Human Flower Project
Floral form may suggest a mating strategy, but beware of flying to conclusions.
Morphology (and display): Does this look like a sexual cue to you?
Photo: via medusasmakeup
Why do happily married women wear so much mascara? We look to dark and glam Tacca chantrieri, the bat flower, for clues—with thanks to Tessa Laird for spotting this peculiar species.
A native to Southeast Asia, Tacca chantrieri has been puzzling a busy team of botanists. This plant, and others in its family, seem to be generally self-pollinating, so what are the lipliner, blush and long lashes for?
“Investment in attractive structures represents an allocation cost that animal-pollinated plants pay to secure the ﬁtness advantages that accrue from cross-fertilization,” write Ling Zhang and fellow researchers. “In contrast, for species in which pre-dominant selﬁng is the primary mating strategy, investment in attractive structures is superﬂuous, and resources are instead redirected to alternative structures or activities.” Like fruit production or philosophy.
Tacca chantrieri (a.k.a. bat flower), putting on a Gothic show, but for what?
Photo: Scott Glovsky
But that’s not so with Tacca chantrieri. The researchers presumed that its podlets in shades of maroon and dangly whiskers (“large, purple involucral bracts and long, ﬁliform bracteoles”) had evolved to draw in carrion flies. Lovely.
“In areas where T. chantrieri occurs, local inhabitants liken the appearance of the species to a ﬂying bat, a sinister face, or a mean tiger with whiskers,” write the botanists. There are a number of other plants—most of them stinky as well, which Tacca apparently is not – that, human observers have ascertained, pose as rotten meat.
“These features have been assumed to function as a ‘deceit syndrome.’’” the scientists write; “reproductive structures resemble decaying organic material attracting ﬂies that facilitate cross-pollination (sapromyiophily).”
Tacca chantrieri: flashy even from the back
Photo: via TANAKA Juuyoh
Studying four groups of bat flowers in South Yunnan, China, the researchers set out to learn whether indeed flies do pollinate Tacca chantrieri. Read the whole study, including the fine points of their experimental methods here.
They found that these plants actually do NOT attract flies, nor do they reproduce principally through cross-pollination; “Our results indicate that despite considerable investment in extravagant display, populations of T. chantrieri are highly selﬁng” (meaning self-pollinating).
The researchers’ labors—involving transplanting, random selection, estimating numbers of pollen grains, monitoring inflorescences every two hours for two days, removing bracts, counting insects and categorizing them as “pollinators” or “visitors,” staking, bagging flowers, along with many other operations, for three years— wind up with more questions than answers. They offer a few very tentative ideas why a self-pollinating plant would put on such a show. But in the main they stress that their experiment “warns against inferring patterns of mating from ﬂoral morphology alone.” In other words, don’t presume to know the sexual habits of a species just by appearances.
Good advice. The realm of human “display” certainly bears out their findings – and echoes their warning! Not everyone (female or male) who takes pains to glamorize her/his appearance is doing so to attract a swarm of mates. There are plenty of well groomed, even flashy monogamous types. Is all that effort for a partner? Maybe, but we doubt it.
‘Bad’ as a bat flower
Photo: via Michael Jackson Romania
We all know plenty of “self-pollinators,” too; in fact, they often seem to allocate the most energy of all in looking beautiful, sinister and dangerous. Is that an effective strategy to draw attention AND repel intimacy at the same time?
It could be be that “visitors” (rather than pollinators) enhance what is essentially a selfing strategy. Brows drawn arched and black, cheeks purpled may be overtly social ways of gaining self-esteem. If generations of Tacca chantrieri could only talk…
Lacking that, let’s hear from you experts in cosmetics. Whiskered eyes and devilish lips, what does the whole “suite of display” amount to? A barrier or a come on, a “deceit” or a form of self-enjoyment —or something altogether different? Are you posing as rotting meat? Meanwhile, Tacca chantrieri is endangered and an exhausted team of botanists is standing by.