Thursday, June 6, 2013
SEASONAL WORKERS
By Sara SCUDIER
OSU Ext. Master Gardener Volunteer
Summer is nealy upon us. Flowers are everywhere and you have probably noticed all of the bees and other pollinators who visit them.
Some plants, such as trees and corn, are pollinated by the wind. There are even some animals that pollinate flowers, but insects are the most common pollinators.
Bees are the most numerous visitors, as they actively collect nectar and pollen, but wasps, flies and beetles are also visiting.
These pollinators also visit the flowers on food crops; they are responsible for one in every three mouthfuls of food and drink we consume.
Bees and wasps are closely related, but they have very different diets. Generally, bees are vegetarians and wasps are carnivores. Young bees are fed pollen and nectar and young wasps are fed insects and bits of meat scavenged by their mothers from animal carcasses — and your picnic. Most adult wasps and bees feed on carbohydrates, either flower nectar, rotting fruit or even sugary sodas left over from humans.
Many people call yellow jackets bees. They are, in fact, wasps, and they are carnivores. They, along with hornets and paper wasps are social nesters. They have multiple females cooperating in constructing and defending a nest to rear offspring.
When threatened, these social wasps will aggressively defend their nests by a succession of painful stings. This habit, along with their common appearance at picnics to scavenge food and drinks, make them familiar to anyone who spends much time outdoors.
Many bees and wasps will sting when threatened, although some bees lack the ability to sting. While yellow jackets, hornets and paper wasps are aggressive, most bees and wasps are very placid. Because many people think of yellow jackets as bees, their aggressive behavior leads us to assume that all bees act the same. This is far from the truth. If they have the ability to sting, they will do so only when physically attacked.
Bees rear their young in a number of different ways. Some are solitary, some gregarious — they share a nesting area but do not do so cooperatively, and some are social.
The most widely known ground-nesting bee is the native bumblebee. These are social bees — they have nests that consist of a queen and many workers. These workers are the queen’s daughters. The queen lives for a year and the workers live much shorter lives. They work as a community to survive. The queen emerges in the spring and finds a location for a new nest. This site is often an old mouse nest in the ground, but it can also be a tuft of grasses. Bumblebees like something “fluffy” to nest in, which is why mouse nests are a favorite site.
The new queen then lays eggs and feeds them with pollen. As these new workers emerge, they take over care of the young and the queen focuses on producing offspring.
Late in the year, she begins laying eggs that will become next year’s queens and males.
The queen determines the sex of the offspring by fertilizing — or not — the eggs. Males are unfertilized eggs; females are fertilized eggs, having genetic material from both parents.
The queens and males mate, and the queens than find a safe place to hibernate through the winter.
All of the other members of the colony die at the end of the season.
In the spring the cycle starts again.
Many ground-nesting bees are solitary. Each female lays her eggs in a nest that she does not protect, as social nesters do. She lays each egg in a cell in the nest.
In some species, a number of females will share a nest site, but they do not work cooperatively.
One such ground nester is the squash bee. These bees pollinate squash, cucumbers and pumpkins. Their lifecycle follows that of the plants they pollinate. They nest in bare earth near the plants and emerge when the flowers become available for their food source.
Another is the leaf cutter bee. These bees cut pieces from leaves that they use to separate the nest cells as they lay their eggs. They have a very sharp mandible that they use to cut the leaves. This makes a very neat, even cut on the leaves of their preferred plant. It may appear as damage, but this behavior does not harm the plant.
Another nesting strategy involves building nests in abandoned beetle nests in trees, in hollow stems, in wooded structures.
Mason bees pollinate fruit trees and are thus invaluable to orchardists. They are solitary bees and lay their eggs in mud banks, the hollow stems of plants and will use “nests’ made of straws supplied by gardeners.
Spring brings pollinators other than bees.
Some species of butterfly and moth overwinter as adults or pupae that emerge as it warms up.
The cabbage whites are small white moths that emerge early as adults.
Many flies and wasps pollinate early flowers. Wasps carry pollen from flower to flower while hunting for prey, and many species of fly also carry pollen while feeding on nectar or insects.
OSU Extension has a wonderful website and staff dedicated to pollinators in Ohio. You can join a mailing list, find out the latest news about honeybees and even watch webinars to learn about protecting and attracting pollinators.
For more information on all of these pollinators, visitwww.osupollination.com.