Diet of wrinkle-lipped free-tailed bat (Tadarida plicata Buchannan, 1800) in central Thailand: Insectivorous bats potentially act as biological pest control agents

Abstract

Insectivorous bats are major predators of nocturnal insects and have the potential to act as biological pest control agents in farmlands. The objective of the present study was to establish the diet of the guano bat, Tadarida plicata. The study was carried out at the Khao Chong Pran Cave, which houses 2.6 million bats, and is surrounded by rice fields. A total of 1,925 faecal pellets were collected from 385 bats during their morning return from January to December 2002. Faecal analysis indicated that T. plicata fed on at least nine insect orders: Homoptera (28.4%), Lepidoptera (20.8), Hemiptera (16.4), Coleoptera (14.4), Diptera (7.0), Hymenoptera (6.6), Odonata (6.0), Orthoptera (0.5) and Psocoptera (0.1). Light traps indicated that Coleoptera (41.2%), Homoptera (25.3), Hemiptera (18.8) and Diptera (12.7) were the most abundant insects in the study area. Homopterans, most of which were white-backed planthopper (Sogatella sp., Delphacidae) had the highest percentage frequency of occurrence in the bats' diet indicating that T. plicata potentially plays an important role in controlling this major crop pest. The presence of macropterous planthoppers and a large proportion of moths in its diet suggests that T. plicata feeds on windborne migrant insects at high altitude. Female bats fed significantly more on lepidopterans and coleopterans and less on damselflies than males. The diet diversity index of lactating females was higher than pregnant females. Diet did not differ significantly between the dry and rainy seasons for either sex.

Full text

INTRODUCTION
Insectivorous bats have been suggested
as the primary consumer of nocturnal in-
sects (Kunz and Pierson, 1994). They prey
on a number of major farmland pests such
as corn borers, planthoppers, tobacco bud-
worms, and oriental armyworms (Whitaker,
1993). Thus, large colonies of insectivor-
ous bats may result in the large-scale deple-
tion of pest insects in surrounding farm-
lands. Since biological pest control involves
the use of natural enemies to suppress pest
population densities to levels lower than
they would otherwise be (Van Driesche and
Bellows, 1996), insectivorous bats poten-
tially act as biological pest control agents
(e.g., Lee and McCracken, 2005). Several
genera of bats including Tadarida and Mi-
niopterus form very large colonies up to
several million individuals in caves (Dwyer,
1966; Lekagul and McNeely, 1988; Mc-
Cracken, 1996). In Thailand, a total of ap-
proximately eight million individuals of
the wrinkle-lipped free-tailed bat, Tadarida
Acta Chiropterologica, 7(1): 111–119, 2005
PL ISSN 1508-1109 © Museum and Institute of Zoology PAS
Diet of wrinkle-lipped free-tailed bat (Tadarida plicata
Buchannan, 1800) in central Thailand: insectivorous bats potentially
act as biological pest control agents
WATCHAREE LEELAPAIBUL1, SARA BUMRUNGSRI2, 3, and ANAK PATTANAWIBOON1
1Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, Thailand
2Department of Biology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
3Corresponding author: E-mail: sara.b@psu.ac.th
Insectivorous bats are major predators of nocturnal insects and have the potential to act as biological pest control
agents in farmlands. The objective of the present study was to establish the diet of the guano bat, Tadarida
plicata. The study was carried out at the Khao Chong Pran Cave, which houses 2.6 million bats, and is
surrounded by rice fields. A total of 1,925 faecal pellets were collected from 385 bats during their morning
return from January to December 2002. Faecal analysis indicated that T. plicata fed on at least nine insect
orders: Homoptera (28.4%), Lepidoptera (20.8), Hemiptera (16.4), Coleoptera (14.4), Diptera (7.0),
Hymenoptera (6.6), Odonata (6.0), Orthoptera (0.5) and Psocoptera (0.1). Light traps indicated that Coleoptera
(41.2%), Homoptera (25.3), Hemiptera (18.8) and Diptera (12.7) were the most abundant insects in the study
area. Homopterans, most of which were white-backed planthopper (Sogatella sp., Delphacidae) had the highest
percentage frequency of occurrence in the bats’ diet indicating that T. plicata potentially plays an important role
in controlling this major crop pest. The presence of macropterous planthoppers and a large proportion of moths
in its diet suggests that T. plicata feeds on windborne migrant insects at high altitude. Female bats fed
significantly more on lepidopterans and coleopterans and less on damselflies than males. The diet diversity
index of lactating females was higher than pregnant females. Diet did not differ significantly between the dry
and rainy seasons for either sex.
Key words: biological pest control, diet, Tadarida plicata, planthopper, Thailand

