Dance … or die!
However, careful analysis of the story reveals that the fast changes in lizards are not evidence of evolution at all.
Beware the fire ant!
Fire ants (Solenopsis invicta) were accidentally introduced to the USA from South America in the 1930s. They soon impacted their new surrounds. If a reptile, bird or mammal strayed onto a fire ant mound, the consequences were often fatal.3
The fire ants will also actually attack far away from their mound, to obtain food. They inject neuromuscular venom into the skin to paralyze their prey, then begin to eat.
“It takes just 12 of them less than a minute to kill a three-inch [75-mm] long fence lizard,” explained Penn State University biologist Tracy Langkilde. “In fact, they have even been known to eat animals as large as calves, stripping them down to their bones.”4
Langkilde’s Ecology research paper showed that some fence lizards (Sceloporus undulatus) are better than others at escaping fire ants, thanks to longer legs and a ‘twitch dance’.5
Survivor lizards dance the ‘twitch’
To attack a lizard, a fire ant will lift a scale covering the lizard’s skin in order to expose some soft flesh, and then inject the neuromuscular toxin that can paralyze and kill it. Lizards show two different responses if they unfortunately come into the ‘line-of-fire’ of foraging fire ants.
Response #1: Lizards remain stationary (a strategy that usually works well to camouflage themselves from predators, such as birds), doing nothing as ants crawl over them, and are soon killed.
Response #2: ‘Survivor lizards’ quickly abandon the motionless camouflage tactic as soon as fire ants begin to crawl onto them, and take remedial action. As Tracy Langkilde explained, “They do this big body shimmy, or a body twitch, where they shake their body to fling the ants off them, and then they run away from the mound.” It really is a spectacularly vigorous ‘twitch’!6
In fire ant territory, the lizards have changed
Collecting lizards from different regions to ‘road-test’ on fire ant mounds,7 Langkilde observed a very interesting phenomenon. Only 40–50% of the lizards from an area not invaded by fire ants did the shimmy-and-run. This was in stark contrast to the up-to-80% ‘twitch’ rate of lizards from areas long invaded by fire ants.
Also, lizards from fire ant regions had longer hind legs. Langkilde suggests that longer leg length was likely genetically selected because it gives the lizards more leverage to shake off the ants and flee more quickly.
When she examined baby lizards in the fire-ant-occupied regions and found they too had longer legs, it confirmed that there had been an inherited change in the makeup of the population, rather than merely a growth response to local conditions.
Furthermore, a comparison of museum specimens collected before the coming of fire ants showed that there were no differences in the lizard populations across the regions, also indicating a change in the makeup of the populations since the fire ant invasion.
Dance, baby, dance
Langkilde observed that all hatchlings do the twitch dance, i.e. irrespective of whether they were from fire-ant-affected areas or not. Langkilde explains that this is probably because the baby lizards have soft scales and so are vulnerable even to native, non-venomous ants. The scales of adult lizards, however, provide sufficient protection against most ants, and so the twitch dance is no longer necessary. It actually could be disadvantageous, given that overt twitching and fleeing would draw the unwelcome attention of predators to the otherwise well-camouflaged lizards.
When fire ants move in, however, Langkilde suggests that any advantage of being motionless is lost, as only the lizards that maintain the twitch-and-flee behaviour into adulthood survive to pass on their genes.
‘Evolution, evolution, evolution’?
Not surprisingly, the likes of National Geographic proclaimed these genetic changes as being a hallmark of evolution, e.g.:8
“Long legs and skittish behavior are recently evolved traits”1
“The findings, Langkilde said, are evidence of a rapid evolutionary response to the fire ants.”1
“Langkilde noticed that longer hind limbs are more prevalent at birth in lizards from fire-ant exposed populations, indicating an evolutionary adaptation”.1
“Duncan Irschick is a biologist at the University of Massachusetts in Amherst who uses lizards as a model to study evolution. He said Langkilde’s research presents solid evidence that these are evolved traits. … ‘It says there is some hope for species, that they can rapidly evolve to meet new challenges,’ Irschick said.”1
However, when they speak of ‘evolved traits’ and ‘rapid evolution’ etc., they are not referring to features that appeared out-of-the-blue. The twitch dance characteristic, for example, is exhibited by all hatchlings. Since the coming of the fire ants, natural selection has favoured individuals in the population that retain the juvenile shimmy dance into adulthood.9 Given the very powerful ‘selection pressure’ wielded by natural selection here—within 60 seconds any lizard that doesn’t do the shake-shimmy-twitch is ‘dead meat’!—it’s not surprising that its impact is so dramatic.
Similarly, the rapid increase in the gene frequency for lizard long-leggedness is also not ‘evolution in action’ as the genes for long legs were already present in the population. (This is made plain by Langkilde’s reporting that longer legs were merely “more common” in fire-ant-infested regions than in fire-ant-free zones, rather than something new.) The role of natural selection was, as always, eliminative: wiping out lizards that lacked these genes.
