In collaboration with the Conservation Biology course taught by Dr. Karen Beard here at Utah State University, where I am a Ph.D. student, I have been involved in gathering life history data on ~400 species of reptiles that have been introduced outside of their native ranges for an analysis of how life history traits (e.g., diet, fecundity, longevity) interact with other factors to influence the likelihood of successful establishment. Appendix A of Fred Kraus’ 2009 book Alien Reptiles and Amphibians is the source of the species list we are using, and included in this analysis are 26 species of Anolis. This is where you come in.
First, we coded all anoles as (i) sexually-dichromatic, (ii) diurnal, (iii) non-venomous, (iv) oviparous, (v) omnivores that lack (vi) temperature-dependent sex determination and (vii) parthenogenesis. Is anyone aware of any exceptions to these seven generalizations?
Second, we searched for data on clutch size, clutch frequency, incubation time, and longevity. The Anole Classics section of this site and the Biodiversity Heritage Library were particularly useful. After conducting what I feel to be a pretty thorough literature scavenger hunt, I am forced to conclude that some of these data simply do not exist at the species level for all of the species we’re interested in, or are not explicitly stated in a way that is obvious to a non-anole-expert. Of course, there is a lot of literature, including many books that I don’t have access to, and there are also lots of credible observations that don’t get published. I’m hoping that some of the readership here can help fill in at least some of the blanks in the table below. As one member of the team, I did not collect all of the data that are filled in myself, nor have I personally vetted every value, so if you spot an error please do point it out.
Two important points:
- Many environmental factors obviously influence the life history parameters of our beloved and wonderfully plastic reptiles, so we appreciate that many of these values would be better represented by ranges and are dependent on latitude, altitude, climate, and many other factors. Where a range is published, we are using its median value.
- I should also emphasize that, because of the large size of this study and the diversity of taxa included (ranging in size from giants like Burmese Pythons, Nile Crocodiles, and Aldabra Tortoises to, well, anoles and blindsnakes), it is more important for the data to reflect the relative values of these life history parameters across all anoles (and all reptiles) than it is to specifically and precisely represent all known variation within a given species of anole.
Without further ado (for your enjoyment, and because I know from my own blog that nobody reads posts lacking pictures, I’ve embedded an image of each species):
| Species | Median clutch size | Median clutches per year | Incubation time (days) | Maximum longevity (months) |
 A. aeneus |
2 | |||
 A. baleatus |
||||
 A.bimaculatus |
2 | 43 | 84 | |
 A. carolinensis |
1.15 | 6 | 41.5 | 65 |
 A.chlorocyanus |
1 | 18 | ||
 A. conspersus |
1 | |||
 A. cristatellus |
2.5 | 18 | 83 | |
 A. cybotes |
1 | 18 | 45 | |
 A. distichus |
1 | 16 | 45.5 | |
 A. equestris |
1 | 1 | 48 | 149 |
 A. extremus |
||||
 A. ferreus |
1 | 18 | ||
 A. garmani |
1.5 | 18 | 67 | |
 A. grahami |
1 | |||
 A. leachii |
||||
 A. lineatus |
||||
 A. lucius |
1 | 3.5 | 60 | |
 A. marmoratus |
2 | 50 | ||
 A. maynardi |
||||
 A. porcatus |
1 | 18 | 63.5 | |
 A. pulchellus |
1 | |||
 A. richardii |
1 | |||
 A. sagrei |
2 | 20 | 32 | 22 |
 A. stratulus |
||||
 A. trinitatis |
2 | 50 | ||
 A. wattsi |
1 |
Thanks in advance. I think this is a great blog and I hope to post something more interesting on here soon.
- Fill In The Blank: Obscure Anole Life History Traits - June 27, 2013
James (Skip) Lazell
Fascinating project! You used six of my illustrations: glad to help. Wish I had data to contribute. Onwards! Skip
Andrew Durso
They are wonderful illustrations! I enjoyed reading the paper they were in very much.
Daniel Scantlebury
Honestly, I was surprised to hear of any species laying more than 1 egg at a time. I’m sure it can happen, but often enough to warrant consideration?
Andrew Durso
Sounds like probably not. I suspected that this might be the case.
Kevin de Queiroz
Two caveats: 1) Not all anole species are sexually dichromatic (sexual monochromatism is common among crown giants and twig dwarfs). 2) You should be careful about how you assess clutch size from the literature. The common wisdom is that anoles lay single-egg clutches (though the character has not been surveyed throughly across the clade); however, in the literature, reproductive condition is often assessed by checking for the presence of oviducal eggs, and two eggs may be present in the oviducts even though only one will be laid at a time.
Andrew Durso
Thanks Kevin, I suspected that literature reports of two-egg clutches were due to this tendency. It certainly wouldn’t do to represent some anoles as twice as fecund as others. I think we’ll likely change all clutch sizes to 1.
Robert Powell
I’ve certainly not examined all of the species on your list, but have delved into quite a number of anoles. Even in heavy-bodied species that often have two eggs in the oviducts, they are almost never at the same stage of development (one shelled, one not or one yolked, one not). So, I think you’re safe in using a clutch size of one, although some of the husbandry literature suggests that females can hold eggs if conditions aren’t right and lay one shortly after another.
Robert Powell
Although calling them omnivorous is technically accurate, I doubt that plant material of any kind is a major component in the diet of most anoles. Do you have categories that place unequal weight on dietary components? If so, a more accurate description might be to say that anoles are primarily insectivorous and facultatively omnivorous, which would address the opportunistic or seasonal consumption of flowers, fruits, and nectar (pretty sure leaves and twigs found in occasional stomachs are inadvertently consumed and largely indigestible). That more-detailed categorization, however, would exclude the occasional instances of carnivory, especially by the larger species. Maybe you don’t need such detail for your analyses, but categorically referring to anoles as omnivorous seems a bit of a stretch.
James (Skip) Lazell
I. too, have always believed anoles lay one egg at a time, but that is annecdotal observation: I have never studied the question. I observe three species of anoles feeding on nectar regularly and fruit and flowers occasionally. But they are not as omnivorous as iguanas!
Gregor Weidlich
Hey, I am an Anolis breeder from Germay. I have kept and bred many species from the bimaculatus-series and the roquet series over the years. And I have never witnessed a clutch of other than one egg at a time. One of my breeding-techniques, I used to have was setting one female in a terrarium with no “furnishing” other than a branch and a small pot with peat or coco humus. The females would always lay their egg inside the peat/coco substrate at a depth of about 5cm. I never found a clutch of more than one egg. I obtained about 100 eggs from different species. mostly A. marmoratus ssp., A. roquet summus., A. bimaculatus, A. ferreus, A. oculatus winstoni. The most eggs I had from the A. marmoratus subspecies – they definately never ever layed two eggs at a time, as was posted above. Sorry for not being able to supply precise data. And of course this is just an observation made under artificial conditions, but maybe it can help here.
Thank you for this interesting post. keep und the work on Anoles!
Greetings from Germany