All data were collected in a private domestic garden (Hazelmere, Magham Down, East Sussex, 50.880, 0.284) between 1000 and 1600 h during July and August 2021 and in weather conditions suitable for all flower-visitor activity (generally sunny, ≥16 °C and light wind). We used exotic Asteraceae to minimise the likelihood that flower visitors in the area had experienced these species: Rudbeckia hirta (var. ‘Black Eyed Susan’), and Helenium autumnale (var. ‘Sahin’s Early Flowerer’). These varieties were also selected for their large and conspicuous ray petals. Asteraceaeae were ideal subjects as the capitulum inflorescence is robust and easy to manipulate by removing ray-floret petals manually. Importantly, the central disc in the study species was large so the removal of petals did not render the remainder of the flower inadequate for the study insects to land on. In many flowers, the petals form part of the landing platform, so removing them would compromise insect visitation.
Each of the four study patches measured approximately 4 m2 and comprised 16–20 plants of a single variety in full bloom with, on average, 132 (standard deviation, ±33.6) inflorescences. The plants were in 10 l pots, 0.5–1 m in height, and were placed close together so that the distance between inflorescences was <20 cm. For the experienced flower-visitor experiment, we set out one patch of each study plant variety with inflorescences of the three treatments on 20 July 2021. For the naïve flower-visitor experiment, we set out a further patch of H. annus on 19 August 2021 and a further patch of R. hirta on 20 August 2021.
Because honeybees and other flower-visitors show an innate preference for symmetrical flower shapes [14 (link),15 (link),16 (link)](Giurfa et al., 1996; Möller and Sorci, 1998; Orban et al., 2015), we used symmetrical ray petal treatments. Each capitulum was subject to one of three treatments: (i) zero ray petals (i.e., all petals removed), (ii) four ray petals in a cross arrangement, and (iii) all petals (i.e., all petals left intact). By judicially selecting which treatment newly blooming inflorescences received we ensured each patch contained equal numbers of inflorescences per treatment and that the treatments were dispersed approximately evenly across each patch. Treatments were equalised throughout the experimental period as needed. Old inflorescences were removed.
Each of the four study patches measured approximately 4 m2 and comprised 16–20 plants of a single variety in full bloom with, on average, 132 (standard deviation, ±33.6) inflorescences. The plants were in 10 l pots, 0.5–1 m in height, and were placed close together so that the distance between inflorescences was <20 cm. For the experienced flower-visitor experiment, we set out one patch of each study plant variety with inflorescences of the three treatments on 20 July 2021. For the naïve flower-visitor experiment, we set out a further patch of H. annus on 19 August 2021 and a further patch of R. hirta on 20 August 2021.
Because honeybees and other flower-visitors show an innate preference for symmetrical flower shapes [14 (link),15 (link),16 (link)](Giurfa et al., 1996; Möller and Sorci, 1998; Orban et al., 2015), we used symmetrical ray petal treatments. Each capitulum was subject to one of three treatments: (i) zero ray petals (i.e., all petals removed), (ii) four ray petals in a cross arrangement, and (iii) all petals (i.e., all petals left intact). By judicially selecting which treatment newly blooming inflorescences received we ensured each patch contained equal numbers of inflorescences per treatment and that the treatments were dispersed approximately evenly across each patch. Treatments were equalised throughout the experimental period as needed. Old inflorescences were removed.
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