Population dynamics of Coccus viridis, a ubiquitous ant-tended agricultural pest, assessed by a new photographic method

Ant and homopteran mutualisms are complex because they depend on the behavior, abundance, and predation levels of both insect species. Because homopteran populations are critically impacted by these seasonally varying factors, it is important to measure the population dynamics of ant-tended homopterans outside of the laboratory. In this study, we develop a new method for documenting the population dynamics of sessile ant-tended homopterans in the field, using digital photography. We monitored the population dynamics of Coccus viridis (Green) (Hemiptera Coccidae), the green coffee scale, over a two year period, with and without the protection of the ant, Azteca instabilis (Smith) (Hymenoptera Formicidae). Our results reveal that C. viridis birth is episodic over the course of a single day, and that long term population dynamics depend critically on seasonality. We found that parasitization, chewing insect predation, and fungal infection are distinctive between C. viridis life-stages and that all three are critical factors governing C. viridis population growth and survivorship.