User:Eisel.17/sandbox

FINAL DRAFT: Evolution of the Exploding Ant
Evolution of the Exploding Ant

The Camponotus genus includes a wide variety of carpenter ants, but in some species of these ants, a unique ability to “explode” is used as a defense mechanism. Although self-destruction seems to be a plausible use for killing the ants’ enemies in territorial battles, it is questionable how self-destruction could be an advantageous adaptation of the ant. However, this trait can be explained to be helpful to the ants by its usefulness in other species, its altruistic nature to benefit the colony as a whole by protecting the ants from predators and its use in territorial battles. The use of autothysis in ants is also more successful when compared to other defenses, and the ants release pheromones to communicate to the other ants when autothysis is a necessary weapon to utilize. Self-destruction of these ants is an interesting phenomenon and when examining the evolution of this defensive trait, it is important to understand some of the anatomy and chemistry of these ants. Worker ants of the complex Camponotus cylindricus display a unique, enlarged mandibular gland extending from its head to the end of the ant, known as its gaster (Jones et al., 2004). Jones et al. make note of the chemicals contained in the mandibular gland of these ants as corrosive and irritating compounds like m-cresol and resorcinol and mention that the products from the mandibular glands have a white color. Mixed in with these compounds are aliphatics, which could be octadecanol or possibly sugars that act as adhesives. The combination of these compounds with adhesives allows for the products to be useful in sticking to and killing the ant and its nearby enemies when released (Jones et al., 2004). The release of the mandibular gland products by the ants is also an important concept that needs to be understood before answering evolutionary questions about these explosive ants. It was observed in the Campontus saundersi species that after being mechanically disturbed, a burst occurs at an intersegmental fold in the gaster as well as the mandibular glands as a result of contracting their gaster and that burst releases the sticky corrosive product (U. Maschwitz and E. Maschwitz, 1974). This phenomenon of self-destruction by these ants and other related species was given the term “autothysis,” which means self-sacrifice in Greek (U. Maschwitz and E. Maschwitz, 1974). Despite how unusual this defensive trait may seem, it is not unique to just the few Camponotus species that use it, but species of termites have also been observed to use autothysis. The well-known termite species, Globitermes sulphureus use the suicidal defensive behavior of autothysis to help protect their territory from attackers (C. Bordereau et al., 1997). C. Bordereau, A Robert, V. Van Tuyan and A. Peppuy conducted a study where they observed a colony of Globitermes sulphureus defending an attack by ants. Their main defense against such an attack was to mechanically engage their enemies by catching them and using their mandibles to pierce them, but some highly excited soldiers were found with droplets of liquid flowing from their neck (C. Bordereau et al., 1997). These droplets were indeed the product of the autothysis of these termites. The convergent evolution of this trait in other organisms helps explain that this trait is selected for and can be quite useful as a defense mechanism. Even though the termites use self-sacrifice just as the Camponotus ants do, their use of this behavior and the origin of sticky, corrosive compounds from their body is slightly different when compared to the ants. In the termites, the products were released from the neck, whereas the ants released it from their mandibular glands. The two arthropods are also different in this behavior in that the termites ‘exploded’ only if they were highly excited and were able to continue fighting for a short while after autothysis, while the ants were stuck in it and died with their enemies. Although the termites were not initially very reliant on autothysis as a defense and have some differences in their use of this defensive trait, it still appeared to be a successful behavior for protecting their territory and helps give an example as to why ants would have adapted a self-destructive trait analogous to the termites (C. Bordereau et al., 1997). When comparing defensive strategies of the exploding termites to the exploding ants, the question of why the ants do not defend their colony like the termites and use mechanical defenses as the main tool to kill their enemies instead of sacrificing themselves might arise. Jones et al. explain that stinging was used as a weapon in the early ants, but the stings were not as effective in battles with different colonies of ants or other insects for territory as they were for engaging large vertebrate enemies. For this reason as the ants evolved over generations, they adapted to use chemicals to fight multiple arthropod enemies at one time (Jones et al., 2004). The Camponotus genus of ants has adapted to using autothysis as an altruistic defensive trait in order to fight against arthropods and to possibly deter vertebrate predators for the benefit of the colony as a whole. Exploding ants have been known to grab ahold of legs or antennas of intruding ants on their foraging territory before they release the deadly mandibular gland product and sacrificing itself. The worker ant has also been observed to wrap itself around an opponent, placing its dorsal gaster onto the opponents face preceding the expulsion of sticky corrosive product from its mouth and gaster, permanently sticking to the opponent while killing itself and the enemy, as well as any other enemies that become stuck to the products (Davidson, Salim and Billen, 2011). As mentioned before, these ants have evolved to use autothysis to better defend against arthropod enemies. The reason behind this is simply because the sticky properties of the mandibular gland products adhere to the legs and mandibles of arthropods, while being rather ineffective towards larger vertebrate predators such as lizards or birds (Shorter and Rueppell, 2011). However, the evolution of this defensive trait is not completely useless against vertebrate predators. All individuals in the colony are equipped with the chemicals produced from autothysis, which are inedible to vertebrate predators that may try to eat the ants. In this case autothysis may even deter some predators from eating these ants in the future (Sands, 1982). Another trait that is related to the ants preserving their territory is their release of pheromones from the mandibular gland. These different pheromones are involved in several different interactions between individuals in the colony, however the release of alarm pheromones as secretions from the mandibular glands is an important role in the biology of Camponotus (Torres et al., 2001). The alarm pheromones help ants exhibit a characteristic of changing their fighting behavior when defending their territory in accordance with what would be most necessary. The ants will either attempt to sacrifice or preserve themselves in battle if their colony would suffer as a result of the opposing action (Batchelor and Briffa, 2011). This example not only explains how the adaptation of a self-destructive trait can prove to be more than suicide, but also again presents that the ants display altruistic actions by their use of autothysis in order to help the colony as a whole. The defensive trait of autothysis used in some of the ants belonging to the Camponotus genus would at first look, appear to be a disadvantageous adaptation, however this defense mechanism is explained to provide a benefit to the colony as a whole. Autothysis is efficient in territorial battles by sticking the deadly substance to multiple enemies and has been observed in species of termites, proving that this trait is advantageous due to it being analogous in some species of termites and ants. The use of autothysis as a defense could be viewed as a negative trait if all the ants used it in battle, but this is not a problem because there are certain triggers that changes the ant’s behavior from self-sacrifice to self preservation of it would be an unnecessary loss to the colony.

