Tomato: An investigation into poor pollination performance by the native bumblebee, Bombus terrestris audax

These pages summarise AHDB-funded research, which had the goal of reducing financial losses for growers following the legislated change from non-native (Bombus terrestris terrestris [Btt] and Bombus terrestris dalmatinus [Btd]) to native (Bombus terrestris audax [Bta]) bumblebees for the pollination of UK tomato crops.

British tomato growers had used bumblebees to successfully pollinate their crops for over two decades before legislation forced change to a native subspecies in 2015. 

Read about how the change to native subspecies was associated with poor fruit set and, in some cases, resulted in significant financial losses.

Growers representing 98% of the UK tomato production area contributed to pollination surveys. This unprecedented response illustrated how concerned the growers were about this issue.

Following a comprehensive review of the literature, Chandler et al. (2019) concluded that there was insufficient reliable and consistent evidence to support claims that the use of Btt/Btd was harmful to wild populations of B. terrestris in the UK. Questions are raised about the current classification of B. terrestris subspecies.

Bta colonies generally went into decline soon after placement in tomato crops. This was in stark contrast to experience with Btt/Btd. 

It is useful to describe the structure of the tomato flower and the process of fertilisation as this is critical to understanding the process of fruit set.

Studies are in progress to learn more about fruit set in cv Piccolo and, in particular, the possible impact of high temperature on pollen viability in that cultivar.

Our results indicate that Bta colonies placed in tomato crops do not ‘take-off’ in terms of rearing brood and producing new foragers in the same way that colonies normally do when held outside under more natural conditions.

Bombus terrestris collectively thermoregulate their nests in response to cold and heat in order to maintain a relatively constant temperature for brood rearing. Find out about the effect of high temperature of within-hive activity and whether there is a difference between Bta and Btt/Btd.

A system is being developed to remotely monitor bumblebee activity within hives which can be used both as an experimental tool in future studies and as an aid to the management of Bta in commercial crops.

The content of these pages was authored for AHDB by Dr Rob Jacobson (Rob Jacobson Consultancy Ltd), Dr D Chandler, Mrs G Prince, and Dr K Cocksull.

This information on this page and the linked pages is correct and up-to-date as of March 2022.

While the Agriculture and Horticulture Development Board seeks to ensure that the information outlined on these pages and in the project reports is accurate at the time of publishing, no warranty is given in respect thereof and, to the maximum extent permitted by law the Agriculture and Horticulture Development Board accepts no liability for loss, damage or injury howsoever caused (including that caused by negligence) or suffered directly or indirectly in relation to information and opinions contained in or omitted from this information.