Le Sueur’s Wing-gland Bat
The Le Sueur’s wing-gland bat, also known as Lesueur’s hairy bat, is a small insectivorous bat endemic to southern Africa. It is one of only two species in the genus Cistugo, which is considered an evolutionary link between free-tailed bats (Molossidae) and vesper bats (Vespertilionidae). This species is notable for its unique wing glands, which distinguish it from other bats. Despite being rarely observed, it plays an important ecological role in controlling insect populations within its range.
Meet Le Sueur’s Wing-gland Bat
Classification
Le Sueur’s wing-gland bat is a small bat with a head-body length ranging between 40 and 54 millimeters (1.6 to 2.1 inches), a tail length of 32 to 50 millimeters (1.3 to 2.0 inches), and a forearm length of 35 to 39 millimeters (1.4 to 1.5 inches). It typically weighs between 5 to 10 grams (0.18 to 0.35 ounces), making it a small bat compared to many of its relatives.
Its fur color varies from yellowish-orange, yellowish-brown, pale brown, to reddish-brown on the dorsal side, while the ventral side is lighter, ranging from pale brown to whitish. The facial skin is dark brown and hairless, while its ears are rounded with a narrow tip.
A key characteristic of Cistugo lesueuri is the presence of two small glandular masses on each wing membrane, a feature unique to its genus. The function of these wing glands remains uncertain, but researchers believe they could be involved in scent marking, communication, or reproductive signaling. The tail is long and completely enclosed within the broad uropatagium (tail membrane), which is semi-transparent and covered externally with fine, cream-colored hairs.
Where Does Le Sueur’s Wing-gland Bat Live?
Biogeographic Realm: Afrotropic
Continents: Africa
Subcontinents: Southern Africa
Countries: South Africa, Lesotho
Le Sueur’s wing-gland bat is found in regions of South Africa and Lesotho, primarily in mountainous terrains above 1,500 meters (4,920 feet). It has been recorded at elevations up to 2,420 meters (7,940 feet) in the high plateaus of Lesotho, where it inhabits wet alpine meadows interspersed with small lakes.
It thrives in a range of biomes, including Afromontane forests, Highveld grasslands, and Karoo shrublands. Unlike many other bat species, it appears to be well-adapted to open landscapes, though it prefers areas near water sources, where insect prey is more abundant. The species is often found roosting in rock crevices or small caves, though further studies are needed to fully understand its habitat preferences.
What Do Le Sueur’s Wing-gland Bats Eat?
Le Sueur’s wing-gland bats are insectivores, feeding on a variety of small flying insects. Fecal analyses from the Northern Cape Province of South Africa indicate that their diet consists primarily of dipterans (flies), which make up about half of the consumed prey volume. Hemipterans (true bugs) are also common, comprising around one-third of their diet. Additionally, they consume hymenopterans (wasps, bees, and ants), beetles, caddisflies, and mayflies, indicating a strong association with water-rich environments.
Their foraging strategy suggests they are clutter-edge foragers, hunting along vegetation borders, near rocky outcrops, and possibly over open grasslands. Echolocation call characteristics indicate that they use short, frequency-modulated calls, which allow them to detect and capture insects at close range.
What Eats Le Sueur’s Wing-gland Bats? – Predators & Natural Enemies
As with most small bat species, Le Sueur’s wing-gland bat is vulnerable to predation by:
- Birds of Prey: Nocturnal raptors such as barn owls (Tyto alba) and eagle owls (Bubo spp.) are known predators of small bats.
- Snakes: Some arboreal and ground-dwelling snakes may prey on bats when they roost in rock crevices.
- Carnivorous Mammals: Genets, mongooses, and wild cats may opportunistically hunt bats, particularly when they leave their roosts at night.
Further studies are required to determine specific predator-prey dynamics for this species.
Behavior & Lifestyle
Le Sueur’s wing-gland bat is nocturnal, emerging shortly after sunset to forage. It is believed to roost in rock crevices and cliff faces, though some individuals have been found resting in abandoned buildings. Unlike many other bat species, it may not be highly social, though mixed-sex colonies of up to 40 individuals have been recorded.
Echolocation studies show that its calls consist of short, frequency-modulated components followed by a brief constant frequency segment. These calls are adapted for maneuvering through complex environments and detecting small insect prey at close range. During winter months, the species may enter a state of torpor to conserve energy, though it does not undergo full hibernation.
How Do Le Sueur’s Wing-gland Bats Reproduce?
Reproductive data on Le Sueur’s wing-gland bat is limited, but available evidence suggests that females give birth to a single pup per reproductive cycle, with occasional instances of twins. Pregnant females have been collected in October and December, indicating that mating likely occurs in late winter or early spring. Males with scrotal testes have been observed in February, suggesting seasonal reproductive activity.
Like most small bats, the young are likely altricial, born blind and hairless. They depend on maternal care for warmth, protection, and milk until they are old enough to begin independent foraging. Further studies are needed to understand the species’ reproductive strategies in greater detail.
Are Le Sueur’s Wing-gland Bats Endangered? – Conservation Status & Threats
Le Sueur’s wing-gland bat is currently classified as Least Concern by the International Union for Conservation of Nature (IUCN). This classification is based on its relatively wide distribution and the lack of immediate threats to its population. However, due to the species’ rarity in scientific records, its population trends remain poorly understood.
Potential threats include:
- Habitat Loss: Mining operations and land development could disrupt roosting sites and reduce insect prey availability.
- Wind Farms: Expanding wind energy infrastructure poses a collision risk for bats, particularly in open landscapes where they forage.
- Climate Change: Changes in rainfall and temperature patterns may impact insect populations, indirectly affecting food availability.
Although currently not considered endangered, continued monitoring and ecological studies are necessary to better understand population dynamics and assess potential conservation needs for this species. Protecting natural roosting sites and ensuring the availability of foraging habitats will be key to maintaining healthy populations of Le Sueur’s wing-gland bat in the future.
