroides are most abundant on the deer between November and April. Though present in low numbers throughout the year, Watson and Anderson noted that no adults of this species could be found during July and August (1975). Immature lice, however, were most abundant between February and April. (Price and Graham, July 1997; Watson and Anderson, 1975)

  • Breeding season
    Most breeding takes place in the winter months, between November and April

Female lice provide nutrients to their eggs before they are laid, and then they abandon them.

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

No information is available on the lifespan of these lice.

Behavior

Tricholipeurus lipeuroides is very host specific. Once on a host, unless the host dies or is in close contact with another animal, these lice tend to stay within one species, and almost always on one host (Kocan, 2001).

Tricholipeurus lipeuroides, as an ectoparasite, is found only on the outside of its host. This species migrates to different areas of the host's body throughout the year, but never below the surface of the skin. While T. lipeuroides is found primarily on the belly of the deer during peak months, the immature lice are found in separate areas of the body, mainly on the back, neck and shoulders. During the warmer seasons when T. lipeuroides is found in fewer numbers, adults prefer the belly, forelegs, brisket, and rump. (Kocan, 2001; Watson and Anderson, 1975)

Communication and Perception

Lice have short antennae with chemoreceptors and tactile hairs. No information is available on how these lice communicate with one another.

Food Habits

Tricholipeurus lipeuroides uses its mandibles to feed on epidermal scales, skin secretions, and other material found on the skin of its host. (Davidson, et al., 1981)

Ecosystem Roles

Tricholipeurus lipeuroides is an obligate ectoparasite of deer, usually white-tailed deer. It is estimated that adult T. lipeuroides are found on approximately three-quarters of the white-tailed deer population.

Tricholipeurus lipeuroides may compete with other deer parasites for resources on the host. Between May and October, when populations of T. lipeuroides are very low, the adults of another species of louse, Tricholipeurus parallelus, occupy the same host as T. lipeuroides. Watson and Anderson therefore came to the conclusion that "the temporal separation in abundance of these two species may (be) the result of competition or regulatory environmental factors..." (1975). (Watson and Anderson, 1975)

Species Used as Host

Economic Importance for Humans: Negative

These lice, as well as most of the parasites on these deer, are not easily transmitted to domestic animals, and don't tend to survive well. However, in the rare case that they do, T. lipeuroides does not harm its new host (Kocan, 2001). Tricholipeurus lipeuroides is therefore not a vector for any pathogen transmittable to humans.

Many studies which have followed white-tailed deer and their parasites have noted that these parasites in particular, unless densely inhabiting the host, do not cause serious damage, if any at all (Demarais et al., 1987; Davidson et al., 1981). In fact, normal healthy white-tailed deer in Canada were noted to each have between 14,000 and 70,000 chewing lice on their bodies (Price and Graham 1997). (Davidson, et al., 1981; Demarais, et al., 1987; Kocan, 2001; Price and Graham, July 1997)

Contributors

Allison Poor (editor), University of Michigan-Ann Arbor.

Gayle Soskolne (author), University of Michigan-Ann Arbor, Barry OConnor (editor), University of Michigan-Ann Arbor.

Glossary

Nearctic

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

agricultural

living in landscapes dominated by human agriculture.

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.

chaparral

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.

chemical

uses smells or other chemicals to communicate

ectothermic

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

forest

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

heterothermic

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.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

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.

motile

having the capacity to move from one place to another.

native range

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

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parasite

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

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

tactile

uses touch to communicate

temperate

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).

References

Burgess, N., G. Cowan. 1993. A Colour Atlas of Medical Entomology. London, UK: Chapman & Hall Medical.

Davidson, W., F. Hayes, V. Nettles, F. Kellogg. 1981. Disease and Parasites of White-Tailed Deer. Tallahassee, Florida: Tall Timbers Research Station.

Demarais, S., H. Jacobson, D. Guynn. 1987. Effects of season and area on ectoparasites of white-tailed deer (Odeocoileus virginianus) in Mississippi. Journal of Wildlife Diseases, 23(2): 261-266.

Kocan, A. 2001. Parasitic and infectious diseases of white-tailed deer in Oklahoma. Journal of Veterinary Medicine, 13(1): 23-30.

Lane, R., R. Crosskey. 1993. Medical Insects and Arachnids. London, UK: Chapman & Hall.

Price, M., O. Graham. July 1997. Chewing and sucking lice as parasites of mammals and birds. United States Department of Agricultrue, Technical Bulletin #1849.

Watson, T., R. Anderson. 1975. Seasonal changes in louse populations on white-tailed deer (Odocoileus virginianus). Canadian Journal of Zoology, 53: 1047-1054.

Webster, W., R. Stewart. 1964. Tricholipeurus lipeuroides from a white-tailed deer in Quebec. Canadian Journal of Zoology, 42: 323.

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