Orit Peleg

Orit Peleg Awarded 2020 Research & Innovation Seed Grant: "Bee-Honeycomb Formation under Geometric Frustration"

Anonymous — Wed, 15 Apr 2020 23:10:51 +0000

Orit Peleg Awarded 2020 Research & Innovation Seed Grant: "Bee-Honeycomb Formation under Geometric Frustration" Anonymous (not verified) Wed, 04/15/2020 - 17:10

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Social inhibition maintains adaptivity and consensus of honeybees foraging in dynamic environments

Anonymous — Mon, 30 Dec 2019 20:55:18 +0000

Social inhibition maintains adaptivity and consensus of honeybees foraging in dynamic environments Anonymous (not verified) Mon, 12/30/2019 - 13:55

To effectively forage in natural environments, organisms must adapt to changes in the quality and yield of food sources across multiple timescales. Individuals foraging in groups act based on both their private observations and the opinions of their neighbours. How do these information sources interact in changing environments? We address this problem in the context of honeybee colonies whose inhibitory social interactions promote adaptivity and consensus needed for effective foraging. Individual and social interactions within a mathematical model of collective decisions shape the nutrition yield of a group foraging from feeders with temporally switching quality. Social interactions improve foraging from a single feeder if temporal switching is fast or feeder quality is low. When the colony chooses from multiple feeders, the most beneficial form of social interaction is direct switching, whereby bees flip the opinion of nest-mates foraging at lower-yielding feeders. Model linearization shows that effective social interactions increase the fraction of the colony at the correct feeder (consensus) and the rate at which bees reach that feeder (adaptivity). Our mathematical framework allows us to compare a suite of social inhibition mechanisms, suggesting experimental protocols for revealing effective colony foraging strategies in dynamic environments.

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Collective ventilation in honeybee nests

Anonymous — Tue, 29 Oct 2019 17:50:25 +0000

Collective ventilation in honeybee nests Anonymous (not verified) Tue, 10/29/2019 - 11:50

European honey bees (Apis mellifera) live in large congested nest cavities with a single opening that limits passive ventilation. When the local air temperature exceeds a threshold, the nests are actively ventilated by bees fanning their wings at the nest entrance. Here, we show that colonies with relatively large nest entrances use an emergent ventilation strategy where fanning bees self-organize to form groups, separating regions of continuous inflow and outflow. The observed spatio-temporal patterns correlate the air velocity and air temperature along the entrances to the distribution of fanning bees. A mathematical model that couples these variables to known fanning behaviour of individuals recapitulates their collective dynamics. Additionally, the model makes predictions about the temporal stability of the fanning group as a function of the temperature difference between the environment and the nest. Consistent with these predictions, we observe that the fanning groups drift, cling to the entrance boundaries, break-up and reform as the ambient temperature varies over a period of days. Overall, our study shows how honeybees use flow-mediated communication to self-organize into a steady state in fluctuating environments.

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The effect of step size on straight-line orientation

Anonymous — Tue, 29 Oct 2019 17:47:44 +0000

The effect of step size on straight-line orientation Anonymous (not verified) Tue, 10/29/2019 - 11:47

Moving along a straight path is a surprisingly difficult task. This is because, with each ensuing step, noise is generated in the motor and sensory systems, causing the animal to deviate from its intended route. When relying solely on internal sensory information to correct for this noise, the directional error generated with each stride accumulates, ultimately leading to a curved path. In contrast, external compass cues effectively allow the animal to correct for errors in its bearing. Here, we studied straight-line orientation in two different sized dung beetles. This allowed us to characterize and model the size of the directional error generated with each step, in the absence of external visual compass cues (motor error) as well as in the presence of these cues (compass and motor errors). In addition, we model how dung beetles balance the influence of internal and external orientation cues as they orient along straight paths under the open sky. We conclude that the directional error that unavoidably accumulates as the beetle travels is inversely proportional to the step size of the insect, and that both beetle species weigh the two sources of directional information in a similar fashion.

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Do plants have social networks?

