Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A rarity among arachnids, predatory whip spiders have a sociable family life

14.03.2007
Whip spiders, considered by many to be creepy-crawly, are giving new meaning to the term touchy-feely.

In two species of whip spiders, or amblypygids, mothers caress their young with long feelers and siblings stick together in social groups until they reach sexual maturity. This is surprising behavior for these arachnids, long-thought to be purely aggressive and anti-social, according to a Cornell researcher.

Social behavior is extremely rare in arachnids, a class that includes spiders, amblypygids, scorpions and mites, among others; only 76 (or less than 0.1 percent) out of the 93,000 known arachnid species have been observed living in social groups. The research, appearing in recent issues of both the Journal of Arachnology and Natural History magazine, marks the first time social behavior has been reported in amblypygids.

"This was the best example I had ever seen of friendly behavior in an arachnid," said Linda Rayor, senior research associate in entomology and the lead author of both articles. Rayor describes in the articles how mothers habitually stroke their offspring with their long, thin whiplike front legs and how the siblings congregate in social groups.

... more about:
»Rayor »amblypygid »arachnid »diadema »siblings

"I was amazed at how incredibly interactive the groups are," said Rayor. "They are in constant tactile contact with one another. They are constantly exploring one another and interacting with their siblings."

Scientists have long thought these creatures were solitary and cannibalistic predators, as past studies have focused mainly on the adult's dramatic courtship and fighting behaviors. Rayor believes that because young amblypygids slip easily into tight crevasses and their coloring matches their backgrounds, the social behavior of the youngsters has been missed in the wild.

Rayor's research on two species in captivity (the dime-sized Phrynus marginemaculatus from Florida and a much larger Damon diadema from Tanzania) suggests that both mothers and siblings form long-lasting, socially interactive groups. As soon as the siblings approach sexual maturity though (about 12 to 14 months of age), they start showing aggressive, life-threatening behavior toward each other.

To test if D. diadema were congregating simply to inhabit a preferred site in the cages, Rayor and Lisa Taylor, CALS '01, created cages with uniform plywood surfaces and found that the siblings grouped together but changed their location daily, suggesting individuals preferred proximity to each other over a specific location. When siblings were removed from a familiar cage and scattered about another large unfamiliar cage, within minutes, they gathered back together.

In one experiment conducted by Rayor and Rachel Walsh, A&S '05, when 7- to 9-month-old D. diadema were separated from their families and later returned to cages with either their own group or an unfamiliar group, they reacted more aggressively toward the new group than their own.

Rayor suspects that benefits of whip spider social behavior include enhanced safety from predators. Although there are few reports of other creatures eating them, a mother nearby may offer young amblypygids some protection. When Rayor disturbed D. diadema youngsters, they gathered closer to each other or their mother. Now and then, the mother threatened Rayor. The adolescents, though, tended to scurry away and hide when faced with threat. While sharing prey is an advantage for other arachnids with social tendencies, Rayor said she has yet to witness amblypygids intentionally sharing prey.

More than 100 amblypygid species live in tropical areas worldwide. These arachnids, whose bodies range from one-eighth to about one and three-quarters inches long, have two elongated pedipalps (like arms) in front tipped with stilettos that are used to capture prey. The first pair of legs has developed into long whiplike feelers that are three to four times longer than the remaining three pairs of legs. The exceptionally flexible whips can move 360 degrees around their bodies and are covered with hairs that sense their environment.

Krishna Ramanujan | EurekAlert!
Further information:
http://www.cornell.edu

Further reports about: Rayor amblypygid arachnid diadema siblings

More articles from Life Sciences:

nachricht Molecular evolution: How the building blocks of life may form in space
26.04.2018 | American Institute of Physics

nachricht Multifunctional bacterial microswimmer able to deliver cargo and destroy itself
26.04.2018 | Max-Planck-Institut für Intelligente Systeme

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>