Phenomenon of Slave-Making Behavior in AntsBiology 342 Fall 2014
Emma Schweitzer & Rob Haas |
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MechanismMechanism is the particular method ants may employ to enslave their neighbors, be it coupling dulotic and inquiline behaviors together or creating their own new behaviors. A.) Polygyny- when an ant colony has more than one reproducing queen, helping create a large population base. Focusing on P. Americanus ants, dulotic tactics and strategies will be considered in this website, but we encourage you to look at other information concerning polygynous and polydomous behaviors. Dulotic ants are different from their polygynous and polydomous counterparts because they make use of more scouting and slave raiding behaviors. Before any new ants are enslaved, the process begins with scout ants from the parasitic colony evaluating their raiding options, and reporting back to their colony. How they make their decision is rather unclear, but it is argued that the more aggressive ant colonies within the slave-making ants vicinity is targeted. Once the rest of the posse is organized, the parasitic worker ants will go out on a “raid”, which varies depending on the species, but results in harmful attacks and deaths in all strategies observed to date. Dulotic ant societies often utilize interspecific cocoon caring. Enslaved ants care for slave-driver larvae, or Slave-driver ants can care for slave larvae. Or some ants kill all the eggs they find. All of the colony recognizing odors are different from colony to colony, even among conspecifics. There are multiple hypotheses about how complex behaviors in themselves, like brood transport or polydomy are coupled together into dulosis in other ant societies. Chemical Compounds Behind Slavery Figure 1. The backbone chemical structure for colony odors. Odors vary between different ant colonies depending on geographic region and species, so every ant colony will likely something similar to this foundational odor chemical structure with added complexity to create the specific smell associated with a particular colony. One particularly advantageous mechanism is found in obligate parasitic ants (ants that must exploit a suitable host to carry out their full life-cycle). These ants are able to easily raid other ant colonies by being odorless, that is they do not produce a specific olfactory chemical, or they produce relatively undetectable levels of their colony odor. More research is needed to quantify if the former or the latter is actually the case. This chemical insignificance makes these ants seem invisible when they move in since there is no alert signal to be picked up on by the colony ants they are invading, facilitating nest usurpation. Figure 1. Head physiology, the deep grooves in the head of the T. americanus ant, another slave-making species sharing a physical head feature of the P. americanus, can be seen here. Both have been observed to tuck their antennae into these grooves during scouts and raids using them as a defensive mechanism to protect themselves from harm. |