MAR 2020  
Special Report
Faithful Fathers and Crooked Cannibals

Raorchestes chalazodes is an arboreal frog that was presumed extinct and is currently listed as critically endangered. The frog is found in a narrow region of the southern Western Ghats restricted to elevations 1200 m above sea level. K. S. Seshadri and David Bickford in their article ‘Faithful fathers and crooked cannibals: the adaptive significance of parental care in the bush frog Raorchestes chalazodes, Western Ghats, India’ discuss about R. chalazodes  and the parental care given by adult males.  The discovery of a novel reproductive mode in the white-spotted bush frog (R. chalazodes) from the Western Ghats biodiversity hotspot of peninsular India has been an exciting revelation.

K.S. Seshadri speaks about the adaptive significance of parental care in bush frog (R. chalazodes) found in Western Ghats, India. He spoke about his work and the difficulties he encountered while doing field research. Seshadri said “This work was undertaken in the remote forests of the Kalakad Mundanthurai Tiger Reserve near Tirunelveli in Tamil Nadu. The reason was that the bush frogs are found there. It was challenging because the place is remote, it takes about a half a day’s journey to reach a good hospital, there is only one place to eat, and there are no means of transport. The frogs being active at night, we had to start looking for them in the evenings. On numerous instances, we have walked into leopards and elephants and even snakes. Working in the bamboo habitat is risky and if you slip you can fall into a stream or hurt yourself by falling on bamboo stalks, which are sharp as spears when cut or broken”.

Seshadri added that finding the frogs was very difficult. The frogs sit inside bamboo internodes and the scientists had to use an endoscope to look inside and record behaviour. “All this was quite a task at night with rains and wildlife all around us,”he said.  

On asking Seshadri about how he got interested in frogs, he says, “The story of this goes many years back. When I first saw these frogs in 2011, I became excited and wanted to study frogs in general. I began observing R. chalazodes. A couple of years later, I came to know that they breed inside bamboo and began watching their behaviour more seriously. One night, I, my former boss Dr Ganesh T., and a colleague Prashanth M.B. were going into the field, when we stopped by to check on the bamboo frog. We walked into a clump of bamboo, trying to locate the call of this frog. We saw a frog near the entrance of a cavity, on a bamboo stalk. We stood there in silence, looking at the frog and the frog decided to wriggle and squeeze into the bamboo stalk, via a small opening. This was really a struggle for it. On seeing this, we became super excited and began wondering about why these frogs go inside a bamboo and call. Later that night, Ganesh and I again discussed about this behaviour and that is when we realized that a lot of ecology and natural history work can be done on R. chalazodes.” Later, Seshadri went to the National University of Singapore to do his doctorate and there his supervisor David Patrick Bickford, co-author of the paper, helped him mould his ideas into the framework of evolutionary ecology and write about his findings. 

On asking the reason for choosing R. chalazodes and what sparked his interest, Seshadri says, “It was the eyes! Look how beautiful they are. We also pretty much know nothing about most frogs. This one was charismatic, and had a unique behaviour of breeding inside bamboo. That’s what intrigued and drove me to pick this species.” 

Parental Care Behaviour of Frogs

Scientists have identified eight distinct modes of parental care behaviour among frogs. These are: egg care, transport, and brooding; tadpole care, transport, brooding, and feeding; and froglet transport. The type of parental care in frogs is often correlated with ecological factors, such as the process of laying eggs in small waterbodies and accompanied by life history traits such as deposition of few but large-sized eggs, which undergo direct development, skipping the traditional tadpole stage. 

Adult males of this species care for the eggs deposited within the hollow internodes of Ochlandra travancorica bamboo species. The frogs enter the internodes via narrow openings made by the rodents. The scientists revealed that the males are usually smaller in snout vent length compared to females and have vocal sac. To attract females, the males vocalize on leaves and also inside the hollow internodes. The females deposit a few, large direct developing eggs near the upper end of the internode. Occasionally, water accumulates in the lower part of the internode. 

The Western Ghats- the Hotspot of Biodiversity

The Western Ghats are older than the Himalayas. Covering an area of around 140,000 km2 in a 1600 km long stretch, it has an exceptionally high level of biodiversity The Kalakad Mundanthurai Tiger Reserve (KMTR) is located in the southern-most tip of this mountain chain and located within the Agastyamalai Biosphere Reserve. The region receives a mean annual rainfall of ~3000 mm per year, from two distinct monsoon seasons, June–September and October–January. Observations and experiments on R. chalazodes were made along the headwaters of river Manimuthar.

Locating the Frogs

The researchers located the frogs inside bamboo internodes via audio-visual encounter surveys.  They used pipe inspection cameras/endoscopes to observe them. The cameras could record videos as well as capture photographs. The researchers were able to locate, mark, and monitor 43 egg clutches from an adult R. chalazodes. Once every 24 hours the internodes were inspected.  The endoscope was inserted slowly and carefully within 5 cm from an adult frog or eggs. 

