Monday, February 8, 2016

[Herpetology • 2015] Breeding in Bamboo: A Novel Anuran Reproductive Strategy discovered in Rhacophorid Frogs of the Western Ghats, India

Figure 2. Raorchestes chalazodes in natural habitat. A, Ochlandra travancorica bamboo along streams. Height about 5 m. B, Male R. chalazodes on the internode. C, Male R. chalazodes vocalizing outside the internode opening.

Amphibians exhibit extraordinarily diverse sets of reproductive strategies among vertebrates. Understanding life history strategies in an evolutionary framework is lacking for many amphibian species in the tropics. Here, we report a novel reproductive mode where adult frogs enter hollow internodes of bamboo via a small opening, deposit direct developing eggs, and provide parental care. This behaviour is observed in two species of the frog genus Raorchestes. The first description of this unique life history and details of nest site characteristics and embryo development are provided along with ecological comparisons. Evolution of novel reproductive modes and parental care are discussed in context of natural selection. Dearth of natural history information on amphibians in the Western Ghats and much of the South-East Asian region is highlighted with suggestions for further studies.

Keywords: amphibian ecology; direct development; evolutionary ecology; natural history; parental care; reproductive strategies 

Figure 3. Snapshots of male R. chalazodes entering the nest cavity inside a bamboo internode.
A, male entering by inserting head; B, mid dorsum and forearms inserted; C, forearms used to haul body in; D, forelimbs almost completely inserted; E, anterior portion of body almost entirely inserted, legs remain outside and; F, legs being pulled inside, one-by-one. Entry sequence lasted almost 30 s.
Measurements of frog and internode provided in text. A video grab of this sequence is available at: 10.1111/bij.12388

Figure 4. Inside bamboo internode and nest cavity.
A, Adult male with a clutch of five eggs; B, two different aged egg clutches inside one internode, one clutch with seven eggs and another with only four eggs are visible; C, an emerged froglet from a different clutch with seven eggs seen near developing embryos.


Researchers from the National University of Singapore have discovered a new reproductive mode in frogs and toads - breeding and laying direct developing eggs in live bamboo with narrow openings - which was observed in the white spotted bush frog (Raorchestes chalazodes).
photo: Seshadri K S  DOI: 10.1111/bij.12388

Adult male Raorchestes chalazodes enters hollow internodes of the flute bamboo Ochlandra travancorica where they vocalise to attract mates. It enters the bamboo with considerable resistance as the narrow openings are often less than 5 to 10 millimetres long and 3 to 4 millimetres wide.
photos: Seshadri K S

Kadaba Shamanna Seshadri, Kotambylu Vasudeva Gururaja and David Patrick Bickford. 2015. Breeding in Bamboo: A Novel Anuran Reproductive Strategy discovered in Rhacophorid Frogs of the Western Ghats, India. Biological Journal of the Linnean Society. 114(1); 1–11. DOI: 10.1111/bij.12388 

Researchers discover for the first time that a rare bush frog breeds in bamboo