Saccopteryx

Saccopteryx sp.

The sac-winged or Two strips bats ( Saccopteryx ) are a genus of living in America Myotis bats - free tails ( Emballonuridae ).

Naming

The genus includes Saccopteryx four species found from southern Mexico to southeast Brazil. Name key to this genus is a sac-like invagination in the front wing membrane ( foreleg ) of the males ( saccus: Latin of the bag; pteron: gr the wing). Females have only a rudiment of this bag. The species name of Saccopteryx bilineata refers to two stripes in the coat on his back, but also carry the other three species of the genus Saccopteryx.

Quarters

Bats of the genus Saccopteryx spend a day on relatively well-lit places, for example at the openings of tree hollows, in the niches between buttress roots in indentations of tree trunks or even to human structures. They depend not usually from the ceiling, but on vertical structures. The individuals of a colony keep a minimum distance of a few centimeters apart upright.

Behavior

Most observations of behavior were carried out on Saccopteryx bilineata. The bag of the males includes a fragrant liquid that is fanned by the males in Schwirrflug females ( Bradbury & Emmons 1974). Histological studies showed that the Taschenepithel no gland cells possess ( Stark 1958, Scully et al., 2000). In the afternoon fill the male secretions from various regions of the body into the pockets (saliva, urine, secretions of Gulardrüse and a genital gland ). The scent of the pockets after the females fanned ( Bradbury & Emmons 1974 Voigt & Helversen of 1999, Voigt 2002). In addition to courtship in Schwirrflug, the males also express chants with which they attract females ( Behr & von Helversen 2004).

Mating systems

So far, only the mating system of Saccopteryx bilineata and leptura are described. According to Bradbury & Vehrencamp (1976, 1977) Saccopteryx leptura has a monogamous mating system in which related a male with a female in the daytime roosts usually. The colonies of Saccopteryx bilineata several dozen individuals include ( Bradbury & Emmons 1974). The social sub-unit consists of one adult territorial males and several females. In the past, such as mating systems harem - polygynous described ( Bradbury & Vehrencamp 1976, 1977 ) were. Molecular genetic analysis provided that the territorial harem males can not monopolize the females of their group ( Heckel et al., 1999 ). Nevertheless, evidence harem males produce more offspring than those who defend no female group ( Heckel & von Helversen 2002). The number of offspring of a male harem increases with harem size ( Heckel & von Helversen 2002). As males, no females defend the group, also produce offspring, it is presumed that the female choice is (german female choice) in this mating system of meaning. Males interact only rarely with the territorial males. Experiments in a colony of sac-winged bats provided that males without females group stand in line to take the place of a harem - male, if this is missing ( Voigt & String 2003). Since there are few direct male - male interactions and maneuvers both in territorial defense and courtship of importance, small males probably have a selective advantage ( Voigt et al. 2001, 2005 )

Species

The following four species are placed in this genus:

• Large sac-winged bat ( Saccopteryx bilineata )
• Saccopteryx canescens
• Saccopteryx Gymnura
• Saccopteryx leptura