Inventory and ecological aspects of bioluminescent beetles in the Cerrado ecosystem and its decline around Emas National Park (Brazil)

Abstract

Abstract Among the richest ecosystems in bioluminescent Coleoptera in Brazil, the Cerrado (savannas) is the most threatened one by agricultural expansion. The Emas (PNE) and Chapada dos Guimarães (PNCG) National parks are 2 of the last main remnants of the original Cerrado ecosystems in Central-west Brazil. During the past 3 decades, we have conducted several expeditions to collect, observe and study bioluminescent beetles occurring in the PNE and surrounding farms. More recently we also started to investigate the PNCG. We recorded a total of 51 bioluminescent species, including fireflies (n = 29), click beetles (n = 11), phengodids (n = 10), and staphylinids (n = 1). The PNE region was the richest one, especially for phengodids (n = 9). Among the habitats that compose the Cerrado physiognomy, the Cerrado and cerradão hosted most of the bioluminescent species, followed by forest, open fields and marshes. Most fireflies inhabiting the Cerrado ecosystem emit yellow-green light, whereas most click beetles emit predominantly green light, and among phengodid species, orange and red-light emission was found in 3 species. The spectacular click beetle Pyrearinus termitilluminans Costa-lodging luminous termite mounds were found in PNE and also reported for the first time at PNCG. In the farms around the PNE, however, a declining number of bioluminescent species was recorded in cerradão areas after the replacement of the surrounding cattle pastures by sugarcane plantations, especially adult phengodid males that were no longer attracted to light traps. Habitat reduction, use of agricultural pesticides and artificial night lighting are thought to be the major causes of such impact on bioluminescent beetle diversity.