Botanising Israel, part 11 – Little pink flowers and bee flies.

Little pink flowers and bee flies.

During the years I have been visiting Israel and learning about its incredible diversity of wild flowers I have gone from making my very first forays into identifying the general flora of the region to developing a deeper understanding of the plant communities and their ecology.

I have unearthed stories as diverse as that of the male solitary bees that take shelter in the Iris flowers overnight (another time maybe) to the importance of the flora to the culture and history of this area of the middle east.

However, there is one little ecological story that I particularly adore. That of Linum pubescens and its pollinator, the Bee-Fly (Usia bicolor).

In every Linum flower there is a Bee Fly up to something!

In every Linum flower there is a Bee Fly up to something!

Linum pubescens Banks & Sol. (Linaceae) is a common, annual, plant in Israel and is found growing in large swathes among the Maquis and Garrigue vegetation across the eastern end of the Mediterranean. Linum pubescens flowers last just a few days and open a few at a time over their flowering period from February to May. Whilst the overall colour of the flower is a strong to light purplish pink (RHS Colour chart 6th ed.) the colour of the base of the petals is dimorphic – some petal bases are dark and some light.

One day whilst walking on Mount Gilboa I noticed the bee‐fly Usia bicolor regularly frequents the flowers of L. pubescens and has an, obviously, intimate association with the flower.

On asking Yuval Sapir (Director of Tel Aviv University Botanic Garden) about this interaction he pointed me to a study produced by his lab on the nature of this relationship – quite one of the most engaging plant/insect relationships I have come across. The bee flys use the pale centered flowers in the morning for feeding and the dark centered flowers in the afternoon as breeding platforms. On cool mornings the flys that used the dark centered flowers the previous evening remain in the dark centered flowers overnight and sit in them for longer in the morning. Sometimes, if you look at the flowers in the afternoon you will see a little bbe fly orgy going on in the centre of each dark centred flower.

If like me you want to know more about this interesting interaction between a unassuming plant and its lovely little pollinator you can download the papers below…

‘Response of bee-flies to the shape and pattern of model flowers: implications for floral evolution in a Mediterranean herb’ S.D. Johnson & A. Dafni.

 

‘Pollinator-mediated selection on floral size and tube color in Linum pubescens: Can differential behavior and preference in different times of the day maintain dimorphism?’ M. Lebel, U. Obolski, L. Hadany & Y. Sapir.

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