Nectar feeding bats are powered by pure sugar
Nectar feeding bats are powered by pure sugar
mongabay.com
August 6, 2007
Nectar-feeding bats are particularly vulnerable to environmental change due to their high-energy dietary requirements, reports a new study published in the British Ecological Society’s journal Functional Ecology.
Studying a captive breeding colony of long-tongued bats (Glossophaga soricina) in Germany, Dr Christian Voigt of the Leibniz Institute for Zoo and Wildlife Research in Berlin and Professor John Speakman of the University of Aberdeen found that nectar-feeding bats “burn sugar faster than any other mammal on Earth.”
“We found that nectar-feeding bats made use of the sugar they were drinking for their metabolism within minutes after drinking it, and after less than half an hour they were fueling 100% their metabolism from this source,” said the authors. “For comparison, the highest rates reported in humans are for athletes who can fuel up to 30% of their metabolism directly from power drinks.”
Voigt and Speakman say that because the floral nectars upon which bats feed contain only small amounts of simple sugars, bats must metabolize the sugars directly — instead of converting them to fat or glycogen for later use — to maximize the energy they can get from the sugars. The bats, which hover like hummingbirds, have especially high energy requirements. They consume up to 150 percent of their body weight as nectar on a daily basis.
“All animals need energy to power their metabolism. Ultimately this energy comes from food, but usually only a small fraction of the energy being used comes directly from the food. Normally, most of the food is converted into storage and this is drawn on later to fuel metabolism,” wrote the authors. “Small nectar-feeding bats have among the highest metabolic costs among mammals, and mostly eat a diet low in fat and protein but rich in sugars. Metabolising these sugars immediately they are consumed saves the costs of converting them to and from storage.”
Voigt and Speakman report that the bats rapidly deplete their fat stores.
“We found the bats depleted almost 60% of their fat stores each day, but even this phenomenal rate was still barely enough to sustain their metabolism when nectar was absent. This underlines how accurately these bats must balance their energy requirements every day and how vulnerable they are to ecological perturbations that might interrupt their fuel supply for even a short period,” they wrote.
This article is based on a news release from Blackwell Publishing