Back to Biodiversity Explorer main pageGo to Iziko Museums of Cape Town home pageAbout Biodiversity Explorer - history, goals, etc.Send us your questions about southern African biodiversityPeople who have contributed content and images.Search Biodiversity Explorer

Gladiolus longicollis (Honey flower)

Aandblom [Afrikaans]; khahla-e-nyenyane, khukhu-rupa [South Sotho]; sidvwana [Swazi]; umbejo [Zulu]

Life > eukaryotes > Archaeoplastida > Chloroplastida > Charophyta > Streptophytina > Plantae (land plants) > Tracheophyta (vascular plants) > Euphyllophyta > Lignophyta (woody plants) > Spermatophyta (seed plants) > Angiospermae (flowering plants) > Monocotyledons > Order: Asparagales > Family: Iridaceae > Genus: Gladiolus

Description

  • Flowers are creamy yellow to white and have a long flower tube (35-130mm in length) that has nectar at its base.

Distribution and habitat

Widely distributed in southern Africa, from the southern Cape to Limpopo Province and Swaziland. Occurs in low, open grassland.

Life cycle

  • Flowers in spring and early summer but usually only after fire in the preceding winter.
  • The flower is closed for most of the day, starting to open only from about 17h00, earlier if it is cloudy. In the evening it produces a strong, sweet frangrance, attractive to hawk moth pollinators (Johnson and Alexandersson 2002).

Ecological interactions

Pollinators

Johnson and Alexandersson (2002) studied pollination of this species by hawkmoths (Lepidoptera: Sphingidae) at a site near Pietermaritzburg. The following hawk moth species, captured at a light trap, had Gladiolus longicollis pollen on them:

Of these species, only Agrius convolvuli has a proboscis long enough to reach the nectar of flowers in this study area. The other species would have tried to reach it unsuccessfully but in the process would have picked up some pollen and affected pollination of a few flowers. However, it was clear that Agrius convolvuli was the main pollinator at this site. They found that flowers with longer tubes were more likely to produce fruit than flowers with shorter tubes. If the tube is longer than the moth's proboscis, then the moth has to press its head into the flower to get to the nectar and in so doing presses it against the anthers and the stigma where pollen transfer then takes place. If the tube is shorter than the proboscis then the moth can reach the nectar without having to press its head into the flower and hence does not pick up pollen.

There is extensive variation in flower length over the distribution of Gladiolus longicollis and one would expect that in areas where the dominant hawk moths have shorter probosces, flower length would be shorter as well.

Publications

Text by Hamish Robertson


Contact us if you can contribute information or images to improve this page.

Biodiversity Explorer home   Iziko home   Search