Towards predicting responses to an extreme event: traits that influence ground-dwelling beetles' susceptibility to volcanic ash

Abstract

Extreme events are important determinants of environmental changes at multiplegeographical and temporal scales, influencing the ecology and evolution of species.Volcanism in particular can modify entire landscapes through ash deposition, affecting the survival and abundance of susceptible species and favouring tolerant ones.However, there is still a lack of information for predicting which species will be moreor less affected by volcanic disturbances. We test the hypothesis that the effect of volcanic ash will differentially affect taxa according to their morphological traits. We useda ground-dwelling beetle community that was sampled before and immediately afterthe last eruption of the Puyehue-Cordón Caulle (PCC) volcano. We measure traits thatmight help predicting responses to the ash deposition in insect species susceptible tothe PCC volcanic eruption – i.e., their abundance decreased considerably – and compared them to others that were tolerant. We examined cuticle thickness, its structures(i.e., hairs) and microsculptures, and body size. We found that traits associated withsmoothness of the cuticle (fewer hairs and microsculptures) and a small body enablesspecies to better tolerate the negative effects of volcanic ash. These results are thefirst to explicitly test for traits that could help to predict which species will be moretolerant to volcanic ashes, a widespread disturbance associated with volcanism.