Insect communication

Insects can communicate use ‘smells’. But the way they sense ‘smells’ is different to the way we humans do. When we breathe in air through our our noses, we also breathe in little bits of dust and chemicals. These chemicals are what we smell when we sniff something delicious cooking or the bad smell of rotting food, the smells being detected by sensory cells inside the nose.

Insects don’t really have noses, so how do they sense smells? Have you ever seen an insect’s antennae? These are the insect’s ‘noses’. Antennae are able to detect chemicals in the air in a similar way to the sensory cells in our noses.

Insects can make smells (or chemicals) called pheromones that they can use to communicate with. Some are attractive, such as the ones that ants use to lead other ants towards the food they have found. Some are repulsive and tell other insects not to visit somewhere.

ACTIVITY: Talk like a bee

You’ll need:

• Cardboard flowers: 5 or more paper plates or cardboard pieces
• ‘Pheromones’: A mixture of 50% lemon juice with 50% water in a spray bottle
• A decoy: A spray bottle with 100% water

Set-up:

• Spray all of the cardboard flowers with the 100% water. This is so that your ‘bees’ will not see which ‘flower’ has been sprayed and which haven’t.
• Spray one plate with the lemon juice and water mixture (take care not to spray close to your eyes as the lemon juice is an acid that will sting). This is you behaving like a bee and ‘marking’ the flower that you have visited.

Now test the smelling power of your family or friends by asking them to behave like a foraging bee

How to play:

1. Your ‘bees’ (friends or family members) must find a cardboard flower that does not smell like lemons.
2. Each time they select a flower, spray it with the lemon juice and water mixture.
3. Mix up the order of the plates between turns so that your bees do not know which is which.
4. Eventually there will be one cardboard flower left without any ‘pheromones’ on it. The final bee will have the hardest job finding the remaining flower!

Living life as a bee would be tricky without this ability to communicate using smells. It’s a bit like leaving a note for your friends on the flowers you have visited. This is useful as it says that you have taken the nectar from that flower, and it will take time to refill its stocks so any bee coming after you is better off going to another flower for now.

Find out more about pollinators and the important job they do in ecosystems with our Pollinators Nature Classroom.

Build a winter refuge

Many animals try to avoid the worst of the winter weather by hunkering down in a safe space (a refuge). Insects are no exception. They rely on the sun’s heat to provide their bodies with warmth and power their flight. There are also fewer flowers around to provide energy rich nectar to pollinators over the winter months, so insects such as bees often have to wait it out until new flowers bloom in Spring.

There are around 250 species of solitary bee in the UK, which all have slightly different life cycles. Many species of solitary bee make use of winter refuges and stay tucked away until temperatures begin to rise.

One of the most common species of solitary bee is the red mason bee. Female red mason bees seek out nest sites in holes left behind by beetles in old wood, as well as hollow plant stems and cavities in stone walls. Within each hole she will lay several eggs in a row, providing each with its own chamber and a store of pollen and nectar as a food source. She will then seal the entrance to each chamber with mud for protection.

In the safety of their nests, the eggs hatch into larvae and begin to feed on their supply of pollen.  When fully grown, the larvae spin cocoons and pupate, with new adults forming in September. They remain in the cocoon over winter, with the new generation of adults emerging in Spring to repeat the cycle.

How can we help?

Lots of gardens and green spaces are now kept very ‘tidy’ and lack the natural nooks and crannies where solitary bees like to nest. We can give them a helping hand by building them their very own bespoke winter refuge.

A new winter refuge will be too late to help most bees this year but if you build it over winter it will be ready for the new generation when they emerge in Spring.

Building a bee hotel

Bee hotels can be really simple and a small one done right can be even better than a large one trying to do too much.

There are lots of free guides online, which you can see below for guidance, but the basic idea is to provide a collection of nesting tubes for bees to lay their eggs in. Hollow bamboo canes cut to size and tied together, or an old block of wood with holes drilled into one side, do a great job.

Free online guides:

Wildlife Trusts: How to make a Bee Hotel

Bumblebee Conservation: Bee Nest Boxes

Top tips:

1. Add a lid or cover to stop the rain reaching your nesting tubes. Some sort of covering extending over the front of nesting tubes will prevent the developing larvae getting damp.
2. Provide a range of nesting tubes with different sized holes to attract a range of species. Most solitary bees will do well with holes ranging from 3 – 5mm but try not to go beyond 2 – 10mm, which could otherwise be too big or too small.
3. Aim for your nesting tubes to be at least 15mm long. This will give enough room for female bees to create a series of egg chambers in a line.
4. Avoid using plastic straws to make the nesting chambers. Try more breathable material instead, such as wood, which will help prevent damp and mould building up.
5. Hang the bee hotel up on sunny wall. Positioning your refuge one or two meters up in a sunny spot will improve its chances of being used by bees flying through the area in search of warm nesting sites.

Dive into the hive with more bee activities…

Learn all about Ivy Bees from expert Dr Lynn Dicks here:

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Discover more about the wonders of bees from research assistant Matt Hayes here: World Bee Day

Turn your garden into an insect paradise with our insect hotel building guide: A warm welcome for minibeasts

This activity was created as part of the Cambridge Zero Climate Change Festival 2020