Nutrition or Detoxification: Why Bats Visit Mineral Licks of the Amazonian Rainforest

Abstract

Many animals in the tropics of Africa, Asia and South America regularly visit so-called salt or mineral licks to consume clay or drink clay-saturated water. Whether this behavior is used to supplement diets with locally limited nutrients or to buffer the effects of toxic secondary plant compounds remains unclear. In the Amazonian rainforest, pregnant and lactating bats are frequently observed and captured at mineral licks. We measured the nitrogen isotope ratio in wing tissue of omnivorous short-tailed fruit bats, Carollia perspicillata, and in an obligate fruit-eating bat, Artibeus obscurus, captured at mineral licks and at control sites in the rainforest. Carollia perspicillata with a plant-dominated diet were more often captured at mineral licks than individuals with an insect-dominated diet, although insects were more mineral depleted than fruits. In contrast, nitrogen isotope ratios of A. obscurus did not differ between individuals captured at mineral lick versus control sites. We conclude that pregnant and lactating fruit-eating bats do not visit mineral licks principally for minerals, but instead to buffer the effects of secondary plant compounds that they ingest in large quantities during periods of high energy demand. These findings have potential implications for the role of mineral licks for mammals in general, including humans.

Use of Mineral Licks by White-Bellied Spider Monkeys (Ateles belzebuth) and Red Howler Monkeys (Alouatta seniculus) in Eastern Ecuador

“…If true, such differences might account for use of some sites and not others. Although we did not sample soils during our study, ongoing studies focused on use of saladeros by bats (Voigt et al 2007(Voigt et al , 2008 suggest that saladero soils are more mineral-rich than soils at control locations in the forest (C. Voigt, pers. comm.).…”

“…Soil or water from mineral licks may provide a dietary supplement or may help detoxify plant secondary compounds ingested as part of the diet (Dominy et al 2004;Ferrari et al 2008;Mahaney et al 1995;Voigt et al 2007Voigt et al , 2008. For example, mountain tapirs (Tapirus pinchaque) use licks where water has a higher sodium and nitrogen content (Lizcano and Cavelier 2004), suggesting that use of such sites may be beneficial when such minerals are low in concentration in the environment (Brightsmith and Muñoz-Najar 2004;Emmons and Stark 1979;Matsubayashi et al 2007).…”

Preference for Collpa Water by Frugivorous Bats (Artibeus): An Experimental Approach

“…This approach should allow us to distinguish which minerals (especially sodium, e.g., Bravo et al 2010) or clay (e.g., Voigt et al 2008) are the principle resources drawing bats to collpas.…”

Atmospheric salt deposition in a tropical mountain rainforest at the eastern Andean slopes of south Ecuador – Pacific or Atlantic origin?

“…Because nutrient availability regulates ecosystem processes and functions, the changes currently affecting the nitrogen and phosphorus budgets are expected to have wide-reaching impacts in forest ecosystem structure and diversity (Bobbink et al, 2010;Homeier et al, 2012;Matson et al, 2014;Peñue-las et al, 2013;Pett-Ridge, 2009;Wang et al, 2014;Wilcke et al, 2013). The role of sea salt availability has very recently gained attentions, as it has been found to condition the behaviour of herbivores, in addition to affecting carbon cycling and organic matter decomposition in tropical ecosystems (Dudley et al, 2012;Kaspari et al, 2008Kaspari et al, , 2009Powell et al, 2009;Voigt et al, 2008). At the western rim of the Amazon forest, in Peru, Ecuador, and Colombia, there is evidence that herbivorous and frugivorous birds and mammals visit mineral licks to compensate for low sodium concentration in plant and fruit tissues (Lee et al, 2009;Lizcano and Cavelier, 2004;Powell et al, 2009;Voigt et al, 2008).…”

“…The role of sea salt availability has very recently gained attentions, as it has been found to condition the behaviour of herbivores, in addition to affecting carbon cycling and organic matter decomposition in tropical ecosystems (Dudley et al, 2012;Kaspari et al, 2008Kaspari et al, , 2009Powell et al, 2009;Voigt et al, 2008). At the western rim of the Amazon forest, in Peru, Ecuador, and Colombia, there is evidence that herbivorous and frugivorous birds and mammals visit mineral licks to compensate for low sodium concentration in plant and fruit tissues (Lee et al, 2009;Lizcano and Cavelier, 2004;Powell et al, 2009;Voigt et al, 2008). Furthermore, some taxa of arthropod have reportedly begun practicing geophagy to deal with salt scarcity in plants (Kaspari et al, 2008).…”