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.
Lesser bamboo bats also use their vision, sense of smell, and sense of touch to perceive their environment and to communicate effectively among individuals.
Communication Channels: tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; ultrasound ; echolocation ; chemical
Lesser bamboo rats are considered lower risk/least concern by the IUCN. Populations seem stable currently.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of T. pachypus on humans.
Humans benefit from T. pachypus through their control of insect populations. They can eat thousands of insects a night.
Positive Impacts: controls pest population
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.
Species Used as Host:
Commensal/Parasitic Species:
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.
Animal Foods: insects
Primary Diet: carnivore (Insectivore )
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).
Biogeographic Regions: oriental (Native )
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.
Range elevation: 180 to 1220 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest
Other Habitat Features: agricultural
The lifespan of T. pachypus is not reported. Like other vespertilionids, they may have relatively long lifespans, given their body size.
Lesser bamboo bats are small bats with well developed tails that are completely enclosed in a tail membrane.
Range mass: 2 to 5.8 g.
Range length: 35 to 50 mm.
Range wingspan: 25 to 33 mm.
Range basal metabolic rate: high (high) cm3.O2/g/hr.
Other Physical Features: endothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
Predation on these bats is rare, but they have been known to be preyed on by owls when foraging at night.
Known Predators:
Anti-predator Adaptations: cryptic
Mating systems in lesser bamboo bats are not known, although polygyny is suspected based on some observed roosting patterns.
Mating System: polygynous
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.
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.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
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.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female)
The lesser bamboo bat or lesser flat-headed bat (Tylonycteris pachypus) is one of the smallest species of vesper bat,[2] and is native to Southeast Asia.
The bat, the size of a bumble bee, is among the smallest mammals on earth,[3] measuring about 4 cm (1.6 in) in head-body length with a tail about 2.5 cm (0.98 in) long and a wingspan of 19 cm (7.5 in). Adults weigh between 1.4 and 5.2 g (0.049 and 0.183 oz).[4]
The fur ranges from golden or cinnamon to dark brown, and is paler on the underside of the body. The head is flattened, with a short snout and triangular ears with a wide tragus.[4] The name pachypus means "thick-footed" and refers to the presence of smooth fleshy pads at the base of the thumb and on the heels of the feet, which help the bat grip onto bamboo stalks.[5] The wings have an aspect ratio of 6.2, allowing the bat to be agile in flight at the expense of a slow speed.[6]
A 4.8 gram T. pachypus has about an 80 mg brain.[7]
Lesser bamboo bats are found throughout Southeast Asia from Bangladesh to southern China and Indonesia and also in southern and eastern India. It inhabits deciduous forests with extensive areas of bamboo growth, at altitudes from sea level to 1,260 m (4,130 ft).[1]
Five subspecies are recognised:[4]
Lesser bamboo bats typically roosts in the slit bored into the shoots of bamboo by leaf beetle larvae. The entrance slit to such cavities is too restrictive for most predators, such as snakes, but the flattened head of the bamboo bat allows it to enter. Although the exact species vary across their range, in Malaysia, the preferred bamboo is Gigantochloa scortechinii, and the beetles are most commonly Lasiochila goryi. The bats sometimes use rock crevices or holes in trees as alternative roosting sites.[8] Females tend to roost in small groups of about five individuals, although larger groupings of up to 38 have been reported. Males roost alone, or in small groups of up to six.[8][9] Individuals switch roosts every day, and larger groupings tend to be temporary.[4]
The bats are insectivorous, with flies, beetles, and hymenopterans forming the bulk of their diet.[10] They catch insects on the wing, using echolocation calls that start at 125 kHz and drop to 50 kHz.[4]
Lesser bamboo bats are polygynous, with females mating with multiple males throughout the September to November breeding season. Unusually for a tropical species, the females store the sperm after mating, with ovulation and fertilisation not occurring until January. Gestation lasts 12 to 13 weeks, with the young being born between April and May. Most births are of non-identical twins, although identical twins, singletons, and triplets are born on occasion.[9][11]
Newborn young are blind and hairless and weigh about 0.6 g (0.021 oz). The mother carries her young for the first couple of days, but then leaves them behind in the bamboo chamber. The young are weaned and able to fly 22 to 25 days after birth. When their fur first begins to grow it is dark in colour, taking on the lighter and more reddish adult hue by October of their first year. Both males and females are sexually mature by the start of the first breeding season after birth.[9][11]
Bat flies which have the lesser bamboo bat as its host include Basilia brevipes, Basilia majuscula, and Basilia fletcheri.[12]
The lesser bamboo bat or lesser flat-headed bat (Tylonycteris pachypus) is one of the smallest species of vesper bat, and is native to Southeast Asia.
