The next time a wasp visits your picnic, if you make a note of whether it goes for protein or sugar, you can help UCL scientists better understand the wasp life cycle.
Throughout the summer, wasps are busily fetching food wherever they can find it, which often turns out to be our own dinner plates or picnic spreads. But their food choices vary throughout the season, as they seek protein early in the summer, and go for sugar sources in late summer.
A team led by Professor Seirian Sumner (UCL Centre for Biodiversity & Environment Research, UCL Division of Biosciences) is seeking the public's assistance to help clarify when this shift from protein to sugar foraging happens, to gain more insights into the wasp's life cycle and to help with wasp management.
Professor Sumner explains: "When wasps show up at your picnic, they're not just looking for any food, as their needs depend on the season. Early in the summer, worker wasps are seeking out protein sources - generally meat but they might also go for your hummus - which they will take back to their colonies to feed thousands of larvae.
"But once the larvae have pupated, they no longer need to be fed, so the demand for protein foraging diminishes, and wasps will only need to feed themselves. Worker wasps have a largely liquid diet and will generally seek out sugary options, like jam or lemonade.
"So the next time a wasp visits you while eating outside, please let us know - did she go for your ham or your jam?"
How to help as a citizen scientist
Professor Sumner and colleagues are asking people to fill out a very simple online survey to report whether a wasp was looking for protein or sugar - or both - and what date this occurred on. This only applies to outdoor dining, and only if the food laid out included both protein and sugary options for the wasp to choose from.
Professor Sumner explained: "Wasps might not be very popular animals, but they play very important roles in the local ecosystem and in our lives. It's very useful that citizen scientists can help us understand these under-appreciated insects.
"Wasps are particularly useful for agriculture, as they pollinate hundreds of plant species, while also serving as natural pest controllers by predating on aphids and caterpillars that can damage crops."
More about wasp food preferences
The differences in foraging habits of worker habits are dictated by the fact that wasp larvae are carnivorous, but adult wasps go for a largely liquid diet due to the shape of their bodies (they effectively have a very narrow waist between the thorax and abdomen).
When the worker wasp is feeding larvae, the larvae themselves return a bit of nourishment to the workers with a nutritious liquid secretion, which the wasp supplements with nectar from flowers - as wasps are useful pollinators for a wide variety of plants. But a sip of your lemonade could also hit the spot.
Professor Sumner added: "If your picnic is being disrupted by wasps, if you provide them with an offering - a small portion on a separate plate, which you can place slightly away from your food - often they will happily stick to their own share and leave you to dine in peace. And by responding to our survey, we'll then be better placed to help advise on when exactly you should offer a wasp some ham or some jam."
