Ontogenetic Reflectance Changes in Foot Flagging Frogs

S. guttatu

S. parvous

Many organisms show ontogenetic changes in their coloration. This can result from environmental or hormonal changes within the organism as it develops. These striking colorations and pattern can provide toxicity information as well as affect mate choice and other intra-species interactions. Recent studies have highlighted the evolution of color in dendrobatids. Other anuran species have been studied to increase our knowledge of communication through modes other than acoustic methods. The researchers observed the Bornean foot-flagging frogs Staurois parvus and S. guttatu. During a 12 month period for S. parvous and a 7 month period for S. guttatu. The reflectance levels of both the feet webbings and dorsal surfaces of all individuals were taken over the time period.

A and B graphs show the spectra from the foot webbing whereas C and D show the dorsal spectra.

The results of the study concluded that the reflective spectra of the foot webbings increased in mean reflectance as the individual grew old.  Also it was shown that wild populations of the two species expressed a significantly larger amount of reflectance than their lab reared counter parts. This could be attributed to change in diet or other environmental factors that have been yet to be explored. The ontogenetic changes during life history can affect reproductive behaviors, male territorial displays and other important anuran interactions to aid in conservation activities.

Graphs A and B show the compared spectra of the lab reared and the wild individuals.

Here is a link to the full article:
http://www.bioone.org/doi/10.1655/HERPETOLOGICA-D-14-00014

Article Citation: Judith Stangel, Doris Preininger, Marc Sztatecsny, and Walter Hödl. 2015. "Ontogenetic Change of Signal Brightness in the Foot-Flagging Frog Species Staurois parvus and Staurois guttatus." Herpetologica, 71(1):1-7