Animal Behavior/Pheromones in ants and bees

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One of the many ways in which organisms can communicate with each other is through the use of pheromones. An organism generates and emits these hormonal chemicals in order to relay a message to another member of the same species. Ants and bees demonstrate two prominent examples of pheromone usage, which acknowledges their incredible capability to organize the behaviors of the whole colony.

Ants produce numerous different pheromones, each with its own distinct purpose. Ants secrete pheromones to attract mates, to signal danger to the colony, or to give directions about a location. Other pheromones act as deterrents keeping out unwanted ants from foreign colonies or preying insectivores. Still other pheromones communicate ants to congregate. This explains how assiduous ants exercise remarkable cooperation in building a colony. Pheromones maintain the cohesiveness and organization of the complex ant communities. Certain types, such as alarm pheromones, produce a “releaser effect”, which induces a quick response and may be used to tell other ants to evacuate a dangerous area such as an approaching lawnmower. For example, when a spider approaches an ant will release alarm pheromones that alert all the other ants. Ants may also discharge alarm pheromones as a result from being diverted from their work, e.g. heavy human steps. Releaser pheromones are also used to mark territory. As the chemical deposited dries, it signals to other species members of the territory’s occupant.

Other pheromones create a “primer effect” that entices other ants for actions. Such pheromones are useful in mating rituals and only affect ants of the opposite sex. Primer pheromones can send signals to the endocrine system, to make appropriate changes, for instance ovulation required for successful mating.

Biologist E.O. Wilson discovered in the 1960’s that the organic chemical for each pheromone varies tremendously depending on what signal it entails. Ants taste and smell a substance that evaporates off the chemical laid down by another ant. Wilson observed in slow motion films that ants do this by moving their antennae from side to side. For example, alarm pheromones are discharged into the air, and expand in a circle of smell. Ants can determine the concentration of the pheromone, and thus determine the proximity of the source of danger.

Bees are also well known for communicating through the use of pheromones. Like ants, bees have a variety of purposes associated with the pheromones, such as marking and behavior. Honeybees release chemical signals for marking food sources, marking their hive, in scenting potential hive sites, and in assembling swarms for flight. Although each hive has a particular scent, different colonies can be easily integrated during times when honey flow is heavy since the colony’s odor is inundated with the scent of nectar. Virgin queen bees emit a behavioral pheromone released with their feces. When the new queen feels threatened by the workers she uses this pheromone as a repellent.

Another widely identified chemical signal in bees is the Queen Mandibular Pheromone (QMP). This pheromone ensures that the queen is the only reproductive female in the hive by compromising the reproductive systems of worker bees. It also provides an attractant signal to the drones.