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.
Perception Channels: tactile ; chemical
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
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.
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
Primary Diet: carnivore (Insectivore )
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).
Biogeographic Regions: ethiopian (Native )
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.
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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.
Range length: 58 to 80 mm.
Average wingspan: 36 cm.
Other Physical Features: endothermic ; bilateral symmetry
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).
Known Predators:
Courtship rituals include a pair flying over each other and circling one another.
Mating System: monogamous
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.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal )
Both male and female partners care for the offspring. The male protects the offspring while the female nurtures the offspring.
Parental Investment: altricial ; male parental care ; female parental care
The yellow-winged bat (Lavia frons) is one of five species of false vampire bat (family Megadermatidae) from Africa and is the only known species of its genus, Lavia.
The yellow-winged bat has a total length of 58–80 mm (2.3–3.1 in)[2] and a body weight of 28–36 g (0.99–1.27 oz).[3] Females tend to be slightly larger than males. The wingspan averages 36 cm.[4] This specie's pelage is made of long hairs that are typically pearl grey or slaty gray. Males may have greenish-yellow fur on the hindparts and on the ventral surfaces.[5] As their name suggests, the bat has wings that are reddish-yellow which is also the color of their other membranes as well as their noseleaf and ears. The membranes are largely hairless although there is some fur on the upper arms.[5] The ears are fairly long and have a spiky tragus.[4] They have an elongated noseleaf with a blunt but pointed tip.[5] Although the yellow-winged bat has an advanced interfemoral membrane, it lacks an external tail. The dental formula is 0.2.1.11.2.3.3. Glands exist on the lower back of males and discharge a yellow substance.[2] Females have false nipples near the anus and are used by the young to hold on to.[6]
The yellow-winged bat has an extensive range throughout sub-Saharan Africa south to northern Zambia. The bat mostly lives in woodland and savannah habitats and in elevations of less than 2,000 m.[5] They prefer acacia trees and thorn bushes near bodies of water,[7] around which they fly.[8] They prefer to live in areas where the vegetation is well spaced, which allows them to view more of their surroundings.[7] The yellow-winged bat primarily roosts in small trees and shrubs.[8] They can also be found roosting in trees cavities and buildings.[2] They will roost in two separate trees; a primary and a peripheral tree. Bats use their primary roost in the morning and again before evening.[9] Bats travel between primary and peripheral roost trees, especially on hot days, as they may need shade. These flights are typically short but longer flights have been recorded in midday.[9]
Unlike other false vampire bats, the yellow-winged bat feeds only on insects and not small vertebrates. They will feed on both soft- and hard-bodied insects.[3][9] Bats may feed on termites, scarab beetles, orthopterans, lepidopterans and dipterans.[3][9] The size of prey ranges from "very small to relatively large".[3] The yellow-winged bat is a sit-and-wait predator. They perch and listen for prey and if it flies by, the bat launches their attack. This species, while potentially vulnerable to predation, is very alert. Mambas, bat hawks, night tree vipers and common kestrels may prey on this species.[5]
The yellow-winged bat is a monogamous species. Males and females form pairs during the breeding season and establish their own foraging territories.[9] They are no more than 1m apart when roosting together. One member is vigilant during the day, and is able to turn its head 225° and move its ears. Between the foraging periods in the morning and evening, the male visits the peripheral roost, protecting it from potential intruders.[9] In the morning, the pairs interact with each other before splitting up for the day. The male and female meet again at the primary roost tree before evening to interact.[9] The maximum amount of male-female social interaction occurs between May and early June. This is when insects are more numerous and the young are able to hone their hunting skills.[6] The exact time at which the yellow-winged bat gives birth can vary by region; parturition occurs at the close of the dry season in October in Zambia, while at Lake Baringo in Kenya, it occurs the start of the so-called "long rains" in April.[5] Females are pregnant for around 3 months[3] with only one young being born. During the first few weeks, young hang on to their mothers.[6] Soon, the young stay at the roost for around a week and develop self-sustained flight.[5] Young are weaned when they are around 55 days old.[6]
Calls produced by this species include search-phase echolocation calls and some social calls that can be heard by humans.[5] Echolocation helps give the bat information on close objects.[9] Social calls are associated with aggression, copulation or mother-offspring interactions.[5]
Little is known about human impacts on the population of the yellow-winged bat and the population dynamics of the species have not been recorded.[5] It does not appear to be particularly threatened but is likely not very common.[5]
The yellow-winged bat (Lavia frons) is one of five species of false vampire bat (family Megadermatidae) from Africa and is the only known species of its genus, Lavia.