plicata from 17 caves were reported, mak-
ing it the most abundant mammal in Thai-
land (Boonkerd and Wanghongsa, 2002). In
Khao Chong Pran Cave, the largest colony
of T. plicata in Thailand, houses 2.6 million
bats (Hillman, 1999). Previous studies indi-
cated that Tadarida forages at high altitude
up to several kilometres, and as far as 25 km
from caves (William et al., 1973). As it
feeds on high altitude windborne insects
(McCracken, 1996; Fenton and Griffin,
1997), Tadarida potentially regulates insect
populations over a much larger area than its
feeding range. However, no detailed study
on the diet of T. plicata has been carried out.
Given that a bat ingests insects about half of
its body mass per night, 2.6 million T. pli-
cata (ca 15.5 g) will consume many tons of
insects a night. Rice fields make up the ma-
jority of farmland in central Thailand where
planthoppers are known to be the major pest
(Vungsilabutr, 2001). How much these in-
sects contribute to the diet of this bat is
therefore of interest. The larger the propor-
tion of pest insects in the diet, the higher po-
tential of this bat as a biological control
agent. The primary objective of the present
study is to establish the diet of T. plicata by
faecal analysis.
Female T. plicata experience two breed-
ing periods a year (Hillman, 1999; Leel-
apaibul, 2003). Reproductive females have
a higher demand for nutrients and energy
than nonreproductive females and males
while their foraging efficiency is affected
adversely by their higher body mass (Jones,
1990). Thus, the diet of reproductive fe-
males may differ from that of non reproduc-
tive females and males. Thus, the secondary
objective of the present study is to examine
dietary differences between sexes.
MATERIALS AND METHODS
Study Site
Field work was carried out in Wat Khao Chong
Pran Nonhunting Area (13°43’N, 99°47’E) which is
about 100 km west of Bangkok. Khao Chong Pran
(KCP) is a 12 ha limestone outcrop, surrounded pri-
marily by rice fields, sugar cane plantations, and
sparse local settlements. Its elevation ranges between
70–180 m a.s.l. Five caves are present in KCP and the
largest is inhabited by T. plicata, Eonycteris spelaea,
and Taphozous sp. The cave is approximately 150 m
long, 50 m across at its widest point, and 40 m high
(Hillman, 1999). Local villagers collect bat guano
from this cave once a week under the guidance of
monks from the local monastery. The climate is char-
acterised by a tropical monsoon with 1,486 mm annu-
al rainfall, most (90%) of which occurs in the rainy
season. Generally, there are two seasons: the rainy
season (May–October) and the dry season (Novem-
ber–April). However, unusually high rainfall com-
pared to ten year averages occurred in November
2002 (123.1 mm), so it was treated as part of the rainy
season. The vegetation at KCP is mixed deciduous
forest, where Pterocarpus macrocarpus, Streblus as-
per, Lagerstroemia sp. and Diospyros sp. are domi-
nant.
Study Species
The wrinkle-lipped free-tailed bat (T. plicata ) is
the smallest species in the genus, and the ears are typ-
ically joined by membrane over the forehead. Its fore-
arm is 43.1–50.2 mm. Average male body mass is
15.51 g (SD = 1.20, n= 424) whereas that of a nonre-
productive female is 15.93 g (SD = 1.10, n= 186)
(Leelapaibul, 2003). It roosts in caves, rock crevices,
and tree hollows. There are at least 17 caves in
Thailand reported to support populations of this bat,
most of which are in central Thailand (Yenbutra and
Felten, 1986; Boonkerd and Wanghongsa, 2002). It
has two breeding periods, the majority of late preg-
nant females were found in February–March and Au-
gust –September (Hillman, 1999). However, lactating
females were found nearly every month except in Jan-
uary–March and August. Tadarida has a narrow wing
suggesting that it is a fast flying open-space bat. Wing
loading of males is 0.21–0.29 (n= 12) while nonre-
productive females is 0.20–0.26 g/cm2(n= 5). Its as-
pect ratio is relatively high (YY: 15.47–19.08; XX
16.00–17.39 — Leelapaibul, 2003).
Bat Trapping
A number of studies indicate reduced bat activity
during full moon (Morrison, 1978; Reith, 1982; No-
winszky, 2004). However, the present study also
aimed to quantify insect abundance without bias to-
ward light-attracted insects such as moths (Bowden
and Morris, 1975). Thus, bat and insect trapping were
112 W. Leelapaibul, S. Bumrungsri, and A. Pattanawiboon

