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

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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.
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-
nual report of Wildlife Research Division
Diet of Tadarida plicata in central Thailand 117
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Diet of Tadarida plicata in central Thailand 119
Received 27 November 2004, accepted 17 April 2005
... For example, the value of these services to agriculture in the continental USA has been estimated at approximately US$ 22.9 billion /year, including the reduced costs of pesticides that are not needed to suppress the insects consumed by bats (Boyles et al., 2011). In Thailand, populations of the wrinkle-lipped free-tailed bat Mops plicatus (Molossidae) are regarded as important pest control agents because they may consume as many as 55 tons of insects per night, a signifi cant portion of which comprises major agricultural pests (Leelapaibul et al., 2005). ...
... Analysis of bat faeces can provide valuable information on the insect taxa consumed by bat species. These have shown that insect orders commonly consumed by insectivorous bats include Homoptera, Coleoptera, Heteroptera, Lepidoptera, Diptera, Hymenoptera, Neuroptera, Trichoptera, Odonata and Araneae (Leelapaibul et al., 2005;Oliveira et al., 2015). Some studies have shown that certain bat species mostly consume soft-bodied insects such as moths, whereas other species are less specifi c in their preferences (Bogdanowicz et al., 1999;Ghazali & Dzeverin, 2013;Weterings & Umponstira, 2014). ...
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Bats provide economically significant ecosystem services in insect pest suppression. As little is known regarding the diets of insectivorous bats in Cambodia, we sampled these in the Chambok area of Kampong Speu Province in August 2018 so as to describe and compare their specific diet preferences. Our field survey yielded 294 faecal pellets produced by five insectivorous species (Rhinolophus shameli, R. pusillus, Hipposideros pomona, H. cf. larvatus and Megaderma spasma), 120 of which were examined by microscopy. These samples contained fragments representing nine insect orders, and included fragments of mites (Acari) and Rodentia. The most common orders in terms of their percentage frequency of occurrence were Lepidoptera and Coleoptera, followed by Heteroptera, Hymenoptera, Homoptera and Diptera, whereas the least common were Rodentia, Acari, Isoptera, Trichoptera and Orthoptera. Comparisons based on the percentage volume of the most common orders indicated significant differences in the amounts consumed by rhinolophid and hipposiderid bats, whereas M. spasma showed a preference for small vertebrates. Further studies are warranted to develop understanding of the diet preferences of Cambodian bats, not least because these likely give rise to economically significant ecosystem services.
... Por otro lado, el guano que produce la colonia podría ser utilizado como fertilizante, ya que los insectos no digeridos son ricos en nitrógeno y fosfatos (Gillieson, 1996). En otras partes del mundo este producto se vende y se usa en muchas economías locales, como ser en Asia y Madagascar (Leelapaibul et al., 2005;Aye, 2006;Buliga, 2010;Furey & Racey, 2016). ...
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El Instituto de Limnología del Noroeste Argentino (ILINOA) presenta aquí un notable conjunto de investigaciones biológicas y geográficas que hace años se viene realizando en el dique Escaba y su cuenca hidrográfica. La importancia de este dique y su zona de influencia queda manifiesta en los resultados presentados en los nueve capítulos que conforman este libro; es fascinante constatar la presencia de una enorme diversidad biológica. Por ejemplo, se registraron más de 130 especies de algas diferentes, 19 especies de peces, 66 especies de aves, y 16 especies de murciélagos. Los cambios que se produjeron en el paisaje de la cuenca, y la calidad del agua del embalse a lo largo de los años, son también temas estudiados con detenimiento. La gestión de la cuenca recibe la atención de los autores de todos los capítulos, especialmente en los relacionados con los bosques de ribera y su posible recuperación, como en el de política hídrica. La interesante historia de la creación del dique y el enfoque general del libro son expuestos extensamente en el primer capítulo. Reunir la información conocida de este cuerpo de agua constituye una contribución sobresaliente al conocimiento de las riquezas naturales de Tucumán.
