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Lavia fronsyellow-winged bat

By Guru Srinivas

Geographic Range

Lavia frons is found throughout Middle Africa. This yellow-winged bat can be seen from Gambia to Ethiopia and from Southern to Northern Zambia. Lavia frons has also been observed as south as Northern Rhodesia. In general, Lavia frons occupies territory in Africa from 15° north to 15° degrees south latitude (Vaughan and Vaughan, 1986).

Habitat

Lavia frons occupies low-lying savannas and woodlands with open space. This species generally prefers areas where trees and bushes occur near rivers, swamps, or lakes. Apparently, trees near and around water provide sites for roosting. Lavia frons is usually seen roosting in Acacia tortilis trees at elevations below 1000 meters.

  • Range elevation
    1000 (high) m
    3280.84 (high) ft

Physical Description

Lavia frons is an average-sized bat with the female slightly larger than the male. The weight of Lavia frons (male and female considered) ranges from 28 to 36 grams (Kingdon, 1974). The length from head to tail of females ranges from 63 to 80 mm while the length of males goes from 58 to 80 mm (Rosevear, 1965).

An important defining characteristics of bats is their forearm length. Females have forearm lengths of 55 to 63 mm; males, from 55 to 60 mm. Ear length of females ranges from 36 to 47 millimeters and for males, from 35 to 45 mm. The tibia length ranges from 33 to 37 mm for females and from 32 to 36 mm for males. The length of the skull ranges from 23.3 mm to 26.1 mm for females and 22.8 to 25.0 mm for males (Rosevear, 1965). Members of this species have prominent postorbital processes.

The dental formula is 0/2 1/1 1/2 3/3 (upper/lower incisors, upper/lower canines, upper/lower premolars, upper/lower molars). Lavia frons, like other Megadermitidae, has no upper incisors. The molars are dilambdodont, which is consistent with eating insects. There is a cingulum on the canine as well as two secondary cusps. The premolars are quite large with the posterior premolars being bigger than the anterior premolars. Finally, the incisors of the lower jaw have rounded crowns (Rosevear, 1965).

Lavia frons have a bluish gray body with some members having a lower back that is somewhat brownish or green. The wings are broad and the wingspan is about 14 inches (Rosevear, 1965). The color of its wings is a mixture of red and yellow and hence, Lavia frons is often referred to as the African Yellow-Winged bat. Its ears, like its wings, are reddish yellow. The ears contain a divided tragus that is relatively spiky. The eyes are quite large. In fact, Lavia frons has the second largest eyes of any African microchiroptera, second only to Cardioderma cor (Vaughan and Vaughan, 1987). The noseleaf of Lavia frons is distinctive in that it is enveloped by a pointed spike. Other physical characteristics include glands on males that secrete a yellow substance that discolors the lower back and a pair of false nipples near the anus of females.

  • Range mass
    28 to 36 g
    0.99 to 1.27 oz
  • Range length
    58 to 80 mm
    2.28 to 3.15 in
  • Average wingspan
    36 cm
    14.17 in

Reproduction

Courtship rituals include a pair flying over each other and circling one another.

Members of Lavia frons are monogamous with members of a pair roosting together and engaging in courtship rituals, which include flying together and circling one another. The gestation period usually begins in January and lasts about three months with offspring being born in early April (there have also been reports of births in October and January; Vonhof,1999).

After birth, a young bat adheres to its mother by attaching its mouth to a pair of false nipples located near the mother's tail. To further insure attachment to the mother, the young bat wraps its legs around the back of its mother's neck. Despite the added weight of the offspring, the mother continues to forage. For roughly three months, the mother and its offspring stay in close proximity. During this time, grooming generally occurs with the mother eating the metabolic wastes of the baby in an apparent water conservation mechanism (Vaughan and Vaughan, 1987). In addition, the young bat observes the foraging and hunting techniques of its parents. The young Lavia frons hangs from its mother and practices flapping its wings until it begins flying by itself. At that point, the young bat is left alone.

Approximately 20 days after the young bat begins flying alone, weaning begins. For 30 more days, the young Lavia frons shares the territory of its parents (Vaughan and Vaughan, 1987). After this 30 day time period, the young bat is no longer solely dependent on its parents.