carried out during full moon. Bats were captured
during their morning return (04:30–07:00 h) once
a month during January–December 2002, on or
around the full moon. Thirty five males and 35 fe-
males were captured per month with a hoop net at the
main entrance. Captured bats were weighed, sexed
and their reproductive condition was noted following
Racey (1988). Bats were kept in cloth bags for about
two hours before they were released in the cave. Bat
faeces collected from bags were air dried and kept in
labeled Eppendorf tubes. In the laboratory, five faecal
pellets (Whitaker et al., 1996) per individual from 15
mature males and 15 females in each reproductive
condition were randomly selected, and washed in
50% alcohol for 15 minutes (Fenton et al., 1998).
Insect parts in faeces were identified using a stereo-
microscope by comparison with reference collections
and following Whitaker (1988), Borror et al. (1989)
and Wilson and Claridge (1991). Ingested insects
were identified to order, or to genera for Homoptera
(Wilson and Claridge, 1991). Identified insects were
scored as present/absent. The relative importance of
insects in bat faeces was expressed as percentage fre-
quency (McAney et al., 1991): the number of occur-
rences of particular category divided by total occur-
rences for all categories, multiplied by 100.
Insect Trapping
In order to evaluate the availability of prey for
T. plicata, an aerial feeding bat, that is likely forage in
open spaces, insects were sampled using three light
traps set permanently with 8 m high bamboo poles in
the rice fields in proximity to local villages. Each
light trap station was set at >1 km distance from the
others and within 15 km from the cave (within the av-
erage foraging range of T. brasiliensis, William et al.,
1973). There are no streetlights in such local villages.
Insects were trapped from 18:00 to 06:00 h on the
same night as bats were trapped. Trapped insects were
stored in 90% alcohol. One millilitre of trapped in-
sects was sampled and identified to family. The pres-
ence of insects in the traps was presented by percent-
age frequency.
Intraspecific Diet Variation
The Chi-square contingency test was applied to
determine intraspecific diet variation and seasonal
variation based on the frequency of each dietary item.
Dietary diversity index (DDI) of ingested insects was
calculated using the Shannon-Wiener index (Brack
and LaVal, 1985). The DDI was calculated and com-
pared between lactating and pregnant females during
its first breeding season (March–May) as data were
available.
RESULTS
Diet
The faecal analysis of 1,925 faecal pel-
lets from 385 bats indicated that T. plicata
fed on at least nine insect orders. Homopte-
ra showed the highest percentage frequency
in bat faeces (28.4%) followed by Lepido-
ptera (20.8), Hemiptera (16.4), and Co-
leoptera (14.4). These four orders of insects
made up the majority (80%) of the diet.
Diptera (7), Hymenoptera (6.6) and Odo-
nata (6.0) contributed a small proportion to
the bats diet (Table 1). For Homoptera, 90%
were in the Delphacidae, most of which
were white-backed planthoppers (Sogatella
sp.). In the study area, Coleoptera (41.2),
Homoptera (25.3), Hemiptera (18.8) and
Diptera (12.7) were the most common in-
sects (98.0) in the light traps, while Lepi-
doptera were relatively rare (0.3) (Table 1).
There was significant differences in insect
abundance between months (Friedman test,
χ2= 59.59, d.f. = 6, P< 0.001). Coleoptera
showed the highest frequency percentage in
traps for most of the year, except in April,
August, September and December when ei-
ther Homoptera or Hemiptera was the most
abundant (Table 1).
Each bat fed on insects from between
one to seven orders each night (0± SD
= 3.7 ± 1.43). As there was a dietary shift
between months, Homoptera was the most
important for six months (February, March,
June, October, November and December),
Lepidoptera and Hemiptera for two months
(May, September and January, August re-
spectively), and a month for Coleoptera and
Hymenoptera for one month each (July and
April respectively) (Table 1).
Intraspecific Diet Variation
Tadarida plicata showed a significant
variation in diet between the sexes (χ2=
14.05, d.f. = 7, P< 0.05). Females fed more
Diet of Tadarida plicata in central Thailand 113

