How spiders build webs, time lapse video


This 16 February 2020 video says about itself:

Spider Web Building Time-lapse | BBC Earth

We filmed a garden orb-web spider building their amazing spider web in this time-lapse as well as slow-motion footage as they capture their first prey with it!

Orb-weaver spiders’ colours attract prey


This 3 July 2019 video from Indonesia says about itself:

Kemlanding or giant golden spider or giant golden orbweaver (Nephila pilipes) is a species of web-making spiders, living in forests and gardens, carnivores, rectangular, black and yellow, living in clay, limestone and karst hills at an altitude of about 100-400 meters above sea level.

Females growing up to 5 cm (overall 20 cm) while males only 0.5 cm. Sexual dimorphism of giant golden spider has two main hypotheses, female gigantism and male dwarfism.

N. pilipes builds fine, asymmetrical and elongated nets for up to 2 meters wide at 1-2 meters above the ground. The net is built between pineapple (Ananas comosus), sonokeling (Dalbergia latifolia), teak (Tectona grandis), pine (Pinus merkusii), Earleaf acacia (Acacia auriculiformis) and various shrubs.

From the British Ecological Society:

Orb-weaver spiders’ yellow and black pattern helps them lure prey

February 11, 2020

Summary: Being inconspicuous might seem the best strategy for spiders to catch potential prey in their webs, but many orb-web spiders, which hunt in this way, are brightly colored. New research finds their distinct yellow and black pattern is actually essential in luring prey.

Researchers from Australia, Singapore, Taiwan and the UK placed cardboard cut-out models of the golden orb-weaver, Nephila pilipes, onto real webs in the field. Testing different combinations of colours and patterns they discovered that both the yellow colour and the black and yellow mosaic pattern are essential for luring prey during the day.

The webs of Nephila pilipes also capture prey during the night, and the experiments demonstrated that the yellow colour alone was very effective at luring nocturnal insects.

Orb-weaving spiders are found in different light conditions, and comparisons between many different species revealed a link between light environments and orb-weaver body colour patterns. Species that build their webs in well-lit environments are more likely to evolve the yellow mosaic colour pattern, found to be so effective at luring prey in these experiments.

However, this colour pattern rarely evolves in species that have little opportunity to lure prey, perhaps because they are concealed in a retreat or build their webs in dark caves.

Dr Po Peng, lead author of the study, said, “Our discoveries indicate that the effectiveness of colour-luring to attract prey might be a major driver for the yellow mosaic pattern being present in distantly related orb-weaver spiders.”

The significance of the yellow colour may be due to yellow pollen and flower heads being common in flowers that signal to diurnal (active during the day) pollinators. Previous research has also found that some nocturnal (active at night) Lepidoptera (moths and butterflies) can discriminate colours under dim light conditions and innately prefer yellow.

Orb weaving spiders comprise around 12,500 species, making up 28% of the 45,000 described spider species. The groups defining trait is that they construct webs which they sit in the middle of to forage for prey.

Nephila pilipes were used in these experiments as they are active both diurnally and nocturnally, making them excellent species to study visual prey lures. Flies and bees make up the majority of their diurnal prey; moths and butterflies make up the majority of their nocturnal prey.

The researchers conducted the field experiments at Huayan Mountain in Taiwan between 2008 — 2009. They created five types of cardboard models that looked like Nephila pilipes with their legs outstretched. One accurately mimicked the spiders’ natural colouration. The second had blue spots rather than yellow to test the importance of colour. The third amalgamated the combined area of the yellow into one area to test the importance of the pattern. The fourth and fifth model types were entirely yellow and entirely black.

“To find paper with colour properties most similar to the body parts of N. pilipes, Szu-Wei Chen (co-author) and I did several tours over dozens of stationery stores collecting samples and measuring their reflectance.” Said Po Peng.

In the field experiments, the researchers removed a live spider from its web and randomly selected one of the models to be placed in the centre. They recorded the responses of insects to the cardboard spiders, collecting a combined 1,178 hours of video footage over day and night.

In this study the researchers only looked at the effects of the spiders’ colour and pattern on luring prey and not how they’re perceived by predators. “Previous studies suggest that the area of bright body parts is constrained by diurnally active, visually hunting predators” said Po Peng, “But our results indicated that the yellow mosaic pattern on nocturnal spiders does not represent a trade-off between prey attraction and predator avoidance.” The effect of both colour and pattern on risk from predators or parasitoids is something the researchers feel warrants further investigation.

