Foraging behavior of Xylocopa fenestrata Fab. and its role in pollination of ridge gourd, Luffa acutangula (L.) Roxb.
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Date
2017
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Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur)
Abstract
The present studies on “Foraging behavior of Xylocopa fenestrata Fab. and its role in pollination of ridge gourd, Luffa acutangula (L.) Roxb.” was carried out during the year 2016-17 at University Apiary, DRPCAU, Pusa. Objectives of this investigation were to study the relative abundance of insect pollinators, foraging behaviour of Xylocopa fenestrata, and its effect on pollination of ridge gourd. The results indicated that the total eight insect species visited ridge gourd flowers, viz. five hymenopterans, two dipterans and one from odonata. Among these Apis mellifera L., A. dorsata F., A. florea F., Xylocopa fenestrata F. and Polistes sp. were found to be most frequent pollinators. The relative abundance (no. of insect/m2/10 minutes) revealed that Apis mellifera (20.0) was most dominant species followed by Apis dorsata (16.7), Xylocopa fenestrata (15.9), Apis florea (11.3), Eristalinus sp. (6.3), Polistes sp. (5.1), Paragomphus sp. (2.9) and Musca domestica (2.0). Irrespective of species, the mean population was maximum (13.3/m2/10 minutes) at 0700-h of the day. The coefficient of correlation between mean population of pollinators species and temperature was found positive and significant while negative correlation was found with relative humidity indicating that temperature plays an important role on activity of insect pollinators.
The result on foraging behaviour of X. fenestrata revealed that they started visiting ridge gourd flowers in early morning and ceased their activity later in the evening. It remained active throughout the flowering period. The foraging rate of X. fenestrata was minimum in the morning (3.9 flower/min.) and evening (3.2 flower/min.) hours and maximum during the mid day hours (7.3 flower/min.) and its foraging speed was maximum in morning (17.6 sec.) and evening (23.5sec.) whereas, minimum in mid day hours (11.1 sec.) and there was inverse relation
between foraging rate and foraging speed. The heaviest pollen load was carried by the Xylocopa in the evening hour while lightest pollen load was carried in the noon hour which indicated that more pollen was collected by Xylocopa during morning and evening hours from ridge gourd flowers.
The yields of fruit and seed of ridge gourd increased significantly by pollination of Xylocopa. The fruit set was highest in open pollination (78.70%) followed by Xylocopa pollination, viz. XP3 (72.20%), XP2 (63.60%) and XP1 (52.70%), whereas lowest in pollination exclusion (50.00%). The number of fruits per plant was maximum in OP (18.50) followed by XP3 (16.20), XP2 (14.00), XP1 (11.50) and was lowest in PE (10.00) treatments. Similarly, fruit weight was maximum in OP (85.60 g) followed by XP3 (80.50 g), XP2 (4.30 g), XP1 (70.10 g) and was lowest in PE (51.80 g). The fruit yield was maximum in OP (82.30 q/ha), followed by XP3, XP2 and XP1 (81.00, 75.50 and 73.60 q/ha, respectively) and the lowest in PE (60.20 q/ha). The result reflected that there was 36.80% increased in fruit yield in OP while, it was 34.50% in XP3, 25.30% in XP2 and 22.20% in XP1 treatment over pollination exclusion. The highest number of seed per fruit was found maximum in OP (27.00) followed by XP3 (25.50), XP2 (24.00), XP1 (22.20) and was lowest in PE (19.50) treatment. The weight of 100-seed was maximum in OP (15.20 g) followed by XP3 (13.10 g), XP2 (12.50 g), XP1 (11.00 g) and was lowest in PE (9.00 g). The percentage increment in seed yield was recorded highest in the OP (70.00%) followed by XP3 (50.00%), XP2 (30.00%) and XP1 (10.00%) over PE treatment. The insect pollinators play significant role in pollinating ridge gourd flowers and enhancing yield of crop.
Therefore, Xylocopa fenestrata can be utilized for pollinating ridge gourd for increasing qualitative and quantitative parameters of the crop and therefore, higher monetary return.
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