Goldberg, Stephen R.

Huang, Shao-Chang

Mao, Jean-Jay

Norval, Gerrut

University of Queensland eSpace

An understanding of the natural history and ecology of 
reptile and amphibian species is essential for successful 
conservation and management programs (Bury, 2006). A 
crucial part of the natural history of an animal is its diet, 
because not only does it reveal the source of the animal’s 
energy for growth, maintenance, and/or reproduction 
(Dunham, Grant and Overall, 1989; Zug et al., 2001), it 
also indicates part of the ecological roles of the animal. 
Since there may be temporal and spatial variations 
in the diet of a species (e.g. Lahti and Beck, 2008; 
Rodríguez et al., 2008; Goodyear and Pianka, 2011), 
there is a need for dietary descriptions from different 
localities. For this reason, observations made on an ad 
hoc basis and descriptions from small collections can be 
instrumental in developing a better understanding of the 
diet of a species. Herein, we describe the dietary items 
of six lizards that died when they were accidentally 
collected in 2003 by pitfall traps that were set as part 
of an ecological study in Yangmingshan National Park, 
northern Taiwan. We also incorporate and describe the 
dietary items of three DOR (dead on road) specimens 
of the scincid, Eutropis longicaudata, collected on an 
ad hoc basis, from tarred roads in an agricultural area 
of Santzepu, Sheishan District, Chiayi County, south-
western Taiwan.
The lizards were treated as follows; the snout-vent 
length (SVL) and tail length (TL) were measured to the 
nearest mm with a transparent plastic ruler; and the tail 
was scored as complete or broken. The E. longicaudata 
were weighed (body mass) to the nearest 0.1g with a 
digital scale, but since the specimens from northern 
Taiwan were partially dissected and not intact, their 
body masses were not recorded. All the lizards were 
dissected by making a mid-ventral incision, and the 
stomach was removed and slit longitudinally, after 
which the stomach content was removed. The stomach 
contents were spread in a petri dish and examined under 
a dissection microscope, and all the prey items were 
identified to the order level and, if possible, to family 
or species level. 
Three Japalura polygonata xanthostoma (Agamidae), 
were examined. Two were females, and both had a SVL 
of 58 mm, but one had a TL of 115 mm, while that of 
the other was 104 mm. The sex of the third specimen 
was not determined. It had a SVL of 39 mm and a TL of 
70 mm. On the 29th of March, 2002, we collected an E. 
longicaudata male, with a SVL of 109 mm, TL of 174 
mm, and body mass of 30.2 g (the exact locality was not 
recorded), and on the 18th of March, 2003, we collected 
another male (at 23º25’47”N, 120º28’52”E; datum: 
Herpetology Notes, volume 5: 453-456 (2012) (published online on 7 October 2012)
Notes on some dietary items of Eutropis longicaudata (Hallowell, 
1857), Japalura polygonata xanthostoma Ota, 1991, 
Plestiodon elegans (Boulenger, 1887), and Sphenomorphus indicus 
(Gray, 1853) from Taiwan
Gerrut Norval 1,*, Shao-Chang Huang 2, Jean-Jay Mao 3, and Stephen R. Goldberg 4
1 Applied Behavioural Ecology & Ecosystem Research Unit, 
Department of Environmental Sciences, UNISA, Private Bag 
X6, Florida, 1710, Republic of South Africa.
2 Queensland Brain Institute, QBI Building (79), Upland 
Road, The University of Queensland, St Lucia, QLD 4072, 
Australia.
3 Department of Forestry & Natural Resources, National Ilan 
University. No. 1, Sec. 1, Shen-Lung Rd., Ilan, 260, Taiwan, 
