The Charles Darwin frog (Minervarya charlesdarwini), endemic to the Andaman Islands, is exhibiting unusual mating and egg-laying behaviors due to climate change. Researchers from India and the United States have observed these changes over three consecutive monsoons.
Research Findings
- Study Duration: The extensive study spanned from 2019 to 2021, encompassing three monsoon seasons.
- Behavioral Observations:
- The frogs engage in upside-down mating and egg-laying.
- They use human waste and artificial objects as breeding grounds.
Research Teams and Publication
- Collaborating Institutions: University of Delhi, Zoological Survey of India, Harvard University, and the University of Minnesota.
- Publication: The findings were published in Breviora, the journal of the Harvard Museum of Comparative Zoology.
Key Discoveries
- Inverted Position: Both male and female Charles Darwin frogs mate and lay eggs while hanging upside down on tree cavity walls, with their bodies out of the water.
- Hatchlings’ Development: Eggs hatch into tadpoles that later descend into the water.
- Breeding Sites: The frogs increasingly use artificial objects such as plastic bags and discarded containers due to habitat loss.
Conservation Implications
- Vulnerability: The Charles Darwin frog is listed as ‘vulnerable’ on the IUCN Red List.
- Habitat Loss: The shift to breeding in artificial sites is a response to the fragmentation of their natural habitats.
- Conservation Need: There is a pressing need to protect natural breeding sites and understand the long-term consequences of this behavior.
Mating Behavior and Competition
- Complex Calls: Male frogs produce three types of complex calls to attract females.
- Aggressive Behavior: Males may engage in fights, using limbs and biting, to compete for mates. These fights, though intense, rarely result in death.
Species Specifics
- Endemic Nature: The Charles Darwin frog is found exclusively in a few Andaman Islands.
- Family: Dicroglossidae, a large group with over 220 species.
- Unique Features: The observed behaviors are unprecedented and highlight the diversity of amphibian reproductive strategies.
Expert Opinions
- S. D. Biju: The upside-down spawning behavior is extraordinary and crucial for understanding the species’ survival needs.
- Sonali Garg: Urged for protection of natural breeding sites and further research into the causes and impacts of using artificial breeding sites.
- James Hanken: Emphasized the need for conservation efforts to protect the species and its specialized habitats.
Multiple-Choice Questions (MCQs):
- What unusual behavior has been observed in the Charles Darwin frog?
- A) Upside-down mating and egg-laying
- B) Mating in the water
- C) Using plants as breeding grounds
- D) Breeding in groups
- Which institutions were involved in the study of the Charles Darwin frog?
- A) University of Delhi, Zoological Survey of India, Harvard University, University of Minnesota
- B) University of Cambridge, Indian Institute of Science, MIT, University of Oxford
- C) University of Delhi, Wildlife Conservation Trust, Harvard University, University of Chicago
- D) University of Kerala, National Institute of Ecology, Harvard University, Stanford University
- Where was the study on the Charles Darwin frog published?
- A) Nature
- B) Breviora
- C) Science
- D) Journal of Herpetology
- Why are the Charles Darwin frogs using artificial objects for breeding?
- A) Due to increased food supply
- B) Due to habitat loss and fragmentation
- C) Because of predator presence
- D) Due to higher temperatures
- What is a unique feature of the Charles Darwin frog’s mating behavior?
- A) It mates in groups
- B) It uses vocalizations to attract mates
- C) It mates while hanging upside down
- D) It lays eggs in tree canopies