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BIOLOGY
The weird and wonderful world of frogs
Indraneil Das and Pui Yong Min out frog 'hunting'
Masters of Survival Broadly speaking, a species’ life history (or life cycle) refers to the schedule and duration of key events during its life. Natural selection influences individuals from conception to death. By understanding how organisms successfully cope with their environment, it is possible to build up a picture of the evolutionary and ecological basis for everything, from the way a frog looks to how it behaves.
Take for example, tiny Microhyla nepenthicola. It is named after a species of plant, Nepenthes ampullaria, because the frogs attach their eggs to the inside of the plant’s pitchershaped leaves. The plant has retained its ability to capture, kill and partially digest insects, but has moved away from carnivory towards a diet based on leaf litter and other organic matter. Nevertheless, it will still Nepenthes ampullaria consume insects such as ants by digesting them in liquid filled sacks. So how do newly hatched frogs survive? The tadpoles are unharmed by the plant’s digestive liquid and the froglets’ tiny feet are specially adapted to help them climb up the pitcher’s slippery interior. Thus, the plant serves as a protective barrier against animals or birds that would otherwise prey on the tadpoles. By understanding how this tiny frog interacts with its environment, how it breeds, where it lives and what it eats, researchers are also in a better position to protect such species in future. Species do not thrive in isolation. Trying to ‘save the tiger’ without consideration for the forest it lives in is as futile as trying to grow plants without water. The same is true for this tiny frog. Marrying culture and conservation To find out more on this issue, UNIMAS researchers have been investigating human attitudes towards amphibians in various indigenous societies, and examining the effect on amphibian conservation. Information was gathered from several sources, including cultural artifacts, ancient texts documenting folklore, beliefs and taboos, the uses of amphibians for biological control, food and medicine and their representation in advertisements, models, toys and other products. Many cultures respect frogs and other amphibians for their role in controlling insect populations. This has been recognised in China since ancient times. A Sung Dynasty edict (1250 AD) prohibited the capture or killing of frogs, because of their value as insect killers. Today restrictions still apply to certain species. In China, for example, Nanorana boulengeri males may be captured but collection of females is not allowed. Local restrictions on the harvest of frogs have also been placed in Laos, in response to noticeable decline in populations of Hoplobatrachus rugulosus.
NepGrower
Universiti Malaysia Sarawak’s (UNIMAS) Institute of Biodiversity and Environmental Conservation has a long tradition in herpetology, the study of amphibians and reptiles. ResearchSEA spoke to Prof. Indraneil Das to find out about recent discoveries of new species, frog ‘hunting’ and the interaction between frogs and humans. “Right now my table is full of bottles filled with unknown species that have yet to be identified,” says Prof. Das. His humble nature and down-to-earth fieldwork ethic is refreshing in a time when many scientific disciplines are focused on the ‘high tech’. With enthusiasm he explains that the great thing about biology is that you only need a pencil and a note book to make a start. This approach continues to serve him well: he recently re-discovered a species last seen in the 1920’s (see p. 9). Then in 2004, Prof. Das and Alexander Haas, from the University of Hamburg in Germany, discovered one of the world’s smallest frogs, Microhyla nepenthicola. Male adults of this species grow to less than one centimetre in length. “But,” says Prof. Das, “just describing species is so protracted; it’s not very interesting. I am much more interested in learning about species’ life history.”