We all know that bees and other pollinators are crucial to our ecosystem and food supply, but did you know that it takes some really specialised pollinators to help grow pumpkins and apples?
October is pumpkin season, with colourful pumpkins the centre of attention at harvest festivals, vegetable produce competitions and fabulous displays in supermarkets and garden centres. One of the best displays in the UK each year is at Kew Gardens where the Lily House is transformed into a seasonal display of Pumpkin, Gourds and Squash. Millions of plants are grown each year for jack-o-lantern carving at Halloween and throughout North America pumpkins are cooked and eaten at Thanksgiving.
A seasonal display of Pumpkin and Squash
Pumpkins are members of the Cucurbit family (along with Squash, Cucumber, Cantaloupe Melon, Gourds, Courgette and Marrows). Cucurbits have a very specific and short pollination window – they are generally receptive early in the morning when the pollen is freshest and the heat of the sun has yet to wilt the delicate flowers and cause them to perish.
Honey Bees can pollinate Pumpkin but they don’t like the early starts that suit the cucurbits as they are reluctant to fly at the crack of dawn when air temperatures are often much cooler. Bumble Bees with their higher metabolism and furry bodies can fly in cooler temperatures and are also important in pumpkin pollination, but like the Honey Bee they may be tempted away from the crop by other flowers which yield more nectar. The real Pumpkin pollinator specialists though are the solitary Peponapis and Xenoglossa bees of Central and North America – find out more about them in our Bee of the Month blog later this month.
Bees are also crucial to the pollination of the apples you might find yourself bobbing for at Halloween parties. As well as Halloween, October is also traditionally the month in the UK when we hold National Apple Day and celebrate the 7,500 varieties grown globally with apple tasting, apple crumble bake-offs and apple dunking competitions.
In the past, apples would have been predominantly pollinated by Bumblebees and Solitary bees like the Ashy Mining Bee (and on the continent the European Orchard Mason Bee). Today they are grown on a mass scale and require hives of Honey bees be brought in to pollinate them. To successfully pollinate apples, the beekeepers place 4-6 hives at 150 yard intervals and 100 yards from the edge of the orchard. The hives need contain at least 6 brood frames covered in bees to guarantee that enough bees transfer enough pollen to aid a good fruit set. Larger orchards may place groups of 8-16 hives every 300 yards or so as they require even more bees to pollinate the larger areas of crops.
Whilst Honey bees are used to pollinate commercial apples, by far the most efficient pollinator of apple trees is the Oriental Orchard Mason Bee, Osmia lignaria. With this bee, 300 female bees can perform the pollination role of 90,000 Honey bee foragers! Again, this is because they fly earlier in the day when the flowers are most receptive and also because this bee lands in a different part of the flower and so transfers more pollen than a Honey bee.