Wild About Fireflies
Photinus fireflies were the main subject of Jim Lloyd’s doctoral thesis (Lloyd 1966), where he described their geographic and habitat distributions, courtship flash behavior, and more. The frontispiece from this work is shown in Figure 3-1 (used here with permission from University of Michigan’s Museum of Zoology), which artfully illustrates the male flight paths and flash patterns for the following Photinus species: 1) consimilis slow-pulse 2) brimleyi, 3) consimilis fast-pulse, 5) marginellus, 6) consanguineus, 7) ignitus, 8) pyralis, and 9) granulatus.
Defining the Indefinable
Charles Darwin’s quote is from a letter written to his good friend and confidant, the botanist Joseph Hooker.
Darwin, C.R. Letter to J.D. Hooker. 24 December 1856. Darwin Correspondence Database.
Heading into the Night
Carl Zimmer highlighted our firefly research in the New York Times:
Zimmer, C. (2009, 29 June). Blink twice if you like me. The New York Times.
We describe the courtship behaviors of Photinus greeni fireflies in Demary and colleagues (2006) and Michaelidis and colleagues (2006).
A Light Snack
Lloyd (2000) reports tracking a couple hundred males belonging to Photinus collustrans to see how likely they were to find a female vs. encounter a predator. Various predators that feed on fireflies are described in Lloyd (1973), Day (2011), and Lewis and colleagues (2012).
In Lewis & Wang (1991), we delve into the courtship and mating behavior of two New England fireflies, Photinus marginellus and Photinus aquilonius.
To the Victors Go the Spoils
Trivers (1972) suggested that diffences in male and female sexual behavior resulted from the asymmetry in parental investment between the sexes. Biologist Darryl Gwynne and his colleague won an IgNobel Prize (“Achievements that make people laugh, and then think”) for discovering some males that aren’t choosy at all; in the Australian beetle Julodimorpha bakervelli, males often copulate with discarded beer bottles along the roadside (Gwynne & Rentz 1983).
Erica Deinert kindly showed me mate-guarding Heliconius butterflies in Costa Rica. Lynn Faust has described male pupal-guarding behavior in two fireflies, Photinus carolinus (Faust 2010), and Pyractomena borealis Faust (2012).
Courtship is fiercely competitive for many Photinus fireflies, as described by Maurer (1968), Vencl & Carlson (1998), and Faust (2010). The hooked wing covers of male Pteroptyx fireflies, which clamp around the female’s abdomen during mating, were described by Steve Wing and colleagues (1982). Lloyd (1979) described the pseudo-female flash responses sometimes given by firefly males that have been unsuccessful in finding a female.
The Darwin quote is from Part II, p. 38, of his book, The Descent of Man and Selection in Relation to Sex (1871), in which he describes what sexual selection is all about.
Fisher (1930) first modeled how female choice could trigger the elaboration of extravagant male bits such as the peacock’s tail. Female choice in Photinus fireflies has been studied using photic playback experiments conducted by Branham & Greenfield (1996), Cratsley & Lewis (2003), and Taki Michaelidis and colleagues (2006). Kristian Demary and colleagues (2006) show that females preferentially give response flashes to certain males, and these males have better mating success. Lewis & Cratsley (2008) give a more technical review of what scientists have learned about flash signal evolution, courtship and predation in fireflies.
Lewis & Wang (1991) describes the seasonal shift in firefly sex ratios, and Cratsley & Lewis (2005) show that late-season males generally choose females who have more eggs.
More on Sexual Selection
In the second part of his 1871 book, Darwin describes the power of sexual selection to shape animal form and function. After outlining the principles and mechanisms of this fascinating evolutionary process, in separate chapters Darwin describes how sexual selection has led to the evolution of many wonderful and sometimes bizarre male features in crustaceans, molluscs, insects, amphibians, reptiles, birds, and even humans.
Darwin, C. (1871). The Descent of Man and Selection in Relation to Sex. London: John Murray. http://darwin-online.org.uk/converted/pdf/1871_Descent_F937.2.pdf
Here are two more excellent accounts of sexual selection – both shorter and also a bit more witty than Darwin’s. Under the guise of a sex advice column for lovelorn beetles, stick insects, stalk-eyed flies, mice and manatees, Olivia Judson’s hilarious book describes some of the weird structures and behaviors that have evolved as a result of sexual selection.
Judson, O. (2002). Dr. Tatiana’s Sex Advice to All Creation. Metropolitan Books, Henry Holt and Company, NY. 320 pp.
Cronin, H. (1993). The Ant and the Peacock. Cambridge University Press, NY. 504 pp.
Traveling the Firefly Trail with Jim Lloyd
Jim Lloyd’s monograph on U.S. Photinus fireflies describes their geographic and habitat distributions, courtship flash behavior, and more, and is available free online:
Lloyd, J.E. (1966). Studies on the flash communication system in Photinus fireflies. University of Michigan Miscellaneous Publications Vol. 130: 1-95.
Between 1997 – 2003, Jim Lloyd published a series of articles in the open-access scientific journal, Florida Entomologist, called “On Research and Entomological Education.” Written in the form of letters addressed to his students, these ramblings are packed with information about firefly natural history, and are chock-full of ideas for field studies.
Lloyd, J.E. (1997). On research and entomological education, and a different light in the lives of fireflies (Coleoptera: Lampyridae; Pyractomena). Florida Entomologist 80: 120-131.
Lloyd, J.E. (1998). On research and entomological education II: A conditional mating strategy and resource-sustained lek(?) in a classroom firefly (Coleoptera: Lampyridae; Photinus). Florida Entomologist 81: 261-272.
Lloyd, J.E. (1999). On research and entomological education III: Firefly brachyptery and wing “polymorphism” at Pitkin marsh and watery retreats near summer camps (Coleoptera: Lampyridae; Pyropyga). Florida Entomologist 82: 165-179.
Lloyd, J.E. (2000). On research and entomological education IV: Quantifying mate search in a perfect insect-seeking true facts and insight (Coleoptera: Lampyridae, Photinus) Florida Entomologist 83: 211-228.
Lloyd, J.E. (2001). On research and entomological education V: A species (c)oncept for fireflyers, at the bench and in old fields, and back to the Wisconsian glacier Florida Entomologist 84: 587-601.
Lloyd, J.E. (2003). On research and entomological education VI: Firefly species and lists, old and now. Florida Entomologist 6: 99-113.