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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.
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.
Perception Channels: tactile ; chemical
US Federal List: no special status
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.
Development - Life Cycle: metamorphosis
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.
Negative Impacts: causes or carries domestic animal disease
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).
Ecosystem Impact: parasite
Species Used as Host:
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).
Animal Foods: blood
Heterodoxus spiniger is found on canines on all continents except Antarctica and Europe.
Biogeographic Regions: nearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native )
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).
Habitat Regions: temperate ; tropical
Terrestrial Biomes: desert or dune ; savanna or grassland ; forest ; rainforest ; scrub forest
Other Habitat Features: urban ; suburban ; agricultural
No information is available on the lifespan of these lice.
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).
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: sexes shaped differently
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.
Range age at sexual or reproductive maturity (female): 3 to 4 weeks.
Range age at sexual or reproductive maturity (male): 3 to 4 weeks.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); oviparous
Female lice provide nutrients to their eggs before they are laid; then the females abandon them.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female)