  • Breeding season
    January-April
  • Average number of offspring
    1
  • Average gestation period
    3 months
  • Average weaning age
    55 days

Both male and female partners care for the offspring. The male protects the offspring while the female nurtures the offspring.

Lifespan/Longevity

.

Behavior

Roosting Behavior

Members of Lavia frons, unlike the majority of mammals, are monogamous. A pair roosts one meter apart from each other but at least 20 meters from another roosting pair. A primary roost is established by a pair. A primary roost is a site that members of a pair return to after roosting in other sites or foraging. In general, Lavia frons roosts on branches that are one cm in diameter (Vaughan and Vaughan, 1987). During daytime, these bats can be seen slowly revolving their heads to observe their surroundings and potential predators.

Social Behavior

Lavia frons is monogamous, and a male and female protect each other and work together to provide parental protection for an offspring. After foraging, the female returns to the primary roost first. This happens approximately 10 minutes before sunrise. The male usually follows the female 15 minutes later and begins monitoring the surrounding area for danger. During roosting, members of a pair are often seen flying over one another. Males fly close to females and females follow males to another perch. Approximately 30 to 40 minutes before sundown, members of a pair start grooming each other. After sundown, they begin foraging again with the male proceeding first to survey the area for possible predators and insects (Vaughan and Vaughan, 1986).

Maximum social interaction often takes place between May and early June. During this time, rains are abundant, insects are plentiful, and young are learning how to forage. Courtship htakes place during this time period with members of a pair flying around each other (Vaughan and Vaughan, 1987).

Foraging Behavior

Each pair forages independently of other pairs, with each pair having their own territory. Lavia frons forages earlier in the evening and later in the morning than other bats in the area.

Communication and Perception

Food Habits

Lavia frons are insectivorous. They eat a variety of insects ranging from grasshoppers to mosquitoes. Lavia frons can often be seen eating alate termites, which are readily available during the rainy season. They tend to forage near Acacia tortilis trees that attract insects throughout the year. Rather than searching for their food, these bats wait for insects to travel near their foraging perch and then attack them. They move to different foraging sites when insects are not available. In fact, Lavia frons moves every few minutes to a different perch to increase the chances of catching prey. Lavia frons attacks insects that fly as high as 20 to 30 meters above the ground to insects that fly as low as 1 meter above the ground (Vaughan and Vaughan, 1987). The attack is almost completely horizontal with the bat usually returning to its original perch to consume its prey (further information on foraging behavior discussed in behavior section).

  • Animal Foods
  • insects

Predation

Lavia frons rotates its head almost 180 degrees to observe predators. They are always on the watch and therefore, are not frequently preyed upon. There have been, however, reports of Lavia frons being captured by predators (Vaughan and Vaughan, 1986).

Ecosystem Roles

Lavia frons plays an important part in protecting Acacia tortilis trees by regulating insect population. Acacia tortilis trees are roosting sites for these bats. They flower in the dry season during the time from mid-December to February (Vaughan and Vaughan, 1986). This flowering attracts swarms of insects, which damage the leaves of the trees while trying to gain access to the flowers. By capturing and eating insects, Lavia frons helps prevent damage to the trees.

Conservation Status

Other Comments

Many behavioral traits of Lavia frons have evolved in order to save energy. These include shifting perching locations in response to weather, monogamy (male and female Lavia frons expend much less energy in raising young when they are in a monogamous relationship), and the close relationship of the bats to Acacia tortilis trees.

Contributors

Guru Srinivas (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

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

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

male parental care

parental care is carried out by males

monogamous

Having one mate at a time.

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

seasonal breeding

breeding is confined to a particular season

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.

tactile

uses touch to communicate

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

References

Kingdon, J. 1974. East African Mammals: An atlas of Evolution in Africa vol II. London: Academic Press.

Rosevear, D. 1965. The Bats of West Africa. London: Trustees of the British Museum.

Vaughan, T., R. Vaughan. May 26, 1987. Parental Behavior in the African Yellow-Winged BAt. Journal of Mammalogy, 68: 217-223.

Vaughan, T., R. Vaughan. 1986. Seasonality and the Behavior of the African Yellow-Winged Bat. Journal of Mammalogy, 67: 91-102.

Vonhof, M., M. Kalcounis. May 5, 1999. Lavia frons. Mammalian Species, No. 614: 1-4.

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