Wednesday, June 07, 2023

Study reveals honey bee nest structure is surprisingly adaptive, resilient


Peer-Reviewed Publication

AUBURN UNIVERSITY COLLEGE OF SCIENCES AND MATHEMATICS




Researchers from the Department of Biological Sciences at Auburn University have discovered that honey bee colonies have surprising abilities to adapt and maintain their nest structure, even in the face of severe disruptions.

Contrary to previous assumptions, the researchers found that the disruption of three-dimensional nest structure while colonies were building their nests did not hinder colony performance. The findings shed new light on the adaptive nature of honey bee colonies and how nest structure contributes to colony function.

The study focused on the intricate three-dimensional nest building behavior of honey bee colonies. To investigate the development of honey bee nests over time, the research team employed non-destructive, photo-based sampling methods using moveable wooden bee-frames. This approach allowed them to observe and analyze the growth and organization of combs within the nests without sacrificing the colonies. They found that honey bees rapidly build a well-connected spheroid nest composed of parallel combs that expand in all directions from the nest origin.

To test how important this stereotyped structure is for colony development, the international team of researchers disrupted the nest structure of another group of colonies by rearranging the movable wooden bee-frames in a new randomized order every week. They initially hypothesized that this disruption would negatively impact colony-level performance. However, the study revealed no significant difference in worker population, comb area, hive weight, or nest temperature between colonies with intact nest structures and those with disrupted nest structures.

The surprising lack of difference in colony performance led the researchers to explore the mechanisms behind the honey bees’ ability to compensate for repeated disruptions. By modeling the colony’s building behavior, they found that colonies prioritize structural connectedness when expanding their nests, actively repairing connections in the three-dimensional nest structure following the experimental disruptions. This highlights the colony’s ability to adapt their comb shape to the available space within a cavity, an essential skill in the wild, where cavities are not uniform.

The study also identified potential reasons why honey bees prioritize nest connectedness. A well-connected nest reduces the surface area-to-volume ratio, potentially enhancing thermoregulation efficiency, improving larvae development and winter survival. It also may facilitate information-sharing among colony members and optimize travel distances within the nest for essential activities such as foraging, feeding larvae, and egg-laying.

“We were all surprised that the shuffled colonies performed as well as they did,” said Auburn’s Peter R. Marting, the first author of the study. “We expected some shuffled colonies wouldn’t even survive the summer. The bees’ resilience led us to take a closer look at how and where exactly workers were adding new comb to shape their nests and ultimately led us to develop the predictive comb growth models.”

The research team believes that understanding the underlying mechanisms behind these adaptive building strategies in social insects can provide valuable insights into collective intelligence and resilience in complex systems.

The study, “Manipulating nest architecture reveals three-dimensional building strategies and colony resilience in honeybees,” appears in the journal Proceedings of the Royal Society B: Biological Sciences and is available for reference.

“Honey bees are an extremely well-studied system, but many basic developmental questions remain unanswered, because we don’t typically look at the colony’s natural life cycle,” said Michael L. Smith, senior author of the study. “Sometimes you just have to do the experiment and see what the bees will do.”

Watch Visual Abstract: Honeybee Nest Architecture.


When it comes to bumblebees, does size matter?

Entomologists abuzz over questions about bumblebee bodies

Grant and Award Announcement

UNIVERSITY OF CALIFORNIA - RIVERSIDE

Bumblebees 

IMAGE: BUMBLEBEE BODY SIZES ARE A MYSTERY TO ENTOMOLOGISTS, FOR NOW. view more 

CREDIT: HOLLIS WOODARD/UCR


Certain crops, like greenhouse tomatoes, eggplant, peppers, and blueberries, rely on bumblebees for a style of pollination that only bumblebees can perform. Among growers, the preference can be for bigger-bodied bumblebees because they’re thought to be more efficient pollinators. 

Enabled by a $750,000 grant from the National Institute of Food and Agriculture, the research team will investigate factors suspected of influencing bumblebee biology and body size, including climate change, wildfires, and the presence of nearby honeybee colonies.

In many cases, individual animals are born smaller when their habitat has less nutrition available. The researchers want to know if this is also true for bees. “One idea is that honeybees are taking more food resources, resulting in smaller bumbles. This is part of what we will be testing,” said UCR entomologist and project lead Hollis Woodard.

To test this, the researchers will collect bumblebee size data over the next four years from places both with and without honeybees nearby. “It’s hard to find anywhere in the lower 48 without either managed or feral honeybees. For this reason, we’re headed to Alaska for part of the study,” Woodard said.

Fire may also play a role in bumblebee development. Some research has shown that bumblebees are born bigger, and in higher numbers, during the years following a wildfire. Since wildfires are common in California, the research team will also be collecting data from places throughout the state with different types of fire histories.

In addition to the mystery of what influences the bees’ body size, it’s also unclear what role size plays in a bumble colony. While all bumblebee workers perform the same functions, variation in size could allow the hive as a whole to collect pollen from a wider variety of flowers. 

Though bigger bees can collect more pollen, they might not be right for every plant species. For some flowers, especially those that are trumpet-shaped, smaller bumblebees are better pollinators. 

“There are theories that bumblebee sizes are just random, or that it’s just generally good to have variation,” Woodard said. ‘Right now, we don’t yet know exactly what this variation in size does for colonies.”

In addition to benefitting crop growers, the team’s findings could ultimately benefit the bees themselves. “Any insights we gain into factors affecting the bumblebees could help us better understand how to bolster their dwindling populations,” Woodard said. “Helping them in turn helps ensure the health of wildflowers, as well as our food supply."

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