... Por otro lado, el guano que produce la colonia podría ser utilizado como fertilizante, ya que los insectos no digeridos son ricos en nitrógeno y fosfatos (Gillieson, 1996). En otras partes del mundo este producto se vende y se usa en muchas economías locales, como ser en Asia y Madagascar (Leelapaibul et al., 2005;Aye, 2006;Buliga, 2010;Furey & Racey, 2016). ...
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"Las Yungas de Argentina es una de las eco-regiones más diversas y la que está sufriendo mayor degradación antrópica, en ella se encuentran representadas el 66% de las especies de murciélagos presentes en la Argentina. En el sur de las Yungas se encuentra la comuna de Escaba donde se emplaza el Dique Escaba que aloja una de las colonias de cría más grandes en una construcción humana de una especie migradora, Tadarida brasiliensis (Molossidae). Este trabajo tuvo como objetivo determinar la diversidad del área, estudiar la colonia alojada en el dique y poner en conocimiento de la comunidad de Escaba sobre la importancia de la conservación de los murciélagos. Para cumplir con dichos objetivos, se realizaron muestreos en y alrededor del dique desde 1992, como así también actividades con la comunidad de Escaba. Debido a los estudios realizados hace unos años, el dique Escaba fue declarado SICOM (Sitio de Importancia para la Conservación de los Murciélagos) debido a la importancia de conservar la colonia y su refugio; y recientemente el área de influencia fue declarada como AICOM (Área de Importancia para la Conservación de los Murciélagos) por proteger especies de importancia para la conservación y una alta diversidad en esa porción de las Yungas."
... Woodlice were retained in this dataset since they did occur, albeit rarely, in previous guano analyses (e.g., Kaňuch et al., 2005;Leelapaibul et al., 2009;Rydell et al., 2016). The springtail was also kept as it is possibly large enough (3 mm) to be targeted by bats or accidentally consumed during grooming (Vesterinen et al., 2013). ...
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Ecological theory postulates that niches of co-occurring species must differ along some ecological dimensions in order to allow their stable coexistence. Yet, many biological systems challenge this competitive exclusion principle. Insectivorous bats from the Northern Hemisphere typically form local assemblages of multiple species sharing highly similar functional traits and pertaining to identical feeding guilds. Although their trophic niche can be accessed with unprecedented details using genetic identification of prey, the underlying mechanisms of resource partitioning remain vastly unexplored. Here, we studied the differential diet of three closely-related bat species of the genus Plecotus in sympatry and throughout their entire breeding season using DNA metabarcoding. Even at such a small geographic scale, we identified strong seasonal and spatial variation of their diet composition at both intra- and inter-specific levels. Indeed, while the different bats fed on a distinct array of prey during spring, they showed higher trophic niche overlap during summer and fall, when all three species switched their hunting behavior to feed on few temporarily abundant moths. By recovering 19 ecological traits for over 600 prey species, we further inferred that each bat species used different feeding grounds and hunting techniques, suggesting that niche partitioning was primarily habitat-driven. The two most-closely related bat species exhibited very distinct foraging habitat preferences, while the third, more distantly-related species was more generalist. These results highlight the need of temporally comprehensive samples to fully understand species coexistence, and that valuable information can be derived from the taxonomic identity of prey obtained by metabarcoding approaches.
... For example, a colony of a million bats of T. brasiliensis in Texas can produce 22 kg of nitrogen in the form of guano (Kasso & Balakrishnan 2013). In Thailand and Cambodia, the collection of guano in refuges of Mops plicatus and Scotophilus kuhlii contributes to the local economy (Leelapaibul et al. 2005;CBNRM 2009;Chhay 2012), and its use increases the growth of plants compared to other types of fertilizers (Sothearen et al. 2014). ...
