Washington, Apr 23 : Scientists have often wondered why the green parts of vegetables that contain secondary plant compounds don't have a detrimental effect on fruit-eating pregnant or lactating bats, especially as it could damage the embryo or the juvenile. Now, they say they have found the answer to this question.
In a study published in the online journal PLoS ONE, researchers from the Berlin Leibniz Institute for Zoo and Wildlife Research (IZW), Boston University and Cornell University, found evidence that fruit-eating bats take up large amounts of mineral rich water and clay from so-called mineral licks to detoxify the secondary plant compounds they ingest in fruits.
Bats include more than 1200 species, represent the second most species rich mammalian group and are important seed dispersers in tropical rain forests. Dr. Christian Voigt and his colleagues captured pregnant and lactating bats at mineral licks in the Amazonian rainforest of Ecuador.
"At first glance it seemed that bats visit these sites for the same purpose as other animals such as large tapirs or birds, i.e. to meet their daily mineral requirements," Voigt describes their initial thoughts when they started the study.
Bat mothers have particularly high mineral demands, because their juveniles cannot be weaned before they have reached almost adult size.
"To our amazement, we found fruits to be relatively rich in minerals compared to insects," states Dr. Voigt.
In the present study, the researchers focused on one bat species that feeds on both fruits and insects. The study demonstrates that although insects and not fruits had a low mineral content insufficient for bat reproduction, only bats with a fruit-dominated diet visited mineral licks.
The researchers assume that female bats ingest more fruits than usual during pregnancy and lactation. Therefore, they are directly exposed to the detrimental effects of secondary plant compounds. Female bats seem to be able to compensate the toxicity of secondary plant compounds by consuming mineral rich clay or water.