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Many animals are capable of constructing structures to modify the environment for their own benefit. The design of these structures requires animals to perceive dimensions. However, how animals take measurements to achieve the final design of the structures they construct is known for only very few species. In the Neotropics, a few bat species build roosts or leaf tents that serve different purposes. Thomas's fruit-eating bat (Dermanura watsoni) constructs tents that have complex designs, when compared to other tent building bats. The bifid tent is a design built by producing a long, J-shaped cut on each side of understory plant leaves. We expect that to accomplish this complex design bats would require precise measurements during tent construction. We measured several bat morphological traits to infer which of them, if any, was used by the bats as a measuring device. Dermanura watsoni uses the distance between their lower canines to increase the perpendicular distance of the J-cut to the central vein of the leaf along the J-cut. The bat adds the distance between the canines to each subsequent secondary vein cut. This is the first study to infer which body part D. watsoni most likely uses as a measuring tool. Our results provide new insight into the evolution of body parts as measuring devices during tent construction in related and unrelated tent-building bat species.
Roosting ecology and its correlates are among the major forces driving the evolution of bats. However, roost ecology remains one of the most poorly understood topics on the basic biology of bats. Ectophylla alba is endemic to Central America with a very small distribution. This species generally modifies leaves of a certain size within the genus Heliconia. Here we explore this species' habitat preferences for the construction of its roosts. We identified three variables as the requirements of a suitable tent-building habitat: canopy coverage, understory coverage between 0–1 m of height, and density of Heliconia. Our results show that the process of habitat selection for roost construction is highly specialized to an intermediate stage of secondary succession, which in turn, makes Ectophylla even more vulnerable to extinction than previously believed.
Roost ecology in bats is a complex interaction of behavioral, morphological and physiological adaptations, thus, there are many factors involved in roost selection by bat species. Approximately 22 species of bats are able to modify leaves to establish their roost, 17 of which are in the Neotropics. Although there are many studies of tent-roosting bats, this is the first describing the structure of the interaction between bats and the plants they are using as roosts. We describe a potential antagonistic network between these bats and the plants used for tent construction in La Selva Biological Station in Costa Rica. We calculated descriptors of the network such as the number of bats and plants interacting, as well as the number of pairwise interactions based on published records or direct observations. We also tested for connectance and nestedness in the network structure. We propose a name for this non-trophic antagonistic interaction, which is a structural antagonism, where bats damage the leaves, reducing their lifespan and the plant fitness. In La Selva the network is composed of eight bats and 45 plant species reported by 60 pairwise interactions. Only 2.16% of vascular plant species in La Selva are being modified as tents. The network had low connectance (0.167) and no significant nestedness or modularity. Considering the species richness of plants in La Selva, there are few links between tent-roosting bats and plants species, which shows the specialization of these interactions and the high dependence of most of these bats on a few plant species, even if they are very specific and temporary resources.
Five new specimens of the poorly known Sanborn's bonneted bat, Eumops hansae (Chiroptera: Molossidae), are reported for Costa Rica's central and northern Pacific lowlands based on a subadult male collected in 1990 and four adult females collected in 2003. We also report the second known specimen of Eumops underwoodi from Costa Rica and additional specimens of Cynomops mexicanus, Eumops glaucinus, Molossus molossus, and Molossus pretiosus. Most of the females captured in August and April were either lactating or pregnant, suggesting that parturition in these molossids occurs in the late dry season and the early to middle rainy season, periods when insects are especially abundant in this dry forest. Characters used previously to distinguish between the similar-sized E. hansae and E. nanus are evaluated, and external and cranial measurements for the specimens of E. hansae are provided. The best single character for distinguishing the two species is size and shape of the upper incisors. In E. hansae, the upper incisors are thin and recurved, whereas they are thick, straight, and slightly procumbent in E. nanus. The six sympatric species of free-tailed bat found in the gallery forest along the Río Enmedio vary in size, jaw thickness, and wing shape suggesting coexistence through resource partitioning in this molossid bat assemblage.
Folivory can be defined as the consumption of foliage, including leaves, stems and leaf content. This trophic strategy has been documented in two families of bats, Pteropodidae (Old World fruit bats) and Phyllostomidae (New World leaf-nosed bats). Existing folivory hypotheses for bats suggest this behavior provides a dietary supplement of protein and other essential minerals due to a deficiency of these in a frugivorous diet. The Caatinga is a seasonally deciduous tropical dry forest where most of the vegetation is leafless and dormant during the extended dry season. Here we present the first evidence of folivory in bats from the Brazilian Caatinga, with evidence for the phyllostomid Artibeus planirostris ingesting the leaves of at least 16 species of plants. We include a bibliographic review of bat folivory in the tropics. Additionally, we propose a new hypothesis on folivory in bats for this semiarid environment.
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