Lambir gecko project (proposal)
From BiodivBorneo09
Sexual-Size Dimorphism And Weight–Length Relationships In Two Species Of Gecko From Lambir, Malaysia
Sreekar R, Ridwan Abdul Rahman, and Agri Rachmayuningtyas
Contents |
Introduction
Within reptiles, body size is an important life history trait that influences microhabitat type, diet, vulnerability to predators and reproductive success (Lobo et al., 2004). Weight-to-length relationships have been documented in many species of snakes (Kaufman and Gibbons, 1975; Guyer and Donnelly, 1990; Das, 1991; Lobo et al., 2004). In two thirds of the snake species for which data are available, female snakes grow longer and consequently weigh more than males (Shine, 1993).
There have been very little study done on the weight-length relationships and morphometric patterns in lizards and it is not clearly known if the information obtained from snakes applies to all the reptiles. Here we take an opportunity to study two allopatric species of gecko, Hemidactylus frenatus and Cyrtodactylus pubisulcus to obtain the correlation of the snout-vent length to the weight, tail length and axil to groin distance along with notes on sexual size dimorphisms (SSD) and life history. We believe that these ratios differ between sexes and between Hemidactylus and Cyrtodactylus.
Questions
- What are the relationships between snout-vent length to the weight, tail length and axil to groin distance in Cyrtodactylus pubisulcus and Hemidactylus frenatus?
- Does these relationships vary among these two allopatric gecko species?
Methods
Geckos will be examined between 12 Jun 2009 to 18 Jun 2009 at six different sites in the forest and on the edges. Snout to vent length (SVL), tail length (TaL), axilla-groin distance (A-G) and weight (W) will be measured using a measuring tape (in mm) and a pesola weighing scale (in gm). The geckos will be measured within 5 minutes at the site of capture and released at the same location.
The scatter plot will be used to depict the relationship between TaL, A-G and W to SVL in the opposite sexes within the species. A t-test will be employed to test the variations among sexes. The Sexual Size Dimorphism (SSD) is used to measure the degree of sex difference in body size by dividing the mean size of the larger sex by the mean size of the smaller sex.
References
- Das, I. (1991). Morphometrics of Eryx conicus (Schneider) at a locality in south India (Squamata: Boidae). Hamadryad, 16(1&2): 21-24.
- Guyer, C. and M. A. Donnelly (1990). Length-mass relationships among an assemblage of tropical snakes in Costa Rica. Journal of Tropical Ecology, 6: 65-76.
- Kaufman, G. A. and J. W. Gibbons (1975). Weight–length relationships in thirteen species of snakes in the southern united states. Herpetologica, 31: 31-37.
- Lobo, A., B. Pandav and Karthikeyan Vasudevan (2004). Weight-length relationships in two species of marine snakes along the coast of Goa, Western India. Hamadryad, 29(1): 89-93.
- Shine, R. (1993). Sexual dimorphism in snakes. In: Snakes- ecology and behavior. pp: 49-86. R. A. Siegel & J. T. Collins (Eds). McGraw-Hill Inc., New York.
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