Polypedates leucomystax (Four-lined Tree Frog) is a moderate to large-sized frog, with a snout-vent length (SVL) reaching 50 mm in males and 75 mm in females (Berry, 1975; Inger and Stuebing, 1989; Grismer, 2011). This commensal species is distributed throughout Bangladesh, Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Singapore, Thailand and Vietnam (IUCN, 2014). In Peninsular Malaysia, P. leucomystax is a commonly encountered frog, occupying many habitat types, but can be found most frequently around human habitations in both urban and rural areas (Berry, 1975; Ibrahim et al., 2008; IUCN, 2014). It has been documented from several forested areas on the peninsula including Bubu Forest, Perak (Ibrahim et al., 2011), Bukit Fraser, Pahang (Norhayati et al., 2011), Bukit Hijau, Kedah (Shahriza et al., 2011), Peta Endau-Rompin, Johor (Shahriza et al., 2012), Bukit Larut, Perak (Shahriza and Ibrahim, 2014a) and Ulu Paip, Kedah (Shahriza and Ibrahim, 2014b).

Frogs represent a principal dietary component for many predators including eagles, owls and snakes. At least 30 categories of defensive behaviours have been described, which frogs use to protect themselves from potential predators (e.g. remaining motionless, death feigning, reducing exposed surfaces by crouching or contracting the body, body raising, stiff-legged and unken reflex) (Duellman and Trueb, 1986; Toledo et al., 2011). The most commonly employed defensive strategies among mobile animals, including the frogs, are to remain motionless or to flee from potential predators (Toledo et al., 2011). Thanatosis (death

feigning) behaviour, in which a frog adopts a posture that gives it the appearance of being dead, is common among non-toxic species. This posture will inhibit or divert the attack of a potential predator (Toledo et al., 2010). Through reported for other anuran species (Shahriza, 2014a,b), thanatosis has not previously been documented in P. leucomystax. Herein we provide the first record of thanatosis and two additional defensive behaviours (body flattening and semi-contracting) in P. leucomystax.

On 14 June 2014, between 2030 and 2130 hours, five adult males of P. leucomystax (Fig. 1) were collected from Sungai Sedim Recreational Forest, Kedah, Malaysia (5º25’N, 100º46’E; elev. approximately 125 m asl). Three of the specimens were captured while actively calling from vegetation (approximately 1 m above ground), overhanging a rock pool at the edge of the river. Two additional specimens were collected on

Herpetology Notes, volume 9: 163-165 (2016) (published online on 24 August 2016)

Defensive strategies of Polypedates leucomystax (Gravenhorst, 1829) (Anura: Rhacophoridae) from Peninsular Malaysia

Shahriza Shahrudin

School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Penang Malaysia

Author e-mail: shahriza20@yahoo.comFigure 1. An adult male P. leucomystax from Sungai Sedim, Kedah, Malaysia.

Shahriza Shahrudin164

the ground, near a shallow pool (1 m x 2 m x 0.15 m) in an open area, approximately 6 to 8 m from the main river. All specimens were brought to the laboratory, where SVL and weight (W) were recorded using digital callipers and electronic balance, respectively. Subsequent to this study, all specimens (14USM-SS-PL01, 02, 03, 04, 05) were euthanized, fixed with 10% formalin, transferred to 70% ethanol and were deposited at School of Pharmacy, Universiti Sains Malaysia (USM).

When approached or handled, three individuals displayed several types of defensive postures including

death feigning, body flattening and semi-contraction. The other two individuals did not show any defensive behaviour. The defensive behaviours of three specimens are described below:

Specimen A (14USM-SS-PL01; male; 47 mm SVL, 8 g): When approached, the specimen attempted to flee by leaping in an erratic pattern. When recaptured and placed on dry leaves (to be photographed), the frog turned upside down (venter up) and inflated its body with air. Fore limbs were raised upward and hind limbs were held close to the body. It remained in this stationary position with both eyes open for approximately 2 minutes (Fig. 2). Subsequently the frog resumed a normal posture and proceeded to crawl under the dead leaves to hide.

Specimen B (14USM-SS-PL02; male; 48 mm SVL, 8 g): When approached, the specimen lept away and then began to crawl beneath dead leaves in an attempt to hide. Leaves were removed slowly in an effort to recapture the frog. When uncovered, the frog remained stationary with chin, belly and limbs flattened and touching the substrate. Fore and hind limbs were tucked close to the body, and the specimen remained motionless in this position for approximately 3 minutes with both eyes open (Fig.3). Subsequently, the frog resumed a normal posture and lept away.

Specimen C (14USM-SS-PL03; male; 45 mm SVL, 7 g): When transferred from the vivarium to the dead leaf substrate, the frog made several attempts to flee during a three to four minute period by leaping away in an erratic pattern. When approached again, the frog assumed an inverted position (venter up) and remained

Figure 2. Death feigning behaviour of P. leucomystax.

Figure 4. Semi-contraction behaviour of P. leucomystax

Figure 3. Body flattening behaviour of P. leucomystax.

motionless for approximately 2 minutes. The specimen then flexed its head ventrally with both eyes open. Limbs were adpressed to body with palmar and plantar surfaces and webbing exposed (Fig. 4). Then the frog resumed a normal posture and proceeded to crawl under dead leaves to hide. We consider this behaviour a type of semi-contracted posture because the digits of manus and pes were not fully adpressed.

From these observations, it is evident that P. leucomystax possesses a suite of strategies and postures that are used to avoid potential predators. Further studies are needed to determine under which circumstances and against which kind of predator the different strategies are exerted, and whether additional defensive strategies are employed by this species.

Acknowledgements. I wish to express my heartfelt gratitude to Universiti Sains Malaysia, Penang for the facilities and amenities provided. This manuscript was greatly improved by comments and suggestions from David S. McLeod as a pre-reviewer. This research project was funded by Universiti Sains Malaysia, Short Term Grant (304/PFARMASI/6312127).

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Defensive strategies of Polypedates leucomystax from Peninsular Malaysia 165

Accepted by Maximilian Dehling