Coevolution: Planalto Hermit Humming Bird and Ornithophilous flower

Throughout the continuous evolution of new species over time, coevolution has been a mechanism for multiple species to selectively put pressure on each other, thereby affecting each other’s evolution. It has influenced the evolution of host species to stay resistant to parasites by reproducing sexually, which allows a higher chance of immunity. The parasite is pressured to evolve in response to have a better chance at infecting the host. This cycle continues as demonstrated in the Red Queen’s hypothesis (Cronk & Ojeda 2008).

Additionally, the Planalto hermit humming bird (Phaethornis pretrei) has coevolved a mutually beneficial relationship with the ornithophilous flower (Beloperone californica) (Faria & Araujo, 2008). The flowers itself are “characterized by having brightly colored (e.g. red or yellow) odorless flowers, tubular and evenly curved corollas, diurnal anthesis and sucrose-rich nectar” (Faria & Araujo, 2008). The plants have morphologically co-adapted these traits overtime with the hummingbird. Specifically, the flowers’ long and tubular shape appeals to hummingbirds because the bird’s bills are oriented similarly, allowing them to easily probe these flowers as opposed to other flowers (Cronk & Ojeda 2008). Over time, the plant species are selectively pressured to evolve flowers that are more tubular in shape, so that the hummingbirds will prefer to pollinate their flowers instead of other plants. In turn, the hummingbird species morphologically co-adapt a more similar shaped beak to fit smoothly into the flowers in order to get nectar. The plants have also evolved to produce a higher volume of nectar with a higher sugar production than other plants that are pollinated by insects to meet the birds’ energy requirements (Cronk & Ojeda 2008). The co-evolution patterns go as far as the plants’ flowers’ colors evolving to suit the humming bird specie’s vision. Birds prefer red pigmentation in flowers because they have a good sense of color discrimination and spectral sensitivity at the red end of the visual spectrum (Faria & Araujo, 2008). Therefore, the hummingbird has selectively pressured the plant species to evolve more red-toned flowers over the course of many generations., which encourages the hummingbird to take pollen from their flowers to reproduce instead of other plants. The convolutions have gone as far as the blooming times of the flower to coincide with hummingbird breeding seasons (Faria & Araujo, 2008).

Work Cited:

Cronk, Q., & Ojeda, I. (2008, March 7). Bird-pollinated flowers in an evolutionary and

molecular context. Retrieved October 19, 2014.

Faria, R., & Araujo, A. (2009, August 31). Flowering phenology and pollination of

ornithophilous species in two habitats of Serra da Bodoquena, Mato Grosso do
Sul, Brazil. Retrieved October 19, 2014.