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Bats play crucial ecosystem services as seed dispersers, pollinators, controllers of insect, and nutrient recyclers. However, there has not been a thorough global review evaluating these roles in bats across all biogeographical regions of the world. We reviewed the literature published during the last two decades and identified 283 relevant studies: 78 studies where bats controlled potential insect pests, 80 related to the suppression of other arthropods, 60 on the dispersal of native or endemic seeds, 11 related to the dispersal of seeds of introduced plants, 29 on the pollination of native or endemic plants, one study of pollination of introduced plants, and 24 on the use of guano as fertilizer. Our literature search showed that queries combining the terms “seed dispersal”, “insectivorous bats”, “nectarivorous bats”, “use of guano” and “ecosystem services” returned 577 studies, but less than half were experimental in nature. We found that the evaluation of ecosystem services has been mostly conducted in the Neotropical and Palearctic regions. To detect differences in the selected studies, and to explain trends in the study of ecosystem services provided by bats, we performed generalized linear mixed models (GLMM) fitted with a Poisson distribution to analyze the potential of different sampling methods. We identified 409 bat species that provide ecosystem services (752 insect species consumed by bats and 549 plant species either dispersed or pollinated by bats). Our review summarizes the importance of conserving bat populations and the ecological services they provide, which is an especially crucial concern during the current coronavirus pandemic. This article is protected by copyright. All rights reserved
... The greatest pestremoval benefits apply to cotton crops (for a review, see Taylor et al., 2018), worth $3.7 to $53 billion annually across the United States and can depend on the type of cotton grown (Boyles et al., 2011). Yet, most economic estimates that exist are based on large colonies (thousands to millions) of obligate cave-roosting bats (Leelapaibul et al., 2005;Federico et al., 2008) that forage in open space, despite the occurrence of many clutter and edge-space foraging bats in agroecosystems worldwide (Taylor et al. 2018). Whilst these estimates are important in identifying the enormous pest reduction service provided by large bat colonies (mainly Tadarida sp.), a dominant common bat species may not always be present in agricultural landscapes and the year-round pest reduction services provided by clutter and edge-space foraging bats roosting nearby to crops may also be important. ...
Article
Insectivorous bats exert top-down pressure on pest insect populations in agricultural systems globally. However, few economic estimates exist of their value as pest control agents in many high value crops. We calculated the economic benefit of direct predation of insect pests by bats and the damage averted to cotton yield, a high value commodity crop in Australia. Using a combination of bat dietary studies, average daily energy requirements (estimated by field metabolic rate), prey energy content and acoustic data of bat feeding attempts in cotton crops, we show the direct value of insectivorous bats to the Australian cotton industry is likely between $99–126 ha⁻¹ in dryland Bt-cotton and $286–361 ha⁻¹ in irrigated Bt-cotton through the consumption of pest moth Helicoverpa armigera, amounting to $63.6 million annually. We estimate that a population of bats can remove between 77–119 t of moths from Australian cotton crops in an average year across the growing season. However, different bat species consume different insect pests, highlighting the need to conserve bat diversity in agroecosystems. These results provide further incentive for growers to manage non-crop bat roosting habitat to benefit from natural pest control in crops.
... Cave-roosting bats provide multiple ecosystem services, including agricultural pest suppression and guano production. Many cave-roosting bat species are insectivorous and have a large economic impact on rice production (Wanger et al. 2014), with one study finding that a single colony of 2.6 million wrinkle-lipped bats in Thailand can consume at least four tons of white-backed planthoppers (Sogetella sp.), a serious pest of rice, each night (Leelapaibul et al. 2005). Additionally, large bat colonies are a source of guano, which is widely used in Southeast Asia as an organic fertilizer. ...
