Foraging Activity of Four Bee Species on Sesame Flowers During Two Successive Seasons in Ismailia Governorate, Egypt

Abstract

Foraging activity of four bee species, Apis mellifera L., Osmia spp., Ceratina tarsata Morawitz and Xylocopa pubescens Spinola on sesame flowers was studied during two successive seasons of 2011 and 2012. Experimental observations were made during four periods of the day: 9:00-11:00 am, 11:00 am-1:00 pm, 1:00-3:00 pm and 3:00-5:00 pm, starting from initial flowering until the final session. Observation time was five minutes during each period and four bee species were observed visiting each square meter area. Five spots of 1 m2 area were selected randomly, and the number of different species of bees visiting was counted for five minutes by using electronic stopwatch, voice recorder and digital video camera. The results of the study indicated that the four bee species were most abundant on sesame flowers between 11:00 am and 1:00 pm, and between 1:00 and 3:00 pm. Among the bees, Apis mellifera was the predominant species, followed by Ceratina tarsata, in the season of 2011, while a reverse order of the two was recorded in 2012. The average time spent per flower was highly significantly different among these four species.

Ispaša četiri vrste pčela, Apis mellifera L., Osmia spp., Ceratina tarsata Morawitz i Xylocopa pubescens Spinola, proučavana je na cvetovima susama tokom dve uzastopne godine, 2011. i 2012. Eksperimentalna posmatranja obavljena su tokom četiri perioda u toku dana: 9:00-11:00, 11:00-13:00, 13:00-15:00 i 15:00-17:00, u vreme između početka cvetanja i poslednjeg pregleda. Tokom svakog perioda, posmatranje je obavljeno u vremenu od pet minuta, a četiri vrste pčela su zabeležene u svakom kvadratnom metru. Pet tačaka od po 1 m2 izabrano je po principu slučajnog uzorka, a pčele različitih vrsta brojane su tokom pet minuta pomoću elektronske štoperice, diktafona i digitalne video-kamere. Rezultati pokazuju da je najveći broj pčela sve četiri vrste posetilo cvetove susama između 11:00 i 13:00, i između 13:00 i 15:00. Među pčelama Apis mellifera je bila najzastupljenija vrsta, a potom Ceratina tarsata tokom 2011. godine, dok je naredne 2012. godine redosled ove dve vrste bio obrnut. Prosečno vreme zadržavanja na cvetu se vrlo značajno razlikovalo za ove četiri vrste.