Hand pollination and natural pollination by carpenter bees (Xylocopa spp.) in Passiflora edulis Sims. f. flavicarpa Deg. (yellow passion fruit)

Abstract

We investigated the fruit set and quality of yellow passion fruit subjected to hand and natural pollination by carpenter bees (Xylocopa spp.) in the Philippines. We also recorded the foraging behavior of the bees. A quadrat measuring 6 m x 7 m was marked in a yellow passion fruit plantation for the investigation. Two groups of 20 flowers that had been either hand pollinated or visited by the bees were followed to determine fruit set and quality. The hand pollinated flowers had significantly greater fruit set (15/20 versus 7/20), fruit weight, transverse diameter, longitudinal diameter, peel weight, number of seeds, and juice yield. Flowers that were self-pollinated by hand produced no fruit. Bee flower visit times and patterns were also investigated. The carpenter bees started visiting the passion fruit flowers from 7:00 AM to 5:00 PM, with peak visitation at 1:00 PM. The greatest mean duration of flower visits was observed at 11:00 AM (304 s), which coincided with the observed peak hour of flower opening. We observed random distances in the flight patterns of the carpenter bees, which was independent of flower distances (Kolmogorov-Smirnov test; µ=3.34 < σ²=7.91 vs. µ=2.40 > σ²=1.20). We conclude that passion fruit farmers can utilize supplemental hand pollination to increase yield when the main pollinators such as Xylocopa spp. are not available in sufficient numbers.

Keywords:

• Anthesis
• foraging
• fruit setting
• fruit quality
• Lucban
• pollinators

Acknowledgements

This paper is part of the undergraduate thesis of KDT and JAP who were given partial financial assistance from the Department of Agriculture-Bureau of Agricultural Research under the project of Dr. Cleofas R. Cervancia. The Passion Fruit and Vegetable Growers Association of Lucban Inc. (PAFVEGMAL) is greatly acknowledged for allowing us to use their farm as experimental site. We recognize the University of the Philippines Los Baños (UPLB)-Bee program headed by Dr. Cleofas R. Cervancia for their generous support, most especially in providing recommendations for the improvement of the study. Dr. Jomar F. Rabajante from the Institute of Mathematical Science and Physics, UPLB, is also acknowledged for helping us in the statistical analysis.

Disclosure statement

The authors declared no conflict of interest.