Article
Bat populations are declining worldwide because of anthropogenic activities, including habitat destruction and hunting. Cambodia represents an important case study for studying human-bat interactions, as loss of karst caves and the destruction of forests threaten the stability of bat populations and the ecosystem services they provide. Cambodians rely on bats for tourism revenue, fertilizer from guano, and as a source of protein. However, there is a lack of information on people’s attitudes towards and relationships with cave-roosting bats. In 2019, we interviewed 60 residents around three karst outcrops (Sampeau Hill, Banan Hill, and Reichietra Hill) in Battambang Province, northwestern Cambodia, along with agricultural professionals in Battambang Town, the province’s capital. The primary objectives of the interviews were to examine people’s: (1) attitudes towards bats, (2) experiences with bats, (3) and engagement in high-risk behaviors associated with transmission of bat-related diseases (e.g. guano mining, hunting, etc.). Most respondents (70%) held positive attitudes towards bats and listed guano production, pest control, and tourism as benefits bats provide. Additionally, all informants believed bats should be protected and stated that they would feel sad if bats were extirpated. Conversely, respondents noted that many people eat bats. We followed these semi-structured interviews with five key informant interviews involved with the conservation of bats, which provided information on the history of human-bat interactions within these communities. Respondents’ positive attitudes towards bats and recognition of ecosystem services bats provide indicate they would support bat conservation policy and may be interested in developing community-based conservation programs around karst outcrops.
... There are also recent concerns that bats could have been one source of Covid-19 near Wuhan-China [2]. However, on the positive side, bats are essential pollinators [3], [4], insectivores [4], [5], and integral cogs in valuable ecosystems that humans benefit from, and hence their rapid population decline [6] is a great cause of worry for the environment. Bats as a species are not the problem, but rather the rise of virus outbreaks finds its explanation in the spread of human disturbances in habitats where bats live, as people encroach upon their territories [7]. ...
Article
The extent to which organic farming can support biodiversity has been extensively studied. However, most of the research has been conducted on organic farms in temperate regions, with the focus mainly being on birds, insects, and plants and rarely on insectivorous bats, especially in Southeast Asia. We studied pairs of matched organic and conventional rice fields along a gradient of landscape complexity in the Songkhla Lake Basin and conducted acoustic surveys using bat detectors to analyze the influence of farming system and landscape characteristics on bat activity and prey availability. We also tested the “intermediate landscape complexity” hypothesis, which states that local conservation efforts are most effective in landscapes of intermediate complexity compared to extremely simple or extremely complex landscapes. We detected no difference in bat species richness, total bat activity, feeding activity, and insect prey abundance between organic fields and conventional fields. Even though organic farming did not increase bat activity on its own, it was most beneficial to bat activity in landscapes of intermediate complexity. Our findings suggest that landscape traits contribute more to bat activity than farm management and that insectivorous bats have species- and guild-specific responses to various landscape contexts. We also found that disturbance caused by tropical storms negatively impacts the activity of insectivorous bat.
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The diverse functional roles of over 6,000 species of extant mammals that range in body size across eight orders of magnitude, from blue whales (Balaenoptera musculus) to tiny Etruscan shrews (Suncus etruscus), contribute to shaping Earth’s ecosystems. Large mammalian herbivores (e.g., African elephants [Loxodonta africana], American bison [Bison bison], hippopotamuses [Hippopotamus amphibius]) and carnivores (e.g., wolves [Canis lupus], pumas [Puma concolor], sea otters [Enhydra lutris]) often have significant effects on primary producers in terrestrial, aquatic, and marine systems through nutrient cycling, energy flow, and the exertion of bottom-up and top-down processes. Small mammals, like bats, are important pollinators, dispersers of fruits, and consumers of arthropods, and others, especially rodents and primates, are important predators and dispersers of seeds. Many of these mammal-mediated processes occur simultaneously in the same ecosystem, and have significant effects on community structure of primary producers that in turn alter communities of other vertebrates and invertebrates. Many mammals also are ecosystem engineers (e.g., elephants, American beavers [Castor canadensis], porcupines [Erithezon dorsatum], prairie dogs [Cynomys spp.]) that create, significantly modify, or destroy habitat, and by doing so, they alter ecosystem structure and function and increase habitat heterogeneity and biodiversity. The extensive influence mammals have on ecosystems results in important services that contribute to human well-being, such as pollination, insect pest control, and bioturbation of soils. The rapid declines in abundance of many mammal populations and the associated increase in extinction risk raise conservation concerns for mammals. To maintain mammalian diversity and the critical ecosystem processes they provide, scientists need to mobilize concern for their status and strive for more effective and comprehensive conservation action. We provide insights and synthesis on the ecological role of mammals and highlight key research questions and future directions for their conservation.
