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!
Nanocages in the lab and in the computer: how DNA-based dendrimers transport nanoparticles
19.10.2018 | University of Vienna
Less animal experiments on the horizon: Multi-organ chip awarded
19.10.2018 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS
Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.
Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...
Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles
Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...
When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.
We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...
Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...
Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...
17.10.2018 | Event News
16.10.2018 | Event News
02.10.2018 | Event News
19.10.2018 | Life Sciences
19.10.2018 | Physics and Astronomy
19.10.2018 | Trade Fair News