Mottled Snailsucker (Sibon argus)

Mohamed bin Zayed Species project number 13255881

Dipsas and Sibon, two genera of snakes native to Central and South America, were presumed molluscivores feeding exclusively on shelled and unshelled mollusks because of their highly specialized morphology. However, recent work suggests that these two genera have a broader diet than expected. Dipsas sp. feeds regularly on bromeliad oligochaetes while Sibon feeds, at least seasonally, on amphibian eggs deposited on leaves overhanging mountain streams. The discovery of broader dietary intake came hand-in-hand with the rapid and devastating invasion of chytridiomycosis, which has spreading throughout Central America and around the world. Chytridiomycosis is a disease carried by a fungus and it has been responsible for the loss of nearly 60% of the local amphibians within a time period of months. The direct effect on amphibians has been realized, the trophic cascades that must follow have been more difficult to fully assess. Snakes serve as a model for upper trophic levels as several species utilize frogs or frog eggs as prey and snakes are fairly abundant. What was unexpected was the dependency of Sibon on amphibian eggs. Preliminary studies indicate that Sibon fare best when their diet includes amphibian eggs (better body condition, higher population densities). The most recent discovery is that Sibon will feed on bromeliad oligochaetes in the absence of amphibian eggs, putting them in direct competition with Dipsas at many sites.

OBJECTIVES
o To assess the population status of Sibon spp. in Omar Torrijos National Park (OTNP) eight years after local amphibian populations declined because of chytridiomycosis.
o To compare populations of Sibon spp. from OTNP to other sites with existing preliminary data (Fortuna, Santa Fe National Park, and Altos del Maria).
o To assess the current dietary intake of Sibon spp. and compare results to previous data.
o To survey the local environment to determine presence of mollusks, oligochaetes, and amphibian eggs.
o To understand how Sibon and Dipsas sp. partition the habitat.