Perception Channels: tactile ; chemical
Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%. While there are currently no reports of Lasiurus ega mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.
CITES: no special status
IUCN Red List of Threatened Species: least concern
Several cases of rabies have been reported in Lasiurus ega in southen California. In one instance, an individual landed on a human's bare foot and punctured the toe. Before 1979, there were no known instances of this species carrying rabies.
May help to control harmful species of insects.
L. ega eats primarily insects caught in flight but is also known to alight on vegetation to pick off insects. Feeding flights are 6-15 m. above ground.
Lasiurus ega is widely distributed from Mexico south to Argentina, but the range seems to be extending northward into parts of California, Texas, Arizona and New Mexico.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Bats of the genus Lasiurus generally occur in wooded areas and roost in foliage. Occasionally these bats roost in tree holes or buildings. In the U.S. L. ega is associated with introduced palms, which is thought to be a reason for its recent expansion northward.
Terrestrial Biomes: forest ; rainforest ; scrub forest
A whitish buff, yellowish, or orange, usually with a blackish wash. Tail membrane is well furred.
Range mass: 10 to 18 g.
Average mass: 12 g.
Other Physical Features: endothermic ; bilateral symmetry
Normal litter size is 2 or 3 young, although individuals have been known to have single young. Estimated gestation period is 80-90 days. Mating occurs in the late summer or fall with sperm being stored overwinter in the uterus. Ovulation and fertilization occur in the spring with births occurring from late May to early July.
Range number of offspring: 2 to 4.
Range gestation period: 90 to 105 days.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; sperm-storing
The southern yellow bat (Dasypterus ega) is a species of vesper bat that belongs to suborder microchiroptera (microbat) in the family Vespertilionidae. It is native to South, North and Central America, from the Rio Grande Valley of Texas in the United States to Argentina.
The southern yellow bat is a small bat covered with yellow fur as its name. Generally, females are larger than males. Forearm length of female averages 4% (1.83 mm) greater than that of males.[2]
Southern yellow bats occur in the southwestern United States to northern Argentina and Uruguay, with the most austral record being Buenos Aires province, Argentina, at 40° S.[3] They reside in wooded area such as forest, foliage, and palms.[4] They occasionally occupy other sites that resemble large dead leaves, such as dried corn stalks and thatched roofing [5] This species roosts in trees and vegetation.[6] In Texas, their preferred roosting sites are the frond "skirts" of both wild and ornamental palm trees, such as Sabal mexicana and Washingtonia robusta. These are collections of dead fronds against the trunk and provide a favored dark habitat for the bats. Palms are also home to insects, which the bats eat.[7]
The southern yellow bat is a nocturnal insectivore. They forage for one to two hours after sunset on small to medium-sized flying insects. They usually feed near their roost, and go no farther than necessary for water.
Lasiurus ega copulates before the end of hibernation, but a female L. ega delays its ovulation and stores the sperm for 6 months and fertilizes it later. All reproductive organs involuted following mating in July (early winter) and remained inactive until the following April (autumn).[8] Gestation is continued for 3-3.5 months, and young are born in late. This species is monoestrous.[2]
The southern yellow bat flies far out to sea and seasonally migrates southward from extreme northern portions of its range.[2]
In the northern hemisphere, males of L. ega become scarce between April and June, while females are present year-round, suggesting a migratory strategy.[2] L. ega shows a tendency to migrate toward the Equator, as described for other species of the genus.[2] Southern yellow bats that migrate along coastlines take shortcuts over water. Many North American migrant bats can be found at a distance of several kilometers from their normal destination during fall and spring migrations, probably having been blown there by wind.[9] Both records of L. ega in the Southern Hemisphere indicate movements at the end of summer and beginning of fall, supporting the theory that at least some animals migrate to avoid cold temperatures. With this second sighting, the probability that both records of this species over the South Atlantic were the result of wind has become less likely.[3]
The southern yellow bat (Dasypterus ega) is a species of vesper bat that belongs to suborder microchiroptera (microbat) in the family Vespertilionidae. It is native to South, North and Central America, from the Rio Grande Valley of Texas in the United States to Argentina.
