Context
Researchers have discovered a unique biological phenomenon in a freshwater crab species within the Silent Valley National Park (Kerala). This marks the first-ever reported instance of gynandromorphy within the freshwater crab family Gecarcinucidae.
1. Key Biological Term: Gynandromorphy
- Definition: A rare biological condition in which an individual organism exhibits both male and female physical characteristics on the same body.
- Mechanism: In this specific case (Vela carli), the crabs displayed male reproductive structures alongside female features, such as gonopores (genital pores in crustaceans).
- Occurrence: While documented in some marine and freshwater crustacean families, it was previously unknown in the Gecarcinucidae family.
2. The Species: Vela carli
- Status: An endemic freshwater crab.
- Habitat: Found only in the forests and streams of the Central Western Ghats.
- Behavioral Note: The specific specimens in this study were found living in tree holes.
3. Geographical Context: Silent Valley National Park
The location is a frequent subject for UPSC map-based and ecology questions.
- Location: Palakkad district, Kerala (within the Nilgiri Biosphere Reserve).
- Ecosystem: It contains some of the last undisturbed tracts of South Western Ghats mountain rain forests and tropical moist evergreen forests.
- River: The Kunthipuzha River flows through the entire length of the valley (from north to south).
- Flora/Fauna: Famous for the Lion-tailed Macaque (Endangered).
Consider the following statements:
1. Silent Valley National Park’s Kunthipuzha River provides habitat for freshwater crab species.
2. Crabs in the park play a role in nutrient cycling and ecosystem balance.
3. Lion-tailed Macaque preys extensively on crabs in the river.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Answer: A
Explanation:
The correct answer is A) 1 and 2 only.
Here is the detailed UPSC-style breakdown of the statements based on the recent findings and ecological facts:
Analysis of Statements
• Statement 1 is correct: As per the recent discovery in Silent Valley National Park, the freshwater crab species Vela carli is endemic to the streams and forests of the Central Western Ghats. The Kunthipuzha River, which flows through the entire length of the park, provides the primary perennial freshwater habitat for such species.
• Statement 2 is correct: In any forest ecosystem, especially in the Western Ghats, freshwater crabs are vital "ecosystem engineers." They assist in nutrient cycling by breaking down leaf litter and detritus. They also serve as a crucial link in the food chain, acting as prey for various birds, small mammals, and reptiles, thereby maintaining the ecological balance.
• Statement 3 is incorrect: While the Lion-tailed Macaque (LTM) is the flagship species of Silent Valley, it is primarily frugivorous (fruit-eating). Its diet consists mainly of fruits, seeds, and occasionally insects or small tree-dwelling animals. They do not "extensively prey" on riverine crabs; most of their foraging happens in the upper canopy of the rainforest, not in the river beds.
