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Tylonycteris pachypuslesser bamboo bat

By Kyle Wollin

Geographic Range

Lesser bamboo bats, Tylonycteris pachypus, are found in Bangladesh, India, Myanmar, South China, Thailand, Laos, Cambodia, Vietnam to peninsular Malaysia, the Philippines, Sumatra, Java, Borneo, Bali (Indonesia) and the Andaman Islands (India). (Zhang, et al., 2006)

Habitat

Lesser bamboo bats occupy lowland agricultural areas that contain bamboo stands. In a study done by Zhang et al. (2006), lesser bamboo bats were observed in three habitat types: along trees and houses, pathways along bamboo forest, and above bamboo forest. Of 145 individuals caught over a 28 day period, 45 % were collected on the pathway, 52 % were collected along the trees and houses and 3 % were collected above the bamboo forest. (Zhang, et al., 2006)

  • Range elevation
    180 to 1220 m
    590.55 to 4002.62 ft

Physical Description

Lesser bamboo bats are small bats with well developed tails that are completely enclosed in a tail membrane. (Medway and Marhsall, 1970)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    2 to 5.8 g
    0.07 to 0.20 oz
  • Range length
    35 to 50 mm
    1.38 to 1.97 in
  • Range wingspan
    25 to 33 mm
    0.98 to 1.30 in
  • Range basal metabolic rate
    high (high) cm3.O2/g/hr

Reproduction

Mating systems in lesser bamboo bats are not known, although polygyny is suspected based on some observed roosting patterns. (Zhang, et al., 2005)

Mating seems to be seasonal, with males being fertile from mid-October to mid-January and females are in estrous from mid-October to mid-November. One offspring is usually born, sometimes two. Gestation is from 12 to 13 weeks long and the young are nursed for 5 to 6 weeks after that. The young are independent immediately after weaning and can breed in the first year after their birth. (Zhang, et al., 2006)

  • Breeding interval
    Lesser bamboo bats breed once each year.
  • Breeding season
    Breeding season takes place from mid-October until mid-November.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    2
  • Range gestation period
    84 to 91 days
  • Range weaning age
    35 to 42 days
  • Range time to independence
    5 to 6 weeks
  • Range age at sexual or reproductive maturity (female)
    8 to 9 months
  • Range age at sexual or reproductive maturity (male)
    8 to 9 months

Mothers care for their young on their own. Because they roost in groups, they need efficient and distinctive communication calls to ensure successful reunions. In T. pachypus, recognition between the mother and pup is mutual. Recognition involves visual, acoustic and olfactory cues. Vocal signals that mediate recognition can be the mother’s echolocation calls, isolation calls from the infant, or other communication calls from the mother or infant. Infant bats often emit distinctive isolation calls (i-calls) which assist the location of offspring by the mother. (Zhang, et al., 2005)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female

Lifespan/Longevity

The lifespan of T. pachypus is not reported. Like other vespertilionids, they may have relatively long lifespans, given their body size.

Behavior

In lesser bamboo bats the sexes display 2 different roosting behaviors. Males are solitary and females are gregarious. In some roosting sites, a single male, twelve adult females and 24 infants were found. Lesser bamboo bats are active at night and roost during the day.

Home Range

Home range size in lesser bamboo bats is not known.

Communication and Perception

Vocalization from infants occurred for precursor for echolocation calls and as isolation calls (i-calls) to attract the mother. As the infants grew older the 2 calls increased. Female directive calls are different than their infants calls by having lower frequency and longer duration. (Zhang, et al., 2005)

Lesser bamboo bats also use their vision, sense of smell, and sense of touch to perceive their environment and to communicate effectively among individuals.

Food Habits

Lesser bamboo bats are strictly insectivorous. The diet consists primarily of 7 different orders of insects. Hymenoptera, Diptera, Coleoptera, and Hemiptera are the 4 main orders, making up 62.3 %, 29.6 %, 6.0%, and 1.5%, respectively, of their diets. Other insects eaten include Homoptera, Blattodea, and Embioptera. Swarming termites, Isoptera, are also a small portion of their diet. Seasonal variation from spring to autumn occurs in their diet, no order of insects made up more than 50% of the total diet from March to April. From May to October, Hymenoptera made up more than 50% of the diet by volume. (Zhang, et al., 2005)

  • Animal Foods
  • insects

Predation

Predation on these bats is rare, but they have been known to be preyed on by owls when foraging at night. (Lewis, 1995)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Lesser bamboo bats keep insect pest populations down by eating thousands of them each night. Some of these insects are considered pests because they will destroy agricultural fields. Bamboo Gigantochloa scortechinii is used for roosting. Basilia hispida, a bat fly, is an ectoparasite of T. pachypus. (Marshall, 1971)

Species Used as Host
  • bamboo Gigantochloa scortechinii
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Humans benefit from T. pachypus through their control of insect populations. They can eat thousands of insects a night. (Marshall, 1971)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of T. pachypus on humans.

Conservation Status

Lesser bamboo rats are considered lower risk/least concern by the IUCN. Populations seem stable currently.

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Kyle Wollin (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.

Glossary

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

echolocation

The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Lewis, S. 1995. Roost Fidelity of bats. Journal of Mammology, Vol. 76 No. 2: 481-496.

Marshall, A. 1971. The ecology of Basilia hispida.. The Journal of Animal Ecology, Vol. 40 No. 1: 141-154.

Medway, L., A. Marhsall. 1970. Roost site selection among flat-headed bats. Journal of Zoology, 161: 237-245.

Zhang, L., G. Jones, S. Rossiter, G. Ades, B. Liang, S. Zhang. 2005. Diet of flat headed bats, << Typlonycteris pachypus>> and << T. Robustela>>, in Guangxi, South China. Journal of Mammalogy, Vol. 86. No. 1: 61-67.

Zhang, L., B. Liang, S. Wei, S. Zhang. 2006. Morphology, echolocation and foraging behaviour in two sympatric sibling bats species, << Tylonycteris pachypus>> and T. robustula in South China. Journal of Zoology ( London).

Zhang, L., J. Gareth, P. Stuart, B. Liang, S. Zhang. 2005. Development of vocalization in the flat headed bats, Tylonycteris pachypus and T. robustula . Acta Chiropterologica, Vol. 7 No. 1: 91-99.

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