Fireflies use bioluminescent flashes to establish a dialogue between conspecific males and females. Through this dialogue, receptive females attract conspecific males for mating. In most firefly species, the males act as independent agents. That is, as they fly and flash in search of a responding female they do not appear to coordinate their activities with other males. In marked contrast, the males of some firefly species coordinate their flashes to coincide with those of other conspecific flashing males, resulting in synchronous flashing across local populations. We propose that the need for synchrony in these species may be driven by constraints imposed by the female visual system. Since males are flying while flashing and may appear to flash from different spatial locations, the female must attend to flashes over a wide visual field. But doing so has a drawback. She may see the flashes of multiple males within her wide visual field and their flashes could interfere with her ability to respond to any single male. We present evidence of a sensitive period during which extraneous flashes interfere with a female's response to a conspecific male and develop a model to predict how the number of independently flashing conspecific males affects the female's responsiveness. By coordinating their flashing, the males reduce the chance that any of them will flash during the female's sensitive period. This minimizes interference with establishing the male-female dialogue that would otherwise result by the presence of many patrolling males being in the female visual field. We conclude that the constraints imposed by the female visual system could be a factor driving the need for males to synchronize their flashing if they tend to fly and flash at high population density.

North American Photinus fireflies use bioluminescent flashes to communicate an individual’s species and sex, and to attract potential mates. A female firefly responds to a male firefly’s courtship flash with her own species-specific flash. We used a photic stimulator to produce male-like species-specific P. carolinus LED courtship flashes. These evoked species-specific response flashes from a female. The female’s flashes were preceded by a flash gesture comprising a sequence of abdominal postural adjustments (pitch, roll, and yaw). These gestures changed her lantern’s orientation which, at rest, was downward towards the substrate. Our results demonstrate that these gestures mediate a lateralization of the female’s response flashes towards the direction of the stimulating LED. That is, she directs her response to the left of midline when stimuli are presented from her left, and similarly, she directs her response to the right of midline when stimuli are presented from her right. The directional aspect of the flash gesture adds a new perspective to the complexity of the behaviors associated with flash communication in fireflies. Lateralization of the flash gesture suggests that the female’s visual system processes information about the location of male’s flashes as well as their temporal pattern.

Most firefly species (Coleoptera: Lampyridae) use bioluminescent flashes for signaling. In some species, the flashing between males occurs rhythmically and repeatedly (synchronically) with millisecond precision. We studied synchrony's behavioral role in the North American firefly, Photinus carolinus. We placed a female in a virtual environment containing artificial males that flashed at varying degrees of synchrony. Females responded to an average of 82% of synchronous flashes compared with as few as 3% of asynchronous flashes. We conclude that one function of flash synchrony is to facilitate a female's ability to recognize her conspecific male's flashing by eliminating potential visual clutter from other flashing males.

An inexpensive miniature stage goniometer compatible with a conventional optical microscope was developed to study the size and distribution of ommatidia facets across the compound eye of fireflies (Coleoptera: Lampyridae). The goniometer device was used to take sequential overlapping images of the hemispherical surface along longitudinal great-circle arcs of each eye of Photinus carolinus firefly and Photuris sp. males and females. Images covering the entire eye required 7 great circle scans at increments of 26° rotation. Using the multiple images, we minimized distortions associated with imaging a spherical surface in 2 dimensions and measured surface features with an error of <1.5%. A polar plot provided a consistent display format to relate facet area with location on the surface of the eye. We tested the functionality of the goniometer on a small number of male and female fireflies. It enabled us to make accurate measurements of surface features and address whether there is sexual dimorphism in firefly eyes. Within our limited sample, our results indicated that male eyes were larger than female eyes. In both firefly species the difference between the two sexes in the eye surface area was found statistically significant (P< 0.0001, unpaired t-tests). Male and female eyes also exhibited regional variation in facet area. We hypothesize that the sexual dimorphism and regional variation of firefly eye reflect functional and behavioral capabilities.

