Notes on the Biology of the Green Tree Skink Lamprolepis smaragdina philippinica (Scincidae) in Siquijor Island, Philippines Observations on the biology of the Green Tree Skink Lamprolepis smaragdina were conducted in Siquijor Island, Philippines. Morphological features such as body proportions, scale counts, and coloration of the population in Siquijor were contrasted with those from neighboring population on Negros Island. The population density of the species was also determined. Incidental observations on the foraging behavior are also presented. Keywords: biology, behavior, Lamprolepis smaragdina, skink, Siquijor Authors: Abner A. Bucol Silliman University Angelo King Center for Researchand Environmental Management Jocelyn Elise Basa Biology Department Silliman University Michael Lawton R. Alcala Biology Department Silliman University Irish Sequihod St. Paul University Dumaguete City Rosalina Catid Siquijor State College Larena Albert Pagente Siquijor State College Larena Will Kilat Siquijor State College Larena Introduction The Green Tree Skink Lamprolepis smaragdina philippinica Mertens, 1929 is widely distributed from Taiwan and the Philippines southward and eastward, through the Indo-Australian Archipelago, to northern Australia (Cape York), the Solomon Islands, Santa Cruz Islands, and to easternmost parts of Micronesia (Brown & Alcala, 1980; Perry & Buden, 1999; Iskandar & Erdelen, 2006; Linkem et al., In Press). The species is characterized by having only the head and anterior part of the body green and the rest of the body brown (Brown & Alcala, 1980; Brown et al., 1996). However, some of its populations in small islands like in Micronesia (Perry & Buden, 1999), Caluya Island (Siler & Linkhem, 2011) and Siquijor (this study) in the Philippines are generally green with black blotches on dorsum while the brown or rufous region is limited only in the proximal dorsal portion of hind limbs. Methods and Materials On several occasions, we made several opportunistic observations on the biology of Lamprolepis smaragdina in Siquijor (Figure 1) on the following dates: 15-20 February, 18-20 March, 05-08 April, 15-16 May, 20-21 June, and 16 July, 2011. In addition, short-term observations of the species in other islands such as in Luzon (15 May 2009), Negros (July, August, September 2009), Panay and associated smaller islands of Gigantes (15 December 2009) and off Carles, Nasidman and Calbazas off Ajuy (12 May 2010) made by the first author were also noted. Preserved specimens at the Silliman University-Rodolfo Gonzales Museum of Natural History (SU-RBG) were also examined. Results and Discussion Morphological Variations In most regions within the Philippines, the species is characterized by having only the head and anterior part of the body green and the rest of the body brown (Brown & Alcala, 1980; Brown et al., 1996). The color pattern of the population in Negros appeared consistent in other populations such as in Luzon, Mindanao, Panay and associated islets except in Caluya (see photos by C.D. Siler in Herpwatch.org). The population in Siquijor has generally green body with black longitudinal streaks forming obscure blotches on dorsum while the brown or rufous region is limited only in the proximal dorsal portion of hind limbs. A summary of the morphometric features of the skink is presented in Table 1. Compared with the available specimens of the neighboring population in Negros Island, the Siquijor population appears to have [1] higher SVL measurements (76-105mm vs. 83mm SVL); [2] higher dorsal (48-51 vs. 42-44) and ventral scale counts (52-59 vs. 51); and [3] color (predominantly green vs. generally brownish). These characteristics were consistent in both juvenile and adult stages of the two populations. The overall green coloration of isolated population in Siquijor Island (Figure 2) has been documented elsewhere such in Micronesia (Perry & Buden, 1999) and Indonesia (Iskandar & Erdelen, 2006). This case might e att i uted to fou de effe t as suggested Pe and Buden (1999). It should be noted that Siquijor Island has been isolated from the rest of the Visayan Ice-age Islands (also known as the Visayan Pleistocene Aggregate Island Complex by other authors) during the last