Ladybirds & Dinocampus coccinellae
Ladybirds are beetles, which like all insects have 6 legs. Like all beetles, ladybirds have hardened wing cases (known as elytra), under which they store their fragile wings. The bright colour of the elytra acts as a warning to any potential predator that might want to eat them.
In the UK, we have 47 different kinds (species) of ladybird, 26 of which are brightly coloured. The remaining 19 remaining species are very small (2-4 mm), generally dull in colour and are known collectively as inconspicous ladybirds.
The most common ladybirds in the UK are the 7-spot (Coccinella septempunctata), 2-spot (Adalia bipunctata), 10-spot (Adalia decimpunctata) and of course the invasive harlequin ladybird (Harmonia axyridis).
The ladybird life cycle
- Eggs: Ladybirds lay oval shaped yellow eggs in little groups, known as clutches. Ladybirds can lay anywhere from 2-100 eggs at a time which hatch in 4-10 days, depending on the species.
- Larvae: Eggs hatch into tiny larvae, which look nothing like adult ladybirds. They still have 6 legs, but are long and black/brown, rather than brightly coloured, and do not have wings. Ladybird larvae go through 4 stages (known as instars), shedding their skin each time to become bigger and bigger. By the 3rd and 4th instar, many species have developed some colour pattern on them (not the same patterning as on the adult elytra), meaning we can start to know which species they are. The size of the larvae is in part determined by the amount of food they are able to eat, but also by the ladybird species. Most ladybird larvae will develop in 3-5 weeks from egg to pupa.
- Pupa: After the 4th instar, the ladybird will then transform into a pupa (similar to the chrysalis formed by a caterpillar before turning into a butterfly). Ladybird pupae attach to a leaf or fencepost by their back end, allowing them to flick/rear up if they are disturbed, which acts as protection against parasites. It can be tricky to identify which species a pupae belongs to, so it can be best to wait until they emerge as adults to identify them with confidence.
- Adult: The adult ladybird emerges from this pupa with very soft wing cases and is often very pale in colour. The ladybird will develop full colours and harden up in about 24 hours. Young adult ladybirds of 7-spot ladybirds (as well as other ladybirds with red colours) are often more of an orange/red which deepens to a dark blood red as the ladybird ages.
The 7-spot ladybird
- Main colour: light to dark red
- Spots: 3 black spots on each wing case, with one centrally spanning the top of both elytra
- Size: 5 to 8 mm long
- Where to find: nettles, brambles, gardens, apple trees, long grasses, hedgerows
- Why it's a 7-spot: it is the only adult ladybird to always have 7-spots that you are most likely to see.
Some common ladybirds
There are 47 species of ladybirds in the UK. 26 of these are brightly coloured, the rest are small and are dull in colour (known as inconspicuous ladybirds). The 2-spot and harlequin ladybird are two common ladybirds that can be confused with the 7-spot. For more information and downloadable resources relating to UK ladybirds visit www.ladybird-survey.org.
The 2-spot ladybird
- Main colour: light to dark red OR black
- Spots: commonly 2 black spots (one on each wing case) on red, OR 2 to 4 red spots on black coloured 2-spots
- Size: 4 to 5 mm long
- Where to find: trees, grass, gardens, often associated with urban areas
- Why it isn't a 7-spot: the 2-spot is generally much smaller than the 7-spot ladybird. The 7-spot will also never have a melanic (black) form, which the 2-spot does. The 2-spot ladybird will never have 7-spots.
The harlequin ladybird
- Main colour: orange to red (most common in the UK) OR black
- Spots: on orange/red, 0 to 21 black spots OR on black 2 to 4 red spots
- Size: 6 to 8 mm long
- Where to find: most commonly seen in urban areas in the South of England: gardens, trees, nettles, hedgerows, brambles.
- Why it isn't a 7-spot: The harlequin ladybird will never have 7-spots in the same pattern of 3 on each elytra and one in the middle between the two like the 7-spot. The harlequin ladybird is also not as domed side-on as the 7-spot ladybird. The harlequin is often recognisable by an M-shaped marking on their pronotum (black plate behind their head).
Rarely seen ladybirds
The scarce 7-spot and 5-spot ladybirds are very similar to the 7-spot but have specific habitats and are rare in the UK.
The scarce 7-spot ladybird
- Main colour: orange to red
- Spots: 5 to 11 black spots
- Size: 6 to 8 mm long
- Where to find: normally found associated with (and very rarely found away from) ant nests.
- Why it isn't a 7-spot: The scarce 7-spot is very similar in appearence to the 7-spot ladybird, however it is distinguishable from the 7-spot ladybird by its more domed shape and white marks below both its middle and front legs (which are absent below the front legs for 7-spot ladybirds).
The 5-spot ladybird
- Main colour: orange to red
- Spots: 5 to 9 black spots
- Size: 4 to 5 mm long
- Where to find: Found on shingle riverbanks, endangered in Britain but common in Europe.
- Why it isn't a 7-spot: The 5-spot ladybird is very habitat specific in th eUK, and is not found away from shingle river banks. It will never have the same pattern of spots (3 on each elytra and 1 between the elytra) as the 7-spot ladybird.
The Harlequin Invasion
The harlequin ladybird is a notorious invader, which is now present in many countries globally. It arrived in the UK in 2004, having been introduced into Europe and America as a way to control aphids on crops (and therefore limit the use of insecticides). Its introduction has now backfired due to the remarkable ability of this little ladybird to fly large distances, produce around 60 eggs a day during the summer and remain largely unaffected by the predators and parasites that affect native ladybirds.
All of these things mean that the harlequin can do better than other ladybirds. It has been suggested that the harlequin will impact 1000 species, this includes ladybirds, but also parasites and other aphid eating insects. This alien ladybird can also successfully eat a broad range of things, including other ladybirds and is toxic to any ladybird that tries to eat it.
The Dinocampus coccinellae wasp
A parasite is an organism that lives on or in another species (the host), from where it takes nutrients in order to survive, negativly impacting the host in return. The parasitic wasp Dinocampus coccinellae in turn attacks the 7-spot ladybird, laying an egg into the adult ladybird. Once the wasp has developed enough it spins a cocoon between the legs of the ladybird, using the host as a zombie bodyguards, as they protect the developing wasp from being eaten by any other predators.
These wasps are not like the big yellow and black wasps you see in your garden. They cannot sting you, but they do have a long egg laying tube (ovipositor) that they use to put a tiny egg inside a ladybird. It's favorite ladybird (or primary host) in the UK is the 7-spot ladybird (Coccinella sepempunctata). All Dinocampus wasps are female and are asexual (meaning they can reproduce without males).
The Dinocampus coccinellae Lifecycle
The adult wasp tracks down an adult ladybird with her antennae and uses her ovipositor (egg-laying tube) to lay an egg inside the ladybird.
The egg develops inside the ladybird, hatching into a grub, which then grows through 4 stages (instars), getting nutrients from inside the ladybird.
When the grub is in its 4th instar, it pushes out the back end of the ladybird and spins a silk cocoon between the legs of the ladybird, fixing it down to the surface it is on. The ladybird is now able to twitch and protect the wasp from being eaten, but rarely can it get away.
The wasp develops inside the cocoon, and, just like a caterpillar to a butterfly, transforms into an adult wasp. The wasp chews its way out of the end of the cocoon before flying off in search of a new ladybird. The Ladybird remains guarding the cocoon and is generally unable to ever get away.