Reduction of pollen viability of cantaloupe melon (Cucumis melo L., Cucurbitaceae) by honeybee body hairs contact
Résumé
Honeybees take part in 80% of Angiosperms pollination. With pollen transport and transfer from flower to flower, they increase fruit and seed set compared to hand pollination. Nevertheless, it was shown in some species that bee contact decreases pollen viability. The aim of this study was to assess the bee contact effect on Cucurbitaceae pollen viability during different times. The studied model is cantaloupe melon (Cucumis melo L.), an economically important crop of Southern France. Pollen was collected and artificially applied to honeybee body hairs. The pollen viability was determined after 1 h; 2.5 h and 4 h of bee contact by fluorochromatic reaction (FCR). After the first hour, the viability of pollen in contact with honeybee body hairs was null whereas the viability of pollen without contact (control) was 45 %. These results show c1early that honeybee body hairs affect the cantaloupe pollen viability since 1 hour of contact. This would be due to substances present on body hairs like cuticular hydrocarbons or secretions of mandibular and labial glands deposited on body hairs by brushing. Studies are in progress (i) to identify the biochemical nature of the substances affecting pollen viability and (ii) to determine the period during which bee can transport viable pollen able to fertilize plant after harvesting.
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