Pollination efficacy, foraging behaviour and colony health of Australian stingless bees as pollinators in glasshouse strawberry production

Abstract

The use of protected cropping environments (PCEs) in horticulture, including the production of fruits and vegetables, has increased over recent decades. This is largely because PCEs such as glasshouses allow for more efficient use of key resources (such as growing substrates, nutrients and water), effective pest and disease management, and out-of-season production and supply to meet the demands of growing human populations. However, most fruit crops require pollination to improve yield and quality, yet the enclosed nature of the most sophisticated PCEs, known as controlled environment horticulture, prevents wild pollinators from accessing and pollinating flowers. One option to overcome this limitation is to introduce managed pollinators such as honey bees, bumble bees and stingless bees. In this thesis, I investigated the pollination potential of two Australian stingless bee species, T. carbonaria and T. hockingsi, in glasshouse strawberry production, and how the glasshouse environment impacts bee colony performance and health, as well as their gut microbiomes. This study shows that two Australian stingless bee species- Tetragonula carbonaria and T. hockingsi are effective pollinators of strawberry crop in a glasshouse environment and may assist commercial growers to increase yield and number of marketable fruits. This study also shows that over-pollination may occur with stingless bees if more colonies than required are deployed for pollination. This is evident in the lower number of marketable fruits achieved with open T. carbonaria pollination compared to 10 and 15 floral individual visits of the same species. This lower number of marketable fruits with T. carbonaria open pollination was not observed with T. hockingsi because we used two colonies of T. hocking in each experimental chamber compared to 4 colonies of T. carbonaria. The information about effect of the glasshouse and a single crop floral resources on the bees’ colony activity rate, weight and microbial community is valuable in ensuring that growers sustainably use the bees for crop pollination. It is important that growers provide additional resources such as supplementary pollen, sugar syrup and resin, for the bees when using them for crop pollination. And where possible, growers should replace the stingless bee colonies after each cropping season to enable the bees recover their colony strength, weight and gut microbial communities.

Date of Thesis submission	2022
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Markus Riegler (Supervisor), Robert Spooner-Hart (Supervisor), James Cook (Supervisor) & Mark Hall (Supervisor)