Bats

10/17/02
Research on bats:
http://www.unb.br/ib/zoo/chiroptera/articles/article6.htm
Study on "Bats from the Metropolitan Region of Sao Paulo, Southeastern Brazil," published in Chiroptera Neotropical 2(1): 39-41

301 bats captured and examined by specialists. They contained 4 families and 24 species: 71.4% molossidae, 23.6% phyllostomidae, 4.7% vespertilionidae, and .3% noctilionidae. 76.1% were insectivorous (molossidae and vespertilionidae).
Structures in the metropolitan region of Sao Paulo (heat-expansion walls in large buildings) provided shelter for bat colonies; street lights trapped insects for food.
7 species of phytophagous (frugivorous and nectarivorous) bats in Sao Paulo. Specie Glossophaga soricina inhabits cellars and lofts in residential dwellings, and drinks nectar. Artibeus lituratus inhabits the crowns of trees, and eats fruit. "In Brasilia, the most common species are A. lituratus and Platyrrhinus lineatus (Bredt & Uieda, 1996)." 33% of Brazil's trees (54 different species) provide suitable food for phytophagous bats.

http://www.unb.br/ib/zoo/chiroptera/articles/article8.htm
Similar study, in Distrito Federal region.
Factors that can determine composition of bat fauna in a given area are not clearly defined (Fenton et al, 1992). Important factors: shelter availability, areas for food searching, and ability to adapt to the environment. Deforesting and the rise of housing has led to population increases in several species of bats which developed synanthropic habits, while sharp decreases in other species. 6 families and 40 species of bats found in Distrito Federal region; 5 other species known to exist in the region.

http://www.wooster.edu/biology/mloveless/OOWthisweek.html:
Neotropical bats in Costa Rica: 103 species: 43 insectivores, 25 frugivores (fruit-eaters), 11 nectivores (nectar-eaters), 3 blood feeders (sanguivores), 2 carnivores, 1 fish-eater, 11 with a mixed diet. All neotropical bats have echolocation systems. They emit pulses of clicks through their nose or mouth, then sense the pulse's returning sound. Ultrasonic in range. Bats have very good low-light vision.
Insectivorous bats catch insects on their wings. Some insects have developed adaptations which enable them to avoid the bats or to throw the bats off their echolocation track. Carnivorous bats use echolocation as well as smells. Vampire bats have weak echolocation, but use sight and smell effectively. Original targets were peccaries, tapirs, and other large mammals. The introduction of cattle by farmers has given them another target. They eat by biting into the animal and lapping up the blood. The blood does not clot because the bat saliva has chemicals that prevent the blood from clotting. The other two blood feeding species specialize on bird blood. Frugivorous bats are important for seed dispersal. Fig eaters eat as many as 10 figs a night, carrying them sometimes as far as 100m away from the source to a feeding roost. Overall frugivorous bat ranges are over a 1 km radius.

http://highwire.stanford.edu/cgi/medline:
Abstract from "Proximate, caloric, nitrogen and mineral composition of bodies of some tropical bats." by EH Studier, SH Sevick, and DE Wilson, from Comp Biochem Physiol A Physiol, Nov. 1, 1994; 109(3): 601-10.
"Proximate (live mass, water, lipid, ash, non-fat organic), caloric, nitrogen, and mineral (sodium, potassium, calcium, magnesium, and iron) concentrations and total body content of individuals of 24 species of Neotropical and Paleotropical bats were determined. Mass-related, concentration patterns were found for all measured variables, except iron. Concentrations increase with size for nitrogen, calcium, and magnesium but are concave, opening upward, for sodium and potassium. These last two elements reach minimal concentrations in bats weighing about 22 and 28 g dry mass, respectively. Total body content of nitrogen and minerals was compared with amounts in similar-sized birds and tetrapodal mammals."

KN Geluso, JS Altenbach, and DE Wilson "Bat mortality: pesticide poisoning and migratory stress." Science, October 8, 1976; 194(4261): 184-6.
"Organochlorine residues in the fat of young Mexican free-tailed bats, Tadarida brasiliensis, reached the brain and caused symptoms of poisoning after the fat mobilization that takes place during migratory flight was simulated. These chemical body burdens were obtained naturally under free-living conditions at the maternity roost. The data obtained support the hypothesis that pesticides have contributed to recent declines in populations of this bat."

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