Why spider webs survive, new research


This 2017 video says about itself:

Beautiful Spider Web Build Time-lapse | BBC Earth

Spiders are the most amazing web architects and using slow motion the Earth Unplugged team captured this Orb spider building a stunning structure.

By Priyanka Runwal in Science News, October 30, 2019 at 6:00 am:

Spider webs don’t rot easily and scientists may have figured out why

Bacteria key to decomposition can’t get at the silk’s nitrogen, a nutrient needed for growth

From spooky abandoned houses to dark forest corners, spider webs have an aura of eternal existence. In reality, the silk threads can last hours to weeks without rotting. That’s because bacteria that would aid decomposition are unable to access the silk’s nitrogen, a nutrient the microbes need for growth and reproduction, a new study suggests.

Previous research had hinted that spider webs might have antimicrobial properties that outright kill bacteria. But subjecting the webs of three spider species to four types of bacteria revealed that the spiders use a resist strategy instead, researchers report October 23 in the Journal of Experimental Biology.

The scientists “challenge something that has gone significantly overlooked”, says Jeffery Yarger, a biochemist at Arizona State University in Tempe, who wasn’t involved in the research. “We just assumed [the silk] has some kind of standard antimicrobial property.”

Spiders spin strings of silk to trap food, wrap their eggs and rappel. Their silk webs can sport leaf debris for camouflage amidst tree canopies or leftover dead insects for a meal later. These bits and bobs lure bacteria and fungi involved in decomposition to the web, exposing the protein-rich web silks to the microbes.

“But [the microbes] don’t seem to affect spider silk,” says Dakota Piorkowski, a biologist at Tunghai University in Taichung, Taiwan.

To check if the silk was lethal to bacteria, Piorkowski’s team placed threads from three tropical spider species — giant golden orb weaver (Nephila pilipes), lawn wolf spider(Hippasa holmerae) and dome tent spider (Cyrtophora moluccensis) — in petri dishes and grew four types of bacteria, including E. coli, in perpendicular lines across the silk. “The idea is that if the silk has antibacterial properties, you should see no growth between the piece of silk and … bacteria,” Piorkowski says.

There was no evidence of this “clear zone” of dead bacteria in spots where the bacteria came in direct contact with the silk, the researchers found. So the team then tested if the silk kept hungry bacteria at bay by blocking them from its nitrogen reserves. Wetting the silk threads with an assortment of nutrient solutions showed that the bacteria readily grew on all three types of spider silk when extra nitrogen was available. That indicated that the bacteria are capable of growing on and possibly decomposing the silk, as long as the threads themselves aren’t the only source of nitrogen.

The researchers hypothesize that an outer coating of fat or complex protein on the silk may block bacteria’s access to nitrogen.

Randy Lewis, a spider silk biologist at Utah State University in Logan, cautions against ruling out antibacterial features in all spider silks, though. Underground webs of tarantulas (SN: 5/23/11), for example, can face environments rife in microorganisms compared with that experienced by aerial web-spinning spiders, he says, and may need the extra protection.

New spider species gets fashion designer’s name


This October 2015 video says about itself:

Jotus remus, an Australian species of spider I discovered on 30 December 2014 when I came home from a camping trip and found it sitting on my luggage when unloading the car. Perhaps interesting to note that I had intentionally left my camera gear at home so I would not be tempted to look for spiders.

This spider was named and described in a paper that David Hill and myself published in the journal Peckhamia.

The courtship behaviour of this spider is extraordinary. Both play a kind of cat and mouse game and when I published this video I still did not know why they behaved in that way. It took almost a year to solve the puzzle and it happened when bringing together virgin females and males, you can see what happens then in the sequel to this video, Spid-a-boo2.

I watched female and males engaging in this way for many hours and regardless of how long the male tried a female that attacked him would not mate. This behaviour is NOT to tire out the female, tiredness plays no role here. The aim is to find a female that is receptive, one that has not yet mated. Instead of chasing the male with his paddle receptive females become calm and placid almost immediately when seeing the male’s paddle appearing over the edge of a leaf and it only takes a couple of minutes for them to decide to mate.

