The science behind wildlife gardening
Earwi'GO!
This project will run in 2023 - update is on the way!
The latest projects from the Buzz Club, Earwi'GO focuses on
a beneficial but often maligned insect group: earwigs. As part
of both the pest control and (probably) pollinator communities,
earwigs are very valuable in garden ecosystems, but have
tended to suffer from bad press due to their omnivory. They
can nibble on soft plant parts like petals and young leaves,
but the damage they do is minor, and the biological control
they provide by munching through aphids is much greater.
So why are we focusing on earwigs? Well, one of the Buzz
Club's main project themes is making homes for overlooked
types of garden insects. As Hoverfly Lagoons has shown, making new spaces can really boost the numbers of insects in green spaces - and help us all get more familiar with our tiny neighbours.
Earwigs would certainly benefit from a little help. They are 'univoltine', which means they only produce one generation per year, so are hit particularly hard by harsh conditions or damaging events, as they struggle to replace lost egg clutches and young. They also do not travel very far (a Belgian study showed disperal distances of ~30m!), and tend to aggregate together where they are present. Due to their historical reputation as pests, a lot of information about 'managing' garden earwigs is about their control, with earwig 'traps' taking advantage of their tendency to seek out tight spaces to rest in during the day. A similar method is used for catching earwigs for ecological sampling, using rolled up cardboard placed on trees.
Earwi'GO! is taking these techniques, and using them to create earwig housing.
Name: Earwi'GO!
Year(s): 2021 -
Focus? Earwig habitat
Status? In development /
Open
Project lead contact:
Project summary
European earwig. Photo by 'Hedera.balitica', 2019, Flickr. CC BY-SA 2.0
The first part of this project (Earwi'GO! again in 2022) is to find out what kind of hotels our garden earwigs like best. This one involves making two hotels with different fillings, and monitoring how many earwigs are found using them
in your garden / green space.
NEW! The second is to look into the pest control service that those earwigs provide (Earwi'GO: Mobile Homes). This involves making a pair of earwig hotels, one in a place with soft flowers (that might get nibbled by earwigs), and one
on a tree where earwigs would be useful pest control. Earwigs found in the 'mobile' hotel (by the flowers) will be counted and moved to the tree instead. Do they stay there?
You can take part in both of these projects if you would like to. Further details on both are below.
Earwig hotels on a garden apple tree.
1) Earwi'GO! (again)
This project will run from June to October.
Earwigs start to emerge from their overwintering nests in summer, and will start to move up trees as they get older. Ideally we would like participants to have access to a tree that they can attach some earwig hotels to; but since earwigs are not exclusively found on trees, you can still take part in a garden without a tree!
We want to test out two types of earwig hotel. Last year the project showed some preference, and has allowed us to narrow down the types of hotel we are using (see our latest newsletter for more details).
The basis for both of them will be a plant pot (recycle a plastic one, or use teracotta if it is not too heavy for your tree / stick), but the fillings will be different. You will need to make the following hotels:
Location, location, location - for the hotels
You only need to do one of these locations for the project. E.g. both hotels on one tree, or above the same patch of ground cover.
Hotels should be somewhere shady, so they do not heat up in the day (earwigs like to be cool).
Since you will need to take the hotels down to count the residents, please don't put them somewhere hard / dangerous to reach!
On a tree.
Position the hotel where a branch meets the trunk.
Cardboard hotel
Using folded toilet rolls to make cardboard tubes for the earwigs to cosy down in.
Straw / leaves hotel.
Using straw / leaves / general dry plant bits.
Add a cover to the top if they start getting very wet (see left). Do the same thing to both hotels for consistency.
<- example of a lid (J, Nell; 2021)
Against a tree.
Fix the hotel onto a ~50cm stick and lean it against the trunk.
On a stick.
Fix the hotel onto a ~50cm stick and position it over some ground cover.
Against a fence.
Fix the hotel onto a ~50cm stick, and rest it against a fence or other vertical structure.
Counting hotel residents
To work out which hotel style earwigs like best, we need to count how many visitors you get to each one by emptying out the hotels into e.g. a large tray. These counts will be done once a week, starting the week after you begin. While we are focusing on earwigs, it would also be interesting to find out what other kinds of inverebrates might be using the hotels - so you will need to count everything. Only identify everything else to a level you are comfortable with - 'spider' and 'beetle' are fine! (Photographs are always useful to us if you can take them.)
Alternative counting options for if your earwigs are too energetic or numerous to count easily:
1)Tip the earwigs into a tray and take a photo of them quickly
before they escape, then count from that.
2)Do an approximate count. Ideally use categories of:
5 or less; 6 – 10; 11 – 20; 21+. E.g.:
Identifying earwigs should be easy - there are very few other insects that look anything like them! Adult males and females can be told apart by the shape of the cerci (pincers) on the end of their abdomen. Males have curved pincers, females have straight ones; juveniles have straight ones as well but are smaller and paler overall. Adults also have wings that are folded up very neatly by their 'shoulders' - looking like a small cloak.
A particularly fiesty earwig might try to pinch your finger, but the cerci are very weak and not sharp or venomous!
Snapping a quick photo means you can count earwigs later from a static image.
Adult male European earwig (Forficula auricularia). Photo by 'Hedera.balitica', 2018, Flickr. CC BY-SA 2.0
Adult female European earwig (Forficula auricularia); top. Nymph, below. Note colour difference and wing cases. Photo by Judy Gallagher, 2020, Flickr. CC BY 2.0
The difference between adult male (eft) and female (right) earwig cerci / pincers. Image from Wisconsin Agriculture.
2) Mobile Homes
This project will run from June to October, and focus on moving earwigs within the garden,
To take part you will need to have earwigs present in your garden (or be fairly sure they are). You will also need some flowering plants (can be in pots), particularly soft flowers like dahlias; and a tree, away from the flowers. Ideally a fruit tree, but any tree should work.
You will need to make two cardboard earwig hotels (see above for details). One will be the 'mobile home', which will be placed on a stick in the flower areas; the second will be on a tree (as above).
Counting, and moving home
Once a week, you will need to empty and count each hotel (see above for counting instructions). The difference is that this time you will release invertebrates from the mobile home hotel under the tree where the tree hotel is (invertebrates from the tree hotel also go under the tree). Then put the empty mobile home back in the flowers.
The idea is to relocate any earwigs found in the flowers over into the environment around the tree. If they prefer being in a tree than being in the flowers, then hopefully they will stay there!
Frequently Asked Questions - Earwi'GO!
1. Can I do more than one location?
You can if you like, but you will need to do all three types of hotel in each place, which might
be a lot. Feel free if you want to try though!
2. I wasn't able to start in June / only just found this project / missed a week.
Is this a probem?
Nope! While we would ideally like as many records over the full time period as possible, we recognise that this might be a big ask. Do what you can, and just make sure to fill in the dates on your recording sheet.
3. About the 'going in your ear' thing...?
A myth, and a silly one! While earwigs show 'positive thigmotaxis' (a fancy term for liking to be in small spaces, and clustered together), your ear really isn't a good hotel. Too warm, too waxy, too loud and - unless you are prone to going to sleep with your head stuck in a tree - not very accessible!