References: Batchelor T.P. and Briffa M. 2011. Fight tactics in wood ants: individuals in smaller 	groups fight harder but die faster. P. Roy. Soc. Lond. B. Biol. 278: 3243–3250 Bordereau, C, A Robert, Tuyen V. Van, and A Peppuy. 1997. Suicidal Defensive 	Behaviour by Frontal Gland Dehiscence in Globitermes sulphureus Haviland 	Soldiers (Isoptera). Insectes Sociaux. 44: 289-296 Davidson D.W., Kamariah A. Salim and Billen J. 2011. Histology of structures used in 	territorial combat by Borneo’s ‘exploding ants’. Acta Zoologica. 92.4: 487-491 Jones, T H, D A. Clark, A A. Edwards, D W. Davidson, T F. Spande, and R R. Snelling. 2004. The chemistry of exploding ants, Camponotus Spp. (Cylindricus 	Complex). Journal of Chemical Ecology. 30.8: 1479-1492. Maschwitz, U. and Maschwitz, E. 1974. platzende arbeiterinnen: eine neue art der 	feindabwehr bei sozialen hau ̈tflugern. Oecologia 14:289–294. Sands, W.A. 1982. agonistic behavior of African soldierless apico-termitinae 	(Isoptera, Termitidae). Sociobiology 7.1: 61–72 Shorter, J.R. and Reuppell O. 2011. A review on self-destructive defense behaviors in 	social insects. Insectes Sociaux. 59.1:1-10 Torres, J. A., Snelling, R. R., Blum, M. S., Flournoy, R. C., Jones, T. H., and Duffield, R. M. 	2001. Mandibular gland chemistry of four Caribbean species of Camponotus 	(Hymenoptera: Formicidae). Biochem. Syst. Ecol. 29:673–680.