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We investigated the timing and variation in evening emergence and dawn return of a maternity colony of Mexican free-tailed bats, Tadarida brasiliensis mexicana, in the summers of 1996 and 1997. In both summers, the onset of evening emergences and the end of dawn returns correlated with sunset and sunrise, respectively. Bats tended to emerge earlier in relation to sunset during late summer than in spring to early summer. Dawn returns ended progressively later in relation to sunrise through the season. Bats emerged much earlier and ended dawn returns later in 1996 than in 1997, coincident with a severe drought in spring to midsummer 1996. Bat captures during different seasons at the cave entrance indicate that patterns of emergence and return were non-random with regard to age, sex, and reproductive classes of bats. Higher proportions of reproductive females emerged earlier in the evening and returned later at dawn. Non-reproductive and post-lactating females and males exhibited an opposite pattern. Higher proportions of juveniles tended to emerge earlier in the evening and to return earlier at dawn.
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Analysis of 597 fecal pellets collected throughout the year from Tadarida brasiliensis antillularum in Puerto Rico revealed that the diet, expressed as percent volume, differs from the Texan subspecies and consists largely of dipterans, hymenopterans, lepidopterans, and homopterans, in decreasing order of importance. This species seemed to prey heavily on swarms of flies or ants, suggesting that it is an opportunist, and appears to be roughly the ecological equivalent of species of Myotis in mainland North American communities. Overall seasonal variations in diet are significant, and at times are marked enough to produce biased estimates when small samples over narrow periods of time are examined.
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We studied foraging activity and food resource use of Brazilian free-tailed bats. Tadarida brasiliensis, from a large maternity colony near Uvalde, Texas. We recorded echolocation calls of bats at replicate sites in towns, cropland, and ranches and quantified the proportions of signal-receiving time, the numbers of feeding buzzes, and the mean attack attempts per unit of activity time to evaluate habitat use by bats. Food habits of the bats were determined from fecal samples, and the composition and relative abundance of various insect orders in the three habitats were assessed using light traps. Towns with mercury-vapor type street lamps appeared to be important feeding areas for the bats, where they exhibited higher foraging activity and attack rates than over cropland or ranches. The common use of street lamps over towns, however, could have affected the efficiency of our traps in insect assessment; towns exhibited lower relative insect abundance than the other two habitats. Insect abundance did not differ between ranches and cropland, but a decline in relative insect abundance occurred in pre-dawn periods over cropland, which correlated to a higher bat activity per unit time over ranches than on cropland. The bats also displayed higher attack rates, and had a broader diet, in evening than in pre-dawn periods. The diet of bats contained 12 orders of insects, which accounted for 80% of insect orders captured in traps. At the ordinal level, the relative importance of these prey in the bats' diet strongly correlated to those sampled by the traps. The differences in relative abundance of major insect orders between midnight and pre-dawn sampling also correlated to those in percent volumes of respective insect orders in the bats' diet. These results agree with our prediction and suggest an opportunistic foraging mode for this species.
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A maternity colony of northern bats, Eptesicus nilssonii, was observed regularly in southern Sweden (57°45′N, 13°25′E) during the reproductive period from 1988 to 1990. On average, females spent ca. 3 h outside the roost each night. Time spent outside the roost diminished during late pregnancy, when body weight was rapidly increasing. Foraging time was longer during lactation than during pregnancy. It increased by >100% between parturition and weaning, a reflection of increasing energetic costs of milk production. Foraging time did not differ significantly among individuals in the same stage of reproduction. Non-breeding females did not show seasonal changes in foraging time. Low body weights and deferred breeding in younger females may be effects of limited opportunities for foraging or competitive relationships among the females.