So, thanks to do-or-die, trial-by-fire-ants natural selection (culling), lizards now are much better adapted to survive the fire ant threat. But beware the ‘bait-and-switch’ one so often sees in secular media reporting, where ‘evolution’ is wrongly used synonymously with ‘natural selection’ and ‘adaptation’ as having caused these changes in the genetic makeup of lizard populations. These changes are not ‘evolutionary’ at all, as they are not examples of the increase in information (new genes) necessary for fish to have ever given rise to fence lizards—no matter how many millions of years an evolutionist might imagine. The changes are rapid because the genetic characteristics are already there.10
Thus equipped to be alert to the bait-and-switch, a discerning reader can confidently peruse evolutionary reporting, teasing out the facts from the ‘evolution-speak’. Here’s another extract from National Geographic News as a sample ‘test’ (with our added emphasis as an aid):
“Sharon Strauss, a professor of evolution and ecology at the University of California at Davis, agrees that Langkilde presents solid evidence for rapid evolution in fence lizards. The pace of evolution, she noted, hinges on ‘how strong the selection is and whether or not there is any genetic variation in the population that allows adaptation.’ A genetic trait for twitching in adulthood is likely to have existed within the lizard population prior to the fire ant invasion, Strauss noted. In order to help species adapt to the changing environment, Langkilde said ‘we need to manage populations so that they have enough genetic diversity so that they can evolve.’”
“Enough genetic diversity”, i.e. pre-existent genetic diversity—the genetic diversity that exists because the Creator provided such inbuilt capacity for variety. This has enabled His creature kinds to fill the many-and-various ecological niches around the planet.
Destroy evolution and defend biblical creation
To this point we have dismantled ‘evolution’ claims in line with the lead given by the Apostle Paul to “destroy arguments and every lofty opinion raised against the knowledge of God” (2 Corinthians 10:5).
But what if somebody tries to strategically shift the burden of proof from evolution to creation by objecting: “Okay, I see that natural selection of twitching, long-legged lizards is not evolution. But the fire ants’ existence clearly shows it’s a dog-eat-dog, survival-of-the-fittest world—your ‘God of Love’ is supposed to have made these agents of mischief and misery?!”
To answer (1 Peter 3:15), firstly we would point out that originally fire ants could not have been wreaking ‘mischief and misery’ as everything was created “very good” (Genesis 1:31). Death and pain are in the present (i.e. post-Fall) world as a consequence of the first man’s disobedience—Genesis 3:14–19, Romans 5:12,17, 8:19–22, 1 Corinthians 15:21–22 (but thankfully not in the future “new heavens and new earth”—2 Peter 3:13, Revelation 21:1,4, 22:3).
Secondly we would look to see if there’s anything about the fire ants’ current lifestyle that might indicate how they could have lived in the pre-Fall world. And indeed there is—fire ants today actually consume large amounts of young plants, fruit, and seeds.11 Certain other Solenopsis species, too—the same biblical ‘kind’ as fire ants—are even greater partakers of vegetarian sources of food. Also, their stingers have a function which would also be important in the pre-Fall world—they mark their trails with pheromones so other ants can follow it.
That tells us something of what it was like in the “very good” world prior to Adam’s sin, when lizards didn’t have to face the terrible selection pressure of dance-or-death.
References and notes
- Roach, J., Lizards evolving rapidly to survive deadly fire ants, news.nationalgeographic.com, 21 January 2009. Return to text
- Other media outlets echoed similar sentiments, e.g. the news video: Discovery News—Lizards show evolution in action, youtube.com/watch?v=PoeIIZFApF4, 30 January 2009. Return to text
- If a person is stung/bitten, although it can feel as if ‘burnt by fire’ (hence the name ‘fire ant’), and can cause extreme discomfort and unsightly lesions that can last for days. However, it is not usually fatal, except in people with sensitive skin or allergies. Return to text
- Bryner, J., Lizards’ dance avoids deadly ants, livescience.com, 26 January 2009. Return to text
- Langkilde, T., Invasive fire ants alter behaviour and morphology of native lizards, Ecology 90(1):208–217, 2009. Return to text
- At the time of writing, video footage of the ‘twitch dance’ could still be viewed online via the Youtube clip given in Ref. 2. Return to text
- It was reported, “Langkilde stopped the experiment after a minute to keep the ants from killing the lizards.” Ref. 4. Return to text
- And many since then have continued to publicly herald this as ‘evolution in action’. E.g.: Harrison, K., 7 animals that are evolving right before our eyes—#4 Lizards are evolving to be dancers, cracked.com, 18 May 2011. Also: Pringle, L., Billions of years, amazing changes: The story of evolution, Boyds Mills Press, Inc., Pennsylvania, USA, 2011, pp. 85–86. (See our comprehensive review of this book at creation.com/pringle.) Return to text
- Twitch retention might possibly result from a genetically-controlled ‘twitch switch’ failing to turn off at the onset of maturity. Retention of juvenile traits is called pedomorphosis. Return to text
- See also: Catchpoole, D. and Wieland, C., Speedy species surprise, Creation 23(2):13–15, 2001; creation.com/speedy. Return to text
- Extension—America’s research-based learning network, What do fire ants eat? extension.org, 29 November 2013. Return to text