R.O.C.
4 Department of Biology, Whittier College, Whittier, California 
90608, USA.
*Corresponding author; e-mail: gnorval@gmail.com
Figure 1. The yellow-mouthed tree lizard (Japalura 
polygonata xanthostoma) is an endemic sub-species, restricted 
to northeastern, northern and northwestern Taiwan, in areas 
below 1000 m (photographed by Jean-Jay Mao).
Gerrut Norval et al.454
WGS84), with a SVL of 122 mm, TL of 179 mm, and a 
body mass of 49.1 g. On the 29th of September, 2002, 
a female was collected (at 23º25’47”N, 120º28’56”E; 
datum: WGS84). The lizard had a SVL of 105 mm, and 
body mass of 27.4 g (including the fragments of the tail 
that could be collected), but since the tail was mutilated 
no TL was recorded. One Plestiodon elegans (Scincidae) 
specimen was examined. It had a SVL of 40 mm and a 
TL of 73 mm. The sex was also not determined. Two 
Sphenomorphus indicus (Scincidae) specimens were 
examined. Both were males, and had a SVL of 68 mm, 
but one had a TL of 105 mm, while that of the other was 
84 mm, of which 24 mm was a regenerated tail. 
Fifty-nine prey items, which belonged to 14 orders 
from 7 classes, were recorded in this study (Table 1). 
The most numerous prey items were ants, followed by 
spiders, earthworms, lepidopteran larvae, woodlice, and 
flies, in that order. 
Most of the prey items of J. p. xanthostoma reported 
herein belong to orders that were also reported by 
Kuo, Lin and Lin (2007) as prey of this species. The 
only exceptions were flies (Diptera), mite (Acarina), 
and earthworms (Haplotaxida). Rather than being due 
to a difference in diet, this may simply be because 
earthworms tend to digest fairly quickly, and may be 
overlooked if lizards are not fixed shortly after being 
collected. It must also be remembered that earthworms 
are rarely active on the soil surface during the day, 
and would thus be a prey item that these lizards rarely 
encounter. The majority of the prey items we recorded 
from E. longicaudata belonged to orders that were also 
reported by Huang (2006) as prey of conspecifics from 
Orchid Island. However, unlike in this study, Huang 
(2006) did not record earthworms (Order: Haplotaxida) 
as prey of E. longicaudata. Again, rather than indicating 
dietary variation, this is more likely due to reasons 
as explained earlier for J. p. xanthostoma. Huang 
(2006) recorded Gekko hokounensis Zhou, 1982, and 
Hemidactylus frenatus Schlegel, 1836, as well as the 
eggs of Eutropis multicarinata (Gray, 1845) (reported as 
Mabuya multicarinata) and Sphenomorphus incognitus 
Thompson, 1912, as dietary items of E. longicaudata 
from Orchid Island, and Norval, Mao and Chu (2004) 
described an instance of E. longicaudata (reported as 
Mabuya longicaudata) predation on Anolis sagrei 
Duméril & Bibron, 1837, an exotic invasive species in 
Taiwan, so ovophagy and saurophagy are known for this 
species. Still, the remains of a lizard egg, and toe and tail 
fragments, as well as scales, of the embryo were found in 
the stomach of the first E. longicaudata described herein. 
Based on these fragments it was possible to determine 
that the egg was that of a Takydromus species. Since 
T. formosanus (Boulenger, 1894) is the only species of 
this genus in the area where the E. longicaudata was 
collected, we are confident that the egg was that of T. 
formosanus. Our observation is thus the first reported 
Figure 2. The long-tailed skink (Eutropis longicaudata) 
is the largest native lizard species in Taiwan, and is often a 
