Biologists from Mainz and Basel investigate food sharing among siblings in 125 earwig families
Looking at the question of how social behavior has developed over the course of evolution, scientists from the universities in Mainz and Basel have gained new insights from the study of earwigs. "Young earwig offspring don't simply compete for food.
Rather the siblings share what is available amongst themselves, especially when the mother is absent," explained Dr. Joël Meunier of the Evolutionary Biology section of the Institute of Zoology at Johannes Gutenberg University of Mainz (JGU). The team of biologists from Mainz University and the University of Basel investigated the interactions between siblings of the European earwig (Forficula auricularia).
To date, insects have been only little studied with regard to cooperative behavior between siblings, except in the case of eusocial species, such as bees and ants. The European earwig provides, as the research project shows, valuable clues to the origins of social behavior patterns.
The animal kingdom has an unbelievable diversity of forms of social life. These encompass situations such as the temporary aggregation of single individuals to social communities based on the division of labor. For evolutionary biologists this poses question of how these ubiquitous social life forms emerged despite the accompanying disadvantages of competition and conflict among group members. When it comes to birds, for example, the competition among siblings is often so fierce that some of the younger animals die.
"In the case of earwigs, we have a system that closely resembles the primitive conditions of family life," said Jos Kramer, a doctoral candidate on Meunier’s team. In fall, female earwigs lay on average 40 to 45 eggs and stay over the winter with them. The mothers watch the eggs, keep them clean by licking off fungi, for example, and carry them back and forth in the nest. Once the young, the so-called nymphs, emerge, they stay in the nest for few weeks with their mothers, even if the presence of this latter is no longer necessary for their survival. Indeed, the nymphs could leave the family unit soon after emergence and take care of themselves from then on.
These sub-social forms of life provide the ideal field of research for investigating under what conditions the advantages of cooperation in a family unit outweigh the disadvantages. For this purpose, the scientists from Mainz and Basel provided 125 earwig families with dyed pollen and observed if and how the food was divided amongst the siblings.
"We found that siblings behave cooperatively and share food and that this behavior occurs much more frequently when the mother is not present and is not feeding her offspring herself," stated Meunier. This may at least partly explain why mobile offspring stay with the family group despite the disadvantages associated with this. In addition, this insight provides an important clue to the early development of social behavior. The previously largely ignored aspect of sibling cooperation is possibly one of the key factors that promoted the transition from solitary to social life.
A female European earwig (Forficula auricularia) with her young
photo: Joël Meunier
A female European earwig both cleans and transports her offspring
photo: Joël Meunier
Joachim Falk et al.
Sibling Cooperation in Earwig Families Provides Insights into the Early Evolution of Social Life
The American Naturalist, 11 February 2014
Dr. Joël Meunier
Institute of Zoology
Johannes Gutenberg University Mainz (JGU)
D 55099 Mainz, GERMANY
phone +49 6131 39-27852
fax +49 6131 39-27850
Petra Giegerich | idw - Informationsdienst Wissenschaft
Two decades of training students and experts in tracking infectious disease
27.11.2015 | Hochschule für Angewandte Wissenschaften Hamburg
Increased carbon dioxide enhances plankton growth, opposite of what was expected
27.11.2015 | Bigelow Laboratory for Ocean Sciences
Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.
Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...
25.11.2015 | Event News
17.11.2015 | Event News
21.10.2015 | Event News
27.11.2015 | Press release
27.11.2015 | Life Sciences
27.11.2015 | Materials Sciences