glacial maxima (Brown et al., 2001, 2008). A molecular phylogenetic study of the L. smaragdina by Linkhem et al. (In Press) revealed that the population in Siquijor is more affiliated to the populations in Camiguin Sur and Palawan and not of the Negros and neighboring islands like Bohol. Aside from L. smaragdina, another lizard (Draco spilopterus) has been known to exhibit slight morphological variation in Siquijor (e.g., color differences; McGuire & Alcala, 2000; McGuire & Heang, 2001). Habits and Behavior The species is generally arboreal but may reach the ground and nearby man-made structures when foraging (Reyes, 1957; Brown & Alcala, 1980; Buden, 2000). The species was often encountered foraging on trees, especially near colonies of ants and termites. It was also seen in mangroves, probably feeding on insects. In one occasion, it was seen feeding on the flying lizard (Draco spilopterus) in Siquijor (E. Basa and M.L.R. Alcala, pers. obsrv.). Sightings of active L. smaragdina (presumed foraging) were usually between 09h00-14h00, with ambient temperatures ranging from 26-30°C. The skinks were not observed during heavy downpour of rain. Skinks were also seen basking about 30 minutes after a short duration of rain had completely stopped. Population Density In a coconut plantation (with an area of 0.5 ha) in Lazi, Siquijor, we counted 22 individuals, thus the spe ies’ e t apolated populatio density would be 44 individuals/hectare in that area alone. It appears that the density of the green skink is dependent on the availability of trees. This species is most frequently observed in coconut plantations a ou d “i uijo ’s heavil populated oastal areas. It is interesting to note the significant decline (from about 1,500 individuals in the early 1960s to about 10 individuals in 2010) in the population of L. smaragdina in Silliman University Campus where A.C. Alcala monitored the population of L. smaragdina for at least three years (1962-1965). Although the number of rain trees (Samanea saman) is more or less the same as it was in the 1960s, it is possible that the ski k’s food items (mainly Lepidoptera, Coleoptera and Hymenoptera) may have declined as a result of recent developments such as contruction of new concrete buildings. Another potential easo fo the spe ies’ population decline is that more skinks may have been sacrificed for classroom studies (as initiated earlier by Reyes, 1957). These possibilities, however, needs further quantitative investigations. Conclusions and Recommendations The above findings highlight the need to conduct a more detailed study on the biology of the green skink L. smaragdina in Siquijor Island. There is also a need to monitor the population of this arboreal skink e ause ost of “i uijo ’s fo ests have ee o ve ted to ope agricultural lands, mainly for corn and cassava. Acknowledgments We wish to thank the Commission on Higher Education (CHED) through its Grant- In-Aid (GIA) Program for fu di g the esea h p oje t A Assess e t of “eño a River in Lazi, Siquijor, in terms of its Biodiversity and Socio-economic Condition of the I ha ita ts alo g the Rive Ba k i ple e ted “i uijo “tate College. Dr. Angel C. Alcala and Dr. Orencio D. Lachica were instrumental in conceptualizing the project. Dr. Rafe M. Brown (University of Kansas, USA) provided useful comments on an earlier draft of this manuscript. REFERENCES Alcala, A.C. (1966). Populations of three tropical lizards on Negros Islands, Philippines. Dissertation. Stanford University. 269p. Brown, W. C. & Alcala, A.C. (1980). Philippine lizards of the family Scincidae. Silliman University Natural Sciences Series No. 2. Dumaguete City, Philippines: Silliman University Press. Brown, R. M., Ferner, J.W., Sison, R.V., Gonzales, P.C., & Kennedy, R.S. (1996). 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Herpetological Review, 42, 605. Materials Examined Lamprolepis smaragdina philippinica SIQUIJOR ISLAND (1 specimen), Siquijor, Caticugan, coll: A. Bucol, L. Averia, and M.L.R. Alcala; 7 August 2010; (7 specimens); Lazi town; coll: A. Bucol, M.L.R. Alcala, E. Basa, I. Sequihod, and R. Catid; 1 July 2011. NEGROS ISLAND, Damsite, Murcia, Negros Occidental; coll: Bago River Project Team; 12 February 2010; 1 specimen.