Anonymous — Wed, 15 May 2019 06:00:00 +0000

Do plants have social networks? Anonymous (not verified) Wed, 05/15/2019 - 00:00

Josh Rhoten

Humans interact in social networks every day around the office coffee pot, online with Facebook and in their communities through political elections. The structure and connections within these networks and others shape how information is shared. That in turn defines much of our modern life and collective behavior, though little is known about how or why these processes work.

That is because it’s difficult to study how these systems, with so many inputs and variables, actually work or affect one another in humans. The same goes for animals where small factors like touch, sight and sound can similarly change the whole dynamic of a network. Research being led by CU Boulder Assistant Professor Orit Peleg is trying to untangle this question by studying social systems in sunflowers through an award from the Human Frontier Science Program.

Peleg acknowledges most people don’t think of plants as having social networks – that is, they don’t think of plants being alive in that way. But for her, that kind of philosophical question is one of the most important aspects of the project.

“There are basic science and philosophical questions to be answered in this work,” said Peleg, who is a member of the Multi-Functional Materials and Autonomous Systems IRTs. “We will be using methodology from physics, engineering and math to understand problems in biology. How do you define a living organism? How do you differentiate between physical and social interactions?”

The Human Frontier Science Program links researchers from different continents and backgrounds. Peleg is joined in the project by Alex Jordan from the University of Konstanz in Germany and Yasmine Meroz from Tel Aviv University in Israel. Their $1.1 million, three-year grant is one of only nine 2019 Young Investigator Grants awarded this cycle to researchers specifically within five years of establishing their independent research group and no more than 10 years from their doctoral degree. In total, the program selected just 34 teams from more than 800 applications representing 60 countries.

Portrait of Orit Peleg

Orit Peleg

Peleg’s team is using sunflowers for this project because they are known to adjust their flower heads and leaves to earn maximum sun exposure, throwing shade on nearby plants in the process. Those neighboring plants then move to avoid being shaded themselves. The ripple effect from this dynamic creates a large network of interactions in the neighboring community of plants.

Peleg said plants are also great for this work because they do not move from location to location like humans or animals, making it easier to collect data. It also opens up agricultural applications for the work in the future as well for things like maximizing planting space.

Peleg, who is based in the BioFrontiers Institute and the Computer Science Department in the College of Engineering and Applied Science, will be working on computer modeling for the project. Her team will be looking at different planting arrangements of the sunflowers, comparing their growth to different light sources.

“By comparing those inside a model, we can say something a bit more microscopic about the interactions between the plants,” she said. “How do they communicate? Is there a benefit to the entire collection from their actions? We may be able to use this knowledge to project on to more complicated networks in the future.”

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Orit Peleg Wings HFSP Young Investigator Award

Anonymous — Thu, 28 Mar 2019 19:26:19 +0000

Orit Peleg Wings HFSP Young Investigator Award Anonymous (not verified) Thu, 03/28/2019 - 13:26

HFSP

Congrats to Orit Peleg on the announcement of her Human Frontier Science Program Young Investigator Award for the dynamics of information flow in a social network of mutually shading plants project!

The International Human Frontier Science Program Organization (HFSPO) announced today some $35 million to support the top 4% of the HFSP Research Grant applications over the coming 3 years. The 34 winning teams of the 2019 competition for the Research Grants went through a rigorous year-long selection process in a global competition that started with 814 submitted letters of intent involving scientists with their laboratories in more than 60 different countries. This year, 9 Young Investigator Grants and 25 Program Grants were selected for funding. Each team member receives on average $110,000 - $125,000 per year for 3 years.

HFSP's collaborative Research Grants are given for a broad range of projects under the umbrella theme "Complex mechanisms of living organisms". The program funds only cutting-edge, risky projects and it is the only international program that funds teams of scientists globally "without borders". HFSP Program Grants appeal to the innovative and creative potential of the research teams. Frontier life science knows no limits as winning teams propose, for example, to investigate fluid trade in hyphal networks extending from the soil into plants, seasonal reversible changes in brain size in shrews, or to image memory storage in the octopus brain.

The HFSP Young Investigator Grants are for applicants within 5 years of establishing their independent research group and no more than 10 years from their doctoral degree. This group of investigators also challenges intriguing concepts such as paradoxical responses of the immune system following injuries, or trying to understand fear generalization across different scales in the brain.

