Now mathematicians at MIT have found that efficient feeding depends on how sugary a flower’s nectar is, and whether an animal dips or sucks the nectar out. The researchers found that animals such as bees, which probe with their tongues, are “viscous dippers,” and are most efficient when feeding on more sugary, or viscous, nectar. Suction feeders, such as birds and butterflies that draw nectar up through tubes, do their best when sucking up thinner, less sugary nectar.
The difference, says John Bush, a professor of applied mathematics, may point to a co-evolutionary process between flowers and their pollinators.
“Do the flowers want a certain type of bug or bird to pollinate them? And are they offering up the nectar of their preferred pollinator?” Bush asks. “It’s an interesting question whether there’s a correlation between the morphology of the plant and the morphology of the insect.”
The researchers published their results in a recent issue of the Proceedings of the National Academy of Sciences.
While Bush is not a biologist, he says curiosities in nature, including nectar feeding, pose fascinating challenges for mathematicians. As he sees it, nectar feeding is a classic example of optimization in nature: The sweeter the nectar, the more energy it delivers, but the more energy it takes to transport. The optimal sugar concentration shifts according to how the fluid is taken up.
As a large-scale analogy, Bush says it’s more efficient to suck up sugar water than molasses through a straw. Conversely, it’s more effective to dip a spoon in and out of honey versus juice. There’s an ideal viscosity for a given uptake mechanism, an optimization puzzle that Bush says is tailored for mathematics.
The birds and the bees
To get at this puzzle, Bush and his colleagues analyzed data from previous papers on nectar-feeding species, which include bats, birds, bees and butterflies. Most papers described two kinds of nectar-drinking mechanisms: active suction, whereby butterflies and moths suck nectar up through long, narrow tubes, or probosci; and passive suction, in which hummingbirds and sunbirds draw nectar up in their tongues via capillary action.
The team compiled the papers’ data and found that both groups of suction feeders were most efficient at taking up the same concentration — 33 percent — of sugar in nectar.Video: Watch the animals feed on the PNAS website
Going a step further, Wonjung Kim, a graduate student of mechanical engineering and lead author of the paper, took an experimental approach, studying live bees in the lab. Kim collected several bees from around MIT and kept them in a box lined with paper towels soaked in a sugar solution. Kim filmed the bees with a high-speed camera, confirming that the insects did indeed dip their tongues in the syrupy surface.
Going with the flow
Bush and Kim plan to examine the ways in which other species drink, in order to model more small-scale fluid dynamics. One target, Bush says, is a certain desert lizard that “drinks” through its skin. The lizard simply has to step in a puddle of water, and an intricate system of cracks in its skin soaks up moisture — a useful trait in extremely dry environments.
“People are now interested in moving around small volumes of fluid for microfluidic applications,” Bush says. “It’s clear that nature has been solving these problems for millions of years. Animals have learned how to efficiently navigate, transport and manipulate water. So there’s clearly much to learn from them in terms of mechanisms.”
Written by: Jennifer Chu, MIT News Office
Caroline McCall | EurekAlert!
eTRANSAFE – collaborative research project aimed at improving safety in drug development process
26.09.2017 | Fraunhofer-Gesellschaft
Beer can lift your spirits
26.09.2017 | Friedrich-Alexander-Universität Erlangen-Nürnberg
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy