After the Lights Go Out
The demise of monogamy was reported by Natalie Angier in the New York Times in 1990. Some scientific ramifications of the “Polyandry Revolution” are explored in a theme issue introduced by Pizzari & Wedell (2013). We describe polyandry among Photinus fireflies in the wild in Lewis & Wang (1991).
Angier, N. (1990, August 21). Mating for life? It’s not for the birds or the bees. The New York Times.
Sperm Wars, Sperm Love
Leigh Simmons, an accomplished evolutionary biologist, provides a comprehensive review of sperm competition theory and mechanisms (Simmons 2001). Quote about male genitalia and Swiss army knives is from p. 22 of Lloyd (1979b). Waage (1979) described sperm removal in the damselfly Calopteryx maculata, and Davies (1983) reports cloacal pecking & sperm ejection by dunnocks, Prunella modularis.
The evidence for sexual selection via cryptic female choice is presented in two books, Eberhard (1996) and Peretti and Aisenberg (2015).
In van der Reijden et al. (1997)we reported our discovery of firefly nuptial gifts in North American Photinus fireflies, and later we discovered them in Japanese fireflies (South et al. 2008).
Finding the Perfect Gift
Many kinds of nuptial gifts along with their evolutionary causes and consequences are described in Lewis & South (2012) and Lewis et al. (2014). Albo and colleagues (2011) report that in the spider Pisaura mirabilis, males offering gift-wrapped worthless (inedible) gifts were as successful in obtaining mates as males that offered genuine gifts (dead flies). But females terminate matings sooner when males deceive them with worthless gifts, so these males have a disadvantage in sperm competition.
Chemical ecologists Tom Eisner and Jerry Meinwald (1995) relate the astounding story of how Ornate Moths, Utetheisa ornatrix, sequester bitter-tasting alkaloids from their larval food plants, and how males then pass these toxins along to females in their nuptial gifts.
Some intimate events that transpire during snail sex have been elucidated by Koene (2006).
Male Sexual Economics
We tested the notion that producing nuptial gifts is costly for male fireflies in Cratsley et al. (2003). In South and Lewis (2012), we found that males gain a paternity benefit from giving larger gifts because they get to sire a greater percentage of offspring.
Bright lights & bling: What’s in it for the female?
Demonstrating how valuable a nuptial gift can be when nutrients are scarce,Yoshizawa and colleagues (2014) describe cave-dwelling Brazilian barklice whose female intromittent organ appears to have evolved through competition for male nuptial gifts.
As discussed in Lewis et al. (2004), gift-giving plays an important role in firefly economics because most fireflies stop eating once they’ve become adults. In Rooney & Lewis (1999), we describe our radiolabelling studies showing that a female uses protein from the male’s gift to help provision her eggs. In Rooney & Lewis (2002), we show that Photinus ignitus females who mate more often subsequently lay more eggs. In Photinus greeni females, a different benefit showed up: females who received larger gifts lived longer (South & Lewis 2012).
Cratsley & Lewis (2003) discovered a correlation between males’ flash duration and their spermatophore size in Photinus ignitus fireflies: these females might be able to use a male’s flash signals to predict what size gift he could offer. But when we looked for a similar relationship in Photinus greeni fireflies, we found none (Michaelidis et al. 2006).
Animal Nuptial Gifts
In this short article we describe the astonishing diversity of nuptial gifts found across the animal kingdom:
Lewis, S.M., A. South, N. Al-Wathiqui, and R. Burns (2011). Quick guide: Nuptial gifts. Current Biology 21: 644-645. ()
This excellent Wired article by Brandon Keim was published on Valentine’s Day, and it goes beyond the ordinary to illustrate animal nuptial gifts.
Keim, B. (2013, February 14). Freaky ways animals woo mates with gifts. Wired.
From Dutch biologist and science writer Menno Schilthuizen come two informative books, both written with enthusiasm, clarity, and humor. Nature’s Nether Regions describes the reproductive equipment of barnacles, slugs, apes, and more, explaining how the bizarre and unusual inventions known as animal genitalia have been forged under postcopulatory sexual selection. His earlier book, Frogs, Flies and Dandelions describes the history of ideas about how new species emerge, and explores the role that sexual selection might play in the speciation process.
Schilthuizen, M. (2014). Nature’s Nether Regions. Viking, NY. 256 pp.
Schilthuizen, M. (2001). Frogs, Flies and Dandelions: Speciation – The Evolution of New Species. Oxford, UK. 256 pp.