Media & Education
Volume 36, Issue 1, 2017
When Love Is in the Air, Show Off
When Love Is in the Air, Show Off
Bats use a dizzying array of tactics to attract mates. From the revolting to the remarkable, courtship behaviors run the gamut of creativity.
Think back, maybe way back, to a time when someone caught your fancy. How did you get their attention? Flowers, chocolates, the boring old usual? Well, if you’re a lady bat, it’s less about the stuff and more about the stink. And the song, and the show. For as little as is still known about bats, even less is known about their courtship behaviors; it’s only within the last 30 years that much has been documented at all. And what’s being discovered gets top marks for animal creativity.
There’s the usual mix of mating between one male and multiple females, or many males and many females, and even monogamy. Bats are rarely directly observed mating in nature (unless you’re theunfortunate pair of eastern red bats photographed in copula in the Baltimore Ravens’ end zone this past August), but more and more, their peculiar and often multi-modal ways of attracting bedfellows are coming to light.
Between mating at night and in places that are nearly impossible to access, much of what is known about bat mating is inferred, said Gary McCracken, professor of ecology and evolutionary biology at the University of Tennessee-Knoxville. He’s been studying bats since the 1970s, and said that for many years, it was just assumed that bat mating happened at random.
“People would enter a cave and see these huge numbers of animals crawling all over themselves. It seems chaotic, but it turns out it’s anything but,” McCracken said. “They use a huge number of cues to evaluate and select mating partners. You’ve just got to be impressed.”
Teri Orr, a postdoctoral researcher at the University of Utah, said while it’s true many attention-grabbing strategies originate from the male side of the equation, and males typically contribute nothing but genetic material, females benefit. “They can basically sit back and let the best male win,” she said.
Here are a handful of ways bats employ their unique biology and habitats to attract a mate.
Some have a bit of a Broadway bent
Producing over 24,000 songs per night, the Eastern whippoorwill is like The Voice champion of the bird world. But, poor will indeed, New Zealand’s lesser short-tailed bat puts it to shame: in a six- or seven-hour period each night during the mating season, male Mystacina tuberculata crank out more than 100,000 songs. Every night. Take a breath! Males also congregate together in certain areas of the old-growth forests where they live and occupy special singing roosts night after night, which oftentimes consist of no more than a crack in a tree or branch. Females, drawn by the males’ unrelenting sweeps, tones and trills, enter the roost, do the deed and depart. What’s more, small groups of larger-bodied males often employ a “timeshare” method to get more overall visits from females by taking cooperative shifts at the roost.
They build special houses for the ladies
Male bowerbirds are famous for attracting mates by building enchanting huts of grass and straw and adorning them with bright bits. While tent-building bats can’t lay claim to quite the same decorating chops as their bird counterparts, India’s short-nosed fruit bat (Cynopterus sphinx) does a fair job: males spend a month or more chewing away stems from within the thick foliage of plants like the mast tree, carving out an artificial cavity within the plant to attract a harem of females.
Females seem to prefer deeper tents, perhaps because males can defend them more easily.
Additionally, males have been observed spreading saliva around the tent’s opening, perhaps to deter other males or attract more females.
They blend irresistible colognes
Central America’s greater sac-winged bats (Saccopteryx bilineata) may never achieve the same notoriety as elite Parisian parfumeurs, but don’t tell that to the females of the bunch. Named for the small pouches located along the upper edges of their wings, male sac-winged bats spend a fair amount of time each day during the mating season filling their sacs with a custom blend of urine and other bodily secretions. With a special hover-and-flap maneuver, they waft their scents toward potential mates.
Each individual scent may relay specific information to females about the male’s health and social status, enabling the female to make an informed choice about the fitness of her suitor.
“Blind as a bat?” Perhaps not. While it seems counterintuitive for bats to use physical adornments to attract a mate, there’s good evidence that the males of several species of bats have specialized fur or other visual markers they use to turn heads. Minor epauletted fruit bats (Epomophorus labiatus minor), as well as several other Old World fruit bats, have patches of light-colored fur on their shoulders that they display during courtship rituals. These tufts may also contain chemical signals to further entice females—which are also thought to contain signaling pheromones. Pteropus conspicillatus, the Australian spectacled flying fox, also employs the visually arresting tactic of smearing cranberry-red secretions on their neck ruffs, though this is probably primarily for its arresting scent rather than its color.
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