The fate of pollen in two morphologically contrasting buzz-pollinated Solanum flowers

Pathways depicting the fates of pollen in a bee pollinated species such as the ones studied here. The diagram shows pollen contained inside the anthers (yellow); pollen removed that can be potentially transferred to conspecific stigmas (blue); pollen lost from the fertilization process, including dislodged pollen that falls to the ground and pollen stored by the bee (e.g., in corbiculae) and thus unable to contribute to fertilization (red); and pollen deposited on stigmas (green). Created with BioRender.com.

 

by Vasquez-Castro et al.

The fate of pollen describes what happens to pollen once it is removed from a flower. Studying it is crucial to understand how much pollen is lost during pollination and how efficiently it reaches other flowers. Another key aspect of pollination is how many pollen grains from one donor flower reach the stigmas of a sequence of other flowers. This helps us understand how far pollen grains can travel, and ultimately, how plants mate.

We studied both aspects of pollination under laboratory conditions with bumblebees visiting two species of flowers with contrasting morphology: Solanum rostratum and S. dulcamara. Both species are buzz-pollinated, meaning they require bee vibrations to release pollen, and they do not provide nectar to pollinators.

We found that both species had very low pollen transfer efficiency (~1 %), as is typical for most plants. Many pollen grains were deposited on the first flower visited, with fewer and fewer reaching subsequent flowers. This means that pollen is used up quickly, limiting how far it can travel between flowers. We also found that our two species showed very different pollen fates, likely explained by their contrasting floral characteristics. This highlights that future studies should investigate how flower morphology impacts pollen fates.

Read the scientific article in JPE 

 

Mail-order solitary bee cocoons as a gateway for biological invasion

Solitary bees sent by mail

 

 

 

 

 

 

by MacIvor & Irwin

Wild bees are recognized as important pollinators of many crops alongside honey bees. In recent years, mason bees have become popular among farmers and gardeners because they are easy to manage and highly effective pollinators. The cocoons of some species can be purchased online and shipped through the mail. However, this growing mail-order trade poses potential risks to biodiversity.

Many online sellers offer cocoons without clear identification, and shipments may contain non-native or even invasive bee species. Once released, these bees can compete with local species for food and nesting space, spread parasites and diseases, and disrupt the delicate balance of native bee communities. For example, the introduction of non-native mason bees in parts of North America has already been linked to sharp declines in local species. Compounding the problem, suppliers may inadvertently mix species or move bees across regions, threatening genetic diversity and local adaptation.

Current regulations in Canada and the United States are inconsistent. We recommend stronger oversight, including species-level identification, restrictions on interregional trade, and support for ethical local suppliers. Public education is also vital as helping people understand that the best way to support pollinators is by protecting and promoting native species where they live.

Read the complete article in JPE