The Benefits of Masquerading as an Ant

Oftentimes, it seems like ants are everywhere. Recently, I found myself thinking about the topic of ant distribution and decided to look into it. The species of ants that we mainly work with, Cephalotes varians, is native to the areas surrounding the gulf of Mexico such as Florida and Cuba. This is a relatively small area, but the genus Cephalotes can be found most places in South and Central America, even up to a few of the southernmost US states such as Texas and Florida. And, when I looked for the distribution of ants overall, I learned that they are found on every continent except Antarctica. One especially interesting thing I learned was that ants’ ubiquitousness and formidable defenses make them an attractive target for mimicry (Huang et al. 2010).

Left: A mimic octopus in the act of mimicking a flatfish [1]. Right: A flatfish [2]

Mimics are fairly common within the animal kingdom, and my personal favorite is the mimic octopus. This is because these octopi able to change their appearance to practice many different types of mimicry. One type that they employ is Batesian mimicry. This type of mimicry occurs when one harmless animal imitates another that has formidable defenses. In the case of the mimic octopus, it can deter predators by imitating poisonous animals such as the lionfish and sea snake. Many jumping spiders also take advantage of Batesian mimicry. Unlike the ants they imitate, jumping spiders do not have many defense mechanisms. Instead, as the Hoy lab at Cornell has found, they emulate antennae by waving their front legs in the air and walk as if they are ants following a pheromone path. Jumping spiders using these techniques were less likely to be attacked than non-mimetic jumping spiders. Due to the effectiveness of this strategy, it is unsurprising that there are many different organisms that mimic ants to make up for a lack of defenses. This list of ant mimics includes beetles, spiders, and even some types of plants.

 

An ant mimicking jumping spider raising its front legs to look like antennae.[3]

Although some jumping spiders mimic ants in order to make up for a lack of defenses, some other spiders mimic ants for a more threatening reason. The spider Aphanlochilus rogersi preys on the ant species Cephalotes pusillus and a few other black ants of the Cephalotini tribe. Oliveira and Sazima found that A. rogersi was able to imitate black ants of this tribe by carrying an ant corpse. In the corpse carrying position, A. rogersi’s mimetic traits combined with the “shield” of the ant corpse accurately mimicked an ant carrying a dead companion. By using this “shield”, A. rogersi is able to infiltrate colonies, where it preys on ants and avoids their bites by attacking them from behind.This not only helps the spider to evade ant patrols and feed more easily on ants, but Oliveira and Sazima propose that their mimicry also has a Batesian component. In this case, it would not only help them prey on ants, but also prevent them from being attacked by predators that would normally avoid these ants due to their biting ability.

While some organisms use ant mimicry to either avoid attack or prey on ants more easily, others use it in order to steal food resources. One species that does this is called Cephalotes specularis, or the “mirror turtle ant”. As Powell et. al found, this species visually mimics its host Crematogaster ampla. It then “eavesdrops on the host’s trail pheromones,” and slips past its defenses to steal food (Powell et. al 2014).

 

The Maculinea rebeli butterfly. A surprising ant mimic. [4]

While some organisms emulate the appearance of ants, others use a different type of mimicry called chemical mimicry. An example of this is the butterfly Maculinea rebeli. In 1999, Akino et al. found that the caterpillars of this species were able to secrete chemicals that caused Myrmica schencki ants to treat them as if these caterpillars were the ants’ own larvae. They also found that, as caterpillars spent more time in the nest, they acquired “chemical camouflage” that allowed them to almost perfectly imitate the odor of the host colony. This incredibly specific mimicry makes it possible for these caterpillars to eat food from the brood chambers of the ants’ nests. Although this strategy is highly specialized and only allows the caterpillars to mimic a particular species of ants, this mimicry is greatly rewarding since it provides the butterfly’s young with easy access to much needed sustenance.Overall, there is a much greater diversity in types of ant mimics than I had first expected. Before I had started my research, I thought that there would only be a few ant species that were common enough or had strong enough defenses to be worth mimicking. However, the sheer number of ant mimics suggests differently. Ants can actually be found almost all over the world, and as Joanna discussed in her previous blog post, many of them are able to sting and bite. This makes them unpopular targets for predators. Since the turtle ants that we work with in the lab are so docile, it is very easy to underestimate how ferocious ants can be. In general, the ubiquitousness of ants and their mimics serves as a reminder not to underestimate ants.



Further Reading

Akino, T., Knapp, J. J., Thomas, J. A., & Elmes, G. W. (1999, July 22). Chemical mimicry and host specificity in the butterfly Maculinea rebeli, a social parasite of Myrmica ant colonies. https://royalsocietypublishing.org/doi/abs/10.1098/rspb.1999.0796


Glaser, L. B. (n.d.). Jumping spiders mimic ants to defy predators. Retrieved from http://news.cornell.edu/stories/2017/07/jumping-spiders-mimic-ants-defy-predators


Oliveira, P. S., & Sazima, I. (2008, January 14). Adaptive bases of ant-mimicry in a neotropical aphantochilid spider (Araneae: Aphantochilidae). Retrieved from https://academic.oup.com/biolinnean/article-abstract/22/2/145/2666307


Powell, S., Del-Claro, K., Feitosa, R. M., & Brandão, C. R. F. (2014). Mimicry and Eavesdropping Enable a New Form of Social Parasitism in Ants. The American Naturalist, 184(4), 500–509. https://doi.org/10.1086/677927


Jin-Nan Huang, Ren-Chung Cheng, Daiqin Li, I-Min Tso. (2010, October 20) Salticid predation as one potential driving force of ant mimicry in jumping spiders. Proceedings of the Royal Society B: Biological Sciences. http://doi.org/10.1098/rspb.2010.1896

Media credits:

[1]: Photo by Klaus Steifel. https://flic.kr/p/asF8TV

[2]: Photo by Frank Starmer. https://flic.kr/p/ioJL

[3]: Photo by Alejandro Soffia. https://flic.kr/p/8WBiCg

[4]: Photo by Jürgen Mangelsdorf. https://flic.kr/p/agKLig