A new study involving bat skulls, bite force measurements and scat samples collected by an international team of evolutionary biologists is helping to solve a nagging question of evolution: Why some groups of animals develop scores of different species over time while others evolve only a few. Their findings appear in the current issue of Proceedings of the Royal Society B: Biological Sciences.
The skulls and faces of a nectar-eating bat (left) an insect-eating bat (middle) and a fruit bat (right). The short skulls of fruit bats allow them to bite harder than nectar or insect-eating bats. Credit: Elizabeth Dumont, UMass Amherst
To answer this question, Elizabeth Dumont at the University of Massachusetts Amherst and Liliana Dávalos of Stony Brook University together with colleagues at UCLA and the Leibniz Institute for Zoo and Wildlife Research, Berlin, compiled large amounts of data on the diet, bite force and skull shape in a family of New World bats, and took advantage of new statistical techniques to date and document changes in the rate of evolution of these traits and the number of species over time.
They investigated why there are so many more species of New World Leaf-Nosed bats, nearly 200, while their closest relatives produced only 10 species over the same period of time. Most bats are insect feeders, while the New World Leaf-Nosed bats eat nectar, fruit, frogs, lizards and even blood.
One hypothesis is that the evolution of a trait, such as head shape, that gives access to new resources can lead to the rapid evolution of many new species. As Dumont and Dávalos explain, connecting changes in body structure to an ecological opportunity requires showing that a significant increase in the number of species occurred in tandem with the appearance of new anatomical traits, and that those traits are associated with enhanced resource use.
"If the availability of fruit provided the ecological opportunity that, in the presence of anatomical innovations that allowed eating the fruit, led to a significant increase in the birth of new species, then skull morphology should predict both diet and bite force" they said. They found support for these predictions by analyzing thousands of evolutionary trees of more than 150 species, measuring over 600 individual bat skulls of 85 species, testing bite force in over 500 individual bats from 39 species in the field and examining thousands of scat samples to identify the bats' diets.
They found that the emergence of a new skull shape in New World Leaf-Nosed bats about 15 million years ago led to an explosion of many new bat species. The new shape was a low, broad skull that allowed even small bats to produce the strong bite needed to eat hard fruits. The rate of birth of new species jumped as this new shape evolved, and this group of bats quickly increased the proportion of fruit in their diet. Change in shape slowed once this new skull had evolved.
It can be difficult for evolutionary biologists to demonstrate that traits related to anatomical changes, also called "morphological innovations" such as a new skull shape, give certain groups a survival advantage when new food sources, such as hard fruits, become available.
"This study conducted during the International Year of the Bat offers a clear example of how the evolution of new traits, in this case a skull with a new shape, allowed animals to use new resources and eventually, to rapidly evolve into many new species," Dumont says. "We found that when a new ecological niche opened up with an opportunity for bats that could eat hard fruits, they shifted their diet significantly, which in turn led to the evolution of new species."
A graphic is available at: www.umass.edu/newsoffice/
There are other figures and a movie at: ftp://marlin.bio.umass.edu/pub/dumont/Bat%20Evolution%20Stills+Video/
Contact: Janet Lathrop, 413-545-0444; firstname.lastname@example.org
Elizabeth Dumont, 413-545-3565; email@example.com
Janet Lathrop | EurekAlert!
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Information Technology