Best Ways Bugs Split Colonies for Success

Jim Crocker
17th April, 2024

Best Ways Bugs Split Colonies for Success

New research on the honey bee, Apis mellifera, reveals that the evolution of colony swarming is driven by harsh environmental conditions where the survival of a new nest is critically dependent on the large size of its founding group.

Photo adapted from: Richard Bartz / CC BY SA (Source)

Key Findings

  • Study from the University of Würzburg shows how honeybee colonies decide between splitting up or a single queen starting a new colony
  • The best strategy is either sending out a single queen or forming large swarms; there's no advantage to intermediate sizes
  • The choice between these strategies depends on swarm size and the survival rates of swarms and single queens
In the world of social insects like bees, ants, and termites, how new colonies are formed is critical to their survival and expansion. Two primary strategies are at play: independent colony foundation (ICF), where a single queen starts a new colony alone, and dependent colony foundation (DCF), where a parent colony splits to form new ones. Understanding which method is more advantageous under different ecological conditions is not just an academic question. It has implications for biodiversity, agriculture, and our environment. Recent research from the University of Würzburg[1] has shed new light on this topic, particularly focusing on honeybees. The study explores the conditions under which DCF might be preferred over ICF. This is significant because, in nature, the choice between these two reproductive strategies can determine the success and resilience of bee populations. The findings from this study are built upon previous research that has highlighted the complex challenges facing bees, such as the decline in honeybee colonies due to various stressors[2], and the impact of urbanization on the social structures of ant species[3]. These studies underscore the importance of understanding social insect colony dynamics in the face of environmental changes and human influences. The University of Würzburg's research uses a resource allocation model to analyze the ecological conditions favoring DCF over ICF. The model looks at factors such as the size of the swarm that leaves the parent colony and the survival rates of these swarms. Interestingly, the study concludes that the size of the swarm is a critical factor. For DCF to be the better strategy, the survival rate of the swarm must be strongly linked to its size, and the survival of single queens must be very low. One of the fascinating aspects of this model is that it suggests a discontinuity in optimal swarm size. In essence, the best strategy is either to send out a single queen (ICF) or to form considerably large swarms (DCF). There's no middle ground, which indicates that a direct evolutionary shift from ICF to DCF is unlikely. This insight could explain why some species have evolved to use both strategies simultaneously. The model also suggests that colony growth rate does not influence the decision between ICF and DCF, and the maximum possible size of a colony is almost irrelevant. This is particularly intriguing because it challenges the notion that bigger is always better when it comes to colony size. Furthermore, the study implies that selective pressures which promote the movement of complete nests or the distribution of colonies over multiple nests (known as polydomy) could have been the catalysts for the transition from ICF to DCF. This ties in with earlier findings on wood ants, where changes in the environment, such as food availability, led to alterations in their social structure[4]. It shows that social insects are capable of adapting their reproductive strategies in response to external pressures. In summary, the research from the University of Würzburg provides a theoretical framework to understand the ecological conditions that favor the use of DCF over ICF in honeybees. It's a step forward in our comprehension of social insect reproduction and could have broader implications for managing and conserving these vital creatures. As we continue to witness changes in our environment, studies like these become increasingly important to inform conservation strategies and agricultural practices, ensuring that we can support the health and growth of insect populations that are essential to our own survival.

EcologyAnimal ScienceEvolution

References

Main Study

1) Optimal fissioning strategies of social insects with respect to colony dynamics and nest founding probability

Published 14th April, 2024

https://doi.org/10.1007/s00040-024-00960-9

Related Studies

2) BEEHAVE: a systems model of honeybee colony dynamics and foraging to explore multifactorial causes of colony failure.

Journal: The Journal of applied ecology, Issue: Vol 51, Issue 2, Apr 2014

3) Consistent signatures of urban adaptation in a native, urban invader ant Tapinoma sessile.

https://doi.org/10.1111/mec.16188

4) Ant colony nest networks adapt to resource disruption.

https://doi.org/10.1111/1365-2656.13198


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