| Lesser Long-nosed Bat | |
|---|---|
| Lesser long-nosed bat | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Family: | Phyllostomidae |
| Genus: | Leptonycteris |
| Species: | L. yerbabuenae |
| Binomial name | |
| Leptonycteris yerbabuenae Martinez & Villa, 1940 |
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The Lesser Long-nosed Bat (Leptonycteris yerbabuenae) is a medium-sized bat found in El Salvador, Guatemala, Honduras, Mexico and the United States.[1] It is sometimes known as Sanborn's Long-nosed Bat or the Mexican Long-nosed Bat, though the last name is better avoided since it is also used for the entire genus Leptonycteris and for one of the other species in it, the Big Long-nosed Bat L. nivalis. The Lesser Long-nosed Bat was formerly considered a subspecies of the Southern Long-nosed Bat.[1] Enthusiasts for the bats often refer to them simply as Leptos because they are the best known members of the genus Leptonycteris.
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The lesser long-nosed bat has a total length of 74-90 mm for males and 73-82 mm for females. Its total mass is averages 26.9 g.[2] There is no sexual dimorphism. The upperparts of the bat are grayish or reddish brown while the upperparts are paler and frosted with white. Juveniles have a gray pelage. The bat’s elongated rostrum bears a small, triangular noseleaf. Its ears are relatively small and simple structure. While the lesser long-nosed bat has 3 caudal vertebrae, it has no externally visible tail.[3] The tongue of the bat is relatively long and is tipped with brush-like papillae, an adaptation for lapping up nectar.[4]
The northern limits of the lesser long-nosed bat range starts from the Picacho Mountains in southern Arizona, southwest to the Agua Dulce Mountains and southeast to the Chiricahua Mountains. It can also be found in southwestern New Mexico in the Animas and Pelonicillo mountains.[5] Further south, the bat’s ranges extends down to the drier parts of Mexico and further to Hunduras, Guatemala and El Salvador.[6]
Lesser long-nose bats take two migration routes when migrating between northern Sonara and southern Arizonia.[7] Bats that arrive in coastal Sonora and southwestern Arizona during the spring travel along the western coast of Mexico.[6] There are some populations in Mexico are resident throughout the year.[6] Bats that arrive in south-central and southwestern New Mexico travel along the foothills of the Sierra Madre Mountains.[7] Lesser long-nosed bats prefer to live in arid grasslands, scrublands and oak forests in the United States.[8] In central and southern Mexico, bats live in arid a grassland, tropical thorn and deciduous forests and pine-oak forests.[6] Long-nosed bats commonly occupy lowland tropical and subtropical dry forest.
The diet of the lesser long-nosed bat is made of nectar, pollen and fruit.[9] Pollen is mostly ingested coincidental to nectar feeding or during grooming.[10] While nectar and pollen make up most of the diet of the bat’s diet, cacti fruit are also eaten, particularly when females are lactating.[11] Nectar and pollen are consumed from paniculate agave flowers as well as the nectar, pollen and fruit produced by columnar cacti, particularly saguaro and Organ Pipe Cactus cacti in Arizona and Sonora.[12] Flowers on a variety of plants are feed on by bats in winter populations in southern Mexico.[9] In Jalisco, Mexico, pollen from species of Bombacaceae is a crucial component of the bat’s diet, as these plants are patchily distributed and the nectar is only seasonally available.[6] The movements and feeding to the flowering of these cacti and agaves. This species is a major pollinator of cacti and Agavoideae and disperser of cactus seeds.[6] During their migrations to and from the Sonoran and Chihuahuan desert, long-nosed bats will feed on the nectar of CAM plants as a corridor nectar.[12] During spring, long-nosed bats feed on at least four night-blooming columnar cacti species and an Agave species during their journey north.[6] The nectar corridor for the bats fall migration south is Agave species.[12]
The foraging ecology of the lesser long-nosed bat involves long, nightly commuting flights.[13] In, Sonora, a bat will leave its day roost shortly after dusk and make a continuously during the early evening with little feeding and scout out and assess the availability.[13] In Arizona, bats forage together in small groups.[14] Usually, an individual bat will visit many flowers spread over many plants growing in a large area, and is far more than necessary to meet energy and nutrient requirements.[13] Lesser long-nosed bats roost in abandoned mines and caves. At night, when they are not foraging, the bats will roost in caves, abandoned buildings, mines, rock crevices, trees and shrubs.[5]
Lesser long-nosed bats live in colonies that are large and densely packed. They usually number from 1,000 to over 100,000 individuals.[15] Long-nosed bat colonies are widely scattered over the landscape.[16] There are seasonal differences in both size and sexual composition of bat populations. In the northern part of their range, females arrive at maternity roosts in mid to late April. It appears that females conceive at slightly different times and possibly at different roosts before migrating to the maternity roost at least in mainland Mexico.[17] In southern Arizona, male live in small groups during the summer.[5]
In central Mexico, mating takes in November and December in the northern spring roosts and in May and June in the southern winter roosts. The young are born around six months later in northern maternity roosts than in southern maternity roosts.[15] In one colony in central Mexico, reproductively active females are present throughout the year.[18] The colony peaks from February to July with a equal number of males and females. Males mate with the females in June and July and leave between September and December, leaving to a decline in the number of individuals.[18] Females give birth to one young per year.[6] Lactation in this species lasts 4-8 weeks.[19] The milk of the lesser long-nosed bat has significant protein content and young are not stressed nutritionally by low levels of milk.[19] Young are able to fly when their forearms reach 46 mm in length.[6]
Throughout its range in both the United States and Mexico, the lesser long-nosed bat is considered to be an endangered species.[6] As such, a recovery plan for the species has been approved.[20] The lesser long-nosed bat was put on the U.S. Endangered Species List in 1988.[21] Mexico lists it has one of its endangered and threatened species.[6] The IUCN lists it as Vulnerable "because of a population decline, estimated to be >30% over the last 10 years, inferred from over-exploitation, shrinkage in distribution, and habitat destruction and degradation".[1] Four main areas form conservation of this species are western Sierra Madre, Balsas Basin, southern Sierra Madre and the southeastern lowlands.[22]