on Lepidoptera and Coleoptera but less on
Odonata (damselflies, Coenagrionidae)
than males (Fig. 1). Intraspecific diet varia-
tion among female bats was investigated.
Overall, pregnant, lactating and nonrepro-
ductive females showed no significant dif-
ferent in their diet (χ2= 12.29, d.f. = 12,
P= 0.42). The same was observed in lactat-
ing and nonreproductive females captured
in the same month (October) (χ2= 1.06, d.f.
= 5, P= 0.95). However, diet was signifi-
cantly different among lactating females in
different breeding seasons (χ2= 57.77, d.f.
= 6, P< 0.001) and different months in the
same breeding season (1st breeding season,
χ2= 32.13, d.f. = 12, P= 0.001; 2nd breed-
ing season, χ2= 32.79, d.f. = 18, P< 0.05).
Significant difference in their diet between
dry and rainy season was not detected in
both males (χ2= 4.83, d.f. = 7, P= 0.68)
and females (χ2= 4.64, d.f. = 6, P= 0.59).
The dietary diversity index of females in
the first breeding season (March–May) was
examined. Female reproductive conditions
influenced the diversity of ingested insects.
Lactating females (1.83) had a higher di-
etary diversity than pregnant ones (1.51).
DISCUSSION
Diet of T. plicata and Implications for
Insect Pest Control
The potential of insectivorous bats as
a biological control agent of pests in agri-
cultural ecosystems is supported by the
present study. Homopterans, lepidopterans,
hemipterans and coleopterans are among
the major pests in farms. Three serious out-
breaks of brown planthopper (Nilaparva-
ta lugens) have been recorded in Thai-
land since 1975. Generally, a large outbreak
occurs every 8–10 years. The loss of rice
yield in 1990 cost about 200–240 million
US dollars (Vungsilabutr, 2001). Growing
susceptible rice varieties and continuous
114 W. Leelapaibul, S. Bumrungsri, and A. Pattanawiboon
Month Homoptera Lepidoptera Hemiptera Coleoptera Diptera Hymenoptera Odonata Others
Faeces Traps Faeces Traps Faeces Traps Faeces Traps Faeces Traps Faeces Traps Faeces Traps Faeces Traps
January 18.16 15.45 22.03 0.21 23.97 11.13 9.44 64.83 7.75 7.53 4.60 0.85 14.04 0 0 0
February 45.28 4.81 16.98 0.11 11.95 18.48 22.33 72.54 0.63 2.99 0 0.85 2.83 0 0 0.21
March 41.97 10.93 26.28 0.57 5.84 14.36 11.31 63.38 0.36 9.87 13.50 0.90 0.73 0 0 0
April 24.55 14.08 17.07 0.44 8.68 36.35 16.77 25.98 1.20 19.71 29.64 3.44 0.90 0 1.20 0
May 19.38 16.98 22.91 0.73 10.35 18.85 15.20 59.38 3.08 3.65 17.62 0.42 11.23 0 0.22 0
June 49.17 25.53 19.27 0.11 9.30 17.31 9.30 49.79 2.99 6.30 4.32 0.96 5.65 0 0 0
July 24.15 26.60 5.57 0.51 29.41 27.62 32.51 42.97 2.17 0.77 4.64 1.53 0.93 0 0.62 0
August 17.05 43.80 17.97 0.50 30.41 16.69 26.04 16.36 3.00 20.33 1.38 0.99 3.23 0 0.92 1.32
September 26.36 42.51 27.57 0.15 11.67 10.08 11.27 8.40 18.71 37.62 1.81 1.17 2.41 0 0.20 0.07
October 24.15 26.10 23.93 0.17 18.96 15.85 15.35 36.61 9.48 19.90 4.51 0.95 1.35 0 2.26 0.43
November 39.72 30.04 23.33 0.19 10.56 17.25 2.78 40.89 8.33 7.75 0 3.68 15.00 0 0.28 0.19
December 26.77 46.35 22.12 0.12 19.69 21.56 3.76 13.65 16.37 15.93 0.88 2.04 9.96 0 0.44 0.36
Overall 28.37 23.75 20.83 0.31 16.36 18.37 14.40 41.73 6.97 14.20 6.56 1.43 5.95 0 0.54 0.20
TABLE 1. Percentage frequency of diet items in faeces and traps during January–December 2002. Other insects included Orthoptera, Psocoptera, Ephemeroptera and
Trichoptera