common species in areas disturbed by anthropogenic activities 
(photographed by Gerrut Norval).
Figure 3. The elegant skink (Plestiodon elegans) is a 
common species island wide in open mountainous areas and 
areas disturbed by anthropogenic activities below 2500 m 
(photographed by Gerrut Norval).
Figure 4. The Indian forest skink (Sphenomorphus indicus) is 
a common species island wide in forested areas below 1500 m 
(photographed by Gerrut Norval).
Notes on some dietary items of lizards in Taiwan 455
instance of predation on the eggs of T. formosanus by 
E. longicaudata. As for P. elegans, the observations 
described herein are the first description of dietary items 
of this lizard in Taiwan. All the prey items from the S. 
indicus described herein belong to some of the orders 
described by Shieh, Juan and Lue (1986) as prey of this 
species from northern Taiwan. 
Based on what is known about the food intake of the 
four lizard species described herein, it is clear that these 
species are dietary generalists. However, there are some 
differences in their foraging modes. The type of prey 
consumed by lizards is often determined by the foraging 
mode of the lizard. Lizard foraging modes can typically 
be classified as a very active, cruising predator (“widely 
foraging”), which tend to prey more on prey types that 
are sedentary, unpredictably distributed, clumped, and/or 
are large and hidden; or as a sedentary, ambush predator 
(“sit-and-wait”), which tend to prey on more active prey, 
that is mobile, on the surface, and visually conspicuous 
(Huey and Pianka 1981; Pianka and Vitt 2003). The 
occurrence of primarily mobile and conspicuous 
prey (e.g. ants, flies, and lepidopteran larvae) in the 
Table 1.  The dietary items of the Japalura polygonata xanthostoma (J.p.x.), Eutropis longicaudata (E.l.), Plestiodon elegans 
(P.e.), and Sphenomorphus indicus (S.i.) described herein. The number of lizards, of each species, that preyed upon each prey 
type is indicated in parenthesis. The prey items belonged to the following orders, Coleoptera (Cole.), Diptera (Dipt.), Hemiptera 
(Hemi.), Hymenoptera (Hyme.), Lepidoptera (Lepi.), Mantodea (Mant.), Orthoptera (Orth.), Scolopendromorpha (Scol.), 
Spirobolida (Spir.), Acarina (Acar.), Aranea (Aran.), Isopoda (Isop.), Squamata (Squa.), and Haplotaxida (Hapl.). (* indicates that 
it is an egg.)
J.p.x. E.l. P.e. S.i.
Class Order Family F % F % F % F %
Insecta Cole. Unknown 1 (1) 3.45 1 (1) 7.14 - -
Scarabaeidae - 1 (1) 7.14 - -
Dipt. Unknown 4 (2) 13.8 - - -
Hemi. Unknown - 2 (1) 14.3 - -
Pentatomidae - 1 (1) 7.14 - -
Hyme. Formicidae 12 (2) 41.4 4 (2) 28.6 - 1 (1) 12.5 
Lepi. Noctuidae 3 (3) 10.3 2 (1) 14.3 - 1 (1) 12.5 
Mant. Unknown - 1 (1) 7.14 -
Orth. Gryllidae - - 1 (1) 12.5 2 (2) 25 
Chilopoda Scol. Unknown 1 (1) 3.45 - - -
Diplopoda Spir. Unknown 1 (1) 3.45 - - -
Arachnida Acar. Acariformes 1 (1) 3.45 - - -
Aran. Unknown 1 (1) 3.45 - 6 (1) 75 -
Crustacea Isop. Pocellionidae 1 (1) 3.45 - 1 (1) 12.5 3 (2) 37.5
Reptilia Squa. Lacertidae* - 1 (1) 7.14 -
Clitellata Hapl. Unknown 4 (3) 13.8 1 (1) 7.14 - 1 (1) 12.5 
TOTAL 29 14 8 8
diet of J. p. xanthostoma suggests that this species is 
an opportunistic ambush foraging species. Because 
millipedes (Diplopoda) are known to produce toxins, 
and active foraging lizards can presumably detect the 
toxic compounds released by these prey and therefore 
avoid them (Vitt and Cooper, 1986), the occurrence of 
prey such as millipedes in the diet of J. p. xanthostoma 
is additional proof of the ambush foraging strategy of 
