Author : A. Kareem, Ali
Behavior, Activity and Pollination Effect of Apis mellifera L. and Native Bees Foraging on Hybrid and Open-Pollinated Varieties of Sunflower, Helianthus annuus L.
journal of kerbala university,
2008, Volume 4, Issue 2, Pages 181-191
This field study carried out in 2008 at the College of Agriculture, Kerbala University dealt with different aspects of behavior, activity and pollination effect of Apis mellifera L. and native bees foraging on heads of two varieties of sunflower, Helianthus annuus L., a hybrid produced in Turkey and called “ Coban ” and an open-pollinated variety called “ Sinn el-Theeb ”. The percentages of total recorded individuals of A.mellifera and all native bees were 52.34 and 47.66%, respectively. The most abundant species of native bees were Megachile sp. and Nomia sp. while Xylocopa fenestrate, X.aestuans and other unidentified species were in fewer numbers. About 72 and 28% of all A.mellifera individuals were nectar-collectors and pollen-collectors, respectively. The displacement behavior practiced by all insect species was very remarkable. About 44% of A.mellifera and 22 to 50% of native bee individuals were forced to leave flowers through physical disturbance committed by other visitors. The study also covered other aspects including seasonal and diurnal visitation patterns and duration of a single visit / insect. The pollinating insects had insignificant effect on the yield of hybrid variety for it was highly self-compatible while they had a great benefit in this regard for the open-pollinated variety which was highly self-incompatible. For instance, mean seed-setting rates of first variety reached 88.1 and 81.4% in open and bagged heads, respectively. The rates of second variety were 79.8 and only 10.1% in open and bagged heads, respectively.