Team finds the movement behavior of an anole species to be more dynamic than previously thought

February 21, 2018 by Julie Cohen, University of California - Santa Barbara
Anolis sagrei, also known as the Bahaman anole or De la Sagra's Anole, is highly invasive. Credit: Bonnie Kircher

Anolis lizards have a thing or two to teach humans about love—or in scientific speak, sexual selection—at least when it comes to territoriality.

Decades of behavioral research on the lizard's mating systems have resulted in near-unanimous agreement among scientists that the males maintain restricted, static territories to defend exclusive mating access to within these territories and are consequently polygamous.

However, recent genetic data shows that female Anolis sagrei—a brown lizard native to Cuba and the Bahamas but well established in Florida—also have multiple partners.

UC Santa Barbara behavioral ecologist Ambika Kamath and colleague Jonathan Losos of Washington University in Saint Louis eschew the framework of territoriality. Rather, they quantify of the lizards and estimate encounters between potential mates. Their finding: The species' movement behavior can be more dynamic than previously thought, leading females to frequently encounter multiple males and suggesting the possibility that may be an important selective force.

Kamath's and Losos' research is published in the Proceedings of the Royal Society B.

"Understanding animals' movement patterns and the encounters they bring about is a key step in characterizing a population's mating system and essential for determining how behavior both facilitates and is subject to sexual selection," explained Kamath, a postdoctoral scholar in UCSB's Department of Ecology, Evolution, and Marine Biology. "The movement patterns of these lizards revealed not only that a majority of males (60 percent) encountered multiple females but also that most females (78 percent) encountered multiple males over the first three months of the . This suggests potentially complex mating patterns with ample scope for female choice."

The researchers characterized sexual selection by examining the predictors of male reproductive success at two levels. First, they asked whether the number of potential mates encountered by males was associated with their phenotype (the spatial extent of their movement and body size). Second, Kamath and Losos tested three hypotheses to understand the phenotypic differences between potential and actual mates: if females bear offspring sired by males they encounter more frequently; if males encountered later in the breeding season are more likely to sire offspring than those met earlier; and if females disproportionately bear offspring sired by larger males.

"Consistent with previous genetic descriptions of anole mating systems, most females—64 to 81 percent—bore offspring sired by more than one male," Kamath said. "In addition, we found that favored that were bigger and moved over larger areas, though the effect of body size cannot be disentangled from last-male precedence."

According to Kamath, these findings raise questions about research assumptions. "If these lizards are not territorial like previously thought, how do we understand the decisions they make?" she asked. "Are there frameworks we can use to think about individuals' decisions that would enable us to predict patterns of selection, both natural and sexual? Our research leaves the field wide open in terms of finding better ways that don't rely on constraining frameworks such as territoriality for describing animals' social lives."

Explore further: Male orb-weaving spiders cannibalized by females may be choosy about mating

More information: Estimating encounter rates as the first step of sexual selection in the lizard Anolis sagrei, Proceedings of the Royal Society B (2018). rspb.royalsocietypublishing.or … .1098/rspb.2017.2244

Related Stories

Female mice do not avoid mating with unhealthy males

March 13, 2015

Female mice are attracted more strongly to the odour of healthy males than unhealthy males. This had already been shown in an earlier study by researchers from the Konrad Lorenz Institute of Ethology at the Vetmeduni Vienna. ...

Mating induces sexual inhibition in female jumping spiders

October 18, 2017

After mating for the first time, most females of an Australian jumping spider are unreceptive to courtship by other males, and this sexual inhibition is immediate and often lasts for the rest of their lives, according to ...

Male pipefish pregnancy, it's complicated

January 4, 2017

In the upside-down world of the pipefish, sexual selection appears to work in reverse, with flashy females battling for males who bear the pregnancy and carry their young to term in their brood pouch. But new research shows ...

Birds choose mates with ornamental traits

September 4, 2017

A recurring theme in nature documentaries is that of choosy females selecting brightly colored males. A new study shows that, in monogamous mating systems, male birds may select their lifelong mates in much the same way.

Recommended for you

Scientists ID another possible threat to orcas: pink salmon

January 19, 2019

Over the years, scientists have identified dams, pollution and vessel noise as causes of the troubling decline of the Pacific Northwest's resident killer whales. Now, they may have found a new and more surprising culprit: ...

Researchers come face to face with huge great white shark

January 18, 2019

Two shark researchers who came face to face with what could be one of the largest great whites ever recorded are using their encounter as an opportunity to push for legislation that would protect sharks in Hawaii.

Why do Hydra end up with just a single head?

January 18, 2019

Often considered immortal, the freshwater Hydra can regenerate any part of its body, a trait discovered by the Geneva naturalist Abraham Trembley nearly 300 years ago. Any fragment of its body containing a few thousands cells ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.