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Heterodoxus spiniger

By Sarah Herhilan

Geographic Range

Heterodoxus spiniger is found on canines on all continents except Antarctica and Europe. (Amin and Madbouly, 1973; Price and Graham, 1997)

Habitat

Heterodoxus spiniger inhabits the skin of domestic dogs (Canis lupus familiaris) and a few other canids, notably the side-striped and golden jackels (Canis adustus and Canis aureus) in Africa, and the coyote (Canis latrans), red wolf (Canis rufus) and gray fox (Urocyon cinereoargenteus) in North America. It is usually found at the very proximal end of the hair shaft, close to the skin, often in the posterior dorsal region of the body (Price and Graham, 1997; Roberts and Janovy, 2000). Heterodoxus spiniger resides mostly in tropical and temperate climates (Price and Graham, 1997), but it has also adapted to more arid conditions (Amin and Madbouly, 1973). (Amin and Madbouly, 1973; Price and Graham, 1997; Roberts and Janovy, Jr., 2000)

Physical Description

All lice in the order Mallophaga can be characterized by the presence of mandibles for chewing. Heterodoxus spiniger is no exception. Like other species in the suborder Amblycera, an adult Heterodoxus spiniger also has visible maxillary palps, and antennae are located within deep lateral grooves on the sides of the head. The body is covered with small hairs called setae that help hold the louse on to its host. There are spiracles on the lateral edges of the body through which breathing occurs. The sclerotized sperm-transfer organ, the aedeagus, distinguishes males. Usually these lice are amber to black in color (Roberts and Janovy, 2000).

Like other members of the family Boopiidae, these lice have two claws on each pretarsus, unlike species in the Ischnoceran family Trichodectidae which may parasitize domestic animals. They also retain vestiges of eyes on the lateral sides of the head (Price and Graham, 1997). (Price and Graham, 1997; Roberts and Janovy, Jr., 2000)

  • Sexual Dimorphism
  • sexes shaped differently

Development

Like all lice, Heterodoxus spiniger experiences a gradual metamorphosis, starting with an egg (nit). The egg hatches, and goes through three nymphal instars including molts in between the stages that resemble the adults, but are smaller and slightly paler in color. The generations are only 3 or 4 weeks apart; they develop rather quickly. ("Louse", 2001; Pennington and Phelps, 1969; Roberts and Janovy, Jr., 2000)

Reproduction

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

Lice reach sexual maturity about three to four weeks after they are laid as nits. Female lice glue nits to the individual hairs of the host, most often very close to the skin. ("Louse", 2001; Pennington and Phelps, 1969; Roberts and Janovy, Jr., 2000)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • oviparous
  • Range age at sexual or reproductive maturity (female)
    3 to 4 weeks
  • Range age at sexual or reproductive maturity (male)
    3 to 4 weeks

Female lice provide nutrients to their eggs before they are laid; then the females abandon them. (Roberts and Janovy, Jr., 2000)

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

Lifespan/Longevity

No information is available on the lifespan of these lice.

Behavior

Heterodoxus spiniger spends most of its life on one host, but can move from host to host as needed. It is fairly host-specific, feeding only on dogs and a few other members of the family Canidae (Price and Graham, 1997; von Keler, 1971). Heterodoxus spiniger was originally identified in Australia on the wallaby, but typically infests only canines. (Price and Graham, 1997). These lice do not typically infest felines, although in one case they were found to have infested a litter of kittens (Colless, 1959). (Colless, 1959; Price and Graham, 1997; von Keler, 1971)

Communication and Perception

Lice have short antennae, which are presumably used for chemoreception as well as for "feeling" their way around. No information is available on how these lice communicate with one another. (Roberts and Janovy, Jr., 2000)

Food Habits

Heterodoxus spiniger feeds on the skin of canines. It has specialized mandibles for chewing and biting through the tough hide of both domestic dogs and other canids (Price and Graham, 1997). It appears to also feed on blood, as many individuals were observed with blood in their guts (Nelson, 1962). (Nelson, 1962; Price and Graham, 1997)

  • Animal Foods
  • blood

Ecosystem Roles

Heterodoxus spiniger is an obligate ectoparasite of canids. It is also the intermediate host to several helminth parasites of dogs including the tapeworm, Dipylidium caninum, and the filarid nematode, Dipetalonema reconditum (Price and Graham, 1997). (Price and Graham, 1997; Roberts and Janovy, Jr., 2000)

Species Used as Host

Economic Importance for Humans: Negative

While not directly affecting humans, as a parasite of domestic dogs, H. spiniger can have negative effects. Infestation is generally not severe. The bites of H. spiniger typically inflict only minor discomfort to the host, unless present in large numbers (Pennington and Phelps, 1969). Price and Graham (1997) review several cases where heavy infestations of these lice have negative effects on canine hosts, one of which was fatal.

