It is an established fact that the spectacular bioluminescent displays of adult fireflies and glow-worms are used as courtship signals; however, the survival value of the glowing behavior of their larvae remained the subject of speculation for many years. Our study is the first that demonstrates that lampyrid larvae use luminescence to signal unpalatability to nocturnal, visually guided predators. Wild-caught toads (Bufo bufo) were more reluctant to attack luminescent artificial prey, and we show that avoidance learning increased this reluctance. After being exposed to glow-worm larvae (Lampyris noctiluca), which the toads experienced as disagreeable, attack latencies to luminescent prey increased, but not those to nonglowing prey. Not all toads showed avoidance learning to the same extent, because of either differences in previous experience with glow-worms or differences in memory.

Fireflies are charismatic beetles with attractive bioluminescent courtship displays that have recently been swept onto the global stage of nature tourism. Here, we provide the first comprehensive review of the geographic scope, magnitude, focal species, and other attributes of the major firefly tourism sites worldwide. Through targeted interviews and surveys, we estimate that in recent years over one million tourists travelled annually to sites located in at least 12 countries for firefly‐watching. Rapid proliferation of firefly tourism provides a timely opportunity to examine how such activities may impact local firefly populations, and to highlight the biological factors that make certain species especially vulnerable to tourism‐associated threats. We offer science‐based best practices for firefly ecotourism that can be tailored to fit local circumstances, including recommendations to: (1) Conserve the habitats required for all life stages to thrive, (2) involve local communities as key stakeholders, and (3) provide training programs for guides and interpretive materials for visitors. Finally, we provide suggestions for transforming tourist behavior to minimize impact on firefly populations. By developing management plans that incorporate these recommendations, firefly tourist sites can enhance the visitor experience, protect natural resources, benefit local communities, and help promote the conservation of invertebrate biodiversity.

Nocturnal light pollution from anthropogenic origin is increasing worldwide and is recognised as a major threat for nocturnal biodiversity. We studied the impact of artificial light on the mate attraction success of female common glow-worms (Lampyris noctiluca L.) by daily monitoring their glowing status in the field, acting as a proxy for mating status throughout the mating season. We found that females in dark surroundings typically stopped glowing after one night, indicating that they had mated, while females in illuminated areas glowed for significantly more nights, in some cases up to 15 nights. Our study confirms previous findings and hypotheses that females exposed to artificial light suffer from a reduced mate attraction success with a negative impact on populations.

We studied the spectral characteristics of the larvae of three sympatric Belgian species of fireflies, Lampyris noctiluca, Phosphaenus hemipterus and Lamprohiza splendidula. An in vivo spectral study was performed to compare bioluminescence spectra. The emission spectrum of a laboratory reared female L. noctiluca was recorded by a different, more exact method. The mean peak wavelength (lambdamax = 546 nm) and shapes of the unimodal emission spectra are visually similar for the larvae of all three species. The emission spectrum of the adult female L. noctiluca peaked in the same range as the larval bioluminescence between 546 and 551 nm. The bandwidth at half-maximum intensity was slightly greater for larval L. noctiluca (77 +/- 4 nm) compared with P. hemipterus (70 +/- 10 nm). The bandwidth of larval L. splendidula (77 +/- 8 nm) was not different compared with the other larvae, whereas the females' bandwidth was somewhat narrower (68 nm). The ecological significance of the color of bioluminescence and conservancy of green emission in larval fireflies and other luminescent beetle larvae is discussed.