Female Display in Anolis cristatellus, and a Call For Your Observations!

In species of Anolis where females have dewlaps, we know very little about exactly how females use their dewlaps. Losos (2009) describes this lamentable situation thus:

“Unfortunately, little is known about how females use their dewlaps, and the little information that is available from three species permits few generalities. Anolis carolinensis females only rarely use their dewlaps in intersexual displays (Jenssen et al., 2000), whereas female A. valencienni use their dewlaps primarily to discourage courting males, including those of other species (Hicks and Trivers, 1983). Both A. carolinensis and A. bahorucoensis females use their dewlaps in intrasexual displays (Orrell and Jenssen, 1998, 2003); in A carolinensis, females use the dewlap more at close range and less at long range in female-female interactions compared to dewlap use in male-male interactions (Jenssen et al., 2000; Orrell and Jenssen, 2003). Unfortunately, without more information on how females use their dewlaps, we will not be able to explain sexual dimorphism and dichromatism in anole dewlaps.”

Since then, Martha Muñoz has added an observation from A. armouribut the numbers are still small.

Attempted forced copulation in Anolis cristatellus

Attempted forced copulation in Anolis cristatellus

In July 2013, I spent ten days observing A. cristatellus in Mayagüez, Puerto Rico, and can add one more species to the list of female anoles that use their dewlaps to dissuade males from mating with them. I was mapping male territories and counting male-male interactions in a park in one of Mayagüez’s fancier neighbourhoods, and came across a male chasing after a female. I sat down to watch the interaction, and was struck by how determined the female seemed to avoid mating with this male. You’ll notice how the male is biting the female much lower down the body than is normal during mating, indicating how the female is trying to get away. Her dewlap is completely extended during this interaction.

The chase went on for several minutes before the female ran to the end of a thin branch and another male showed up to chase the first male away. I proceeded to catch and mark this second male, and later observations revealed him to be the resident territory holder of the tree.

A little later, we caught a male in the tree adjacent to one in which the showdown occurred. In a fantastic stroke of luck that anyone whose work depends on identifying individual animals in the field will appreciate, we were able to determine that this male from the adjacent tree was in fact the first of the two males observed earlier.

How, you ask, did we perform this forensic  wizardry? Observe the second tiny tail of the interloper attempting the forced copulation:IMG_3259

 

Caught red-handed!

I was showing these photos to Jonathan Losos the other day, and he immediately noted that the observation of a female using her dewlap was pretty rare. Of course, the obvious response was to write a blogpost about it, but then we realised that with Anole Annals‘ daily viewership of up to 1500, we could do more than just write a blogpost–we could do citizen science! So this, ladies and gentlemen, is an invitation to all of you to help build a  dataset. It’s more than the usual request for participation and comments that I end many posts with–it’s a challenge to all of us AA readers to keep an eye and camera out for examples of females using their dewlaps, so that we can together figure out a pretty basic piece of Anolis biology.

We’ve done this sort of citizen science before, quite successfully: here’s Kristin Winchell’s call for data on urban anoles, and here’s the resultant analysis.  And there’s all sorts of exciting natural history questions that would be impractical for individuals to tackle on their own, but that we can solve easily as a team. Let’s make this blog a citizen science hotspot!

 

10 thoughts on “Female Display in Anolis cristatellus, and a Call For Your Observations!

  1. I’ve seen female anoles use their dewlaps on a couple occasions, both in the same context: I was recording male displays and it appeared the females were rejecting the male. Similar to what has been reported in A. valencienni. I can give you more details if you like, just email me at lngray@unm.edu.

    Glad to see someone putting together a dataset on this! In Mexico, females of most species have dewlaps and I frequently wonder what they are used for.

  2. I have a casual question on this topic for you, but was originally worried that this might distract from you main question. Following Levi’s comment and the slow rate of early responses I will ask it now.

    Specifically within the behavior literature, are there discussions about intersexual genetic correlations causing correlated changes in behavior during evolution? I think that its safe to say that in the morphological literature on sexual dimorphism this is a pretty well established idea. Certainly in development males and females possess many of the same characteristics early on (even the genitalia start out the same way and diverge relatively late in embryological development). Considering that the dewlap is modified from a deeply conserved structure, the hyoid apparatus, it is not at all surprising to me that both sexes possess the dewlap. Maybe its an over simplification, but perhaps females just use their dewlaps because males do. Is this a completely absurd idea?

    1. Thom that’s a really interesting thought. Off the top of my head, I can’t think of anyone making such an argument about a behaviour, but I’ll keep my eyes open for examples and get back to you if I find one. With a signal like a dewlap, though, given how context-dependent dewlap use can be (i.e. there are specific ways and situations in which males use their dewlaps), I’d be surprised if this particular behaviour could be explained as you suggest. But it’s definitely a possibility that we’d be able to assess better once we know more about when females use their dewlaps!

  3. Over the years I’ve seen females extend the dewlap a number of times. Digging way back I even found a little bit of published data (Fleishman 1988, J. Herpetol.22:13-23) and it supports the observation above. When male A. auratus approached females and the females “displayed” (which in that case I defined as head-bobbing with the dewlap), there was no further interaction. I’ve seen this quite a bit in Puerto Rican anoles — the female dewlapping towards a male means “not interested.” I have also on a few occasions observed females dewlap at one another in what I took to be a territorial dispute, but I can only report that anecdotally.

    1. Thanks for the observations and citation! Do you happen to recall which Puerto Rican species you’ve seen these behaviours in?

      1. Certainly cristatellus and gundlachi, which I’ve spent the most time watching. I can’t remember for certain about the others.

  4. Neat stuff. I have seen females of the A. limifrons group (apletophallus, limifrons, cryptolimifrons) use their dewlaps to communicate with males. Most of my observations have been on apletophllaus and female sof this species use it to display to males and females. In the former, I am not convinced that is only used to deter courting males. I think it is used more generally as a territorial/competition display. Females also display to other females, again I think it is a competition thing. Juveniles of both sexes also display and compete with one another.

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