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Data from: Flowers of a South African succulent plant predict tomorrow’s weather, synchronizing flower opening with pollinator activity

Cite this dataset

Gilbert, Matthew (2023). Data from: Flowers of a South African succulent plant predict tomorrow’s weather, synchronizing flower opening with pollinator activity [Dataset]. Dryad. https://doi.org/10.25338/B8VH25

Abstract

1. Day-to-day synchrony between flower opening and pollinator activity is important for maximizing plant fitness. A succulent, Bulbine frutescens (L.) Willd., is an ideal model for studying synchrony in response to daily weather as it flowers year-round. Additionally, it has self-incompatible flowers that open for just one day, making it essential that flower opening matches pollinator activity.

2. Observations were made on urban plants in California, USA, with validation measurements in the native range in South Africa. Independent observations indicated that flowers open primarily after favorable conditions the previous day, specifically air temperatures above 15°C. Solar radiation was experimentally shown to have limited, but significant effects. Pollinators, mostly bee species, had similar temperature thresholds to flowers.

3. Developmental constraints on flowers were hypothesized to delay opening by a day. Flower bud growth was closely related to temperature, with warm days resulting in sufficient growth for buds to become competent to open the following day. Lab experiments demonstrated that competent flowers were suppressed from opening until at least 16 hours was accumulated in which temperatures were above 12°C; thus, on many cool days, sufficient development to cause flower opening would only occur a day after favorable weather.

4. Based upon regression models of pollinator and flower response to weather, fitness was estimated as a function of synchrony, over twenty years of weather from California and across the natural range in South Africa. Flowers responding to either the previous day’s or current day’s weather resulted in similar predicted fitness, with flower response to the current day’s weather leading to a slightly higher cost, i.e. flowers opened when pollinators would be absent.

5. Multiple temperature-responsive constraints on bud growth and development result in delays in flower opening, such that flower opening occurs the day after favorable weather. Given the high correlation between daily temperatures in the USA and South African winter-rainfall environments, behavior predicting the following day’s weather results in high fitness. Many pollinators share similar temperature thresholds for activity, thus diverse plants may have evolved predictive behavior maximizing daily synchrony between pollinators and flower opening.

Methods

Data were acquired through field observations, long-term monitoring of multiple populations of bulbine, as fully described in the methods for the published article in Functional Ecology. Each data file represents a different analysis or data used to create a figure. Each file contains initial rows that describe the dataset and nature of data in each column, followed by a row of column headings and then the data.

Usage notes

Files are stored as spreadsheets in open-source comma separated ".csv" format, and can be opened by a broad range of software, including Excel.