Holldober+and+Wilson


 * The Multiple Recruitment Systems of the African Weaver Ant**

Summary:

African Weaver Ants use chemical signals to recruit one another to do work that cannot be done individually. They use this to bring nest mates to new food sources, new terrain, to move them to new nesting sites, and to fight short and long-range battles with intruders or rivals. These ants are capable of recognizing cues both visually and chemically. They also use chemical signals to mark off territory. Normally, when a group of ants is simply foraging, they do so independently, but they will group together to fight off enemies. It is thought that these adaptations exist because this species of ant lives mainly in trees. African weaver ants are highly aggressive and prey upon other insects. They also "farm" homopterans for the sugary substance they produce.

Vocabulary:
 * Homopterans: insects such as aphids, mealybugs, cicadas, and whiteflies.
 * Hymenopterans: insects such as ant, bees, and wasps pertaining to the order Hymenoptera
 * eusocial: 'showing an advanced level of social organization, in which a single female or caste produces the offspring and nonreproductive individuals cooperate in caring for young.'
 * olfactory: of or relating to smell
 * pheromone: chemical substance produced and released by animals that causes others of same species to react in specific way.
 * tactile: relating to sense of touch

Notes:

Ants are recruited more strongly to food sources containing sugar - possibly having to do with homopterans in the nest. Ants can build bridges across gaps by recruiting each other to link their bodies together. The ants are capable of organized emigration to new areas and of quickly and efficiently building new nesting sites. Highly territorial, in the wild there are often empty areas between territories because interactions between colonies is so aggressive. Intruders are immediately attacked and usually killed and eaten. African weaver ants are the only social insect that have been found to use true territorial pheromones.

Usually only one colony occupies a tree, while large colonies extend their territory to more than one tree. Each colony has a mother queen. The foragers mostly remain on trees, but will venture to the ground. They are very aggressive to outsiders, including other ant species (page 3). The ants recruit workers to a site by a combination of a trail pheromone and tactile signals... “a more elaborate tactile display was frequently employed, during which the trail-laying ant antennated the nestmate encountered, opened its mandibles as though offering food, and waved its head slowly over that of the nestmate” (page 6). They communicate with motions and signals, as well as secretions/scents. The article states that the more desperately hungry the colony is, the more intense and prolonged the signals are that they use, just like other species the urgency is depicted... “workers were recruited much more strongly to honey and sugar water than to insect prey” a hypothesis is because the honey/sugar water depends on long-range recruitment, more time/more ants, versus the prey which requires a single ant or small group. New terrain versus home terrain, said to be depicted at somewhat by odor trails. The stronger pheromones laid out in the new terrain and weaker in home (page 16).

The question that results from these studies is "why do African weaver ants have more complex communication?" Holldober and Wilson suggest it may be due to their size. African weaver ants are much larger and therefore require larger food that is more scarce in order to sustain themselves. This means that Oecophylla are not able to coexist with other species of ants and must gain complete control over the territory they reside in to ensure they have access to the food they need to survive. This could be why weaver ants are so aggressive and why they needed to develop a more complex communication system. Their communication system allows them to protect their territory better.

The purposes of the ants communication were all integrally connected to being aware of the environment. Chemical or tactile communications of food source or the presence of threat individual signals trigger response direcly related to actual environment. An interesting analogy to human language development is available when viewed from perspective of food availability per area and environmental threats relating complex communication adaptations through evolutionary process. Is it possible that their large size is caused by the adapted advanced communication spandrel allowing for excess food resulting in opportunity to increase in size that later served as a defensive benefit? The continuous question of cause vs causation is still an issue, no? What evidence suggests size came after communication and why is it relevant to come to any conclusion at all? Simple facts relate simple analogies. For example, as ants do, humans will utilize their environment to max potential given physical restraints governed by their adaptations, which are governed by, drum roll please, their environments. This recursion of use to benefit is an obvious connection that can be made without theorizing on classical catch 22's of point of origin cliche's. What should be seen, in my opinion, is that advancement in communication potential provided by environmental adaptations allows species the oppotunity to benefit from the environment. Once "niche" is constructed the environment is changed and a new adaptive potential is reached(Bickerton). The detail of the specialization is governed by frequency of adaptation use and familiarity with environment coupled with the abundance of eternity (time). Our awareness of our environment seems to be an adaptation that may allow more beneficial environment changes that would in turn provide opportunity for even more detailed adaptations.

