The feeding behaviour of wasps is directly related to their anatmony and to their life cycle. Wasps have large powerful mandibles which people frequently mistake for jaws. In truth these mandibles are much more akin to crab claws it’s just that they are located on the wasps’ head. The real mouth parts are located behind the mandibles and wasps have a proboscis, i.e. a structure made from a series of tubes. This means that adult wasps can only eat liquid foods. Because of the way that wasps fly, they consume massive amounts of energy so they need to feed on high energy sweet liquids that are packed with sugars. In early spring the emerging queens get this sweet liquid from plant nectar. In late spring to late summer, adult wasps get sweet liquids from the grubs in their nest who break down chitin from insect skeletons into sugar. From late summer onwards the wasps get their sweet liquids from fruit and late flowering plants and from outdoor food and drinks served by humans.
Hunting wasps adopt different techniques when hunting. Wasps will randomly root around for hidden insects and you will see them rooting through the grass, searching for insects on the underside of leaves, looking into holes and crevices and cracks in bark, searching along twigs and branches, rooting through compost heaps and rooting through faecal matter. They will also scent damage done to leaves and will come looking for any insects that might have caused such damage such as caterpillars. Hunting wasps will hunt on sight and will chase down and catch flies and mosquitos and other flying insects. Hunting wasps will visit and rob out any insects caught in cobwebs and they will do this without getting caught themselves. Wasps will also scavenge for carrion and will strip a corpse of its flesh within hours. During the hunting phase of the wasp life cycle, an average sized wasp nest will eradicate between 4 to 5 metric tons of insect pests in a year.
After wasp nests mature, when there are no more grubs left in the nest, adult wasps are forced to find sugars elsewhere and this brings them into competition with man and makes wasps a nuisance. In nature this coincides with fruit trees producing fruit and when honey is produced by bee hives. It is also the time that we humans like to enjoy outdoor eating and drinking. Wasps find sugars by smell and will fly up scent trails to find sweet foods. One way to reduce risk from nuisance wasps is to make sure that foods are properly sealed to create as little aroma for them to track as possible and to clean away spillages and rubbish and not to leave out dirty plates once they’re finished with.
A critical thing to understand about wasps is that they swarm feed wherever there is a residual food source. If a wasp finds a food source that it can’t consume in one go, the wasp will return back to its nest and recruit its colleagues so that together they can work as a team to consume the food that the wasp found. The reason why wasps behave in this way is that with as many as 1,000 wasp nests per square mile there is an awful lot of competition with wasps from other nests for the same food. Without help in the face of such fierce competition lone wasps would have no hope in defending and consuming a food source from other wasps. This is typical wasp scouting and swarm feeding behaviour which means that once one wasp has found food, if that wasp isn’t prevented from returning to its nest you can be sure that within a short time there will be a veritable swarm around the food source. The size of the swarm will depend on how abundant other food sources are. The less abundant, the bigger the swarms.
Once wasps find a food source, they are programmed to keep returning to it until it is consumed and will by and large ignore other food sources. The reason for this is simple. Finding and consuming food takes a lot of energy and for wasps to survive they must consume more energy than they expend. All of which means that once wasps are swarming on a particular food source they will ignore all other food sources including wasp traps (regardless of the efficiency) until the existing food source has been fully consumed or is no longer available to them. An important strategy for managing swarm feeding wasps is to remove the original food source and replace it with a WaspBane wasp trap in exactly the same position.
Wasps are very adept at navigating to food sources. Once a food source has been found by a scouting wasp, the scouting wasp will convey the location to its colleagues and the precision of their navigation is that they will fly to within millimeters of the food source. This is known as point source navigation and you can have two separate swarms of wasps from two different nests literally within millimeters of each other. In addition to point source navigation, wasps will also terrain navigate. This is where there may be several point source within a terrain but those point sources keep moving. Examples of this include flower beds and fruit trees where the individual sources, the flowers and fruit, are located within a terrain, the flower bed or tree, but those individual sources keep changing as different flowers bloom or different fruit ripen.
Overwhelming Food Sources
In certain situations, there is such an abundance of food that it is almost impossible to manage wasps. Examples of such food sources include lime trees where each leaf on a 60ft tree will be exuding sweet sap and ivy which as the last flowering plant of the season, produces masses of florets each pumping out vast quantities of nectar. Wasp traps cannot hope to compete in such situations and often the only available option is to remove the offending food source which sadly may mean replacing lime trees with other non sapping trees and replacing ivy with other safer climbers.