Increasing trade in wild bee cocoons could disrupt pollinator
communities
Recently, a third misplaced conservation practice has emerged: people
thought of filling up themselves bee hotels with cocoons to control both
the species and the occupancy rate. To do so, online companies selling
wild bee cocoons for bee hotels have arisen (Fig. 1). Before this new
trend, few bee species was reared and commercialized for trap nests
mostly to pollinate crops (Aizen et al. 2020) and the
commercialization of wild bees was restricted to professional
agricultural practices. However, these companies now routinely sell
cocoons of Osmia species (mason bees) and Megachile(leafcutter bees) to anyone wanting to purchase wild bees (e.g.,
https://crownbees.com/; https://masonbeesforsale.com/, among others).
Overall, the potential invasiveness of insects has been associated to
their global commercial success (Gippet & Bertelsmeier 2021) and trade
volumes (Bang & Courchamp 2021). Therefore, in October 2021, using the
keywords “buy bee cocoons”, “buy wild bees” and “wild bees for
sale” we searched in Google in seven languages (English, French,
German, Italian, Russian, Spanish, and Chinese) all website selling wild
bee cocoons online. We found 42 websites selling cocoons for a total of
eight different species (Supplementary material S1). While some sellers
appeared to restrict their shipping to native species or those from a
few neighbouring countries, it was very easy to buy cocoons from another
continent online. For example, in June 2021, a package shipped from
France to Seattle (USA), was seized by the biosecurity service of New
Caledonia, a French tropical archipelago. Inside the package, bamboo
twigs containing 23 lived cocoons of wild bees (Osmia sp. ) with
two recently emerged females (H. Jourdan, pers. obs .).
By promoting the trade of wild bees, we believe that companies selling
bee cocoons create a window of opportunities for ecological disturbances
inside and outside of their native area (Fig. 1). The unregulated trade
of insects worldwide has already caused considerable damages not only to
ecosystems but also to the economy (Diagne et al. 2021) and is
predicted to become increasingly problematic (Bang & Courchamp 2021).
This practice is also highly problematic as it constitutes a potentially
very high propagule pressure of introduced species (repeated
introductions of many individuals in many places). Bees emerging from
cocoons can also compete with native bees for floral resources. For
example, Osmia cornifrons a species whose cocoons are sold
online, is exotic in the United States and has been recently associated
to the strong decline of six native mason bee species either due to
resources competition, pathogen spillover or both (LeCroy et al.2020). As Osmia cornifrons , all bee species currently sold online
are Megachillidae which is also the most represented bee family among
the exotic and invasive bee species recorded worldwide (Russo 2016).
Buying bees online could also arise the risk of transmitting diseases
(Aizen et al. 2020). Parasites and diseases are widespread in
animal husbandry, and even when all possible precautions are taken, the
spillover hazard can never reach zero. For example, Hedtke et al.(2015), demonstrated that O. cornifrons transported fungi from
its native range Japan to the United States. Hence, we believe that the
trade of bee cocoons online is also a misplaced conservation practice as
it a) misinforms the public and blur their perception of the importance
of wild bees especially the native ones, b) leads to a misallocation of
resources: instead of protecting the local populations, people invest
funds in reared species, and c) potentially harms biodiversity by
fostering the spread of exotic species, increasing competition for
floral resources and favouring potential pathogens spillover.
Conclusion :
Misplaced conservation practices have multiplied in recent years (Fordet al. 2021), mainly through the rapid dissemination of
simplified information, putting ecological knowledge and its complexity
aside. The first step towards more appropriate measures is to inform
companies, citizens, and decision-makers about the complexity of species
interactions and orientate their choices based on scientifically sound
arguments. Research in conservation ecology should continue to be
developed to offer comprehensive tools to whom want to set up
conservation practices. For bees, ensuring sufficient resources by
promoting local and native flowering plants, preserving, and protecting
nesting and reproductive sites, is better than introducing more
individuals (especially without considering which species). Removing
current threats on pollinators, such as the agrochemical use, appears
more efficient and more logical than trying to boost existing,
threatened populations. Finally, it is still possible to buy or build a
bee hotel with substrates adapted to local populations while avoiding
the establishment of non-native bee species. These have the added
benefit to educate people involved about ecological concepts as well as
to reconnect them with nature, two aspects that are likely pursued by
those willing to help biodiversity in general, and bees in particular.
Acknowledgements : We sincerely thanks Sherry Stanbury for
English editing. We also deeply thanks Franck Courchamp, Boris Leroy,
Bertrand Schatz and Hervé Jourdan for their help on previous versions of
this article.