Flower biology of Impatiens

Analysis of pollination syndromes and breeding systems in Impatiens (Balsaminaceae)

Master degree at Bonn University

Supervisor: Dr. Stefan Abrahamczyk

My master thesis was divided in two parts: Pollination syndromes and Breeding systems in Impatiens. Impatiens is a genus of plants with more than 1000 species distributed around the world. The genus Impatiens has a high flower diversity adapted to different pollinators. In the picture we can see typical pollination syndromes:

Floral diversity of the genus Impatiens.
A. Impatiens noli-tangere B. Impatiens niamniamensis C. Impatiens platypetala D. Impatiens sodenii E. Impatiens campanulata F. Impatiens mandrakae. Scale bar 0.5 cm. Photos Sissi Lozada (SL) and M. Ackermann (MA).

A) Bee pollination: Flower with a funnel shape, a landing flat platform for the bees, colored and wide opening to guide the insect towards the thin tube-like structure called spur, where the nectar is located.

B) Bird pollination: Flowers have usually vivid colors like red, are very stable with thick stems to support strong movements by the flying birds. Spur is very wide (only narrow at the tip) containing a lot of nectar with high diluted sugars.

C) Butterfly pollination: Flowers with a broad colored frontal display and a long filiform spur. Butterflies use a long proboscis to suck the nectar located in the tip of the spur.

D) Moth pollination: Flowers similar to butterfly pollination in shape but usually are not very bright, with longer spurs and aromatic to attract moths at night.

E) Generalist pollination: Flower pollinated for more than one group bees, butterflies and howkmoths.

F) Fly pollination: Small colorless flowers with no spur and no nectar.

[Here photo of Impatiens rivularis]

Recently in the Trimorphopetalum clade which are endemic species from Madagascar, we report the first case of deceiving fly pollination. These small dark flowers of Impatiens rivularis endemic from humid forests in Madagascar produce a fungi scent that attract small flies. During their life cycle, these flies usually lay eggs in fungi, the flower deceive them with the fungi scent and when the flies are looking for a place to lay eggs, they probably get pollen on their bodies and transport to another individual. Fascinating!

The full publication will be out soon in Perspectives in Plant Ecology, Evolution and Systematics.

It is still very little known about this group of plants and in the future I would like to continue studying them!!

More information about the exciting work in Impatiens by Dr. Stefan Abrahamczyk can be found here [link].

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