The flash communication system of Photinus carolinus in Great Smoky Mountain National Park (Tennessee) is characterized by male firefly synchrony. Photinus carolinus males signal a conspecific female with synchronic trains of flashes. A solitary responding female attracts several males, which is not common in North American rover fireflies. The female and the group of males that she attracts are called a cluster. It is hypothesized that the first male attracted to the female would land closer to the female than would additional males because there would be less tendency for visual confusion. This hypothesis is explored under controlled conditions by replacing the responsive female with an appropriately flashing light-emitting diode (LED) located in the center of a flat target area. When infra-red videography is used to measure the first male and the additional males' landing distances from the counterfeit female (LED), most fireflies land within 15 cm of the target LED, and the first male does not land closer than the additional males. It is suggested that cluster formation is a by-product of male synchrony and is facilitated by the tendency of males to land near, but not on, females.

Soybeans have long been recognized as an excellent source of high-quality protein. The soybean also contains a wide variety of chemical compounds that have potent bioactivity. Among these compounds are the isoflavones and the saponins. The goal of our research was to quantify isoflavone and saponin concentrations in elite soybean cultivars grown in different environments and to identify a naturally occurring high and low variety that could be used in animal studies of colon cancer. We observed significant environment x genotype interactions for the cultivars and selected 2 that provided the range of concentration for isoflavones and saponins. These were grown in an adequate quantity for animal studies, which are ongoing. We explored the influence of isoflavones and saponins on human colon tumor cells in culture, Caco-2, to determine potential mechanisms through which these compounds influence the carcinogenic process. We observed the inhibition of Caco-2 cell proliferation by isoflavones and saponins, suggesting a protective effect of these compounds in colon cancer. Using purified soy saponins, we found no negative effects on mouse growth, organ weights, or intestinal morphology when the diet contained up to 3% saponins by weight. Hence, soy isoflavones and saponins are likely to be protective of colon cancer and to be well tolerated. Continuing studies will explore the cancer-protective effects of these compounds in animal models.

Synchronic flashing in fireflies is a precisely timed behavior. This is a potentially useful tool to study sensory processing, the location and circuitry of the flash oscillator, and neuroeffector processing and coupling. Synchronic flashing, once thought to occur only in Southeast Asian fireflies, has recently been shown to be a prominent part of the behavior of a North American Photinus and Photuris species. To gain insights into the mechanisms of synchronic timing in fireflies, we compared spontaneous flashing and entrainment flashing in Photuris frontalis LeConte, a synchronic firefly found in Georgia's Coastal Plain, to analogous flashing in Pteroptyx malaccae Olivier, a synchronic firefly found in Malaysia. The timing of spontaneously produced flashes and entrainment flashes was recorded by photometry. Artificially produced, rhythmic stimulus flashes were used to induce a counterfeit synchrony (between subject fireflies and an LED), i.e., flash entrainment. We found that the spontaneously produced interflash intervals were repeated with a high degree of precision in P. frontalis and P. malaccae. However, the pattern of flashing was different during spontaneous flashing and flash entrainment. An isolated P. frontalis flashed intermittently during spontaneously flashing and entrainment flashing. Flash entrainment in P. frontalis started with an initial inhibition and then steady-state entrainment occurred with a fixed delay. In contrast, an isolated P. malaccae flashed continuously during spontaneous flashing and entrainment flashing. No initial inhibition occurred at the start of entrainment, and there was a gradual change in interflash interval until steady-state entrainment occurred at a fixed delay. We think that in-depth studies of the flash activities of different synchronic firefly species, including the locally available P. frontalis, could help our understanding of rhythmic temporal coordination of behavior by the nervous system.