To reduce any disturbance and to avoid disturbing the frog or injuring the eggs, the scientists completed each observation within 10 minutes. Each endoscope insertion consisted of recording the presence and activity of adult male or female, the number of eggs, incidence of predation, the egg stage, the behaviour of adult frog(s), the number of froglets, and the response of adult male frogs. The photograph number was also noted. As the low resolution of the photographs and videos hindered detailed staging of egg development, the developmental stages of eggs were classified into four broad categories and the duration of each developmental stage was determined from daily observations and photographs. 

Observations continued until all froglets and the attending male left the site or until all eggs died. Manipulation experiments were performed in-situ using 26 sites comprising 32 egg clutches. In 13 sites adult male were chosen as controls and left undisturbed, and in another set of 13 clutches, the adult male was removed carefully by gently nudging it out of the internode with the endoscope. This procedure lasted 10–20 minutes and did not physically harm the frog. 

Adult male- the Sole Caregiver

The scientists observed parental care behaviour and established that the adult male to be the sole caregiver. Adult male removal experiments were then carried out at all 26 sites, containing 32 egg clutches. Predation was the primary driver of egg mortality, and 83% of all mortality occurred when the eggs were unattended. Of 11 clutches experiencing egg mortality, predation alone accounted for all mortality in 5, a combination of predation and other drivers (desiccation, fungal infections, flies, and unknown causes) accounted for mortality in 4, and other reasons, accounted for mortality in the remaining 2 clutches. Predation comprised egg cannibalism by males of the same species, ants, and a combination of egg parasitism by flies and by ants. 

From the study it was established that adult male R. chalazodes are the sole caregiver. The adult male possesses a range of behaviours predominated by egg attendance and guarding. The study also established that offspring survival drastically decreases without parental care. A major cause of mortality was egg cannibalism by other males. Unattended eggs also died because of predation by ants, parisitation by flies, and other reasons but this was minimal and often occurred only after the unattended eggs were partly cannibalized. Egg cannibalism is the first such report among members of the tree frog family Rhacophoridae.

Harvesting bamboo stalks of large diameter, which coincides with the breeding season of R. chalazodes lasting 4–6 months can exterminate populations. This critically endangered frog needs to be conserved and the first step is mapping its distribution and identifying threatened areas outside of the protected area network. Some of the steps suggested by Seshadri and Bickford towards conserving this frog and its habitat, will be not harvesting bamboo with internodes of larger diameter, stopping harvesting activities when the frogs are breeding (from May until November), and creating artificial egg laying sites.

The findings presented by the researchers have added to the growing body of evidence which demonstrates the importance of parental care behaviour in enhancing offspring survival across similar species. For further studies on parental care evolution R. chalazodes will serve to be an ideal system. It would also help in evaluating the effectiveness of anti-predatory defence mechanisms and identify motivations for cannibalistic behaviour.

Not for the Faint-hearted

As most of the research was done by the scientists at night, they experienced some nail biting moments. Seshadri recounted about encountering wildlife while sampling at night. “We once startled a flying squirrel that was feeding on top of a tall tree,”he remembered. “Another time we walked into a leopard on our way to the sampling site. We also encountered uncommon birds like the Scops owl. The best was when my colleagues ran into an elephant and spent a few hours hiding under a bridge,”revealed Seshadri, which obviously makes the work of a scientist not for the faint hearted. 

Dr Marianne Furtado de Nazareth is a full-time freelance journalist, who writes on a variety of environmental and gender issues. In 2016, she won the Laadli Media Award for Print Journalism for Gender Sensitivity.

© TERI 2020

Nominations open for CSP Today India awards 2013

The inaugural CSP Today India awards ceremony takes place on March 12, and CSP developers, EPCs, suppliers and technology providers can now be nominated.

CSP has made tremendous progress since the announcement of the Jawaharlal Nehru National Solar Mission in 2010. With Phase I projects now drawing closer to completion, the first milestone in India’s CSP learning curve is drawing closer. CSP Today has chosen the next CSP Today India conference (12-13 March, New Delhi) as the time for the industry to reflect upon its progress and celebrate its first achievements.

At the awards ceremony, industry leaders will be recognized for their achievements in one of 4 categories: CSP India Developer Award, CSP India Engineering Performance Award, CSP India Technology and Supplier Award, and the prestigious CSP India Personality of the Year.

Matt Carr, Global Events Director at CSP Today, said at the opening of nominations that “CSP Today are excited to launch these esteemed awards, which will enhance the reputation of their recipients. I am particularly excited to launch the CSP India Personality of the Year award, a distinguished honor for the industry figure deemed worthy by their peers.”

All eyes will be on the CSP Today India 2013 Awards when nomination entry closes on February 4 and the finalists are announced on February 11. The awards are open to all industry stakeholders to nominate until February 4 at or by e-mail to [email protected]

Matt Carr
+44 (0) 20 7375 7248
[email protected]