Noctilio albiventris, Desmarest, 1818

Don E. Wilson & Russell A. Mittermeier, 2019, Noctilionidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 404-411 : 411

2.

Lesser Bulldog Bat

Noctilio albiventris

French: Petit Noctilion / German: Kleines Hasenmaul / Spanish: Noctilio pequeno

Taxonomy. Noctilio albiventris Desmarest, 1818 ,

“I’Amérique méridionale.” Restricted by A. Cabrera in 1958 to Rio Sao Francisco, Bahia, Brazil .

Noctilio albiventris is paraphyletic with respect to N. leporinus . This has been proposed and confirmed using several different molecular markers, including mitochondrial and nuclear markers. Recent studies suggest that N. albiventris is a complex of at least three and maybe four cryptic species yet to be determined but roughly coinciding with the current subspecific arrangement. Four subspecies recognized.

Subspecies and Distribution.

N.a.albiventrisDesmarest,1818—lowerAmazonBasinofVenezuela,theGuianas,andC&FEBrazil.

N.a.affinisd’Orbigny,1836—SEColombia,EEcuador,upperAmazonBasinofVenezuela,EPeru,WBrazil,andBolivia.

N.a.cabreraiW.B.Davis,1976—SBrazil,Paraguay,andNEArgentina.

N. a. minor Osgood, 1910 —- extreme S Mexico (Chiapas), Central America, N Colombia, and N Venezuela.

Descriptive notes. Head-body 65-68 mm, tail 13-16 mm, ear 22-24 mm, hindfoot 16-19 mm, forearm 54-70 mm; weight 22-42 g. The Lesser Bulldog Bat is a smaller version of the Greater Bulldog Bat (N. leporinus ), with some minor differences. Hindclaws of the Lesser Bulldog Bat are much shorter than those in the Greater Bulldog Bat and shorter than calcar. Size and relative length of hindclaws easily allow distinction between the two congeners. Fur is very short and pale brown to bright yellow. Head is almost hairless, with loose cheek skin and hare-like upper lip.

Habitat. Primarily tropical rainforests but also other tropical vegetation types such as dry tropical forest and mangrove from sea level to elevations of ¢. 1100 m. Lesser Bulldog Bats usually roost in hollow trees but can also be found in buildings. They often share roosts with other species of bats such as mastiff bats ( Molossus sp. ). In the Beni Department of Bolivia, Lesser Bulldog Bats commute among forest islands across tropical grasslands and use hollow trees of at least eleven species; roosting trees have greater diameters than non-roosting trees.

Food and Feeding. Diet of the Lesser Bulldog Bat is strongly dominated by insects, primarily hemipterans, beetles, moths, homopterans, and dipterans. According to all published studies, Lesser Bulldog Bats feed copiously on insects, but other studies also show that they eatfruits of species of Moraceae ( Ficus , Brosimum , and Morus ) and Urticaceae (Cecropia) and occasionally fish. Pollen of various tree species has also been reported in stomach contents or fecal pellets. Given that they often fly in open areas, they are believed to be good seed dispersers. One study found many remains of dytiscid beetles, a primarily aquatic species, in the diet, and a pimelodid catfish swallowed a Lesser Bulldog Bat, both suggesting association with aquatic environments. Lesser Bulldog Bats have been observed scooping insect prey from the water surface. Observations in the wild show that they fly in open areas including along slow-flowing streams and rivers, lakes, and estuaries, briefly dipping or dragging their feet or interfemoral membrane in the water to scoop up insects. They spend an average of ¢.120 minutes outside of the roost, most of that time foraging.

Breeding. Reproductive habits of the Lesser Bulldog Bat indicate a monoestrous cycle, with mating in November—-March and young born in April-May in Panama. In other regions, the cycle varies accordingly. Littersize is one, although one instance of twinning was documented. Reproductive accessory glands, including prostate, are very similar in the Lesser Bulldog Bat and other bats in the families Emballonuridae , Phyllostomidae , and Molossidae . Captive juvenile Lesser Bulldog Bats did not fly until 5-6 weeks old and nursed until ¢.3 months old. Lactating females suckled only their young, which they appeared to recognize from acoustic cues emitted by their young. Mother and young call in coordinated duets in the roost and while flying and foraging together. Males have two ancillary skin sacks in the genital area that might have hormonal or glandular function.

Activity patterns. Lesser Bulldog Bats leave their roost quite early, right after sunset, in contrast with their larger congener, the Greater Bulldog Bat that leaves the roost up to two hours after sunset. This difference has been suggested to be a mechanism to avoid competition between congeners. Lesser Bulldog Bats stay active usually between sunset and 1-2 hours after sunset and then return to their roost, with a second peak of activity around midnight.

Movements, Home range and Social organization. Some studies indicate that Lesser Bulldog Bats might be philopatric and very loyal to a particular roost. Social organization seems to be harem-based, with up to ten females per male and several harems inhabiting any particular roost. There is an instance of predation by the great rufous woodcreeper (Xiphocolaptes major)—a bird that is known to capture prey and nest inside hollow trees.

Status and Conservation. Classified as Least Concern on The IUCN Red List. No country considers the Lesser Bulldog Bat at any level of risk of extinction. In Bolivia, some populations might be prone to extirpation because misdirected control of Common Vampire Bat ( Desmodus rotundus ) can destroy hollow tree roosts.

Bibliography. Aguirre, Lens & Matthysen (2003), Aranguren et al. (2011), Beguelini et al. (2016), Botero-Botero etal. (2015), Brown et al. (1983), Cabrera (1958), Camargo & Laps (2016), Davis (1976b), Dechmann et al. (2013), Fenton, Audet et al. (1993), Forman et al. (1989), Gongalves et al. (2007), Hood & Pitocchelli (1983), Howell & Burch (1974), Kalko et al. (1998).

Figures

Plate 31 Species Accounts

Subspecies and Distribution. N.a.albiventrisDesmarest,1818—lowerAmazonBasinofVenezuela,theGuianas,andC&FEBrazil. N.a.affinisd’Orbigny,1836—SEColombia,EEcuador,upperAmazonBasinofVenezuela,EPeru,WBrazil,andBolivia. N.a.cabreraiW.B.Davis,1976—SBrazil,Paraguay,andNEArgentina. N. a. minor Osgood, 1910 —- extreme S Mexico (Chiapas), Central America, N Colombia , and N Venezuela .