COS 108-6 - CANCELLED - Monitoring Social Insect Activity

Abstract: Monitoring and mitigating the influence of human impacts is central to conservation and key to creating sustainable ecosystems. The detrimental effects of human impacts on biological communities are due to an array of factors including climate change, habitat shrinkage and invasive species. However, a major gap in knowledge is how these impacts are felt by small-bodied organisms such as invertebrates, which comprise the bulk of global animal biomass and play vital roles in ecosystem function. Of central importance are species inhabiting the sub-surface zone of leaf litter and soil, such as ants, which comprise a huge fraction of animal biomass. Ants play a vital role in nutrient dynamics and shape the ecosystem through predation and mutualism, yet are almost invisible to observation, representing ecological ‘dark matter’ that has proven challenging to study in situ. The velvety tree ant Liometopum occidentale, is an ecologically dominant ant species found in western North America; their extensive foraging activity drastically shapes local forests, and their nests are a biodiversity hot-spot for a multitude of symbiotic invertebrates. Despite their vital role in the ecosystem, their activity, basic ecology and impacts felt by anthropogenic factors, is largely unstudied.



In this work, we develop a low-cost multi-sensor camera trap, the 'Ethocam,' to capture ant behavioral patterns in the field, and combine this technology with a computer vision approach to track colony activity in an undisturbed fashion. We demonstrate an accurate system (equal to human accuracy) for counting ants built with minimal human labeling. Using our small field dataset (collected in the Angeles National Forest) across 72 hours, we show that L. occidentale activity drops rapidly through the morning and study the effect of environmental conditions on ant count. We also report the occurrences of a pseudoscorpion, a beetle of the genus Silis and two occurrences of Sceptobius lativentris (a symbiotic rove beetle) in our camera trap data. Together, these findings demonstrate the potential of our system to capture the behavior of Liometopum occidentale as well as its complex associations with various local species including symbionts at the colony entrance. Our study provides proof of concept for the promise of low-cost remote monitoring of social insect populations. This is a work in progress, we are currently exploring strategies to expand data collection to nighttime using infrared lighting. The system will then be replicated at other ant colony sites with the aim of long-term landscape scale monitoring.