Desert adaptations: attracting pollinators

Gasteria carinata var. verrucosa

Plants use energy when producing flowers and nectar. This Gasteria carinata var. verrucosa has adapted to attract only those pollinators which are likely to carry its pollen to other plants of the same species.

Gasteria carinata flowers

The unscented, tube-shaped flowers are a perfect match for the beaks of southern African sunbirds, who hover as they suck up the flowers’ nectar. The green and red colours are characteristic of plants mainly pollinated by birds.

An African sunbird on Aloe speciosa

African sunbirds’ long curved bills are adapted to seek out nectar from the tubular flowers of many dryland species. This greater double-collared sunbird (Cinnyris afra) is perched by the flower stem of an Aloe speciosa.

Anna’s hummingbird

Hummingbirds from the Americas have similar-shaped beaks. This Anna’s hummingbird (Calypte anna) is hovering by the green and red flowers of an octotillo (Fouquieria splendens).

Flowers of New World cacti

Just like the African Gasteria carinata and Aloe speciosa, cacti the other side of the world produce unscented tubular red or pink flowers adapted to the bills of hummingbird pollinators. This is an example of convergent evolution.