Projects

Frog Legs: They're not just for eating!

Liu Cindy Jing1, Susanto Dwi2, Kwek Yan Chong3 and Wijayathilaka Nayana4

Frogs' unusual morphology has been suggested to be specially adapted for their jumping mode of locomotion; this study attempts to address that issue by determining which body segment length correlates best with jump distance. Thirty-three individuals from nine species and two families were captured at the stream along the Latak Waterfall trail of Lambir Hills National Park in Sarawak, Malaysia. Mean jump distances and various body segment lengths were recorded and ratios of these measurements relative to body size were calculated. Correlation and ordination analyses were then carried out using the statistical software R. No significant correlations were found between the various body segment length ratios and the mean jump distance; however, the ordination plot appears to hint at partitioning of jumping ability and morphology according to the habitats in which certain species were commonly found.

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Clustering Behavior of Black Urchins

Wijayathilaka Nayana, Eni Hidayati, Nur Edna Hasreena Ahlun, Jovina Jowinis, and Alessandra Markos

The nocturnal and clustering behavior of black sea urchin (Diadema setosum) are believed to be defense mechanisms for avoiding fish predators. We studied the colony size of Diadema setosum between two reef habitats at Malohom Bay, Pulau Gaya, Sabah. A line transect of 20 m by 5 m along the shore line with two replicates was laid on fore reef and crest, and the number of sea urchin per colony was recorded. The results shows that there is a significant bigger aggregation of Diadema setosum in the fore reef zone than the crest zone. This behavior probably acts as a defense mechanism during sleeping to avoid predators. When they form a colony and stay close to each other, their spikes act like a fortress protecting their delicate parts. Colonization makes it harder for predators to flip them. Aside from predators threat, the bigger size in the fore reef probably because the fore reef provides more space for aggregations.

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Intraspecific and Interspecific Competition for Breeding Site among Three Species of Libellulidae in Maliau Basin

Wulan Pusparini1, Nayana Wijayathilaka2, and Nur Edna Hasreena Ahlun3

A study on competitive behavior among three dragonfly species (Neurothermis ramburri, Orthetrum chrysis and Tyriobapta torrida) was conducted along the trail to Belian Camp in the Maliau Basin Conservation Area. Two sampling sites were set up to observe the the perching behavior of the dragonflies. From general observations, it is known that all three species of dragonflies exhibit a more aggressive behavior to intraspecific competition compared to interspecific competition. A map of the dragonflies' perching site was modeled based on the observation done. There was no significant difference in flying and chasing behavior between the three dragonfly species. However, there was a significant difference in the time spent perching between the three species with Orthetrum chrysis being the species that spends most time perching as compared to the other two. The study also shows that the dragonflies exhibit a more aggressive intraspecific competition behavior compared to interspecific competition. Due to this, all three species co-exist in the same water body, not competing with each other for breeding group, but competing among the member of their own species.

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email- nayanata@gmail.com | Tel- 0094 713 284804 | Web- Srilankabutterflies.com

Nayana Wijetilaka, Department of Zoology, University of Peradeniya, Sri Lanka
2008