The clips I used in this video are only a fraction of what I originally shot. You can find many more scenes in my album on Vimeo.

The music for this clip was composed, played and recorded by cellist Kristin Rule. I love her work and I am glad she agreed to help me with this little clip. Research, camera, editing: Jurgen Otto Camera gear used: Canon C100 and 100mm macro lens For more on my work visit me on Facebook.

And now, newly discovered relatives of this spider species.

From ScienceDaily:

Trendy on eight legs: Jumping spider named after fashion czar Karl Lagerfeld

July 2, 2019

New to science species of Australian jumping spider was named after Hamburg-born fashion icon Karl Lagerfeld (1933-2019) after the arachnid reminded its discoverers of the designer. Intrigued by its distinct ‘downplayed’ black-and-white colours, the Hamburg-Brisbane-Melbourne team likened the spider’s appearance to Lagerfeld’s trademark style: his white hair and Kent collar that contrasted with the black sunglasses and gloves.

Thus, the curious species, now officially listed under the name Jotus karllagerfeldii was described in the open-access journal Evolutionary Systematics by Dr Danilo Harms of the Center for Natural History of the University of Hamburg (CeNak), Dr Barbara Baehr, Queensland Museum (Brisbane, Australia) and Joseph Schubert, Monash University (Melbourne).

When compared with other members in the ‘brushed’ jumping spider genus Jotus, the novel species clearly stands out due to its black-and-white legs and tactile organs (pedipalps), whereas the typical representative of this group demonstrates striking red or blue colours.

“The animal reminded us with its colours of the reduced style of Karl Lagerfeld. For example, we associate the black leg links with the gloves he always wore,” Danilo Harms explains.

In fact, what was to be now commonly referred to as Karl Lagerfeld’s Jumping Spider was identified amongst specimens in the Godeffroy Collection. Kept at CeNak, the historical collection was originally compiled by the inquisitive and wealthy tradesman from Hamburg Johann Cesar Godeffroy, who financed several expeditions to Australia back in the 19th century. Here, the research team identified another link between Australia, Godeffroy, Hamburg and Jotus karllagerfeldi.

Besides the tiny (4 to 5 mm) arachnid, whose pedipalps resemble a white Kent collar, the scientists describe another seven new to science species and add them to the same genus. Two of those, Jotus fortiniae and Jotus newtoni, were also named after inspirational figures for their hard work and creativity: educator, molecular biologist and science communicator Dr Ellen Fortini (Perth College, Western Australia) and keen naturalist and photographer Mark Newton. All novel species were found either in the Godeffroy Collection or amongst the jumping spiders housed at Queensland Museum.

Surprisingly, even though the genus Jotus comprises numerous species found all over Australia, there is not much known about these spiders. An interesting feature, according to the scientists behind the present study, are the huge telescopic eyes, which allow for spatial vision. The Jotus species need this ability in foraging, since they do not weave webs, but rather hunt in the open. Thus, they have evolved into extremely fast and agile hunters, capable of jumping short distances.

Curiously, back in 2017, the team of Barbara and Danilo, joined by Dr Robert Raven from Queensland Museum, described another previously unknown, yet fascinating species: a water-adapted spider, whose sudden emergence at the coastline of Australia’s “Sunshine State” of Queensland during low tide in January brought up the association with reggae legend Bob Marley and his song “High Tide or Low Tide.” The species, scientifically known as Desis bobmarleyi, was also published in Evolutionary Systematics.

Spiders start out social but later turn aggressive after dispersing and becoming solitary, according to a study publishing July 2 in the open-access journal PLOS Biology by Raphael Jeanson of the National Centre for Scientific Research (CNRS) in France, and colleagues: here.

Spiders use electricity to fly


This 25 April 2019 video says about itself:

How Spiders Use Electricity to Fly | Decoder

Can spiders fly? When you think of the greatest aviators in the natural world, you probably think of the usual winged suspects like birds, bees, and butterflies. But some of the earth’s eight-legged creatures also have specialized ways of soaring through the skies—no wings necessary.

Researchers at McMaster University who rush in after storms to study the behaviour of spiders have found that extreme weather events such as tropical cyclones may have an evolutionary impact on populations living in storm-prone regions, where aggressive spiders have the best odds of survival: here.