The tropical dry forest is characterized by a dry season of 6 continuous months in which more than 95% of the plants lose their leaves completely. The remaining 6 months of the year are marked by a fast greening of the canopy which is the product of punctual rains intercalated with dry periods. During our studies of lichens in this ecosystem, we noticed that lichen communities constitute an abundant resource that is available regardless of the seasons. In our study area in the Pacific coast of Mexico, there are around 300 species of lichens. Their cover values on the bark of most trees typically reach 80% of the bark’s surface. We asked ourselves, if lichens are providing so much biomass to the system, then who is using those resources and how? We used behavioral observations on the field and in the lab to test which animals interact with lichens.
Results/Conclusions
Our results showed that in our study area invertebrates are the primary consumers of lichens, specifically land snails of the genus Orthalicus, oribatid mites, and several species of caterpillars from the families Batrachedridae and Psychidae. One of the species of caterpillars also used lichens to construct mobile houses in which the caterpillar lives until it becomes an adult. Using molecular techniques we identified the lichens used to build several of these mobile houses and found a high selectivity of lichens species, with only five of the 300 available species used and one species in particular present in all the houses. Currently we are following the study by analyzing the invertebrate feces with molecular techniques to categorized the lichen component in their diet at the species level. Our results showed a diverse trophic network that uses lichens as the primary producer. Given the high seasonality of the tropical dry forest, lichens may constitute a useful resource that helps to maintain the functionality of the ecosystem.