Ant mites love big ants, parasitic ants, and they really, really, really like Lasius

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An Oplitus mite attached to the midleg of a Lasius worker ant (Urbana, Illinois)

We humans share our space with lice, bedbugs, fleas, and other vermin, but we’re not the only societies plagued by little hangers-on. Ants contend with an astounding array of body mites. I bring this up because Insectes Sociaux recently published a thorough survey of which mites live on which parts and which castes of which ant species across an entire ant fauna.

Kaitlin Campbell at Miami University of Ohio examined about 10,000 ants for mites from nearly 300 individual colonies in Ohio & Kentucky. Tedious? Probably. But the results are an unprecedented look at the mitescape- 151 species in total- of an entire ant fauna. Some tidbits:

  • Larger colonies hosted more mites
  • Larger individual ants hosted more mites
  • Most mite species were specific to particular ant species
  • Many mite species were attached only to particular parts of their hosts
  • Male ants don’t carry as many mites as do queens and workers
  • Socially parasitic ant species carry more mites than nonparasitic species
  • The genus Lasius really has a lot of mites.
  • The most nomadic ant species surveyed, Tapinoma sessile, had the lowest mite load.

Most intriguing are patterns that relate to dispersal. Since ant colonies are islands, mites must have trouble colonizing new nests. Many are prone to attaching themselves to young queens and avoid the dead-end males. Those that ride social parasites may be getting a free ride to mature host colonies, circumventing the dangerously high mortality trap of foundress queens.

Although myrmecologists frequently see mites, most of us don’t bother to do much with them. I’m glad that’s starting to change. The natural history of these arthropods is fascinating and wide open for study- just ask Macromite!


source: Campbell KU, Klompen H, Crist TO (2013) The diversity and host specificity of mites associated with ants: the roles of ecological and life history traits of ant hosts. Insectes Sociaux 60: 31-41.

 

6 thoughts on “Ant mites love big ants, parasitic ants, and they really, really, really like Lasius”

  1. The point that ant colonies are isolated, hard-to-colonize islands is an interesting point: if a female mite does latch on to a successful foundress, how do her offspring avoid inbreeding effects, assuming you have no gene flow in between colonies? Do they reproduce asexually? Or maybe there really is enough gene flow between these parasite populations through inter-colony interactions to keep them viable?

    1. Traditional models of inbreeding effects based on vertebrates probably aren’t very useful for mites (or ants). The mites in Kaitlin’s study seem to cover the range of known reproductive modes in the Acari, but there are quite a few that are haplo-diploid with strongly female-biased sex ratios and some all-female parthenogenetic lineages. Most mites that live in restricted habitats will be founding new colonies with limited genetic diversity and often this will include a high level of inbreeding. This doesn’t seem to bother them at all. Perhaps they don’t know about the Red Queen or Mueller’s Ratchet etc.

      What I find interesting is that these mite species maintain their morphological-behavioural integrity in spite of being so highly fragmented and genetically isolated. Even the all-female lineages seem to evolve, though, and apparently have radiated into relatively genetically and morphologically diverse lineages over long periods of time.

  2. At NCSU, a fellow grad student was trying to finish up his thesis, a revision of Oplitus, the mites that cling to the tibial spurs of ants. But the other students kept finding more new species on ants they collected, forcing him to write, write, write!

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