Effects of wildfire and post‐fire salvage logging on insects with below‐ and aboveground life phases: cicadas as an ecological model

ENG- Wildfires are becoming increasingly frequent and intense in the Mediterranean region, and the way we manage forests after fire—especially through logging to recover burnt wood—can have a significant impact on biodiversity. This thesis explores how these disturbances affect cicadas, insects that spend years underground as nymphs and emerge for only a few days as flying adults. To study this, three aspects were addressed. First, using stable isotope analysis of the exuviae (the external skeleton shed during their final molt) of Cicada orni, it was found that cicadas may adjust their underground diet depending on the plant species that regrow after the fire, taking advantage, for example, of the roots of shrubs such as Genista scorpius. This finding may indicate a strong capacity for adaptation to environmental changes in these insects. Second, through radiotelemetry, the movements of adult cicadas (Lyristes plebejus) were tracked in both burned and unburned areas. The results show that cicada movements, home ranges, and survival are influenced by the effects of wildfires and post-fire logging. Specifically, in burned areas, cicadas exhibit larger movements and lower survival rates, particularly in those areas that have been both burned and logged. Finally, wax models of cicadas in different colors—black and gray—were placed on burned and unburned trees to assess predation risk. The black models—resembling species of the genus Tibicina—experienced lower predation when placed on charred trunks, suggesting that having darker pigmentation may be an evolutionary adaptation of certain cicada species to remain camouflaged after fire. Overall, this study highlights the need to adopt integrative post-fire management strategies. These should consider not only forest exploitation but also the preservation of key landscape features such as unburned patches, which serve as refuges that support wildlife survival and ecosystem recovery. Therefore, it is crucial to rethink the management of burned forests with a long-term ecological perspective that minimizes additional impacts and promotes the natural resilience of the ecosystem