Insects like honeybees and bumblebees prefer the shortest distance when they have to fly from one flower to another, according to an American study.
S. Alan Walters of Southern Illinois University and Jonathan R. Schultheis of North Carolina State University came to this conclusion after studying their pollinator movements down and across rows in watermelon, by tracking pollen flow.
The researchers tracked the direction of honeybees under field conditions during 2001 and 2002 at the Southern Illinois University Horticultural Research Center in Carbondale.
Walters says that the evaluation of pollen flow showed a definite pattern of bee movement and gene migration in watermelon.
“Although we detected pollinator movement that was strongly directional in both directions (east and west) down the row from the central block of donor plants, results also indicate that significant movement also occurred across rows in both directions (north and south) from the donor plot,” he said.
Given that watermelon vines grow in multiple directions, bees can easily move across rows if the next closest flower is in that direction instead of down the row.
The researchers have observed that most pollen is deposited on the nearest neighbouring flower from where pollen was collected.
Summarizing the study, Walters said: "Although significant amounts of linear pollinator movements occur down rows of watermelon plants, pollinator movements (in watermelon) are not as simple as just maintaining a linear direction straight down the row, but are related to the short flight distances that most likely occur to the closest neighbouring flower from the one that was previously visited."
The study has been published in the journal HortScience.