Flower’s Pattern Attracts/deters Insects

a bee lands on a bright yellow flower bloom with dozens of pistols resembling bristles of a brush

Biological Strategy

Rose-of-Sharon

AskNature Team

Image: Veronika Andrews / Pixabay / Free non-commercial use

Protect From Animals

Animals–organisms that range from microscopic to larger than a bus–embody a wide variety of harms to living systems, including other animals. They threaten through predation, herbivory, defense, and parasitism, and they compete for resources such as water, nutrients, and space. Any given living organism commonly faces threats from a variety of animals, requiring strategies that effectively defend from each. Trout and other bony fish, for example, escape predators by having scales made of very thin, flake-like pieces of bone covered with slippery mucus. They also have behavioral strategies such as camouflage, fast swimming, and twisting and turning to achieve release from a predator’s grip.

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Send Light Signals in the Non-visible Spectrum

Living systems interact with each other and with their environments to gain information, which is sometimes in the electromagnetic spectrum. Wavelengths of the electromagnetic spectrum are also called the non-visible light spectrum because humans cannot detect them with the naked eye. These include ultraviolet (UV) light, infrared (IR) light, radio waves, and other wavelengths, which living systems can use to send signals. Those signals must not only be targeted to other living systems that can detect them, they must be energy- and material-efficient. This creates both challenges and opportunities. For example, some web-weaving spiders add UV-reflective silk strands to their webs to keep birds and bumblebees (which can see UV light) from crashing into and destroying them. But because the insects the spiders feed on they can’t see UV wavelengths, they fly into the web.

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Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

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Markings on flowers help draw pollinators and at the same time discourage insect herbivores by containing ultraviolet pigments.

“Two categories of pigments, flavonoids and dearomatized isoprenylated phloroglucinols (DIPs), are responsible for the UV demarcations of this flower. Flavonoids had been shown previously to function as floral UV pigments, but DIPs had not been demonstrated to serve in that capacity. We found the DIPs to be present in high concentration in the anthers and ovarian wall of the flower, suggesting that the compounds also serve in defense. Indeed, feeding tests done with one of the DIPs (hypercalin A) showed the compound to be deterrent and toxic to a caterpillar (Utetheisa ornatrix). The possibility that floral UV pigments fulfill both a visual and a defensive function had not previously been contemplated.” (Gronquist et al. 2001:13745)