[This was written by Fran Siebrits and published online by Wild Magazine http://www.wildcard.co.za, 2012]
There is more to the dazzling beauty of spring daisies than one would have thought. Their main aim is to attract pollinators, and they have more than one way of going about this challenge … even if it boils down to being a little deceptive.
Flowers have many ways of attracting pollinators. Over the evolutionary years, and with that inherent drive to 'adapt in order to survive', the beetle daisy, Gorteria diffusa, has learnt how to get what it wants. Pollinated mainly by the bee fly, Megapalpus capensis, beetle daisies mimic patterns of the female of the species, thereby attracting males to spread their seed bank.
Stellenbosch University researchers have been studying the relationship between plants and their pollinators in the diverse vegetation of the Cape. They have discovered that the beetle daisy tricks male bee flies into thinking they are actually the female of their own flying kind.
There has been much excitement in the botany sector since this research. Until recently, only orchids were known to use sexual deception successfully in order to lure pollinators. The beetle daisy, however, displays petal patterns that are irresistible to the male bee fly, thereby attracting their favourite pollinators.
Beetle daisies, which occur in southern Namibia, Namaqualand and the Little Karoo, have insect-like black spots on their petals. “The special markings or ornaments on their petals closely resemble female insects and so attract amorous, pollinating males,” explains Dr Allan Ellis from Stellenbosch University.
Further investigation shows that male bee flies are attracted to daisies with three-dimensional raised spots, glossy spots and spots with tiny ultraviolet (UV) reflecting highlights. “If you have a close look under a UV light, you will see that female flies also have UV highlights on their bodies,” says Marinus de Jager, a doctoral student in botany at Stellenbosch University. “This is probably why male [bee] flies prefer to visit this type of spot, because they actually think it’s a female [bee] fly.”
Who would’ve thought that such an innocent-looking daisy is capable of such sexual deception?
Not only has this research exposed the sexual deception of beetle daisies, it has also highlighted gender-specific pollinator preferences. In the same way men and women have different sense preferences, so are the two sexes of the bee fly attracted to flowers in different ways.
Male bee flies respond to visual cues. The more colourful and vibrant-looking flowers lure male bee flies. Female bee flies are more attracted to floral scents and do not seem to be as fussy, opting for duller flowers while the males head straight for the exciting fields of sensual petals.
Source: Mr Marinus de Jager and Dr Allan Ellis, Department of Botany and Zoology at Stellenbosch University, “Gender-specific pollinator preferences for floral traits”, Functional Ecology.
There is more to the dazzling beauty of spring daisies than one would have thought. Their main aim is to attract pollinators, and they have more than one way of going about this challenge … even if it boils down to being a little deceptive.
Flowers have many ways of attracting pollinators. Over the evolutionary years, and with that inherent drive to 'adapt in order to survive', the beetle daisy, Gorteria diffusa, has learnt how to get what it wants. Pollinated mainly by the bee fly, Megapalpus capensis, beetle daisies mimic patterns of the female of the species, thereby attracting males to spread their seed bank.
Stellenbosch University researchers have been studying the relationship between plants and their pollinators in the diverse vegetation of the Cape. They have discovered that the beetle daisy tricks male bee flies into thinking they are actually the female of their own flying kind.
There has been much excitement in the botany sector since this research. Until recently, only orchids were known to use sexual deception successfully in order to lure pollinators. The beetle daisy, however, displays petal patterns that are irresistible to the male bee fly, thereby attracting their favourite pollinators.
Beetle daisies, which occur in southern Namibia, Namaqualand and the Little Karoo, have insect-like black spots on their petals. “The special markings or ornaments on their petals closely resemble female insects and so attract amorous, pollinating males,” explains Dr Allan Ellis from Stellenbosch University.
Further investigation shows that male bee flies are attracted to daisies with three-dimensional raised spots, glossy spots and spots with tiny ultraviolet (UV) reflecting highlights. “If you have a close look under a UV light, you will see that female flies also have UV highlights on their bodies,” says Marinus de Jager, a doctoral student in botany at Stellenbosch University. “This is probably why male [bee] flies prefer to visit this type of spot, because they actually think it’s a female [bee] fly.”
Who would’ve thought that such an innocent-looking daisy is capable of such sexual deception?
Not only has this research exposed the sexual deception of beetle daisies, it has also highlighted gender-specific pollinator preferences. In the same way men and women have different sense preferences, so are the two sexes of the bee fly attracted to flowers in different ways.
Male bee flies respond to visual cues. The more colourful and vibrant-looking flowers lure male bee flies. Female bee flies are more attracted to floral scents and do not seem to be as fussy, opting for duller flowers while the males head straight for the exciting fields of sensual petals.
Source: Mr Marinus de Jager and Dr Allan Ellis, Department of Botany and Zoology at Stellenbosch University, “Gender-specific pollinator preferences for floral traits”, Functional Ecology.
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