Ancient insect vision tuned for flight amongst rocks and plants underpins natural flower colour diversity - rock, mineral, stick, bark, leaf, bird- and insect-flower petal reflectance spectra

Understanding the origins of flower colour signalling to pollinators is fundamental to evolutionary biology and ecology. Flower colour evolves under pressure from visual systems of pollinators, like birds and insects, to establish global signatures among flowers with similar pollinators. However, an understanding of the ancient origins of this relationship remains elusive. Here, we employ computer simulations to generate artificial flower backgrounds assembled from real material sample spectra of rocks, leaves, and dead plant materials, against which to test flowers’ visibility to birds and bees. Our results indicate how flower colours differ from their backgrounds in strength, and the distributions of salient reflectance features when perceived by these key pollinators, to reveal the possible origins of their colours. Since Hymenopteran visual perception evolved before flowers, the terrestrial chromatic context for its evolution to facilitate flight and orientation consisted of rocks, ...,
Material samples, data collection
Background materials data (non-floral surfaces): rocks, minerals, sand, shells, dry leaves, dry bark, wood, dry seeds, and green leaves.

Background surface data samples were collected across a 2400 km range from the tropical north (16.9°, 145.7°) to the temperate southern tip (39.1°, 146.2°) of mainland Australia.
N = 507 total natural background surface data samples were collected: n = 65 green leaves; n = 96 dry leaves, bark, wood etc. samples; n = 346 rocks/mineral samples.

Flower data (petal surfaces): insect- and bird-pollinated flowers.

Flower data has previously been described and analysed 9,29 and is made available here.

Spectral reflectance measurement
Reflectance curves were measured for background material and floral samples from 300-700 nm (see below – Marker point calculations) using a spectrophotometer with quartz optics and a PX-2 pulsed xenon light source (USB2000+, Ocean Optics Inc., Dunedin, FL, USA) attached to a computer running..., , # Ancient insect vision tuned for flight amongst rocks and plants underpins natural flower colour diversity - rock, mineral, stick, bark, leaf, bird- and insect-flower petal reflectance spectra

The dataset contains spectral reflectance data collected from:

* Australian **background materials**, i.e. non-floral surfaces, likely to appear behind flowers when viewed by pollinating insects and birds : rocks, minerals, sand, shells, dry leaves, dry bark, wood, dry seeds, green leaves.
* Australian **flowers** (petal surfaces): insect- and bird-pollinated flowers.

The data was used to test theories of flower colour evolution targeting visual systems of insect and bird pollinators. It supports the hypothesis that flowers have evolved colours to allow their specific pollinators to detect them against natural backgrounds that form the visual context for pollinator foraging.

Reflectance curves were measured for background material and floral samples from 300-700 nm using a spectrophoto...