rice-growing throughout the year, which re-
sults in year-round food availability for this
insect, were suggested as the main causes of
the outbreaks. Conserving populations of
natural biological control agents of the plan-
thopper and growing insect-resistant rice
varieties can keep its population below eco-
nomic injury level. In this case, insectivo-
rous bats could play an important role as po-
tential biological pest control agents in the
rice field ecosystem. In the present study,
T. plicata feeds mainly on homopterans
identified as white-backed planthoppers
(Sogatella sp., Delphacidae), which was
specifically indicated as the main pest in
the rice fields in the study area (Vung-
silabutr, 2001). Except in the study area,
the brown planthopper is common in rice
fields in central and lower northern Thai-
land. It seems likely that Tadarida will also
feed on brown planthoppers when they are
present.
Assuming that a bat ingest insects equal
to 50% of its body mass per night, Hillman
(1999) suggested that the 2.6 million T. pli-
cata in the study cave could consume 17.5
tons of insects each night. Moreover, since
Kunz et al. (1995) suggested that early lac-
tating female T. brasiliensis consume 73.4%
of its body mass each night, 17.5 tons of in-
sects are a minimum estimate. The overall
population of this bat species in Thailand
has been estimated as eight million (Boon-
kerd and Wanghongsa, 2002), so overall it
could feed on 54.8 tons of insects nightly.
Importantly, this also means that insectivo-
rous bats deliver economically valuable
ecological services and decrease health
risks to humans by reducing dependence on
pesticides. Moreover, bat guano is well
known as high nutrient fertilizer, and the
temple earns about 135,000 US dollars each
year from selling it.
Intraspecific Diet Variation
The variation in diet between male and
female bats may reflect temporal variation
Diet of Tadarida plicata in central Thailand 115
FIG. 1. Ferquency percentage of each insect order in the diet of female (n= 178) and male T. plicata (n = 180)
during January to December 2002

in the time of their return to the cave, which
coincides with the activity times of various
insects. During a breeding period, reproduc-
tive females of T. brasiliensis returned to
the cave later at dawn than males and non-
reproductive females (Lee and McCracken,
2001). Although no intensive study on the
dawn return of T. plicata has been carried
out, trapping indicates that, as in T. bra-
siliensis, fewer males returned to their cave
as the morning progressed (W. Leelapai-
bul, pers. obs.). As moths are largely noc-
turnal, the higher percentage of moths in the
diet of female bats could be the result of
secondary dawn activity in some moths.
Flight activity studies of nocturnal insects
indicate the highest activity occurs immedi-
ately after sunset, followed by a decrease
throughout the night, then followed by a
secondary peak shortly before sunrise
(Whitaker et al., 1996 and references there-
in; see Fullard and Napoleone, 2001).
Whitaker et al. (1996) pointed out that
moths dominated the diet of T. brasiliensis
during pre-dawn feeding bouts. In this spe-
cies, radar observation suggests that bats
encounter moths when these insects arrive
at the feeding ground of the bats in the ear-
ly morning (Whitaker et al., 1996).
The decreased maneuverability of preg-
nant females may be responsible for its low-
er diet diversity compared to lactating fe-
males. During pregnancy, the body mass of
females increases (by about 2 g — Leela-
paibul, 2003), resulting in lowering its as-
pect ratio, and decreased maneuverability.
Jones (1990) also found a similar result in
female Rhinolophus ferrumequinum. Dur-
ing late pregnancy, female T. brasiliensis
lower their feeding rate (Kunz et al., 1995)
while female Eptesicus nilssoni decrease
their foraging time (Rydell, 1993). On the
other hand, lactating females of several
insectivorous bat species double their food
intake during early lactation (Kunz et
al., 1995, and references therein). Rydell
(1993) indicated that female E. nilssoni
doubles its foraging time from early to mid
lactation. The higher food intake and in-
creased foraging duration of lactating fe-
males obviously supports the higher de-
mand for nutrients and energy associated
with milk production and results in higher
diet diversity of these females.
In our study, the significant variation
in the diet of lactating female T. plicata
between different breeding seasons and
between different months in the same sea-
son indicates that this bat is an opportunist.
It is expected that Tadarida, which flies
at high altitudes and feeds on nocturnal
airborne insects (William et al., 1973;
McCracken, 1996; Fenton and Griffin,
1997), should encounter different kinds of
insects at different times of the year. These
insects periodically disperse from their
feeding areas when local environment-
al conditions are not suitable, as in periods
of food shortage. Thus, the major dietary
components in any month could indicate,
at least in part, the dispersal or migration
of insects in the study area. For example,
planthoppers (Homoptera) which rely on
rice as their sole diet, show mass emigra-
tion from the area during dry-season rice
harvesting in February–March, and wet-
season harvesting in November–December
(Vungsilabutr, 2001). During these periods,
faecal analysis indicated that planthop-
pers are the major component of the bats’
diet, contributing 42–45% and 27–40%,
respectively (see Leelapaibul, 2003). In ad-
dition, the relatively high percentage fre-
quency of Homoptera in other months may
result from local movement of these in-
sects, since rice is asynchronously harvest-
ed in this irrigated area (Vungsilabutr,
2001). Several authors also indicated that
T. brasiliensis is an opportunistic feeder
(Kunz et al., 1995; Whitaker and Rodri-
guez-Duran, 1999; Lee and McCracken,
2002).
116 W. Leelapaibul, S. Bumrungsri, and A. Pattanawiboon

