Ivan Leidus via Wikimedia Commons // CC BY-SA 4.0
Ivan Leidus via Wikimedia Commons // CC BY-SA 4.0

Bumblebees’ Hair Helps Them Decide Where to Eat

Ivan Leidus via Wikimedia Commons // CC BY-SA 4.0
Ivan Leidus via Wikimedia Commons // CC BY-SA 4.0

So much of what goes on around us is unseen. We’re each surrounded by a personalized cloud of bacteria, for example. We’re also constantly emitting gases and taking in radiation. And outside, flowers and bees are communicating in secret electric code. Scientists say the little hairs all over bumblebees’ bodies are sensitive to electrical fields—including those emitted by flowers full of nectar. They published their paper in the Proceedings of the National Academy of Sciences. 

Flowers are masters of seduction, using just about every trick in the book to lure in pollinators. Biologists knew that flowers give off electric signals, kind of like billboards, that broadcast their status (recently visited and empty, or full of nectar) to bees, but they didn’t know how the bees were picking these signals up. 

Researchers at the UK’s University of Bristol suspected that either the bees’ antennae or their hair could sense electricity. Earlier studies had suggested that either could be involved; bees watching others perform an electricity-producing waggle dance tend have jiggly antennae, and the small hairs of other insects are sensitive to the movement of water or sand. 

To test their hypothesis, the team generated small fields of static electricity of about the intensity produced by flowers in the wild. They euthanized bees and held them against the field to “charge” them, then used a laser vibrometer and implanted sensors to measure the electricity’s effect on the bees’ antennae and hair.

Image credit: University of Bristol

They found that both the bees’ antennae and their hair moved in response to the electrical field, but the hair moved more, and it moved faster, which suggests that it’s more likely to be picking up what the flowers are putting down.  

"We were excited to discover that bees' tiny hairs dance in response to electric fields, like when humans hold a balloon to their hair,” biologist and lead author Gregory Sutton said in a press statement. “A lot of insects have similar body hairs, which leads to the possibility that many members [of] the insect world may be equally sensitive to small electric fields." 

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Whale Sharks Can Live for More Than a Century, Study Finds
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Some whale sharks alive today have been swimming around since the Gilded Age. The animals—the largest fish in the ocean—can live as long as 130 years, according to a new study in the journal Marine and Freshwater Research. To give you an idea of how long that is, in 1888, Grover Cleveland was finishing up his first presidential term, Thomas Edison had just started selling his first light bulbs, and the U.S. only had 38 states.

To determine whale sharks' longevity, researchers from the Nova Southeastern University in Florida and the Maldives Whale Shark Research Program tracked male sharks around South Ari Atoll in the Maldives over the course of 10 years, calculating their sizes as they came back to the area over and over again. The scientists identified sharks that returned to the atoll every few years by their distinctive spot patterns, estimating their body lengths with lasers, tape, and visually to try to get the most accurate idea of their sizes.

Using these measurements and data on whale shark growth patterns, the researchers were able to determine that male whale sharks tend to reach maturity around 25 years old and live until they’re about 130 years old. During those decades, they reach an average length of 61.7 feet—about as long as a bowling lane.

While whale sharks are known as gentle giants, they’re difficult to study, and scientists still don’t know a ton about them. They’re considered endangered, making any information we can gather about them important. And this is the first time scientists have been able to accurately measure live, swimming whale sharks.

“Up to now, such aging and growth research has required obtaining vertebrae from dead whale sharks and counting growth rings, analogous to counting tree rings, to determine age,” first author Cameron Perry said in a press statement. ”Our work shows that we can obtain age and growth information without relying on dead sharks captured in fisheries. That is a big deal.”

Though whale sharks appear to be quite long-lived, their lifespan is short compared to the Greenland shark's—in 2016, researchers reported they may live for 400 years. 

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Animal Welfare Groups Are Building a Database of Every Cat in Washington, D.C.
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There are a lot of cats in Washington, D.C. They live in parks, backyards, side streets, and people's homes. Exactly how many there are is the question a new conservation project wants to answer. DC Cat Count, a collaboration between Humane Rescue Alliance, the Humane Society, PetSmart Charities, and the Smithsonian Conservation Biology Institute, aims to tally every cat in the city—even house pets, The New York Times reports.

Cities tend to support thriving feral cat populations, and that's a problem for animal conservationists. If a feline is born and grows up without human contact, it will never be a suitable house cat. The only options animal control officials have are to euthanize strays or trap and sterilize them, and release them back where they were found. If neither action is taken, it's the smaller animals that belong in the wild who suffer. Cats are invasive predators, and each year they kill billions of birds in the U.S. alone.

Before animal welfare experts and wildlife scientists can tackle this problem, they need to understand how big it is. Over the next three years, DC Cat Count will use various methods to track D.C.'s cats and build a feline database for the city. Sixty outdoor camera traps will capture images of passing cats, relying on infrared technology to sense them most of the time.

Citizens are being asked to help as well. An app is currently being developed that will allow users to snap photos of any cats they see, including their own pets. The team also plans to study the different ways these cats interact with their environments, like how much time pets spend indoors versus outdoors, for example. The initiative has a $1.5 million budget to spend on collecting data.

By the end of the project, the team hopes to have the tools both conservationists and animal welfare groups need to better control the local cat population.

Lisa LaFontaine, president and CEO of the Humane Rescue Alliance, said in a statement, “The reality is that those in the fields of welfare, ecology, conservation, and sheltering have a common long-term goal of fewer free-roaming cats on the landscape. This joint effort will provide scientific management programs to help achieve that goal, locally and nationally."

[h/t The New York Times]

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