Sains Malaysiana 43(7)(2014): 973–976

A View from a Different Angle: Investigating the Significance of Rattan Spines from

a Small Mammals' Visual Point of View Using Image J

(Pandangan dari Sudut Lain: Menyelidik Signifikan Duri Rotan dari Sudut Pandangan

Visual Mamalia Kecil Menggunakan Image J)

NIK FADZLY*, ASYRAF MANSOR, RAHMAD ZAKARIA & SYED AHMAD EDZHAM

School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia

Received: 27 July 2012/Accepted: 16 September 2013

ABSTRACT

Rattans are one of the most unique and economically important plants for most tropical countries. There is however, a lack of interest in the specific study of the rattan spines. In this paper, we tested a new hypothesis concerning the functional role of rattan spines. We proposed that rattan spines also serve as a visual deterrent against herbivores or seed predators. In our proposed method we used an Imaging software, Image J, to measure the spine area of four species of rattan (Calamus insignis, Myrialepis schortechinii, Plectocomiopsis geminiflorus and Calamus caesius) from two different orientations (root to shoot and vice versa). Our results showed that rattan spines were very heterogeneous and highly variable between different species. One common trait that the rattan spines share is that spine area measurements of shoot to root (ShR) are larger than root to shoot (RH) orientation. We propose that the downwards spine angle might be specifically designed to discourage climbing leaf and seed predators.

Keywords: Anti-herbivory; Image J; rattan; seed predators; small mammals; spines

ABSTRAK

Rotan adalah tumbuhan yang mempunyai keunikan dan kepentingan daripada segi ekonomi bagi kebanyakan negara tropika. Namun begitu, kurang perhatian diberikan pada kajian duri rotan. Dalam kertas ini, kami menguji hipotesis baru mengenai fungsi peranan duri rotan. Kami mencadangkan bahawa duri rotan berfungsi sebagai penghalang visual untuk anti-herbivor atau haiwan perosak biji benih. Kami menggunakan applikasi pengimejan, ImageJ untuk mengukur luas permukaan duri bagi empat spesies rotan (Calamus insignis, Myrialepis schortechinii, Plectocomiopsis geminiflorus dan Calamus caesius) daripada dua sudut pemerhatian (dari arah akar ke pucuk dan sebaliknya). Hasil keputusan menunjukkan duri rotan adalah amat bervariasi dan berbeza bagi setiap spesies. Satu persamaan yang didapati ialah luas permukaan duri dari arah pucuk ke akar (ShR) adalah lebih luas berbanding dariakar ke pucuk (RH). Kami mencadangkan bahawa ini disebabkan oleh sudut duri rotan lebih condong ke arah bawah, kemungkinan berfungsi untuk menghalang pergerakan memanjat oleh haiwan perosak biji benih.

Kata kunci: Anti-herbivor; duri; haiwan perosak biji benih; Image J; mamalia kecil; rotan

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*Corresponding author; email: nroselnik@outlook.com