Statistical analysis reveals the onset of synchrony in sparse swarms of Photinus knulli fireflies

Abstract

Flash synchrony within firefly swarms is an elegant but elusive manifestation of collective animal behaviour. It has been observed, and sometimes demonstrated, in a few populations across the world, but exactly which species are capable of large-scale synchronization remains unclear, especially for low-density swarms. The underlying question which we address here is: how does one qualify a collective flashing display as synchronous, given that the only information available is the time and location of flashes? We propose different statistical approaches and apply them to high-resolution stereoscopic video recordings of the collective flashing of Photinus knulli fireflies, hence establishing the occurrence of synchrony in this species. These results substantiate detailed visual observations published in the early 1980s and made at the same experimental site: Peña Blanca Canyon, Coronado National Forest, AZ, USA. We also remark that P. knulli ’s collective flashing patterns mirror those observed in Photinus carolinus fireflies in the Eastern USA, consisting of synchronous flashes in periodic bursts with rapid accretion and quick decay.

Collective synchrony of mating signals modulated by ecological cues and social signals in bioluminescent sea fireflies

“…2B, bars). Using Z and T statistics to compare our observed signal distributions to these Poisson distributions (modified from [47]), we reject the null for all tests except the Z tests for Trials 1 and 2 (Fig. 2B, p-values), which we attribute to the smaller sample sizes of these collectives.…”

“…(B) Probability of observing N number of signals in 30 s (y-axis; coloured bars) for various signalling rates (x-axis) compared to the null Poisson expectation given the same signalling rate (black line). Goodness-of-fit statistics (Z and T) for a Poisson distribution for each trial, as in [47]. (C) Scatterplot of pairwise signal differences in timing (x-axis) and space (y-axis) show periodic clustering.…”

“…Next, to statistically test if displays are synchronised, we compared the expected number of displays per sampling time to the observed number of displays, as from [47]. Because displays are discrete events, we can consider them to occur from a Poisson process.…”

Collective synchrony of mating signals modulated by ecological cues and social signals in bioluminescent sea fireflies

“…Next, to statistically test if displays are synchronized, we compared the expected number of displays per sampling time to the observed number of displays, as from [47]. Because displays are discrete events, we can consider them to occur from a Poisson process.…”

Preparation and Spectroscopic Identification of the Cyclic CO2 Dimer 1,2-Dioxetanedione

“…This particular species emits collectively synchronized flashes to attract the opposite sex in what is often described by spectators as a once-in-a-lifetime experience. The stunning display of bioluminescence has long attracted the interest of researchers, with both the synchrony of P. carolinus fireflies’ flashes − and the responsible biochemical processes being actively investigated topics to date. While the ethological background and exact mechanism of synchrony have yet to be fully unraveled, the bioluminescent glow has been traced back to the firefly compound luciferin (Figure , A): Upon exposure to air in the presence of adenosine triphosphate (ATP) as the energy supply and the luciferase enzyme, luciferin incorporates dioxygen to form a high-energy dioxetanone, which fuels the bioluminescent reaction .…”