Is the ‘blue-ghost’ really blue? Spectral analysis of Phausis reticulata’s bioluminescence (Coleoptera: Lampyridae)

Fireflies (Coleoptera: Lampyridae) are known for their various colors of bioluminescence and species specific flash patterns, which they use during courtship behavior. Previous studies have quantified the photic emissions of various firefly taxa to accurately determine the specific color of these spectral emissions. The North American species Phausis reticulata (Say) is commonly known as the ‘blue-ghost firefly’ because of the slow, constant, ‘blue’ glow it emits during courtship signaling behavior. Blue spectral emissions are rare in fireflies and have not been documented with quantitative techniques. Phausis reticulata also apparently lacks any species specific timing parameters associated with these signals, as found in many other firefly genera. Recently the discovery of two size morphs of P. reticulata and the presence of green bioluminescence has been observed within the Great Smoky Mountains. In order to quantify the bioluminescence of P. reticulata and to determine if spectral differences suggest possible cryptic species within this species, multiple specimens from various localities within and around the Great Smoky Mountains National Park were measured and analyzed.