The Harlequin ladybird (Harmonia axyridis), the world's most invasive ladybird, has been detected establishing in Auckland. The biosecurity staff of the Ministry for Primary Industries having been work hard to figure out how far it's already spread. Unfortunately, it's sounding like it's already beyond eradication. That would be bad news for NZ ladybirds as the Harlequin ladybird, an Asian native species, has reached high densities in Europe and North America and displaced their native ladybirds.

We urgently need all sightings of Harlequin ladybirds, and also all other ladybirds so we can assess whether the Harlequin out-competes out native ladybirds like it's done overseas. We've set up a project to do just that: NZ Ladybird Watch. Please join us in recording all the ladybirds we can find.

The Ministry for Primary Industries has produced a useful fact sheet on the Harlequin ladybird and its identification.

It can be confused with the similar looking Harmonia conformis ladybird. Here's what Auckland entomologist Stephen Thorpe (@stephen_thorpe) tells us about how to ID the Harlequin ladybird, Harmonia axyridis: "It is a very variable species (how variable in NZ, I don't know). It is conspicuously larger than the other Harmonia species in NZ. The pronotum is (usually) white, with a symmetrical median black pattern. The larvae have 4 yellow papillae forming a square on the abdomen." If in doubt, just post a photo here and entomologists like Stephen will help with the ID.

You can see all of the NatureWatch NZ observations of Harlequin ladybirds here. Below is a selection to help you know what to look out for.

A Harlequin ladybird in Auckland on 9 April 2016 observed by @jacqui4.

A Harlequin ladybird in Auckland on 19 May 2016 observed by @stephen_thorpe.

Another colour morph of Harlequin ladybird, found in Auckland on 22 May 2016 observed by @stephen_thorpe.

A pupa of Harlequin ladybird, found in Auckland on 22 May 2016 observed by @stephen_thorpe.

A larva of Harlequin ladybird, found in Auckland on 15 May 2016 observed by @stephen_thorpe.

There's a lot we still don't know about NZ ladybirds, and in particular we know very little about which species are on the increase and which are in decline. By joining us at NZ Ladybird Watch, you'll be helping us build up knowledge of ladybirds in New Zealand. And celebrating the natural history of these excellent beetles.

All you need to do is upload a photo of a ladybird to the project, either from the NatureWatch NZ website or the iNaturalist mobile app.

When you add your observations, you'll be asked to say "yes" or "no" to "I record every ladybird I see this month." Saying "no" means that you'd adding casual observations when you find a ladybird that's of interest to you. That's really good, as it will tell us what species are found where, at what times of the year, and doing what.

By saying "yes" to "I record every ladybird I see this month", this means that you're taking your devotion to ladybird watching to the next level. It means that we can safely assume that every ladybird you saw that month you added to the project. From everyone doing this we can see what proportion of the ladybirds in an area are different species. This would show us, for example, if an exotic ladybird was taking over from the local natives.

Saying "yes" to "I record every ladybird I see this month" also means that we can can assume that you saw no ladybirds every time and place in that month that you added other non-ladybird observations to NatureWatch NZ. For example, you might keep a look out for aphids, which many ladybirds like to eat, and upload photos of those. Or you might photograph something completely unrelated to ladybirds. Knowing where and when you didn't find ladybirds allows us to track which ladybird species are getting more common and which are in decline. That's something that's hard to do reliably with just casual observations.

If you're keen on ladybirds, you may also want to join the iNaturalist Ladybird beetles of the world project. Since NatureWatch NZ is part of iNaturalist, the same observations you add to our NZ Ladybird Watch can also be added to the Ladybird beetles of the world.