Pteronotus parnellii
TAXONOMY
Phyllodia parnellii (Gray, 1843), Jamaica. Nine subspecies are currently recognized, four occurring in the West Indies.
OTHER COMMON NAMES
Spanish: Murcielago bigotudo.
PHYSICAL CHARACTERISTICS
Smaller, medium-sized bats with forearms ranging from 2.2 to 2.5 in (5.5–6.3 cm), and weighing 0.4–0.9 oz (12–26 g).
DISTRIBUTION
Found throughout the Greater Antilles, and in the mainland of Central America from southern Sonora and Tamaulipas, the south of Mexico to northern South America east of the Andes. They also occur in northern Colombia, Venezuela, the Guianas, Brazil, and Peru.
HABITAT
These bats occur in habitats ranging from arid to humid, tropical forest.
BEHAVIOR
Roost in hollows, usually in caves or abandoned mines. Colonies can consist of hundreds of individuals. Their presence in areas without caves indicates that they also roost in hollows in trees. When bats are active, they are extremely active, to an extent that they require to spend much time sleeping. They are also strongly heterothermic, meaning that their body temperature is highly variable. They can reach and maintain body temperatiures appropriate to their physiological and behavioral needs, thus conserving energy. When they are actively feeding, metabolic activity and body temperature are high. When they are resting, both metabolism and temperature are low. This process of resting under lowered metabolic activity and body temperature is called torpor. And they may enter torpor for a few hours or several months. The intensity of torpor ranges from shallow to deep. Deep, long-term torpor occurring in winder is termed hibernation. Bats spend their periods of torpor in a roost, where they can hang protected from dangers.
FEEDING ECOLOGY AND DIET
These bats hunt flying insects that they detect by Doppler-shifted echoes, separating pulse and echo in frequency. Their echolocation calls are dominated by one frequency, usually around 60 kHz. The bats eat mainly beetles and moths. In forested areas, they often can be observed hunting along trails and roads. Their distinctive echolocation calls makes them easy to recognize with a bat detector tuned to about 60 kHz. In flight, the production of echolocation calls is synchronized to the wingbeat and partly driven by movements of the viscera against the diaphram. Contractions of muscles in the middle ear contribute to the bats' avoiding deafening themselves during production of echolocation signals. Acoustic information acquired during echolocation is represented in the cerebral cortex.
REPRODUCTIVE BIOLOGY
Females bear a single young annually after a gestation period of about 50 days. The young are naked and helpless at birth. The timing of reproduction varies across the species' range, with births usually peaking around the start of the rainy season. For example, if mating occurs in autumn, the sperm is typically stored by females throughout hibernation, sometimes up to seven months, in the uterus. Within a few days of leaving their winter shelter, females ovulate one egg, and sperm are released. Fertilization and implantation then take place shortly afterwards. Typically, females of a population form a maternity colony at a site different than the hibernation site where breeding occurred. Gestation usually lasts from 40 to 50 days and results in a single offspring, usually in the late spring. Birth is a rather uneasy process: hanging inverted, mothers grab the newborn as it emerges from the birth canal and the newborn in turn grabs the abdominal fur of the mother with its hind feet, pulling to facilitate its own birth. Infants usually begin nursing almost immediately after birth. Some reports are indicative of females helping others with the birth of young. Healthy species in the wild live from five to ten years. Probably polygynous.
CONSERVATION STATUS
Classified as Lower Risk/Least Concern by the IUCN.
SIGNIFICANCE TO HUMANS
These bats have occasionally been reported with rabies. Insectivorous bats such as mormoopids eat large quantities of insects, including those that are harmful to crops and humans. For example, a 0.5 oz (13 g) individual could easily consume more than 1,000 insects, including mosquitoes, on an average night.
