REPRODUCTIVE STRATEGIES
There are five strategies used by bats with respect to reproductive behaviour.
Monogomy
Yellow winged bat (Lavia frons), False Vampire (Vampyrum spectrum), Leaf nosed (Hipposideros beatus and H. galeritus), Samoan flying fox (Pteropus samoensis), and Horseshoe (Rhinolophus sedulus) and a few others
Approximately 3% of mammals practice monogomy, while 97% of birds are monogamous! Very few bats practice monogomy, however in the case of the yellow winged bat, the male and the female mate until one or the other dies.
Resource polygyny
Jamaican fruit bat (Artibeus jamaicensis), Common vampire (Desmodus rotundus), and numerous others.
This is where an individual male gains exclusive reproductive access to a group of females by controlling the best foraging areas. In the case of D. rotundus, males will fight for access to preferred female roosting sites, where they will engage up to 80% of all copulation’s. This is the most prevalent mating system in bats.
Promiscuity
Little brown bat (Myotis lucifugus) and many others.
In this system, multiple mating with multiple mates is prevalent. It is a characteristic of highly colonial species of bats. It has often been described as swarming, and in the case of M. lucifugus, takes place prior to hibernation.
Mate polygyny
Greater spear-nosed (Phyllostomus hastatus), White-lined bats (Saccopteryx bilineata and S. leptura), Proboscis bat (Rhynchonycteris naso), African molossid (Tadarida midas), and many others.
Single harem males defend stable groups of females (between 1 and 100) and usually father most of the synchronously produced young. The males attract the females through a variety of stimuli including song, smell, and appearance. The males domination typically lasts for up to three years. Each year young females disperse from roosting clusters to form new groups.
Leks
Hammer headed bat (Hypsignathus monstrous), Wahlberg’s epauleted (Epomophorus wahlbergi), New Zealand short tailed bat (Mystacina tuberculata), Bent winged (Miniopterus minor)
Perhaps the most interesting and possibly the rarest form of reproductive strategy. It is not common in any group of animal, but some birds such as sage grouse and Hermit hummingbirds form leks. Leks are formed for the sole purpose of mating. The lek assemblage may extend for 1600 metres in low riparian forest lined up on branches along the river, or in food rich areas of the tropical forest, with males establishing a 10 metre diameter area. In the case of Hammer headed bats, the males arrive at dusk and begin singing a loud, throaty honk or croak. These honks are produced from a greatly enlarged organ...... the larynx... that extends from the top of the throat, as far down as the center of the chest! They will call from 50 to 120 times per minute, extending their wings and beating them at twice the call rate. The females arrive, and make hovering inspections of each male. The male will increase the rate of call and wing beating when the female is inspecting him. Once the female has made her choice, she will land next to him. He stops calling, and copulation takes place, lasting for 30 to 60 seconds. (Insert your own joke here). The female always terminates the copulation making several loud whinings before she flies off, and the male resumes calling within a minute after copulation.
ALL FIVE OF THESE STRATEGIES CAN BE OBSERVED AT YOUR LOCAL BAR ON ANY FRIDAY OR SATURDAY NIGHT!
