Swimming leeches video from the USA


This video from the Shedd Aquarium in the USA says about itself:

27 April 2015

Shedd researcher Solomon David took this video of aquatic leeches at an agricultural ditch-wetland junction near the Bay of Green Bay. According to him, “I’ve seen many fishes at this site over past years, but never leeches (here or anywhere else) in numbers like this. They were at this site for at least two days.”

Ants have their own Highway Code, new research


This video is about Formica pratensis ants.

From Wildlife Extra:

Researchers find ants have their own Highway Code in high traffic areas

Researchers in Germany have discovered that ants have a sophisticated code of conduct in high traffic areas and their own rules of the road, according to new research published in Springer’s journal The Science of Nature – Naturwissenschaften.

One of the scientists’ observations is that ants speed up in response to a higher density of traffic on their trails, rather than slowing down as might be expected.

Not surprisingly, when the researchers increased the supply of food by leaving it next to the trail, ants accelerated their speed by 50 per cent. What was unexpected was that this was despite more than double the density of traffic.

When food increases in supply, more forager ants are sent out to carry it back to the nest. With this increase in ant density, the number of encounters between outbound and incoming individuals increases.

Researchers at the University of Halle-Wittenberg in Germany suggest that the encounters provide an opportunity for ants to swap information and to change their behaviour according to conditions.

Rules of ant etiquette were also observed. For example, workers returning to the colony more often moved to the left than to the right to avoid colliding with an oncoming ant.

Rather than segregating strictly into lanes like human traffic, the ants used only a degree of segregation, with inbound ants more frequently using the left side of the trail.

The observations were made of the black-meadow ant, Formica pratensis, a species that lives mainly in open grassland and forages on aphid honeydew as its carbohydrate source.

The colonies studied were situated near favoured foraging sites where the ants protect and cultivate aphid populations. Repeated journeys in these colonies are made more efficient by the use of well-worn trails that can persist for over a decade.

A total of 1,865 individual ants were filmed on a 15cm (6in) section of trail. The video was stopped every 50 frames and the number of ants on each lane was counted. At low and medium densities, ants preferred the central lanes.

Of the total number, 496 ants were also studied for their speed. Encounters between ants included touching antennae or exchanging fluids. The number of encounters increased with density but this did not reduce the traffic flow.

“Even under the highest densities we could achieve, we did not observe any traffic jams,” says Christiane Hönicke, co-author of the study. “The ants increased their pace and were driven off the central lanes of the trail, resulting in a self-organised optimisation of the traffic.”

Medicinal leech swims, video


This video shows a medicinal leech, swimming about one meter below the water surface.

Diver Jos van Zijl from the Netherlands made the video. He remembers that last year, a leech bit him and sucked blood.

Ant carrying bee, video


In this video, an ant carries a dead, much bigger, Andrena vaga mining bee to its anthill.

Matthijs Herremans in the Netherlands made this video.

Sea otters in Canada, video


This video says about itself:

Sea Otters vs. Urchins in Canada’s Kelp Forests

7 April 2015

“When you see a sea otter, they’re usually either eating or digesting,” often munching on urchins, says ecologist Anne Salomon, a Pew marine fellow. That’s a good thing for some kelp beds. Without otters to control urchin numbers, the spiky shellfish can devour the beds, leaving barren seascapes behind.

Fifty years ago, sea otters were so sought after for their fur that they disappeared from the Canadian coast. But now they’re bouncing back and—as seen in this video—competing with humans for the region’s shellfish.

Barrel jellyfish coming back to Dorset, England


This video says about itself:

Swimming with a giant Barrel Jellyfish

23 June 2014

This Barrel Jellyfish (Rhizostoma pullmo) was filmed in the Percuil Estuary, near St Mawes, Cornwall. Large numbers of these, the UK’s largest jellyfish species have been seen this year around our coast. They are totally harmless and feed on plankton. They do have stinging cells but they are not able to get through human skin. They can grow to 80cm wide and weigh up to 30 kilos!

From the Dorset Echo in England today:

Warmer weather sees return of the barrel jellyfish to Dorset shores

by Tara Cox, Reporter

APRIL has seen the return of the barrel jellyfish in Dorset due to warmer weather – and experts warn there could be more sightings to come.

Barrel jellyfish, which can grow up to one metre wide, have been spotted in Weymouth Bay and Lyme Bay in recent weeks.

And the Dorset Wildlife Trust claim that during the spring and summer, we could expect to see up to eight different species of jellyfish along the Dorset coast.

Last year, more and more sightings of the sea creatures were reported after members of the public spotted them both in the ocean and washed up on beaches in Weymouth, Portland and West Dorset.

Barrel jellyfish can grow up to one metre wide.

These particular jellyfish do not sting, but the trust is advising members of the public not to touch any jellyfish they find washed up and to report them to the trust to identify and record.

Emma Rance, DWT marine conservation officer, said: “These oceanic drifters can change in shape, colour and size when they are beached.

“We would encourage people to look but not touch and keep their animals away from the jellyfish, because many jellyfish can still sting when dead.

“It’s very likely that we’re going to get more reports of jellyfish due to warmer weather. Barrel jellyfish feed on zooplankton – tiny animals floating in the water – which have increased due to longer days with more sunlight.”

The trust also said that the leatherback turtle and oceanic sunfish feed on jellyfish, so there could also be a possibility of seeing both of these species in Dorset.

Steve Trewhella, a professional wildlife photographer and environmental campaigner, said he was surprised to hear of jellyfish sightings on Portland and Chesil Beach as early as this in the year.

Broadwindsor resident and freelance writer Sophia Moseley spotted a barrel jellyfish on Lyme Regis beach near the iconic Cobb last Friday.

She said: “I took my two children down to the beach for fish and chips and was quite surprised to see it so early in the year.

“The jellyfish was 20 inches in diameter. It’s a worry that they are populating our seashore but there isn’t much we can do about it.”

Sophia tweeted a picture of the jellyfish to the Dorset Wildlife Trust, and said she would encourage others to do the same.

People who see a jellyfish are encouraged to take a photo and report it to the DWT via their Facebook page at facebook.com/dorsetwildlife.

Alternatively, any sighting photos can be tweeted to @DorsetWildlife.