The evolution of tissue migration by parasitic nematode larvae

Andrew Fraser Read, A. Skorping

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Migration by nematode larvae through the tissues of their mammalian hosts can cause considerable pathology, and yet the evolutionary factors responsible for this migratory behaviour are poorly understood. The behaviour is particularly paradoxical in genera such as Ascaris and Strongylus in which larvae undergo extensive migrations which begin and end in the same location. The orthodox explanation for this apparently pointless behaviour is that a tissue phase is a developmental requirement following the evolutionary loss of skin penetration or intermediate hosts. Yet tissue migration is not always necessary for development, and navigation and survival in an array of different habitats must require costly biochemical and morphological adaptations. Migrating larvae also risk becoming lost or killed by the host. Natural selection should therefore remove such behaviour unless there are compensating benefits. Here we propose that migration is a selectively advantageous life-history strategy. We show that taxa exploiting tissue habitats during development are, on average, bigger than their closest relatives that develop wholly in the gastrointestinal tract. Time to reproduction is the same, indicating that worms with a tissue phase during development grow faster. This previously unsuspected association between juvenile habitat and size is independent of any effects of adult habitat, life-cycle, or host size, generation time or diet. Because fecundity is intimately linked with size in nematodes, this provides an explanation for the maintenance of tissue migration by natural selection, analogous to the pre-spawning migrations of salmon.

Original languageEnglish (US)
Pages (from-to)359-371
Number of pages13
JournalParasitology
Volume111
Issue number3
DOIs
StatePublished - Jan 1 1995

Fingerprint

animal parasitic nematodes
nematode larvae
Larva
Ecosystem
Genetic Selection
habitats
natural selection
Strongylus
Ascaris
Salmon
larvae
intermediate hosts
migratory behavior
Life Cycle Stages
skin (animal)
gastrointestinal system
salmon
Reproduction
Fertility
Gastrointestinal Tract

All Science Journal Classification (ASJC) codes

  • Parasitology
  • Animal Science and Zoology
  • Infectious Diseases

Cite this

Read, Andrew Fraser ; Skorping, A. / The evolution of tissue migration by parasitic nematode larvae. In: Parasitology. 1995 ; Vol. 111, No. 3. pp. 359-371.
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The evolution of tissue migration by parasitic nematode larvae. / Read, Andrew Fraser; Skorping, A.

In: Parasitology, Vol. 111, No. 3, 01.01.1995, p. 359-371.

Research output: Contribution to journalArticle

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