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During the summer of 1979 a cave which served as a summer aggregation site for male Indiana bats (Myotis sodalis) was visited every 2 weeks for collection of feces and sampling of the insect fauna available as prey. A comparison of insects eaten, determined by fecal analysis, with insects collected from the foraging habitat showed that large proportions of lepidopterans were eaten throughout the summer, often in excess of proportional availability. Insects from five additional orders were eaten regularly, but they were frequently eaten less than the proportion in which they were available. Throughout the season, dietary intake of aquatic insects was low. Diet diversity decreased from early to late summer. The proportions of several orders of aquatic insects eaten were correlated to three measures of lunar illumination and cyclicity.
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Both search and height-finding radars were used to observe the airborne behavior of free-tailed bats, Tadarida brasiliensis mexicana, near several caves in the southwestern United States. Radar echoes from dense groups of bats covered areas as large as 400 square kilometers and rose to altitudes of more than 3000 meters. The presence of large numbers of bats within these areas was confirmed by visual observation from a helicopter. Bat flights appeared on radar at dusk and at dawn as a slowly expanding or contracting target, usually located near a known roost. The direction in which the echo expanded most rapidly was not due to drift of the bats by winds. This leading edge often moved at more than 40 kilometers per hour, indicating the capacity for rapid, well-directed, high altitude flight in these animals. Bats flying at such high altitudes must employ sensory systems other than echolocation for orientation and navigation.
Article
(1) The diet of the bat Rhinolophus ferrumequinum was analysed from faeces and prey remains from feeding sites through one breeding season. Light traps measured prey availability. (2) Previous studies have indicated opportunistic feeding, but rhinolophids use echolocation which may interpret insect wingbeat characteristics to select insect types (e.g. according to taxa, size). (3) R. ferrumequinum selectively dismembered large prey at perches, reducing energy costs. The diet varied over the season and consisted mainly of Lepidoptera (40.61% by volume) and Coleoptera (33.24%). Hymenoptera and Diptera were taken. More large items than expected by chance could result from the bats' acoustic search fields, or from selection. (4) More males than females of the cockchafer M. melolontha were eaten in May-June. The diet was most diverse in spring and autumn, when preferred prey items (moths) were scarce, and narrowest during late pregnancy, when moths constituted most of the diet. (5) R. ferrumequinum conforms to optimal foraging models for predators sensitive to the environment: selection for prey size, and rejection of unprofitable prey (Diptera and ichneumonids) except when more profitable prey (moths) were scarce was apparent. R. ferrumequinum certainly does not forage opportunistically.
Article
Bat detectors on helium-filled kite balloons revealed echolocating bats active at altitudes ≤ 600 m above the ground over Brachystegia woodland in the Sengwa Wildlife Research Area, Zimbabwe. Feeding buzzes indicated that bats were actively foraging to 600 m. At least seven species of bats were detected, including six molossids and one emballonurid.
Article
In a field experiment designed to evaluate dietary variation in Mexican free-tailed bats (Tadarida brasiliensis mexicana) we found that lactating females fed largely on coleopterans and lygaeid bugs during evening feeding bouts and mostly on moths during morning feeding bouts. These results suggest that interpretations of food habits in this and other species may be biased unless samples from both nightly feeding bouts are included in the analyses. Diets of different individuals during the same feeding bout were strikingly similar, suggesting that lactating females either fed in the same general habitats or that they encountered and preferentially fed on similar prey items among those available. Bats captured upon return from evening feeding bouts produced significantly more fecal pellets than those captured following second feeding bouts. This difference suggests that either more food is eaten in the first feeding bout or, alternatively, highly chitinous insects such as coleopterans and lygaeids contribute more to fecal matter than relatively soft-bodied moths. We found no significant relationship between hardness of prey and number of pellets produced. Individual bats produced an average of 2-3.6 insects/pellet, but no consistent relationship was found between the number of insects eaten and the number of fecal pellets produced. Our analysis indicates that at least five pellets are needed to establish the number of insect taxa (families) consumed by a bat. Results from this study suggests that future research on food habits of insectivorous bats should examine fecal pellets or stomach contents from evening and morning feeding bouts to fully characterize the diet of a given species.