Honey bees (Hymenoptera: Apidae) outnumber native bees in Tasmanian apple orchards: Perspectives for balancing crop production and native bee conservation

Abstract

Apples are a major crop globally, including in Tasmania (Australia)known as 'the Apple Isle' owing to the key role of apples in Tasmania's history and economy. Most apple cultivars are obligate entomophilous species, and fruit quantity, quality and economic value are enhanced under insect pollination. Whilst the introduced European honey bee (Apis mellifera) is often assumed to be the main pollinator of apple in most regions of the world, including Australia, there is an increasing interest in alternative pollinators. The pollinator community of Tasmanian apple crops, however, has never been assessed. In this study, we surveyed four apple orchards for 3 days each during peak bloom in the Huon Valley region to characterise bee assemblages visiting blooming apple trees and the native bee fauna associated with surrounding flowering vegetation. Our results show that honey bees were the predominant visitors to apple blossoms (90.7% of visits), followed by the introduced bumble bee Bombus terrestris (5.9% of visits), with only a minor contribution by native bees (3.3% of visits). Twenty-six species of native bees were collected in total, of which only 10 species (five Exoneura (Apidae), four Lasioglossum (Halictidae) and one Euryglossa (Colletidae) species) were collected from apple blossoms, with Exoneura being the most abundant visitors. Few native bees were captured on apple blossoms, however co-blooming surrounding native vegetation, as well exotic flowers, hosted a high diversity and abundance of native bees. Site conditions influenced community composition, including abundance and representation of introduced bees compared to native bees visiting apples. Additionally, warmer temperatures favoured native bees. Collectively, our results suggest that Tasmania's apple production in its current state is unlikely to rely exclusively on native pollinators. Native bees nevertheless warrant conservation in such an insular crop production system. This can be achievable through retaining native flowering plants and even exotic non-crop flowers in and around orchards. Promoting the diversity and abundance of native bees through habitat enhancement may have additional benefits, such as filling current and future pollination demands and gaps, a key strategy under scenarios of climate change.

The evidence for and against competition between the European honeybee and Australian native bees

“…This industry has an overall estimated gross value of production of AUD1.75 billion/year in direct hive products, with an additional AUD14.2 billion/year through pollination services (BeeAware 2014;Karasinski 2018b). In Australia, honeybees are not only transported at high densities into areas to provide crop pollination services (where native bees tend to be in relatively low numbers due to unfavourable forage conditions, especially for oligolectic bees (Batley and Hogendoorn 2009;Prendergast et al 2021b), but major influxes of honeybees also occur in natural areas such as parks and reserves in order for beekeepers to capitalise on flowering of major honey-source species; key species of high value in terms of production and honey quality include Jarrah (Eucalyptus marginata), Yellow Box (Eucalyptus melliodora), Leatherwood (Eucalyptus lucida), Marri (Corymbia calophylla), and tea tree (Leptospermum spp. ).…”

Pollinators and crops in Bhutan: insect abundance improves fruit quality in Himalayan apple orchards

“…The results presented here provide evidence that, contrary to situations where apple production is supported primarily by honey bees in regions lacking alternative and efficient pollinators (see e.g. Prendergast et al 2021), the communities of insects visiting apple blossoms in Bhutan, including wild bees (Ceratina and Andrena) and hoverflies, may contribute to a substantial share of the crop pollination service. Future research should investigate this issue with greater scrutiny, particularly to test the extent to which wild bees and hoverflies alone are sufficient to provide the pollination service in a context of commercial farms, or if honey bees are systematically required to fulfil the pollination demand.…”

“…The non-native A. mellifera was the dominant visitor overall, as observed in apple orchards globally (e.g. Russo et al 2015;Hutchinson et al 2021;Prendergast et al 2021;Weekers et al 2022). Apis cerana was the second most common flower visitor across all orchards.…”

“…The protocol used in the study was developed as part of the CliPS (Climate change and its effect in Pollination Services) project (2018)(2019)(2020)(2021)(2022). CliPS is a global project that focuses on apple pollination and pollinator communities and has been developed to ensure the highest level of replicability across different sites and regions (Prendergast et al 2021;Leclerq et al 2022;Weekers et al 2022). Three orchards were selected from each of the three districts with a minimum distance of 2 km between orchards.…”

Entrepreneurs’ impact on the wider community: a comparative study of commercial beekeepers through the lens of social role theory

“…Thus, there are views that honeybees will likely remain relevant to crop pollination (Breeze et al , 2011), and so their conservation is crucial (Requier et al , 2019). Beekeeping can have important benefits, for instance, as a predominant pollinating mode for key regional crops, such as in Tasmania’s apple industry (Prendergast et al , 2021), or, as in Macedonia’s case, in supporting and keeping rural families financially stable (Ramadani et al , 2019).…”