Contrasting Temporal Responses of Saproxylic Beetles and Their Natural Enemies to a Catastrophic Hurricane...

Saproxylic beetles (dead wood-dependent) are among the organisms that can benefit from the conditions after hurricane disturbances. These positive effects can propagate throughout the food chain, leading to an increase in populations of organisms at higher trophic levels. After the large-scale windthrow caused by Category 5 Hurricane Patricia (October 2015) in a tropical dry forest of Jalisco, Mexico, we started an experimental two-year (January 2016 and 2017) study assessing the temporal response of saproxylic beetles and their natural enemies (predatory beetles, and parasitoids) to this catastrophic disturbance. Insects were sampled from 148 freshly cut branches of Spondias purpurea (Anacardiaceae) (72 in 2016 and 76 in 2017), left in field for 45 days and then placed in emergence traps. Although the species number and individuals were higher in 2016 (133 species; 22,797 individuals) than in 2017 (82; 11,165), response timing to post-hurricane conditions varied greatly among the most abundant saproxylic beetle families/subfamilies and natural enemy groups. Saproxylic beetles with short developmental times (e.g., Scolytinae, and small Bostrichidae) and parasitoids were more abundant in the sampling soon after the hurricane, while those with longer developmental times (e.g., Cerambycidae, large Bostrichidae, and Lyctinae) and predatory beetles (e.g., Histeridae) were more abundant in the following year. Competition and predation could have been the factors that regulated the populations of small saproxylic beetles and their associated parasitoids in the second sampling year. We conclude that life history traits and density-dependent factors are important forces that mediate the temporal responses of saproxylic beetles to hurricane disturbances.