The Life History, Population and Feeding Biology of Two Paddy Field Frogs, Rana Cancrivora GraVenhorst and R. Limnocharis Boie, in Malaysia

Jaafar, Ibrahim (1995) The Life History, Population and Feeding Biology of Two Paddy Field Frogs, Rana Cancrivora GraVenhorst and R. Limnocharis Boie, in Malaysia. PhD thesis, Universiti Pertanian Malaysia.

[img] PDF
1866Kb

Abstract

The life history, population and feeding biology of two species of frogs (R. cancrivora and R. limnocharis) were studied from April 1992 through September 1993 in the rice growing district of Tanjung Karang, Selangor, Malaysia. The results showed that the breeding periods of the two frogs were correlated with the irrigation phase of the rice growing seasons and were not correlated with the rainfall. The frogs were also found to have two breeding peaks annually as opposed to a single peak for the same species in other localities. Comparison of the life history aspects of the two species showed that R. cancrivora females produced more, and larger sized, eggs than R. limnocharis females. This then produced a chain effect whereby R. cancrivora larvae developed faster and metamorphosed at a larger size than those of R. limnocharis, and then continued to grow at a faster rate, attained a larger size and reached sexual maturity earlier. These factors most probably contributed to the observed disparity i n population size between these two frogs wherein R. cancrivora is about six times more numerous than R. limnocharis. The fact that adults of these two species differ in size is also the main reason as to why they can coexist in the same habitat. Different body sizes allow them to ingest different sized prey items, as was discovered by analysis of their diets, thus avoiding competition for food. Survivor ships from eggs to metamorphosis for both species are low but normal for lentic-water breeding amphibians, and they are deemed sufficient to maintain the population levels if human interference can be substantially reduced. Fluctuations in the population structure are mainly due to recruitment, natural mortality and human interference. The most important food items for both species are insects and about 80% of these insects are pests of rice. Hence these frogs are considered very important biological control organisms in the paddy field habitat.

Item Type:Thesis (PhD)
Subject:Frog culture - Malaysia
Subject:Frog populations - Malaysia
Chairman Supervisor:Dr. Ahmad Ismail
Call Number:FSAS 1995 9
Faculty or Institute:Faculty of Environmental Studies
ID Code:8601
Deposited By: Nurul Hayatie Hashim
Deposited On:03 Dec 2010 03:52
Last Modified:11 Jun 2012 07:14

Repository Staff Only: item control page


Universiti Putra Malaysia Institutional Repository

Universiti Putra Malaysia Institutional Repository is an on-line digital archive that serves as a central collection and storage of scientific information and research at the Universiti Putra Malaysia.

Currently, the collections deposited in the IR consists of Master and PhD theses, Master and PhD Project Report, Journal Articles, Journal Bulletins, Conference Papers, UPM News, Newspaper Cuttings, Patents and Inaugural Lectures.

As the policy of the university does not permit users to view thesis in full text, access is only given to the first 24 pages only.