PS 33-145 - Effect of an invasive ant species on the biological control of the coffee leaf miner (Leucoptera coffeella) in Puerto Rican coffee farms

Background/Question/Methods

Invasive species disrupt pest control by affecting predator-prey interactions. The coffee leaf miner CLM (Leucoptera coffeella) is the main coffee pest in Puerto Rico, causing a decrease in the photosynthetic potential of the plant and subsequent loss in coffee production. Lizards from the genus Anolis spp have been proposed as important agents of pest control due to their generalist diet and high abundance in coffee farms. However, it has been shown that patches dominated by the invasive ant Wasmannia auropunctata in coffee farms have lower abundance of Anolis and higher abundance of CLM than patches where W. auropunctata is not dominant, suggesting that W. auropunctata negatively affects the Anolis and indirectly releases the CLM from predation. To further investigate the effect of W. auropunctata, we conducted monthly surveys at seven coffee farms in Puerto Rico. Prior to the surveys, we determined farms dominated by W. auropunctata. For the CLM and Anolis surveys, we sampled 10 plants per farm from which we estimated the damage of CLM by counting the number of mines on three branches selected randomly. The number of Anolis and their identity was recorded by visual surveys at each plant for two minutes.

Results/Conclusions

Our results suggest that coffee farms dominated by the invasive ant species W. auropunctata present higher abundance of CLM than farms where this ant was not dominant. However, this result was not associated with the reduction in the abundance of the Anolis as predicted. This result suggests that W. auropunctata might not only affect the Anolis community but also other natural enemies of the CLM such as the coqui frog (Eleutherodactylus antillensis) or the CLM parasitoids. Future work investigating the differences in the parasitoid community and the abundance of coqui frogs associated with farms dominated by W. auropunctata and farms dominated by non-invasive ants will allow us to measure the negative impacts of this invasive species on the two important communities of natural enemies of the coffee leaf miner. These preliminary results are important because they reflect the importance of understanding the impacts of invasive species on natural enemies and the implications for pest biological control.