Of the 19 species of blues in Cascadia, about half have their larvae tended by ants (James and Nunnallee. 2011. Life Histories of Cascadia Butterflies, p. 182). But what’s in it for the ants?

Apparently not much. Honeydew glands keep the ants interested while the larvae are above ground (ants & larva of silvery blue at right, on lupine), but from there on it seems to be pure parasitism, not symbiosis.

At least for the European species Maculinea rebeli, the larvae use chemical mimicry to smell like an ant and then acoustic mimicry to sound like the ant queen, thereby getting preferential (truly “royal” treatment from the worker ants (Barbero et al. 2009. Queen ants make distinctive sounds that are mimicked by a butterfly social parasite. Science 323:792-785). If the ant nest is disturbed, the butterfly larvae are rescued first, and if resources in the nest get short, they are even fed ant larvae.

Wow! Makes you wonder when and how this got started.

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