Once the colder autumn weather comes, social wasp colonies begin to disintegrate, and the old queens die. The newly mated queens and the surviving workers spend their time feeding on ripe fruit and the nectar from late blooming flowers.
Social wasps live in large colonies headed by a fertilized queen. There are over 5,000 species of social wasps worldwide. Some nest underground, others choose hollow trees or bushes, and some are parasitic. Their bold yellow and black coloration and tapering abdomen make all these insects easy to identify.
If you want to know more about these wasps, please read on.
The wasp’s year starts with the fertilized queen waking up from hibernation in early spring. She will then try to find a suitable nesting site. Common and German wasps look for places such as small mammal holes in banks, but other enclosed spaces such as attics and sheds may be selected. When the queen has found a site, she starts to build her nest, laying eggs in individual cells as she builds.
The eggs hatch five to six days after nest-building starts, and the queen then brings back nectar and insects she has captured to feed the young larvae. The larvae take about two weeks to fully grow when they spin a silk cap and lining to the cell.
During their feeding stage, they do not excrete any waste. However, with feeding finished, the waste is placed at the bottom of the cells, filling them up so that each cell can only be used two or three times. The larvae change to pupae and emerge as adult wasps after about ten days, by which time the queen has increased the comb to 20 or 30 cells.
All the young wasps at this time are female worker wasps and were subordinate to their mother, the queen. The workers gradually take over any work needed in the nest, allowing the queen to spend her time laying eggs.
The queen isn’t the only female to lay eggs, but this is done later in the year. As the workers never mate, their eggs are all unfertilized, meaning they only produce males. This is the same in wasps, bees, and ants and means that the queen can decide whether to lay fertilized, female-producing eggs or unfertilized, male-producing eggs.
As the number of workers increases, so does the nest size, the number of combs, and the number of larvae needing feeding. Ground-nesting wasps, which use burrows in dirt or soil, also need to enlarge the size of the hole containing the nest by carrying away balls of earth.
Diet and Prey
The leading food of the adult wasps is nectar which they rely on for carbohydrates, but other sources include jam, ripe fruit, and honeydew excreted by aphids, and they can also be seen robbing honey from bee hives. Their mouthparts are adapted to biting, licking, and chewing.
Wasps will seek out the sweetness of fruits, especially those with high fructose. My blackberry bush was decimated recently by birds and wasps, but they also like apples, oranges, and bananas.
Adults need carbohydrates as a ready energy source to maintain their activity. The larvae are also fed on carbohydrates, but their main food is the flesh of other insects. Flies, caterpillars, and spiders all make up their diet.
When wasps search for prey, they move much faster than usual, flying to hedges, trees, and other places where insects can be found easily. Wasps rely on their sight to find their prey.
Once found, the wasp pounces and kills its prey by biting the victim’s neck, decapitating it. It bites off its legs and wings before carrying the prey back to its nest. Wasps will usually choose prey that is resting than flying. They sometimes use their stings on larger prey, like bees.
Worker wasps have three main foraging tasks. They must bring back pulp for building, collect sugary nectar, and capture prey. The length of their adult life varies from two to four weeks. Wasps quickly seek the best places to catch their prey, but they don’t pass on this information like bees.
The larvae indicate they are hungry to the workers by using their mandibles to scratch their cell walls. The social organization of the colony is maintained by a constant exchange of food among the individuals, known as ‘trophallaxis.’
Adults use mouth-to-mouth contact to feed each other and take drops of fluid for the larvae to feed on. If trophallaxis doesn’t happen, the colony will decline and eventually die. The larvae can be stimulated to produce a drop of nutritious fluid eagerly sought by the adults. The queen imbibes large quantities, which help her to maintain her egg output, and newly emerged adults feed on little else.
The amount of secretion depends on the amount of fluid or food that the larva has had. Adult wasps tell each other to pass food stroking each other with their antennae. The queen obtains her food in this way, supplemented by larval secretions.
These exchanges contribute to colony odor and help them identify each other. The presence of a queen ensures a normal colony, but if removed, this will cause different behavior. Without a queen, the workers sit in groups instead of flying out to find food. Scientists believe that the queen produces a substance that permeates the entire colony.
New Queens and Males
When the colony is strong later in the year, larger cells are built at the bottom of the nest. These cells will produce new queens. These eggs develop into queens because of the larger cells and better food. Any males are normally larger than normal worker males.
Males are produced at the same time as the queens from unfertilized eggs placed by the queen or the workers. Males have longer antennae, and they are there to fertilize the young queens. Each colony can produce 1000 or more males and queens. Mating takes place from late August, the males often congregate on sunny days, but it may occur near the nest.
Following mating, the queen finds a suitable place to hibernate. Hibernation doesn’t always happen immediately after mating, and she may fly for another six weeks. A hibernating queen clings onto a support such as a curtain with her mandibles and folds her wings and appendages. Hibernation sites need to be well-insulated with moderate humidity, so a cozy room is preferred.
In late summer, with the appearance of the new males and queens, the social organization of the colony begins to disintegrate, and the old queen dies slowly. The workers desert the nest or die, as do the males when the weather gets colder. In the autumn, the workers no longer capture prey as there are no larvae to feed, and they spend much of their time eating ripe fruit and nectar.