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Antlion larvae are an interesting example of the emergent behavior of communities of low-intelligence individuals. The larvae organize pits into lattices to minimize competition between each other for wandering ants (their primary food source). Observation of these organizational systems may provide evidence for how to construct bottom-up spatial distributions from basic individual interactions. In a previous study, we observed that antlions maintain a certain consistent density in distributing their pits. This study will examine the ways in which antlions communicate to distribute these pits. Cannibalism was hypothesized as a potential explanation in the last study, but this was not exclusively confirmed. Various interruptions in possible communication pathways will be attempted. We expect that antlions likely lack an intelligent mode of communication, so interruptions in the environment (removal of trails, introduction of physical obstacles, fictional pits) will not impact their ability to form nesting patterns, except insofar as they cannot nest immediately adjacent to the obstacles because the primary regulating method is cannibalism.
Procedurally, the experiment started with preparation of the antlions' environment after material acquisition. 24 16oz deli containers were filled with 2.5 inches of play sand and one antlion was placed in each container. Every week, each plastic container (i.e. each antlion pit) was given a small cricket.
The remaining sand (100lbs) was spread into a 24"x24" plastic container at a depth of at least 2 inches. A meter stick and a pen was used to make one-inch separated marks on the vertical and horizontal axes of the box so the antlions' pits' locations could be observed.
Using the grid, each trial was started by distributing a group of antlions in an array shape (the dimensions and populations of which are in a table below), and equally spaced between eachother and the walls, all inserted around the same time. Antlions were transferred between the small containers and the experimental environment by scooping them with a plastic spoon and sifting the sand from the antlion with a sieve. After the first and second days of each two-day trial, the coordinate locations, diameters, and depths of each antlion pit were recorded for later analysis. After each trial, all living antlions were restored to their pits and dead antlions disposed of.
Further trials repeated these same protocols except with modified space restrictions and several methods to disrupt potential communication pathways. Each disruption method was trialled with each space restriction, each trial run over a two day period. There are three different space restrictions and three different disruption methods. The space restrictions are 24"x24" (the initial box size), 16"x16", and 12"x12" (constructed in the original container by cardboard and duct tape barriers). The three disruption methods are "trail erasure," "fake pits," and "artificial obstacles," making for nine trials in total.
"Trail erasure" will be, once a day, brushing away old trails in the sand which antlions have dug out, in an effort to determine if the reduction of this possible communication pathway will destabilize or change the pit distribution. "Fake pits" will be sand scooped out in an inverse cone to mimic an antlion pit, with two or three placed uniformly randomly once a day, except when it would sit on top of an existing pit. This will show if the antlions are intelligently avoiding pits or if cannibalism creates the patterns that are observed in their distribution. "Artificial obstacles" are small stones or hard plastic barriers with a minimum height of .5in above the sand to determine if antlions are aware of the shape of their settlement region and use that to organize the group.
There is limited risk from this project because antlions, even in their adult form, are not significant pests or dangers. Antlions are invertebrates, so consideration of ethics around experimentation with them doesn't need to consider possible risks or safety to them. Instruments like spoons and sieves are used to prevent damage to the larvae, but no precautions are needed to prevent them from escaping because the larvae cannot climb. Food, however, is restricted to once a week per antlion because it is a goal of care during the experiment to prevent them from fully maturing so the experiment can continue.
The data will be examined through calculation of the distance to the nearest neighbor per each pit and determination from that data of how the antlions distributed themselves with various interventions. The analysis will use probabilistic analysis of the antlions in an attempt to disprove the null hypothesis, uniform positioning of the organisms' pits, to provide evidence that specific interventions play a role in the relocation of the pits.
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