If you are not healthy you are out: how honey bees develop resilience towards invasive species events with an immune system at the colony level

Introduction

Honey bees, Apis mellifera, have experienced the full impacts of globalization, including the recent invasion by the parasite, Varroa destructor. This deadly mite has rapidly become one of the main causes of colony losses worldwide, with a huge economic impact on beekeeping.

Survival and Social Immunity

Despite the lethal effects of varroa, some colonies survive infestation. In such colonies, honey bees are able to work together to selectively remove highly parasitized brood, thereby limiting mite spread. Defensive hygiene plays a role at the society level that parallels that of an immune system, and the ‘social immunity’ it confers provides the basis for colony resistance to varroa and other brood diseases.

Challenges in Diagnosis and Regulation

How compromised individuals are accurately diagnosed, and how the collective actions of hygienic bees are regulated at the colony level pose central but yet unsolved challenges.

Project Goals

The BEE HEALTHY project aims to decipher the mechanisms that underpin collective behavioural defences against unhealthy brood in honey bee colonies. Four key breakthroughs support my high-risk high-gain and wide-scoped approach:

1. A new conceptual framework postulating that bees maintain the integrity of the colony by constantly assessing the wellness of conspecifics.
2. A new hypothesis that considers distinct hygienic behaviours as components of a single suite of defences that must be considered together.
3. A cutting-edge experimental strategy that tightly associates studies at the individual bee and superorganism colony level.
4. An integrative biology approach that combines chemical ecology and neurophysiology.

Significance of the Research

This ambitious project promises an unprecedented journey in the understanding of social immunity. In the face of increasing threats from invasive species events, revealing how hosts adapt to detrimental foes has never been more pressing.

Future Implications

This research also opens avenues to deliver tools for more sustainable beekeeping and agriculture through preserved pollination ecosystem services.