this species. As for the skinks (Scincidae), the presence 
of prey that is usually nocturnal (e.g. crickets), cryptic 
(e.g. preying mantis), inactive (e.g. fruits and seeds), 
and/or hidden (e.g. lizard eggs and woodlice), suggests 
that all three species are active foragers.
Acknowledgements. The management of Yangmingshan National 
Park issued a collection permit (No. 0920000848) to Prof. I-Min 
Tso, and we are grateful to him for donating the lizards to us for 
study. The authors would also like to express their gratitude to 
Gernot Vogel and Meng Hsien Chuang for their comments and 
for reviewing this paper.
References
Bury, B.R. (2006): Natural history, field ecology, conservation 
biology and wildlife management: time to connect the dots. 
Herpetological Conservation and Biology 1: 56-61.
Dunham, A.E., Grant, B.W., Overall, K.L. (1989): Interfaces 
between biophysical and physiological ecology and populati-
on ecology of terrestrial vertebrate ectotherms. Physiological 
Zoology 62: 335-355.
Goodyear, S.E., Pianka, E.R. (2011): Spatial and temporal varia-
tion in diets of sympatric lizards (Genus Ctenotus) in the Great 
Victoria Desert, Western Australia. Journal of Herpetology 45: 
265-271.
Huang, W.S. (2006): Ecological characteristics of the skink, Ma-
buya longicaudata, on a tropical East Asian Island. Copeia 
2006: 293-300.
Huey R.B., Pianka E.R. (1981): Ecological consequences of fo-
raging mode. Ecology 62: 991-999. 
Kuo, C.Y., Lin, Y.S., Lin, Y.K. (2007): Resource use and morpho-
logy of two sympatric Japalura lizards (Iguania: Agamidae). 
Journal of Herpetology 41: 713-723.
Lahti, M.E., Beck, D.D. (2008): Ecology and ontogenetic variati-
on of diet in the pigmy short-horned lizard (Phrynosoma doug-
lasii). American Midland Naturalist 159: 327-339.
Norval, G., Mao, J.J., Chu, H.P. (2004): Mabuya longicaudata 
(Long-tailed Skink). Predation. Herpetological Review 35: 
393-394.
Pianka E.R., Vitt L.J. (2003): Lizards: Windows to the Evolution 
of Diversity. Berkeley, University of California Press. 
Rodríguez, A., Nogales, M., Rumeu, B., Rodríguez, B. (2008): 
Temporal and spatial variation in the diet of the endemic lizard 
Gallotia galloti in an insular Mediterranean scrubland. Journal 
of Herpetology 42: 213-222.
Shang, G.S., Lin, S.L. (2001): Natural Portraits of the Lizards of 
Taiwan. Taipei, Big Trees Publishers. (In Chinese)
Shieh, C.J., Juan, L.Y., Lue, K.Y. (1986): The study of the feeding 
habit of Sphenomorphus indicus in Ha-Pen area, Taipei Coun-
ty. Biological Bulletin of National Taiwan Normal University 
21: 73-84. (In Chinese)   
Vitt L.J., Cooper W.E. (1986): Foraging and diet of a diurnal pre-
dator (Eumeces laticeps) feeding on hidden prey. Journal of 
Herpetology 20: 208-415.
Zug, G.R., Vitt, L.J., Caldwell, J.P. (2001): Herpetology. An In-
troductory Biology of Amphibians and Reptiles.  2nd edition. 
San Diego, Academic Press.
Gerrut Norval et al.456
Accepted by Wouter Beukema


Notes on some dietary items of Eutropis longicaudata (Hallowell, 1857), Japalura polygonata xanthostoma Ota, 1991, Plestiodon elegans (Boulenger, 1887), and Sphenomorphus indicus (Gray, 1853) from Taiwan

http://espace.library.uq.edu.au/view/UQ:317557/UQ317557_OA.pdf

Notes on some dietary items of Eutropis longicaudata (Hallowell, 1857), Japalura polygonata xanthostoma Ota, 1991, Plestiodon elegans (Boulenger, 1887), and Sphenomorphus indicus (Gray, 1853) from Taiwan

Abstract

Similar works

Full text

Available Versions

University of Queensland eSpace