Synchronous flashing occurs in certain species of Southeast Asian and North American fireflies. Most Southeast Asian synchrony involves stationary congregating fireflies, but North American synchrony occurs in flying fireflies that do not congregate. Southeast Asian synchrony is usually continuous, but North American synchrony is interrupted. Photuris frontalis, the only member of the North American genus Photuris to synchronize, shows an intermittent synchrony. This involves synchronization and repeated re-synchronizations while in flight. The precision that occurs at the start of synchrony was studied in Ph. frontalis using caged fireflies and photometry. Barrier experiments (using two fireflies) or flash entrainment experiments (using one LED and one firefly) were performed to measure the temporal precision of the first entrained flash. In both cases, the first entrained flash was close to unison synchrony (phase = 1.0) and showed little variability. The behavioral implications of the ability to synchronize with the first entrained flash are not known, but it might facilitate male-male interactions during brief, transient encounters such as maintaining distance between closely flying males in search of females.

Previous articleNext article No AccessGeneral BiologySYNC: The Emerging Science of Spontaneous Order.By Steven Strogatz. Theia Books. New York: Hyperion. $24.95. ix + 338 p; ill.; index. ISBN: 0–7868–6844–9. 2003.Jonathan CopelandJonathan CopelandBiology, Georgia Southern University, Statesboro, Georgia Search for more articles by this author Biology, Georgia Southern University, Statesboro, GeorgiaPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 78, Number 4December 2003 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/382381 Views: 38Total views on this site Citations: 1Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Richard F. Walker A Mechanistic Theory of Development-Aging Continuity in Humans and Other Mammals, Cells 11, no.55 (Mar 2022): 917.https://doi.org/10.3390/cells11050917

Bioluminescence and Chemiluminescence, pp. 157-160 (2001) No AccessMECHANISMS OF SYNCHRONY IN A COASTAL GEORGIA FIREFLYJONATHAN COPELAND, KELSIE FITZGERALD, and ANDREW MOISEFFJONATHAN COPELANDDepartment of Biology and Applied Coastal Research Laboratory, Georgia Southern University 30460-8042, USA, KELSIE FITZGERALDDepartment of Biology and Applied Coastal Research Laboratory, Georgia Southern University 30460-8042, USA, and ANDREW MOISEFFDepartment of Physiology & Neurobiology, University of Connecticut, 06269-4156, USAhttps://doi.org/10.1142/9789812811158_0039Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: The following sections are included: INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS Aknowledgements References FiguresReferencesRelatedDetails Recommended Bioluminescence and ChemiluminescenceMetrics History PDF download

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Previous articleNext article No AccessNew Biological BooksMillions of Monarchs, Bunches of Beetles: How Bugs Find Strength in Numbers. Gilbert Waldbauer Jonathan CopelandJonathan Copeland Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 76, Number 3Sep., 2001 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/394009 Copyright 2001 The University of ChicagoPDF download Crossref reports no articles citing this article.

Continuous synchronic flashing occurs in stationary and flying male congregations of members of some firefly species in Southeast Asia. In the present paper, low-light videography and photometry was used to demonstrate that synchrony occurs in the North American genus Photuris. We found that the Georgia coastal plain firefly Ph. frontalis flashed synchronically. From a distance, the synchronic flashes of a population of flying Ph. frontalis appeared to occur in a continuous synchrony. However, when pairs of males were viewed, it was difficult to verify that their flashing was continuously synchronic. In the laboratory, caged fireflies flashed synchronically, stopped, and then flashed synchronically again. To study this flash behavior, recordings of individual and group flashing were analyzed statistically to validate the conclusions about rhythm and synchrony. Although the mass synchrony appeared continuous, the individual flying males switch on and off, coming in again on the beat. The synchrony in Ph. frontalis is common and pervasive rather than rare and sporadic, as shown by other North American fireflies. The precision of the frontalis synchrony approaches that of Southeast Asian fireflies. The intermittent synchrony of this firefly reinforces the evidence that there is a diversity of synchronies in fireflies.