Lizards will not miss out on an opportunity to speak the language of love, according to a new study from Washington University. The researchers discovered that lizards can create new ways to communicate with each other through chemical signals.
As an experiment, lizards were relocated in small groups to experimental islands. The males quickly developed ways to attract mates using new chemical signals.
The evolution of animal communication is normally focused on visual or acoustic signals, while chemical signals are less obvious. Most existing studies analyzed insect pheromones and agricultural applications.
However, chemical signals are the most widespread form of communication that is used by species ranging from bacteria to mammals.
The researchers explained that these chemical signals represent a valuable opportunity for decoding how animals communicate and perceive the world around them.
“What we’ve discovered is that within species there is important variation in chemical signals depending on your context: Who’s trying to eat you, who wants to mate with you and who you’re trying to compete with,” said study lead author Colin Donihue.
Lizards express messages through secretions from specialized glands on their inner thighs. The substances contain detailed information about the individual lizard that produced them.
“Animals have spent over a billion years developing a complex chemical communication library,” said Donihue. “But we only invented the technology to identify many of those chemicals a century ago, and the experiments for understanding what those chemicals mean for the animals in nature have only just begun.”
For the investigation, groups of eight male and 12 female Aegean wall lizards were relocated from a population in Greece to five small islets that lacked predators.
Over the next few years, the lizard populations expanded rapidly along with competition for resources.
The relocated lizards were tagged so that they could be tracked individually. The study rcevealed that lizards on each of the predator-free islands had rapidly and consistently developed a new “chemical mix” that was different from the language used within their original population.
The study has produced the first-ever solid evidence to show that lizards can “put on a new cologne” to suit their setting.
“Signals to attract mates are often conspicuous to predators,” said study co-author Simon Baeckens. “As such, sexual signals present a compromise between attractiveness and avoidance of detection. However, on these islets, there is no constraint on the evolution of highly conspicuous and attractive signals.”
“In the experimental islands, we found that the ‘signal richness’ of the lizard secretions is the highest – meaning that the number of different compounds that we could detect in the secretion is the highest. Our previous research suggests that this more elaborate signal might advertise the high quality of a male,” said Donihue.
“We found that animal chemical cues can rapidly and flexibly change to suit new settings, but this is only the beginning for understanding what the lizards are saying to each other.”
The study is published in the Journal of Animal Ecology.