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Crabs use fashion to fend off predators
Birgitte Wilms/Minden/Corbis
in Brief Some meat-eaters like a swig of nectar
Crabs use fashion to fend off predators IF THERE’S one thing we have in common with these crabs, it’s a keen sense of fashion. About three-quarters of the 900 species of crab in the family Majoidea decorate themselves, making them nature’s most fashionconscious animal. They improvise accessories using whatever is around, grabbing items such as seaweed, corals and sponges, and sticking them to their shells. Hooked hairs, called setae, keep everything in place (Royal Society Biology Letters, doi.org/5bw). But while we adorn ourselves to be noticed, crabs do
it for the opposite reason: the decorations provide camouflage so the crab can hide from predators. “The nice thing about being a decorator is that wherever you go, you can pull off the old decoration, stick on something new and quickly adapt yourself to whatever environment surrounds you,” says John J. Stachowicz of the University of California, Davis. “If you’re a slow-moving, roving animal, being able to quickly adopt the coloration or background of wherever you are is likely very adaptive.” Some decorator crab species are more picky: they won’t pick just any old outfit. They go for materials that are chemically noxious or adorn themselves with stinging sea anemones. “They are selecting decorations that make them toxic or bad to eat,” says Stachowicz.
Antigravity pump lifts water upwards JACK and Jill can stay down the hill – water can go up by itself. Kesong Liu of Beihang University in Beijing, China, and his colleagues have developed a way to lift water with no need for an external source of energy. The technique works over centimetre-scale distances, so could be useful for microfluidic lab-on-a-chip devices that shift small amounts of water 18 | NewScientist | 20 June 2015
around to analyse diseases. The team first created a waterrepellent surface by treating a copper mesh with an alkali solution to create microscopic pockets on its surface. They placed this superhydrophobic mesh across the bottom of a vertical pipe with a right-angle joint at the top – designed to suppress capillary action. A droplet of water placed under
the superhydrophobic mesh gets sucked through it and into the pipe, causing the water level to rise slightly. The pipe gradually fills until water spills out the end. It may seem like magic, but it’s all thanks to the water’s surface tension. When the droplet touches the larger column of water, its surface tension breaks and the energy used to keep the droplet spherical goes into lifting the water (Advanced Functional Materials, doi.org/f273x3).
THEY like their meat, but genets and mongooses also like to wash it down with a slug of flower nectar every now and then. Sandy-Lynn Steenhuisen at the University of Cape Town, South Africa, captured videos of these carnivores drinking from sugarbush flowers, which are normally pollinated by small ground-dwelling mammals, such as rodents and elephant shrews (African Journal of Ecology, doi.org/5b9). “These genets and mongooses appeared quite keen on the nectar and visited flowers repeatedly, even if it meant climbing a few branches or foraging during light snow,” says Steenhuisen. She thinks they do it for the sugar kick, but given that they had pollen on their snouts they probably end up pollinating the plants, too. They travel further than small rodents, so may help disperse pollen greater distances.
Mini mammaries grown in a dish IT’S not quite a lab-grown breast, but it’s pretty close. Christina Scheel at the Helmholtz Centre for Health and Environmental Research in Munich, Germany, took mammary gland cells from tissue donated from breast reduction surgeries and added them to gels made of collagen fibres. The cells pulled on the fibres, exerting a force that let the cells grow into a new mammary gland in the dish (Development, doi.org/5dc). “We want to model breast cancer using our tool, and test cancer treatments,” says Scheel, adding that first they need to understand how the cells develop normally. “Breast cancer is essentially out-of-control development,” she says.
in Brief Some meat-eaters like a swig of nectar
Crabs use fashion to fend off predators IF THERE’S one thing we have in common with these crabs, it’s a keen sense of fashion. About three-quarters of the 900 species of crab in the family Majoidea decorate themselves, making them nature’s most fashionconscious animal. They improvise accessories using whatever is around, grabbing items such as seaweed, corals and sponges, and sticking them to their shells. Hooked hairs, called setae, keep everything in place (Royal Society Biology Letters, doi.org/5bw). But while we adorn ourselves to be noticed, crabs do
it for the opposite reason: the decorations provide camouflage so the crab can hide from predators. “The nice thing about being a decorator is that wherever you go, you can pull off the old decoration, stick on something new and quickly adapt yourself to whatever environment surrounds you,” says John J. Stachowicz of the University of California, Davis. “If you’re a slow-moving, roving animal, being able to quickly adopt the coloration or background of wherever you are is likely very adaptive.” Some decorator crab species are more picky: they won’t pick just any old outfit. They go for materials that are chemically noxious or adorn themselves with stinging sea anemones. “They are selecting decorations that make them toxic or bad to eat,” says Stachowicz.
Antigravity pump lifts water upwards JACK and Jill can stay down the hill – water can go up by itself. Kesong Liu of Beihang University in Beijing, China, and his colleagues have developed a way to lift water with no need for an external source of energy. The technique works over centimetre-scale distances, so could be useful for microfluidic lab-on-a-chip devices that shift small amounts of water 18 | NewScientist | 20 June 2015
around to analyse diseases. The team first created a waterrepellent surface by treating a copper mesh with an alkali solution to create microscopic pockets on its surface. They placed this superhydrophobic mesh across the bottom of a vertical pipe with a right-angle joint at the top – designed to suppress capillary action. A droplet of water placed under
the superhydrophobic mesh gets sucked through it and into the pipe, causing the water level to rise slightly. The pipe gradually fills until water spills out the end. It may seem like magic, but it’s all thanks to the water’s surface tension. When the droplet touches the larger column of water, its surface tension breaks and the energy used to keep the droplet spherical goes into lifting the water (Advanced Functional Materials, doi.org/f273x3).
THEY like their meat, but genets and mongooses also like to wash it down with a slug of flower nectar every now and then. Sandy-Lynn Steenhuisen at the University of Cape Town, South Africa, captured videos of these carnivores drinking from sugarbush flowers, which are normally pollinated by small ground-dwelling mammals, such as rodents and elephant shrews (African Journal of Ecology, doi.org/5b9). “These genets and mongooses appeared quite keen on the nectar and visited flowers repeatedly, even if it meant climbing a few branches or foraging during light snow,” says Steenhuisen. She thinks they do it for the sugar kick, but given that they had pollen on their snouts they probably end up pollinating the plants, too. They travel further than small rodents, so may help disperse pollen greater distances.
Mini mammaries grown in a dish IT’S not quite a lab-grown breast, but it’s pretty close. Christina Scheel at the Helmholtz Centre for Health and Environmental Research in Munich, Germany, took mammary gland cells from tissue donated from breast reduction surgeries and added them to gels made of collagen fibres. The cells pulled on the fibres, exerting a force that let the cells grow into a new mammary gland in the dish (Development, doi.org/5dc). “We want to model breast cancer using our tool, and test cancer treatments,” says Scheel, adding that first they need to understand how the cells develop normally. “Breast cancer is essentially out-of-control development,” she says.