Does T. plicata Forage at High Altitude?
Tadarida plicata potentially forage at
high elevation based on its high aspect ratio
and high wing loading (Norberg and Ray-
ner, 1987). Previous studies suggested that
T. brasiliensis and other molossids forage at
high altitude, up to 3.1 km (William et al.,
1973; McCracken, 1996; Fenton and Grif-
fin, 1997). In addition to its wing morphol-
ogy, the incidences of macropterous (long-
winged morph) planthopper (Homoptera) in
its diet, which are the only planthoppers that
are able to migrate (Riley and Reynolds,
1987), and the exceptionally large percent-
age of moths in its diet compared to trapped
insects suggests it forages at high altitude.
A number of studies indicated windborne
migration of white-backed planthoppers
and noctuid moths at an elevation of 0.1–2.5
km (Johnson, 1969; Chen et al., 1995; Kisi-
moto and Sogawa, 1995; Feng et al., 2003)
Future Work and Recommendation
Although faecal analysis provides a reli-
able estimate of diet components of insec-
tivorous bats (Kunz and Whitaker, 1983),
diet composition of T. plicata revealed by
this method may be biased towards some
groups of insects. Some bat species includ-
ing T. brasiliensis regularly cull parts of in-
sects before ingesting them (Kunz et al.,
1995). Thus, this method may be biased
against insect taxa that are culled more
heavily. On the other hand, natural markers
like moth’s scales are retained for many
hours after ingestion (Robinson and Steb-
bings, 1993) whereas insects with soft body
are digested easily and are less likely to be
found in faeces.
A number of bat species including
T. brasiliensis and T. plicata double their
foraging bouts during their early lacta-
tion (Rydell, 1993; Whitaker et al., 1996;
Hillman, 1999). Temporal variations in
air-borne insect activity are also document-
ed (Johnson, 1969; Kisimoto and Sogawa,
1995, and references therein). Thus, diet
composition of evening feeding bouts may
be significantly different from dawn feeding
bouts as was indicated in T. brasiliensis.
Coleopterans and hemipterans were the ma-
jor dietary items in the evening bouts of T.
brasiliensis, while moths were the most im-
portant items in the early morning (Whita-
ker et al., 1996). In the present study, only
diet composition from morning bouts was
documented. To fully characterise the diet
of T. plicata, faecal analysis of evening
bouts during reproductive periods is recom-
mended.
In the present study, homopterans,
which are the most common component of
the diet for several months of the year, were
identified as white-backed planthoppers.
This species is very common in rice fields
in the study area whereas brown planthop-
pers are reported to be common in other ar-
eas. Studying the diet of T. plicata from lo-
cations where brown planthoppers are com-
mon, and investigating the relationship be-
tween abundance of this insect in rice fields
and its incidence in bat faeces is recom-
mended.
ACKNOWLEDGEMENTS
We are grateful to the monks of the Khao Chong
Pran temple for permission to carry out research in
their cave. We would like to thank P. Vungsilabutr for
providing information on planthoppers, C. Papata for
his encouragement and hospitality during field work,
D. Wiwatwittaya, P. Pattanothai, S. Saengthongprao
for their help during research planning. S. Sotthi-
bandu, D. Reed and P. A. Racey provided many sug-
gestions that improve this paper. This research was
supported by the Thailand Biodiversity Research and
Training Program (BRT T_345006).
LITERATURE CITED
BOONKERD, K., and S. WANGHONGSA. 2002. Man-
agement of bat caves. Pp. 33–45, in 2001 An-
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Diet of Tadarida plicata in central Thailand 117

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