https://en.wikipedia.org/wiki/Camponotus_saundersi

Three Suggestions to Article
I think that it would be useful to include that the ants adapted to the autothysis defense because it was more useful than other defense mechanisms (like stings) for defending the territory as a whole. I also think that it should be noted that the products from the mandibular glands work more effectively against arthropods than deterring vertebrate predators because of the stickiness of the substance, and that deterring vertebrate predators is a possible function of autothysis because the chemicals are inedible should definitely be added to the article.

One Sentence and One Citation
C. saundersi also uses autothysis to defend against vertebrate predators because the chemicals involved are inedible, which could deter certain predators from engaging this species of ant in the future.

Annotated Bibliography- Seemingly disadvantageous self-destruction defensive behavior of the Camponotus saundersi
1.) Bauman, Joe. “Utahn enters world of exploding ants.” Deseret News. 11 Sept. 2002: 1-2. Web. 14 Sept. 2014. http://www.deseretnews.com/article/936318/Utahn-enters-world-of-exploding-ants.html?pg=all

In this article, Bauman interviews graduate student Steve Cook and Cook describes his experience with the Camponotus saundersi. Cook mentions that the ants are also called kamikaze ants by its researchers. He explains that the ants explode when they are attacked and that the ants have poison sacks in their entire body and further describes the poison as a sticky substance similar to toothpaste.

2.) Bordereau, C, A Robert, Tuyen V. Van, and A Peppuy. "Suicidal Defensive Behaviour by Frontal Gland Dehiscence in Globitermes Sulphureus Haviland Soldiers (isoptera).(author Abstract)." Insectes Sociaux. 44.3 (1997). Print.		This article gives and example of a similar defensive behavior that a species of termites use which is similar to the Camponotus saunderis where they explode with poison, entangling themselves with their enemies. This explains that this self-destruction behavior is successful for protecting a territory because it is used in different types of arthropods.

3.) Jones, T H, D A. Clark, A A. Edwards, D W. Davidson, T F. Spande, and R R. Snelling. "The Chemistry of Exploding Ants, Camponotus Spp. ( Cylindricus Complex)." Journal of Chemical Ecology. 30.8 (2004): 1479-1492. Print.

This article investigates the body extracts of the Camponotus species by finding the types of chemical compounds released by the ants and explaining the source and properties of the compounds released from their mandibular glands, as well as how these compounds are released from these glands. The methods are described and performed on nine species of Camponotus. The results describe which chemicals are released in the ants in detail and include corrosive irritants with adhesives and responsible for the aposematism in the species. The article also explains the uselessness of other defense mechanisms and that the ants use these compounds in territorial battles between ant colonies in an effort to preserve the territory of the colony.

4.) Maschwitz, Ulrich, and Eleonore Maschwitz. "Platzende Arbeiterinnen: Eine Neue Art Der Feindabwehr Bei Sozialen Hautfluglern." Oecologia 14.3 (1974): 289-94. Print.	Ulrich and Eleonore Maschwitz explain that the Camponotus saundersi contract their gaster until it bursts and their mandibular glands also burst to release poison when they are mechanally harassed. The authors propose the term “autothysis” for the phenomenon of the ants’ self-destruction as a means to defend colony territory.

5.) Torres, Juan A. et. al. “Chemistry of the male mandibular gland secretion of the carpenter ant, Camponotus thoracicus Fellah Emery.” Comparative biochemistry and physiology. 78.3 (1984): 687-689. Print.

In this article, four species of males, females and worker ants in the Camponotus genus were analyzed for their volatile components of whole-body extracts. In C. kaura, C. sexguttatus, and C. planatus had volatile mandibular gland components were only found in the extracts of males while in C. ramulorum, all of the ants had volatile components. The authors note that when males and female reproductives and workers all have mandibular gland secretions, the secretions function differently as alarm releasing behavior.