26 



miportant beyond range of sound, for instance in order to identify large, far objects, land 

 marks or the horizon (Suthers 1966; 1970). 



All phyllostomids have weh developed eyes with efficient differentiation of brightness and 

 shapes. Flower bats always keep their eyes open, when active. Some nectar feeding 

 species (e.g., Anoiira ccmdifer) are reported to have a tapetimi (v. Helversen 1993) and 

 perform a well developed ability for pattern recognition. It is, by the way, interesting for 

 this respect that some bat flowers developed conspicous patches for "close range guiding" 

 the bats in approach (Dobat & Peikert 1985). But the absence of retinal cones gives no 

 evidence for colours to be discriminated (Suthers 1970). Anatomicahy however, the 

 optical areas in brain cortex are clearly less developed than the acoustic centers. 



Olfactory sense / Olfactory perception 

 In fruit feeding bats, the leading role of food detection by olfactory sense has been 

 satisfactorily documented (for both Megachiroptera and fmgivorous phyUostomids). This 

 is also confirmed in brain anatomy by relative size of the Bulbus olfactorius. Although 

 this structure turns out smaller in nectar feeding New World Microchiroptera, it still 

 remains considerably larger than in species which exclusively feed on insects having the 

 smallest Bulbi olfactorii among all Chiroptera (Dobat & Peikert 1985). Chiropterophile 

 blossoms are often characterized by a slightly sour, musty scent which is apparently 

 responsible for attracting pollinators. According to observations by Vogel (1958) a sudden 

 breeze finished pollinating activity immediately, which also gives evidence of the well 

 developed olfactory abilities of the nectar feeders. Olfaction does not only serve for long- 

 distance orientation but is also important in short-distance target discrimination - detection 

 of the nectarbearing flowers (v. Helversen 1993). 



Reproductive Biology 



Reproductive data of nectar feeding bat species is mainly based on comments on the 

 sexual stams of captured specimens. Pregnant females give information about size and 

 weight of fetus; lactation periods are easily recorded from tlie dates of netted females 

 carrying juveniles. Development of youngsters, but also relative weight and measures of 

 gonades (enlargement of uterus, ovarian follicles, appearance of corpora lutea in females; 

 size of testicles in males) aUow conclusions on seasonal breeding patterns by comparing 

 the different information to the date of capture. 



So far, we still have poor knowledge on the reproductive behavior of nectarivorous 

 phyllostomid cliiropteres: among the species of tlie tropical rain forest, breeding all over 

 the year without marked seasonal periods is common, whereas those inhabitating subtropic 

 (more arid) zones or andine moimtain forests show one definitely seasonal or two separate 

 (bimodal) reproductive periods per year. 



Lionycteris: Tuttle (1970) reported a pregnant female of L. spiurelli containing one single 

 embryo capmred in Pern on August 5th. 



Lonchophylla: Wilson (1979) took pregnant L. mordax in Costa Rica as well in March as 

 in August. Also in Costa rica LaVal & Fitch (1977) found pregnant L. robust a m 

 February, May, August and October; one lactating female in January. According to 

 Koepcke (1987) the reproductive period of L. thomasi in amazonian Peru occurs during 

 the dry season. She netted sexual inactive bats in June, October, November and December. 



