Abstract
Honeybees have been transported and relocated across the globe, however, the impacts of this introduced species on local ecosystems are only now beginning to be understood. Introduced species are a particularly important factor contributing to biodiversity declines worldwide, with honeybees being considered an invasive species in Australia. Whilst studies in other countries have reported negative effects of introduced honeybees on native plant and pollinator communities, their impact within Australian ecosystems remains largely understudied.Australian biodiversity is unique, with incredibly high rates of endemism, which extends to both vertebrate and invertebrate pollinating species. In fact, there are around 2000 species of native bees in Australia, which have co-existed with native flowering plants for thousands of years and as such have become incredibly efficient pollinators of native plants. Native Australian pollinators therefore play a vital role in the reproduction and persistence of native flowering plants. Thus, understanding how introduced honeybees may impact native pollinators is essential.
As both honeybees and native bees utilise similar floral and nesting resources, there is a potential for competition and for interactions to occur between these groups when co-foraging. However, pollinator behaviour is known to be highly dependent on environmental factors. Therefore, the interactions which occur between honeybees and native bees is likely to be context dependent. In fact, many factors have been shown to influence pollinator foraging behaviours including the availability of flowers within time and space, floral abundance, the quantity, and quality of the floral rewards offered, flower morphology, colour, and patterns.
To investigate how floral characteristics influence pollinator behaviour, we designed and conducted three experiments, specifically focussing on how flower colour and morphology influence the likelihood and outcomes of honeybee-native bee interactions and the effects of different floral guide patterns on honeybee visitation to nectar or pollen provisioning flowers. This included an observational study of honeybees and native bees foraging from natural flowers of various colours and morphologies and two manipulative experiments involving the creation and use of novel 3D printed artificial flowers; one experiment with nectar as the floral resource provided and the other with pollen.
The results of our observational study imply an effect of floral colour and morphology on the probability of interactions occurring between honeybees and native bees when foraging on communal floral resources. Although further studies are required to definitively discern how flower colour and morphology influence honeybee-native bee interactions. Our experiments with artificial flowers demonstrated that our novel 3D printed flower design can be successfully employed in honeybee behavioural studies. However, we found no evidence of an effect of yellow and ultraviolet reflecting floral guides on the discoverability
or attractiveness of nectar or pollen provisioning artificial flowers. Our findings suggest that ultraviolet floral guides may not be as important as other floral cues, such as scent in driving pollinator preferences. The results of our studies contribute towards the growing knowledge of pollinator behaviours and the floral characteristics which influence these behaviours. Studies like ours are important in understanding pollinator preferences and the mechanisms which drive these preferences which dictate plant-pollinator interactions as well as the important role of floral characteristics in pollinator-pollinator interactions, enlightening future studies into the effects of invasive pollinators on native pollination systems.
| Date of Award | 2024 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Amy-Marie Gilpin (Supervisor) & Sally Power (Supervisor) |