Artificial flowers as a tool for investigating multimodal flower choice in wild insects

Abstract

Flowers come in a variety of colours, shapes, sizes and odours. Flowers also differ in the quality and quantity of nutritional reward they provide to entice potential pollinators to visit. Given this diversity, generalist flower‐visiting insects face the considerable challenge of deciding which flowers to feed on and which to ignore. Working with real flowers poses logistical challenges due to correlations between flower traits, maintenance costs and uncontrolled variables. Here, we overcome this challenge by designing multimodal artificial flowers that varied in visual, olfactory and reward attributes. We used artificial flowers to investigate the impact of seven floral attributes (three visual cues, two olfactory cues and two rewarding attributes) on flower visitation and species richness. We investigated how flower attributes influenced two phases of the decision‐making process: the decision to land on a flower, and the decision to feed on a flower. Artificial flowers attracted 890 individual insects representing 15 morphospecies spanning seven arthropod orders. Honeybees were the most common visitors accounting for 46% of visitors. Higher visitation rates were driven by the presence of nectar, the presence of linalool, flower shape and flower colour and was negatively impacted by the presence of citral. Species richness was driven by the presence of nectar, the presence of linalool and flower colour. For hymenopterans, the probability of landing on the artificial flowers was influenced by the presence of nectar or pollen, shape and the presence of citral and/or linalool. The probability of feeding increased when flowers contained nectar. For dipterans, the probability of landing on artificial flowers increased when the flower was yellow and contained linalool. The probability of feeding increased when flowers contained pollen, nectar and linalool. Our results demonstrate the multi‐attribute nature of flower preferences and highlight the usefulness of artificial flowers as tools for studying flower visitation in wild insects.

High variability in the attractiveness of municipally-planted decorative plants to pollinators

“…Artificially-bred cultivars could act as cognitive traps, providing a super-stimulus of colour or odour without providing a large reward, or only providing an unbalanced reward. While there is a correlation between nutritional offering and attractiveness (Comba et al 1999; Corbet et al 2001; SChapman et al 2023), little information exists about the nectar or pollen productivity of most ornamental plants, nor of the nutritional content of the nectar and pollen offered.…”

“…However, the reverse situation also exists – for example, Anthemis tinctoria was reported to attract a wide variety of pollinators such as wild bees, flies, and butterflies, but not honey bees or bumble bees (Rollings and Goulson 2019). While various floral traits have been found to correlate with attractiveness to pollinators (such as floral area cover (Grindeland et al 2005; Marquardt et al 2021a; Kalaman et al 2022), colour (Reverté et al 2016; Chapman et al 2023), shape (Howard et al 2019; Erickson et al 2022; Chapman et al 2023), and nutritional offering (Comba et al 1999; Corbet et al 2001; Chapman et al 2023)), the huge variety of cultivars and interaction with local conditions make accurate prediction of cultivar attractiveness difficult. As such, Rollings and Goulson (2019) recommend that tests for the attractiveness of a wide variety of ornamental cultivars be carried out, ideally at various sites with varying environmental conditions.…”

Innate floral object identification in the generalist solitary hoverfly pollinatorEristalinus aeneus

“…The observer’s line of sight was at the same plane as the models. A response was defined as landings or approaching at least 5 cm above the models, as per other studies (Nordström et al 2017; Matoušková et al 2023; Chapman et al 2023). The time period for each observation was capped at 5 minutes.…”