Black widow spider web DNA, new reaearch

This video says about itself:

Deadly Mates: Black Widow Spider

13 February 2008

If you think the dating world of humans is tough, check out the love life of black widows, where one misstep can lead to a lethal end.

From the BBC:

Black widow spider web gives up DNA secrets

By Helen Briggs

26 November 2015

Spiders can be identified from the DNA they leave on webs, say US scientists.

Analysis of genetic material stuck to spiders’ webs also reveals what they have eaten weeks after catching their prey.

The research may have future uses in monitoring endangered species or tracking down spider pests, experts report in the journal Plos One.

The study looked at black widow spiders kept in a zoo.

If the technique works on other types of spider, it could have widespread practical uses, say experts from the University of Notre Dame in Indiana.

Lead researcher, Charles Xu, extracted mitochondrial DNA from the webs of black widow spiders kept at Potawatomi Zoo in Indiana.

He found that both the spider species and its prey – in this case crickets – can be identified from DNA spider web samples.

Spider webs can potentially be used to collect DNA without having to capture the spiders themselves, he says.

“In the past, identification of spiders has relied on morphology, especially looking at the genitalia of spiders because they’re very different between different species of spider,” he told BBC News.

“But there are a lot of errors associated with these kinds of methods and now with the advent of new genetic technologies we can more accurately identify these species.

“The really cool part about our study is that we used non-invasive samples – so these web samples – where we don’t even have to directly observe or capture these spiders to get their DNA.”


The experts say DNA analysis of spiders’ webs may be useful for monitoring and conservation purposes.

For example, DNA “fingerprinting” of spiders’ webs could be used to find out where a poisonous spider is living or to map the locations of endangered species.

Spider webs have been used in the past by citizen scientists to assess spider biodiversity by examining the structure of webs.

Web DNA samples collected by citizen scientists around the world might also have potential in this area, say the researchers.

“Spider web DNA as a proof-of-concept may open doors to other practical applications in conservation research, pest management, biogeography studies, and biodiversity assessments,” they report in Plos One.

Black widow

Black widow spiders, found in temperate regions around the world, are feared for their venomous bite.

The female black widow spider can be twice as big as the male and will, on occasion, kill and eat the male after mating.

The spiders spin large webs in which females suspend a cocoon with hundreds of eggs.

They also use their webs to trap prey such as flies, mosquitoes, grasshoppers, beetles and caterpillars.

Spider builds web, video

This video shows an European garden spider building its web.

Boudewijn van den Hazel in the Netherlands made this video.

Male spider eaten by female, video

This video is about two cross spiders.

As the male prepares for mating, the female suddenly grabs him, and eats him.

Pieter Schwab in the Netherlands made this video.

Spider removes dewdrops, video

This video shows a male Metellina segmentata spider, which has become wet because of dewdrops.

These dewdrops cause much extra weight and may hinder breathing.

So, the spider removes the drops from his legs, letting them slide down reed stems.

Marijke Scheffer from the Netherlands made the video.

New huntsman spider species discoveries in Africa

This 2013 video is called World’s Biggest Spider: Giant Huntsman Spider.

From the Senckenberg Research Institute and Natural History Museum in Germany:

Four new species of huntsman spiders have been discovered in southern Africa

September 16, 2015

The arachnologist Dr Peter Jäger of the Senckenberg Research Institute in Frankfurt has discovered a new genus from the family of huntsman spiders. He was able to describe a total of four new species within this genus, which occurs in South Africa and Namibia. Besides special setae at the tips of their feet, which likely prevent the animals from sinking into the sand, the eight-legged creatures are characterized by their interesting mating behaviour. The study was recently published in the scientific journal “African Invertebrates“.

To discover a living in the South African deserts is a difficult feat; to study the spider in detail is almost impossible. The eight-legged animals are quick, nocturnal, and dwell in inconspicuous tunnels in the sand. “Fortunately, we have our collection that we can fall back on,” says Dr Peter Jäger, arachnologist at the Senckenberg Research Institute in Frankfurt. In his lab, Jäger was now able to identify a new genus with four associated of huntsman spiders (Sparassidae). “The spiders of one species were collected in the year 2004 by my doctoral student at the time, Dirk Kunz, and I now described them together scientifically as May bruno.” The name was assigned in the context of the bio-sponsorship program (; a daughter uses it to honour her father. Molecular-genetic studies of Jäger’s colleague Henrik Krehenwinkel confirmed that the animals belong to a .

The tips of the feet of these newly discovered desert dwellers with a leg span of 8 to 10 centimetres are particularly conspicuous. They contain unique tufts of setae with feathered tips. “They likely serve to prevent the animals from sinking into the sand and help them remain on the surface,” speculates the spider researcher from Frankfurt. Jäger is well aware of the huntsman spiders’ ingenuity when it comes to moving across the hot desert sand, at the latest since his discovery of a spider in this family that moves by means of flic-flacs or somersaults.

In addition, Jäger found yet another special trait in these spiders. All four females he inspected showed paired bite marks on their cephalothorax. “It is quite possible that these injuries were sustained during mating,” explains Jäger, and he adds, “We were unable to find these marks on the males of the ‘Love Bite Spider'”. Jäger refuses to speculate about the meaning of such behaviour and hopes that his colleagues will be able to observe the copulation in the field. However, since only 6 out of 45,000 spider species worldwide have males injuring conspecific females during courtship or mating, it is a very interesting finding.

Dutch spiders Top Ten, 2015

This video is called National Geographic Super Spider – Fascinating Spider Documentary.

After the Top 5 list of spider frequency in the Netherlands, now a more complete Top Ten list for 2015:

1. Diadem spider, aka orb web garden spider. 2701 individuals counted

2. Cellar spider. 536

3. Linyphia triangularis. 226

4. Metellina segmentata. 210

5. Domestic house spider. 199

6. Silver-sided sector spider. 191

7. Lace webbed spider. 107

8. Tetragnatha extensa. 96

9. Walnut orb-weaver spider. 94

10. Neriene montana. 87