Public Release: 

Discovery of a new mating position in frogs

An Indian night frog mates differently from all others

PeerJ

IMAGE

IMAGE: Eggs of the Bombay Night frog being eaten by a snake. view more

Credit: SD Biju

Six mating positions (amplexus modes) are known among the almost 7,000 species of frogs and toads found worldwide. However, the Bombay night frog (Nyctibatrachus humayuni), which is endemic to the Western Ghats Biodiversity hotspot of India, mates differently. In a new study, scientists have described a new (seventh) mode of amplexus -- now named as dorsal straddle.

In Bombay night frogs, the male does not embrace the female but straddles over her back with his hands holding or resting on substrates such as a leaf, branch or tree trunk. At this moment, the male appears to release sperm over the female's back and then moves away. After that, the female lays her eggs, which are then fertilised by the sperm trickling down her back. Thus there is no contact between the sexes during egg laying and fertilisation. In other frogs, females usually lay eggs during the male-female embrace (amplexus) and males simultaneously release sperms that fertilize the eggs during this process. "This is a remarkable frog with an unprecedented reproductive behavior, which is unique for a number of reasons. This discovery is fundamental for understanding the evolutionary ecology and behavior in anuran amphibians" says Prof. SD Biju from University of Delhi, who led this study.

The uniqueness of this frog does not end there. Females of the Bombay night frog call during breeding season. While males of all frogs call to attract mates, female calls are known to occur in only 25 species the worldwide. Fights between competing males are also a common occurrence among Bombay night frogs. When a male intrudes the territory of another male, a fight ensues until the intruder is forcefully made to leave. The research team also observed eggs of Bombay night frog being eaten by snake -- the first documented observation of snakes eating frog eggs in India.

Indian night frogs are an ancient group of frogs, which diversified approximately 70-80 million years ago. Among these, Bombay night frogs are predominantly stream dwelling frogs and during breeding season they can be seen calling from the ground and overhanging vegetation in large numbers, soon after sunset.

These findings were published in the journal PeerJ on June 14, 2016 by a team of scientists from University of Delhi, NCBS, Bangalore and the University of Minnesota, USA. The research was conducted over a total of 40 nights in the field between 2010 and 2012, during monsoon season in the Western Ghats.

###

Media: Zip file containing an infographic, high resolution images, the PDF of the article and a PDF of this press release: http://static.peerj.com/pressReleases/2016/2117-media.zip

Video: A video has been produced by the authors. It is viewable at https://youtu.be/0Zc8USiH1pE and will be made public when the embargo lifts. You should embed this video link into your article

PDF of this Press Release: http://static.peerj.com/pressReleases/2016/Press-Release-Willaert.pdf

Link to the Published Version of the article (quote this link in your story -- the link will ONLY work after the embargo lifts): https://peerj.com/articles/2117 -- your readers will be able to freely access this article at this URL.

Citation to the article: Willaert et al. (2016), A unique mating strategy without physical contact during fertilization in Bombay Night Frogs (Nyctibatrachus humayuni) with the description of a new form of amplexus and female call. PeerJ 4:e2117; DOI 10.7717/peerj.2117

About:

PeerJ is an Open Access publisher of peer reviewed articles, which offers researchers a lifetime publication plan, for a single low price, providing them with the ability to openly publish all future articles for free. PeerJ is based in San Francisco, CA and London, UK and can be accessed at https://peerj.com/. PeerJ's mission is to help the world efficiently publish its knowledge.

All works published in PeerJ are Open Access and published using a Creative Commons license (CC-BY 4.0). Everything is immediately available -- to read, download, redistribute, include in databases and otherwise use -- without cost to anyone, anywhere, subject only to the condition that the original authors and source are properly attributed.

PeerJ has an Editorial Board of over 1,400 respected academics, including 5 Nobel Laureates. PeerJ was the recipient of the 2013 ALPSP Award for Publishing Innovation.

PeerJ Media Resources (including logos) can be found at: https://peerj.com/about/press/

Media Contacts

For the authors:

Prof. SD Biju
Systematics Lab, Department of Environmental Studies
University of Delhi, India
Website: http://www.frogindia.org
Email: sdbiju.du@gmail.com
Telephone: +91 9871933622

For PeerJ: email: press@peerj.com , https://peerj.com/about/press/

Note: If you would like to join the PeerJ Press Release list, visit: http://bit.ly/PressList

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.