Scymnus suturalis

Pine Scymnus

Scymnus suturalis on Scots Pine, Rothbury, Northumberland
Scymnus suturalis on Scots Pine, Rothbury, Northumberland

Description

A rather tiny inconspicuous ladybird associated with conifers, Scymnus suturalis is brown in colour, ranging from a darker, nut-brown to a paler hazel. The best way to identify this species is to look for a dark central line running down the middle of the wing cases. This is darker than the surrounding base colour and can be almost black in some individuals.

Like many inconspicuous ladybirds, Scymnus suturalis lacks any discernable spots. It is also rather hairy giving a dull appearance when viewed up close. The pronotum, behind the head, is darker than the wing cases and the underside of the ladybird is entirely black.

Scymnus suturalis is not a particularly variable species, at least to the extent of Rhyzobius chrysomeloides or other smaller ladybirds. Generally, the only differences between individuals are the prominence of the black central line or the darkness of the elytra.

What does Scymnus suturalis eat?

This species feeds predominately on aphids and adelgids found on pine and other conifer species.

 Scymnus suturalis found by tapping conifers, Havannah Nature Reserve, Newcastle
Pine Scymnus found by tapping conifers, Havannah Nature Reserve, Newcastle

Habitat

Befitting its alternate name of ‘Pine Scymnus’, this species is a conifer specialist. It is found almost exclusively on pines, with a strong preference for our native Scots Pine (Pinus sylvestris). Finding this species in the heart of dense woodland can be difficult and to date, I’ve had more luck searching conifers growing within woodland edge habitats.

This species can also be frequent on scattered or isolated pines growing in open settings, including heathland. Likewise, where its preferred conifers are planted in isolation, this species readily turns up in urban areas.

Scymnus suturalis showing red-brown elytra, Rothbury, Northumberland
Scymnus suturalis showing red-brown elytra, Rothbury, Northumberland

How to find them

In my (limited) experience, this is one of the easiest inconspicuous ladybirds to find throughout the year. The best way to do so is to identify a suitable conifer and tap it using a net or sheet to catch what falls out. Often, good results can be had by searching the lower branches of pines without any need to exert yourself!

Owing to their small size, this can be a difficult species to find via visual searches. That said, they can occasionally be found this way if you have the patience for a protracted search.

Finding Scymnus suturalis in winter

While this species is said to overwinter among cracks in bark and among moss and lichen, I have had no luck whatsoever looking for it this way. Instead, most of those I have encountered in winter so far have been found by tapping branch tips where the species appears easy to find among the buds and cones.

Scymnus suturalis found by searching branch tips in winter, Havannah Nature Reserve, Newcastle
Scymnus suturalis found by searching branch tips in winter, Havannah Nature Reserve, Newcastle

Status in the UK

At the time of writing this, there are only 1,220 records of Scymnus suturalis held on NBN. This does not seem like many at all but contrasted with other inconspicuous ladybirds, makes this one of the more frequently encountered species across the UK.

Records of Pine Scymnus are widespread across the UK, with noticeable concentrations around London, Manchester and other spots such as Thetford. This would appear to depict the distribution of ladybird recorders, as opposed to ladybirds, with very few records in conifer-rich areas of Scotland and Northern England, for example. See NBN for more information.

Status in the North East

Looking at the distribution maps, this would appear to be a rare ladybird in the North East but in reality, is likely grievously under-recorded. Currently, there are very few records across Northumberland and County Durham,

I have recorded this species frequently across Tyneside and South Northumberland, usually wherever its preferred Scots Pine is present. It stands to reason that with a little more effort, local distribution maps for this species will change markedly.

Where I’ve recorded the Scymnus suturalis

To date, I have recorded this ladybird at several sites around Newcastle and within urban areas of North Tyneside.

James‘ records of Scymnus suturalis, July 2022