Complex preference relationships between native and non-native angiosperms and foraging insect visitors in a suburban greenspace under field and laboratory conditions

Abstract

The introduction and spread of non-native flora threatens native pollinators and plants. Non-native angiosperms can compete with native plants for pollinators, space, and other resources which can leave native bees without adequate nutritional or nesting resources, particularly specialist species. In the current study, we conducted flower preference experiments through field observations and controlled binary choice tests in an artificial arena to determine the impact of field vs. laboratory methods on flower preferences of native bees for native or non-native flowers within their foraging range. We conducted counts of insect pollinators foraging on the flowers of three plant species in a suburban green belt including one native (Arthropodium strictum) and two non-native (Arctotheca calendula and Taraxacum officinale) plant species. We then collected native halictid bees foraging on each of the three plant species and conducted controlled binary tests to determine their preferences for the flowers of native or non-native plant species. In the field counts, halictid bees visited the native plant significantly more than the non-native species. However, in the behavioural assays when comparing A. strictum vs. A. calendula, Lasioglossum (Chilalictus) lanarium (Family: Halictidae), bees significantly preferred the non-native species, regardless of their foraging history. When comparing A. strictum vs. T. officinale, bees only showed a preference for the non-native flower when it had been collected foraging on the flowers of that plant species immediately prior to the experiment; otherwise, they showed no flower preference. Our results highlight the influence that non-native angiosperms have on native pollinators and we discuss the complexities of the results and the possible reasons for different flower preferences under laboratory and field conditions.

A world without bees: new insights from Australia for managing sustainability in a changing climate

“…While all studied bees do share a phylogenetically ancient colour visual system (Briscoe & Chittka 2001) and there is evidence of somewhat similar colour preferences in certain species (Dyer et al 2016;Giurfa et al 1995), other work shows there can be differences in the colour preferences between species that forage within the same environment Koethe et al 2016;Koethe et al 2022). Recent experiments (Howard et al 2019Howard & Symonds 2023) aimed to expand our knowledge of insect foraging preferences (e.g. colour, shape) by shifting from a focus on eusocial bees, such as honeybees and bumblebees, to gain a better understanding of the flower choices and preferences of non-eusocial bees (e.g.…”

Through an animal’s eye: the implications of diverse sensory systems in scientific experimentation

“…In one experiment, when bumblebees were tested in a complex cognitive task, they succeeded or failed according to the colours used during training [ 64 ]. In another study, Australia’s native bees were found to prefer native flowers in the field, but chose non-native flowers in the laboratory [ 65 ]. What appears to be clear is that we need to push for more comprehensive reporting of the relevant environmental cues (E1, table 1 ).…”

Floral Trait Preferences of Three Common wild Bee Species

“…often dominate wild bee communities and their social behavior is well studied [ 18 , 19 ] but have been neglected in studies of floral cue preference (except the study series on Australian Lasioglossum sp. by Howard [ 20 , 21 , 22 ]). Alongside, Osmia bicornis bees, that are commercially used as pollinators of orchard trees and are well studied regarding their pollination efficiency [ 23 , 24 ], are also rarely tested for their floral cue preferences (but see, e.g., [ 25 , 26 ]).…”