The Bay Islands And Cayos Cochinos Of Honduras: Endless Potential For Future Anole Research

The Bay Islands proper consist of a crescent of four land-bridge islands lying approximately 50 km off the northern coast of Honduras in the Caribbean Sea.  About halfway between those islands and the coast lies a smaller sub-archipelago, known as the Cayos Cochinos (or ‘Hog Islands’), which consist of two larger islands (Cayo Mayor and Cayo Menor) and 13 smaller cays (see the map below).  The Cayos Cochinos are famous in the commercial reptile trade for their endemic populations of insular-dwarf ‘pink’ boa constrictors.

The Bay Islands and Cayos Cochinos of Honduras. For scale, Cayo Menor and Cayo Mayor are about 3 km apart. Adapted from Green (2010).

I’ve had the pleasure of conducting herpetological research in the Bay Islands since 2007 thanks to support from a UK-based conservation organization called Operation Wallacea, and a generous team of researchers (Chad Montgomery, Bob Reed, Scott Boback, Steve Green, and Tony Frazier) that have been working on the boa and Ctenosaura populations there for several years, and were nice enough to get me involved.  And while the Bay Islands have gained some notoriety for their exotic snakes, another local squamate has gone (almost) entirely unnoticed.  I’m alluding to, of course, the anoles.  In 2007, when I was helping Chad Montgomery with his Ctenosaura melanosterna project on Cayo Menor, I began to notice just how abundant the anoles on that island were.  The little guys seemed to be on almost every tree in the interior of the island.  After asking around and doing a few literature searches, I started to realize just how untouched, and potentially interesting, this system really was.

Two anole species occur in the Cayos Cochinos, Anolis lemurinus and Anolis allisoni.  Sister species to A. lemurinus, the insular endemics A. bicaorum and A. roatanensis, occur on Utila and Roatan, respectively.  In addition to being found on both Cayo Menor and Cayo Mayor, A. allisoni is native to Roatan and Barbareta.  The latter island, Barbareta, is privately owned and virtually uninhabited, and very few biological surveys have been conducted there.  So it is very possible that a member of the lemurinus species group occurs on Barbareta as well but has yet to be detected.   Only A. allisoni is reported from Guanaja, and three species—A. bicaorum (already mentioned), A. utilensis, and A. sericeus—are known from Utila.  A. utilensis is endemic to Utila, and is a mangrove specialist (the only known species of anole specializing in this type of habitat).  It is unclear whether A. sericeus, a species supposedly occurring on both Utila and the adjacent mainland, has an ecologically-relevant population on Utila, since we have only located one individual of this species (on a power line over a road side café) after two seasons of relatively intensive surveys.  Also, A. sagrei is reported from Roatan, but biologists on the island (resident and visiting) have not observed one for many years and doubt that a self-sustaining population occurs there.

Anolis lemurinus from Cayo Menor.

Anolis allisoni from Cayo Menor.

Anolis bicaorum from Utila.

The Bay Islands offer a cornucopia of future research opportunities to anole biologists for several reasons.  First and foremost, very few studies have been conducted in the archipelago (these include a handful of natural history notes and only two peer-reviewed papers, both published since 2007).  Second, the Bay Islands is one of the few (perhaps the only?) places where a mainland anole (A. lemurinus) has given rise to new island-dwelling species (A. roatanensis and A. bicaorum) in recent geological history. Third, ‘replicated’ two-species anole communities occur on at least three islands, where mainland (A. lemurinus and A. roatanensis) and island-derived (A. allisoni) lineages converge.  I am not aware of another island system where multiple island-derived and mainland-derived species coexist. Lastly, anole populations on the islands generally occur at extremely high abundance (as is true for many Caribbean islands), despite the fact that A. lemurinus is normally found at relatively low abundance on the mainland.

In 2008 and 2009 we conducted a detailed morphological and ecological survey of A. lemurinus in the Cayos Cochinos (published in J. Tropical Ecology this February), and found that, despite their close geographic proximity and low levels of genetic divergence among populations, males differed in dewlap size, body condition, and hindlimb length among islands.  We speculate in the paper that this may be due to differences in population density or predation pressure between islands, but the jury is still out on that question.  Since 2010 we have been studying the thermal ecology of these populations, as well as those on the Bay Islands proper, to understand how predictions for the response of anole communities to climate change might vary depending on physiographic and ecological context (here, we are exploiting the fact that at least 3 of the islands contain similar anole communities, but differ in topographical complexity).

There are plenty of unanswered questions for people interested in studying the anoles of the Bay Islands.  For instance, what happens when island and mainland-derived lineages converge and are forced to coevolve in an island ecosystem?  Why are A. lemurinus so much more abundant on the islands than on the mainland, and how similar is the ecology of mainland A. lemurinus to that of island-dwelling populations?  Have they evolved into one of the classic Anolis ecomorph categories on the islands?  How does A. utilensis from Utila differ from A. pentaprion (their close relative from the mainland), and what adaptations are associated with living in mangrove habitat?

While the well known adaptive radiations that have occurred in the Greater and Lesser Antilles have led to decades of fascinating research, and will, of course, continue to produce scientific fruit for years to come, the Bay Islands of Honduras remain a largely unexploited niche for the ambitious young anole biologist eager to embark on new avenues of scientific inquiry.

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Michael Logan

I'm a post-doc at the Smithsonian Tropical Research Institute in Panama.I'm primarily interested in questions related to thermal adaptation in terrestrial ecotherms.

Latest posts by Michael Logan (see all)

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• The Bay Islands And Cayos Cochinos Of Honduras: Endless Potential For Future Anole Research - April 17, 2012