Blog Post 5 - Mullerian Mimicry in North American Velvet Ants


In this weeks post I will delve into one of the worlds largest Mullerian mimicry rings, North American velvet ants (Hymenoptera, Mutillidae). North American velvet ants are distinct, diurnal parasitoids of harmful bees and wasps that defend themselves with a painful sting (Wilson et al. 2012). Female mutillids are wingless, have a fast-paced, erratic scurrying locomotion and are noncentral-place foragers, covering large areas during their daily active period(s) in search of host nests and broods (Pan et al. 2017). Due to the rapid locomotion, large areas covered, general body plan and size, female mutillids are usually misidentified by predators as ants, and have hence evolved the presence of aposematic colouration (Pen et al. 2017).


There are 21 North American velvet ant genera that form 8 distinct mimicry rings being, Black-headed Timulla, Desert, Eastern, Madrean, Red-headed Timulla, Texan, Tropical, and Western (Wilson et al. 2015; Pan et al. 2017). As discussed in my last post, some of the main factors driving the evolution of Mullerian mimicry include, sexual selection, selection imposed by predation, anti-apostatic selection and geographic pressures.

The morphological and geographical ranges of the 8 mimicry rings found in North American velvet ants.  Sourced from Wilson et al. 2012.

While some amount of shared phylogenetic history is likely responsible for similarities in colour in some velvet ant species, most of the diversity in these mimicry rings is at the level of species rather than races (Wilson et al. 2012). Analyses of recent genomic data sets have shown that a single mimetic phenotype can arise once and spread not only within species but also between species through hybridization, allowing multiple species to participate in the same mimicry rings (Wilson et al. 2017), as seen in velvet ants. Interestingly, an example of this can be seen in Psorthaspisspider wasps, which have been seen to participate in velvet ant mimicry rings since the two groups codiverged to produce a similar colour pattern (Rodriguez et al. 2014). So, morphometric analyses indicate that these mimicry rings are morphologically distinct, and phylogenetic analyses indicate that most of the similarity in colouration within mimicry rings is a result of repeated evolution rather than shared ancestry (Wilson et al. 2012). To finish off this weeks blog, here are a few cool examples of North American velvet ants!

A velvet ant from Tooele, Utah. Source: http://www.bbc.com/earth/story/20151014-superpowers-of-the-near-invincible-velvet-ant Date Accessed:   10/04/2019
Sphaeropthalma arota, a velvet ant from California. Source: http://www.bbc.com/earth/story/20151014-superpowers-of-the-near-invincible-velvet-ant Date Accessed: 10/04/2019
Dasymutilla magnifica, a velvet ant from Texas. Source: http://www.bbc.com/earth/story/20151014-superpowers-of-the-near-invincible-velvet-ant Date Accessed: 10/04/2019
Hoplomutillia opima, a velvet ant from Trinidad. Source: http://www.bbc.com/earth/story/20151014-superpowers-of-the-near-invincible-velvet-ant Date Accessed: 10/04/2019



References

Pan, A.D., Williams, K.A. and Wilson, J.S., 2017. Are diurnal iguanian lizards the evolutionary drivers of New World female velvet ant (Hymenoptera: Mutillidae) Müllerian mimicry rings?. Biological Journal of the Linnean Society, 120(2), pp.436-447.

Rodriguez, J., Pitts, J.P., von Dohlen, C.D. and Wilson, J.S., 2014. Müllerian mimicry as a result of codivergence between velvet ants and spider wasps. PloS one, 9(11), p.e112942.

Wilson, J.S., Jahner, J.P., Forister, M.L., Sheehan, E.S., Williams, K.A. and Pitts, J.P., 2015. North American velvet ants form one of the world’s largest known Müllerian mimicry complexes. Current Biology, 25(16), pp. R704-R706.

Wilson, J.S., Williams, K.A., Forister, M.L., Von Dohlen, C.D. and Pitts, J.P., 2012. Repeated evolution in overlapping mimicry rings among North American velvet ants. Nature Communications, 3, p.1272.



 

Comments

  1. I didn’t know that these animals even existed! That’s so cool! Is there any sort of understanding of the underlying genetic associations with these colour patterns?

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