Hornets and wasps are social insects whose reputation as stinging insects often overshadows their complex ecological role, which is directly tied to their diverse diet. The nutritional needs of these insects shift dramatically between their larval and adult stages, leading to a sophisticated foraging strategy that supports the entire colony. Their feeding habits involve a two-part diet of high-energy sugars and protein-rich meat.
Adult Diet: The Search for Sugars
Adult hornets and wasps, whether workers or queens, primarily require carbohydrates to fuel high-energy activities like flying, foraging, and nest building. They need a constant supply of simple sugars for immediate energy expenditure. Since they cannot effectively digest solid proteins, their adult diet is almost entirely liquid and carbohydrate-based.
Foraging adults seek out a variety of sweet sources in the environment, including flower nectar, overripe or damaged fruits, and tree sap, which they consume directly. They are often seen drinking from sugary liquids, such as spilled soda or human sweets, especially later in the season when natural sources become scarcer. This reliance on readily available sugar provides the necessary fuel to keep the colony running efficiently throughout the day.
Larval Diet: The Demand for Protein
The larvae have an entirely different and more demanding nutritional requirement than their adult counterparts. As they grow rapidly inside the nest cells, they require a diet rich in protein for tissue development and growth. This protein is supplied by adult foragers who transition into dedicated hunters and scavengers to provision the nest.
Adult workers hunt a wide variety of arthropods, including caterpillars, flies, spiders, and beetle grubs, which they often kill with a sting. They then chew the prey into a soft, easily digestible paste, or meatball, before bringing it back to the nest to feed the larvae directly. This hunting behavior is the primary reason wasps and hornets are considered beneficial predators in many ecosystems, as they help control populations of agricultural pests.
The exchange of food between the adults and larvae forms a symbiotic relationship known as trophallaxis. After being fed the protein paste, the larvae excrete a sugary liquid containing carbohydrates and free amino acids. The adults consume this sugary secretion, which provides them with energy and protein-building nutrients they cannot acquire on their own.
Dietary Habits of Common Species
The general feeding strategy of high-energy adults and protein-hungry larvae is adapted by different species based on their ecological niche and foraging style. Yellow Jackets (Vespula species) are known for their highly opportunistic scavenging, which often brings them into conflict with humans. They are attracted to picnic foods, garbage, and carrion, seeking both the sugar from drinks and the protein from meat scraps to feed their large colonies.
Paper Wasps (Polistes species) are generally more focused predators, primarily hunting soft-bodied insects like caterpillars to feed their brood. Their diet remains largely insect-based, and they are less prone to scavenging human food sources than yellow jackets. They are considered highly effective in gardens for their targeted pest control, consuming a variety of garden-damaging larvae.
Bald-faced Hornets (Dolichovespula maculata), technically a type of yellow jacket, are excellent aerial predators that often target flies and other flying insects. They are less interested in scavenging human food and are known for their aggressive hunting of other yellow jackets and pest insects. Their diet reflects a specialized predatory role, focusing on securing live prey for their developing young.