Blog Post 7 - Aggressive Mimicry in Myrmarachne


In my last post I introduced the concept of aggressive mimicry, possibly one of my favourite forms of mimicry I have explored so far. There are numerous, crazy examples of aggressive mimicry, but this week I will focus on ant mimicking spiders. There are hundreds of spider species that mimic ants but for this post I will be focusing on the Myrmarachne group. Ant mimicry is common amongst spiders, occurring in 13 taxonomically widespread families (Uma et al. 2013). Spiders' morphological and behavioural resemblance to ants can range from hardly expressive to astonishingly accurate. Mimetic features seen in spiders often include a constricted mid-body that resembles an ant's narrow ‘waist,’ darkly pigmented regions on the head that suggest compound eyes, and waving of front legs in an ‘antennal illusion’ (Uma et al. 2013). But, what makes the Myrmarachne group so interesting is they not only mimic looks, but they mimic the lifestyle of their ant models (Nelson and Jackson, 2009) in order to gain protection against predators while gaining access to resources. 

The Myrmarachne group specifically, is a group of jumping spiders that use visual ques to improve foraging success. The spiders mimic not only an ant’s appearance but also other everyday behaviours of ants. These include the locomotive traits, limb use, trajectories of following experimentally drawn pheromone trails as ants do and, aggregating and living in groups (Shamble et al. 2017; Nelson and Jackson, 2009). By mimicking ants, these spiders gain protection from their predators, other larger jumping spiders Salticidae (Sherratte, 2017). It also allows them to feed on the broods of ant-averse salticids who flee the nest, leaving their eggs behind when confronted by these spiders, and because they are spiders, they can easily manoeuvre through the silk nests to gain access to the broods (Sherratt, 2017). 

Jumping spider, Myrmarachne sp, also known as the ant mimicking spider. Source: https://upload.wikimedia.org/wikipedia/commons/a/a0/Myrmarachne_sp.jpg Date Accessed: 01/05/2019

Female Myrmarachne formosana from Hong Kong. Source: https://en.wikipedia.org/wiki/Myrmarachne#/media/File:Myrmarachne_formosa_female_Hong_Kong_face.jpg Date Accessed: 01/05/2019


Polymorphism has been found to be very frequent in the Myrmarachne group. The evolutionary processes seen to be driving the mimicry in the spiders include natural selection, geographic isolation, genetic drift, sexual selection, genetic divergence, allopatric speciation causing hybridization, reproductive success of hybrids, and reproductive isolation (Pekár et al. 2017). Ants are not only common, but they are also not to be messed with. Depending on the species, they can bite, sting, spray and rapidly recruit reinforcements. It is therefore no surprise that a wide range animals have evolved to mimic them. Be sure check out the attached video!   

The jumping spider Myrmarachne formicaria:



References:

Nelson, X.J. and Jackson, R.R., 2009. Collective Batesian mimicry of ant groups by aggregating spiders. Animal Behaviour, 78(1), pp.123-129.

Pekár, S., Petráková, L., Corcobado, G. and Whyte, R., 2017. Revision of eastern Australian ant-mimicking spiders of the genus Myrmarachne (Araneae, Salticidae) reveals a complex of species and forms. Zoological Journal of the Linnean Society, 179(3), pp.642-676.

Shamble, P.S., Hoy, R.R., Cohen, I. and Beatus, T., 2017. Walking like an ant: a quantitative and experimental approach to understanding locomotor mimicry in the jumping spider Myrmarachne formicaria. Proceedings of the Royal Society B: Biological Sciences, 284(1858), p.20170308.

Sherratt, T.N., 2017. Behavioural Ecology: Spiders Play the Imitation Game. Current Biology, 27(19), pp.R1074-R1076.

Uma, D., Durkee, C., Herzner, G. and Weiss, M., 2013. Double deception: ant-mimicking spiders elude both visually-and chemically-oriented predators. PloS one, 8(11), p.e79660.

Comments

  1. Tasmin2 May 2019 at 19:36

    That’s really amazing! So, do these spiders actually live in close contact with the ants, which is how they gain some measure of protection?

    ReplyDelete

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