Heterodoxus spiniger carries the tapeworm, Dipylidium caninum, which infests both domestic dogs and humans who accidentally swallow lice after petting their dogs (Roberts and Janovy, 2000). In addition, Heterodoxus spiniger carries the filarid nematode Dipetalonema reconditum, which parasitizes domestic dogs (Price and Graham, 1997).

Treatment of an infestation of lice is with application of louse removal products such as Pyrethrin. (Pennington and Phelps, 1969; Price and Graham, 1997; Roberts and Janovy, Jr., 2000)

Conservation Status

Other Comments

Heterodoxus spiniger has an unusual evolutionary history. All other species in the genus Heterodoxus are parasites of kangaroos and wallabies in Australia and New Guinea. The ancestor of H. spiniger presumably colonized dingos after their transport to Australia by early humans. From the dingo, the louse transferred to domestic dogs after European colonization of Australia, and from there the louse was spread to other parts of the world. (Murray and Calaby, 1971)

Contributors

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

Sarah Herhilan (author), University of Michigan-Ann Arbor, Barry OConnor (editor), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

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

Neotropical

living in the southern part of the New World. In other words, Central and South America.

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.

causes or carries domestic animal disease

either directly causes, or indirectly transmits, a disease to a domestic animal

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

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.

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.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

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

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scrub forest

scrub forests develop in areas that experience dry seasons.

suburban

living in residential areas on the outskirts of large cities or towns.

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).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

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.

savanna

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.

urban

living in cities and large towns, landscapes dominated by human structures and activity.

References

2001. "Louse" (On-line). Accessed (Date Unknown) at http://www.britannica.com/ebc/article?tocId=9370619&query=louse&ct=.

Amin, O., M. Madbouly. 1973. Distribution and seasonal dynamics of a tick, a louse fly, and a louse infesting dogs in the Nile valley and delta of Egypt. Journal of Medical Entomology, 10: 295-298.

Colless, D. 1959. Heterodoxus spiniger (Mallophaga: Boopidae) from cats in Singapore. Journal of Parasitology, 45: 248.

Foster, R., M. Smith. 1997. "Lice (Pediculosis)" (On-line). Accessed May 9, 2001 at http://www.peteducation.com/parasites/lice.htm.

Hoffman, 1930. Informal report to the 130th meeting of the Helminthological society of Washington, May 17, 1930. Journal of Parasitology, 17: 56-57.

Murray, M., J. Calaby. 1971. The host relations of the Boopiidae. Appendix 2 to Keler, S. von, A revision of the Australasian Boopiidae (Insecta: Phthiraptera), with notes on the Trimenoponidae.. Australian Journal of Zoology, Supplement 6..

Nelson, G. 1962. Dipetalonema reconditum (Grassi, 1889) from the dog with a note on its development in the flea, Ctenocephalides felis, and the louse, Heterodoxus spiniger.. Journal of Helminthology, 36: 297-308.

Pennington, , Phelps. 1969. Canine filariasis on Okinawa, Ryukyu Islands. Journal of Medical Entomology, 6: 59-67.

Price, M., O. Graham. 1997. Chewing and Sucking Lice as Parasites of Mammals and Birds. USDA Agricultural Research Service Technical Bulletin, 1849: 7-11.

Roberts, L., J. Janovy, Jr.. 2000. Foundations of Parasitology, Sixth Edition. Boston: McGraw- Hill Inc..

von Keler, S. 1971. A revision of the Australian Boopidae (Insecta: Phthiroptera), with notes on the Trimenoponidae. Australian Journal of Zoology, Supplement 6: 311.

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