The 2019 HFSP investigators display remarkable depth in approach and innovative thinking as they start their intercontinental collaborations. The lists of all 2019 HFSP awards are available at http://www.hfsp.org/awardees/newly-awarded.

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Work with bees could unlock potential strength of natural designs in new materials

Anonymous — Mon, 17 Sep 2018 06:00:00 +0000

Work with bees could unlock potential strength of natural designs in new materials Anonymous (not verified) Mon, 09/17/2018 - 00:00

Josh Rhoten

The natural world has had billions of years of evolution to perfect systems, creating elegant solutions to tricky problems. CU Boulder Assistant Professor Orit Peleg’s work hopes to illuminate and explore those solutions with the long-term goal of applying the answers she finds to the materials we interact with daily.

Her most recent research with bees, recently published in Nature Physics, is a small step toward that goal. The project looked at the honeybee cluster swarms that hang in cone shapes from tree branches and are made up of hundreds of individual insects clinging to one another. While these swarms are hundreds of times the size of a single organism, the individual bees that comprise it are able to maintain the structure’s stability despite wind and gravity forcing changes in the overall shape.

Peleg, who is based in the Computer Science Department and the BioFrontiers Institute at CU Boulder, conducted the research during her time as a post-doctoral fellow at Harvard in 2017. She said the use of bees for the project “was a bit crazy,” but presented a good opportunity to work more on modeling and testing these types of systems at a low cost and with relatively simple imaging equipment.

“It is a good way to connect experiments to theory and go back and forth until we have a good understanding of the system,” she said.

The project tried to untangle how the cluster stayed together in various conditions by attaching one to a board that was shaken with varying amplitude, frequency and duration. The results showed that horizontally shaken clusters spread out to form wider, flatter cones, adapting to the movement, but also going back to normal given time. Something similar happened with sharp, pendular movements, but measurements before and after showed that the flattened cones deform less and relaxed faster than the elongated ones. Meanwhile, vertical movement put less strain on the structure which, in turn, required less change from the bees to adapt to the motion.

In the end, the experiment confirmed what Peleg’s agent-based simulations predicted and opened up new questions.

“Our goal in this experiment was to try to pinpoint local rules for behaviors of bees that dictate the mechanical stability of the structure. A bee on one side of swarm can’t say what another bee at the other side of the swarm is doing. It can only say what is happening in its local environment,” Peleg said. “So, by creating this structure, they have to solve this mechanical problem of stability by only using local information.”

But how do they know to do this? Or why? Peleg’s hypothesis is that individual bees respond to the strain they feel during movement, changing their position in the swarm to match it.

“We can think about a local role, where a bee senses those deformations through connections to other bees. If this exceeds a certain threshold, it moves around to address that,” she said. “It doesn’t consider up or down, it just takes the local gradient information. Going up gradient (magnitude) makes it harder for individual bee, but better for the swarm overall.”

Peleg is part of the Multi-functional Materials Interdisciplinary Research Theme at CU and said this work fits well with that theme’s goal of exploring new materials and applications. While there is still more work to be done in studying the fundamental biology at work, she said this research could have applications in swarm robotics or the creation of materials that can sense their environment and respond to it.

“There is a clear connection to structures that insects make like swarms or ant-towers, for example, that are dynamic and respond to things like temperature or mechanical changes,” she said. “The grandiose vison of this, which we are still far away from, is the creation of construction materials that can sense and respond to earthquakes and become more stable in the same sort of way.”

Peleg has an apiary on East Campus and is planning on continuing this kind of work and this project in particular. Specifically, she said there was still work to be done with imaging the inside of the swarms to help with overall understanding of how this process works.

“We still need to look at the internal structure of the swarm through x-rays, for example, as that is completely unknown right now and could be informative,” she said.

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Orit Peleg Research Video

Anonymous — Tue, 04 Sep 2018 18:42:00 +0000

Orit Peleg Research Video Anonymous (not verified) Tue, 09/04/2018 - 12:42

Orit Peleg is an assistant professor at the BioFrontiers Institute and in the Department of Computer Science at the University of Colorado Boulder. Peleg seeks to understand the behavior of disordered living systems by merging tools from physics, biology, engineering and computer science.

[video:https://youtu.be/Do0njseS2IE]

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