Holldobler and Wilson expound that the complex communication system executed by the African Weaver Ant is due to their uniquely large size and their propensity toward niche construction in tree canopies. Size: their large size means their food sources are more scarce than smaller species of ant. Food scarcity encourages more aggressive territorial behavior toward conspecific ant colonies. Territorial, aggressive behavior: More organized and efficient than other ant species Special communication system benefits: quickly occupy new terrain and defend that terrain. The system distinctions are modified by the replication of behavioral patters. Signal Economy: (Holldobler & Wilson definition) The utilization of the same or similar signals and behavior patterns, in different combinations, to achieve different functions. Invention of a wholly new form of communication: short-range recruitment of enemies. significance: shifts foragers from random spottal pattern to moderate clumping, making it easier to subdue larger opponents. Form of recruitment distinctive of different type of food/harvesting: long-range recruitment for sugar sources (honey) because it is worth the investment of time and energy due to its long-lasting quality. short-range recruitment is reserved mostly for prey food sources due to the fact that an individual ant is often able to kill the prey and carry it to the niche on its own as well as its property of faster decay. True territorial pheromone: a substance to mark the living or foraging space of an animal and that by itself induces aversive behavior in intruders of the same species. 5 recruitment systems exhibited by African Weaver Ant: new food sources, new terrain, emigration to new sites, short-range recruitment to territorial intruders, long-range recruitment to intruders.

---As my mind is still heavily involved with the ideas of niche theory that we delved into with Bickerton, and as it seems we have a good working summary for discussion of Hoelldobler and Wilson's work I am left wondering about extinct/endangered species. Perhaps the species that fall in either of those two categories (facing endangerment or perhaps already extinct) are/did not develop(ing) complex communication systems like these African Weaver ants and thus lost out on fuller fitness. Or perhaps, they in fact continued to advance at such a rate with this constant play on and off of the environment that they set themselves up. What I mean to say is that this species, say the dodo bird or what have you, advanced the environment just out of reach of their ability to evolve with it (to catch up, so to speak). Of course we can consider other species playing into these enthusiastic changes to the environment, but then we have variables and connections between species (links) that are less than likely to prove strongly in correlation.

I guess what I find important now to think about, with all considering: we expand with our expanding environment, and thus have to continue getting more complex ourselves, creating this feedback loop that is infinite. But, is any species feedback loop actually infinite? Will we be surpassed by ourselves? Is there a capacity within humans to continue to evolve even with the rising tides and opening skies?

The African Weaver is a terror to other insects, attacking and demolishing as soon as territory is breached. In many senses we as humans have entered a stage where cut-throat bloodshed is not necessarily socially accepted (obviously). With our relatively new moral codes so to label, have we lost the ability to have environments that grow socially complex as quickly as we may need them to?

--- An earlier editor noticed an analogy to humans in relation to this article, which got me thinking. We humans are very similar in that we are so large and in charge that we do not allow other species to directly compete for our food sources. Not that we share many natural food sources with animals anymore, but if say a predator were to eat a farmers livestock or an herbivore eating produce, this hypothetical farmer would likely get vicious and defend his/her territory more intently. We tend to only allow animals to co-exist with us when they are domesticated pets or non-competitive with us. Another point mentioned earlier that relates to humans is that our language allows us dominion over our territory even more strongly than ants. When one tactic to exploit and reign supreme over our territory fails, people communicate figure out a new strategy ie research.

This article is a clear example of a species using the anatomy they were given to create a communication system. One that has multiple uses, but differs only slightly to convey these five recruitment systems. I found it especially interesting the degree of complexity of the recruitment communication, such as if the tactile ingredient was absent the strategy would fail (in the case of researchers recreating these strategies with extractions from different bodily segments) or that they could distinguish based on visual cues the difference between an artificial and natural trail pg. 32

The penultimate editor (karsen?) you ask if any species feedback loop can be infinite, I would answer yes and culture is a clear display of this. Take music for example: mixtapes, scratching, mixes, mashups, remixing video such as youtube or reusing scenes or themes from movies, etc. I think this idea can be extrapolated to all sectors of culture including technology which suggests we will continue to evolve regardless of environmental factors (as long as we can come together and find a way around them...for the good of the planet or the bad.) Will we reach a singularity, which could be called "surpassing ourselves"? It certainly is an intriguing idea, but a hotly debated subject. I posit that all species exist in an infinite feedback loop, adapting to the feedback loops of other species perpetuates this stream of change. ---