Skip to main content

Solitude breeds aggression in spiders (rather than vice versa)

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.
Many species display sociality only transiently during their life cycle. For example, spiderlings at their earliest developmental stage show mutual attraction and social tolerance before they disperse. This strongly contrasts with post-dispersal, solitary adult spiders that behave aggressively toward -- and sometimes even cannibalize -- other spiders. The onset of dispersal coincides with a sharp decline in social tolerance in many animals, but the causal relationship still remains poorly understood.
To address this question, Jeanson and his colleagues used a combination of behavioral, chemical and modeling approaches in spiderlings of a solitary species (Agelena labyrinthica, the labyrinth spider) to investigate the mechanisms controlling the developmental switch leading to the decline of social cohesion and the loss of tolerance.
They found that the process of maturation naturally causes an increase in mobility, which is itself sufficient to trigger dispersal without requiring any change in social behaviors. After spending an initial period of about five days in close proximity, spiderlings progressively dispersed without any change in the social context, that is, no aggressive interactions were observed before dispersal. By contrast, the social isolation that inevitably followed dispersal triggered aggressiveness by altering the way that individual spiders perceived others from the same species. For example, spiderlings that experienced social isolation were much more aggressive toward siblings than those reared socially. According to the authors, the findings provide strong evidence that aggression is a consequence, not a cause, of dispersal in spiderlings.
"We are now exploring the mechanisms explaining why spiderlings exposed to social isolation behave aggressively," said Dr Jeanson. "Our favorite hypothesis, currently under testing, is that isolation leads spiderlings to forget the social cues emitted by siblings. We believe that our findings open interesting perspectives to understand how permanent sociality, which characterizes about 30 out of the almost 50,000 species of spiders described thus far, has evolved."
Story Source:
Materials provided by PLOS. 
Note: Content may be edited.

Comments

Post a Comment

Popular posts from this blog

Size matters: New data reveals cell size sparks genome awakening in embryos

Transitions are a hallmark of life. When dormant plants flower in the spring or when a young adult strikes out on their own, there is a shift in control. Similarly, there is a transition during early development when an embryo undergoes biochemical changes, switching from being controlled by maternal molecules to being governed by its own genome. For the first time, a team from the Perelman School of Medicine at the University of Pennsylvania found in an embryo that activation of its genome does not happen all at once, instead it follows a specific pattern controlled primarily by the various sizes of its cells. The researchers published their results this week as the cover story in  Developmental Cell . In an early embryo undergoing cell division, maternally loaded RNA and proteins regulate the cell cycle. The genomes of the zygote -- a term for the fertilized egg -- are initially in sleep mode. However, at a point in the early life of the embryo, these zygotic nuclei "wake...
Post a Comment
Read more

Home births as safe as hospital births: International study suggests

A large international study led by McMaster University shows that low risk pregnant women who intend to give birth at home have no increased chance of the baby's perinatal or neonatal death compared to other low risk women who intend to give birth in a hospital. The results have been published by  The Lancet 's  EClinicalMedicine  journal. "More women in well-resourced countries are choosing birth at home, but concerns have persisted about their safety," said Eileen Hutton, professor emeritus of obstetrics and gynecology at McMaster, founding director of the McMaster Midwifery Research Centre and first author of the paper. "This research clearly demonstrates the risk is no different when the birth is intended to be at home or in hospital." The study examined the safety of place of birth by reporting on the risk of death at the time of birth or within the first four weeks, and found no clinically important or statistically different risk between home...
Post a Comment
Read more

Molecular adlayer produced by dissolving water-insoluble nanographene in water

Molecular adlayer produced by dissolving water-insoluble nanographene in water : "Nanographene incorporated micelle capsules" can be prepared by simply pulverizing and mixing nanographene with amphiphilic V-shaped anthracene molecules in water at room temperature. Even though nanographene is insoluble in water and organic solvents, Kumamoto University (KU) and Tokyo Institute of Technology (Tokyo Tech) researchers have found a way to dissolve it in water. Using "molecular containers" that encapsulate water-insoluble molecules, the researchers developed a formation procedure for a nanographene adlayer, a layer that chemically interacts with the underlying substance, by just mixing the molecular containers and nanographene together in water. The method is expected to be useful for the fabrication and analysis of next-generation functional nanomaterials. Graphene is a single layer of carbon atoms arranged in sheet form. It is lighter than metal wit...
Post a Comment
Read more