Factors influencing pollinators of Succisa pratensis

Janovský, Z. (1), Vosolsobě, S. (2), Ponert, J.H. (2), Říhová, D. (3)

1) Department of Botany, Charles University Prague, Czech Republic
2) Department of Plant Physiology, Charles University Prague, Czech Republic
3) Department of Zoology, Charles University Prague, Czech Republic

Pollination is one of the crucial steps in seed production in allogamic plants. For plants of fragmented landscapes it has even a two-fold meaning, since it can help to maintain the gene-flow between the isolated populations. However, little is known whether the pollinators differ in preferences for individual plants and also in distances they carry the pollen to. In this scope, we decided to study the pollinator com-munity of Succisa pratensis, a typical insect-pollinated species of fragmented biotopes. Here we report the results of our pilot experiment searching for plant traits and weather characteristics influencing the activity and preferences of pollinators.

The most important pollinators of Succisa are hoverflies (Syrphidae), especially species Eristalis tenax and E. interruptus (altogether 84% of total visits). Other dipteran families (Sarcophagidae, Muscidae) make up 6% of visits both. Last more abundant pollinator is the honey bee (Apis mellifera) with 3% of visits. The pollinators differed considerably in plant traits and weather characteristics they responded to. The average foraging time spent in one inflorescence was approximately two times longer for Muscidae and Sarcophagidae flies than for all other pollinators.

The commonest pollinators, E. tenax and E. interruptus, were much more influenced by plant traits than by weather characteristics. On the other hand, Muscidae and honey bee responded more to weather characteristics. The largest observed hoverfly, Sericomyia silentis, did not show any particular preference in visited plant’s characteristics.

Based upon these preliminary results, we hypothesize that different pollinator species can affect fitness of Succisa through foraging time spent in one inflorescence, whereby they can vary the proportion of deposited own and foreign pollen. Moreover, different preferences to plant traits could promote either assortative mating or non-linearity in relationship between size of inflorescence and seeds set.

Presentováno na konferenci populačně biologické sekce Německé ekologické společnosti (GfÖ) konané v Bernu ve dnech 21.-24.5. 2009.

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