Iris Sawfly

There are more than 500 species of sawfly in the UK, which usually feed only on their preferred host plants. You will see iris sawfly (Rhadinoceraea micans) on waterside irises like the yellow flag irises at the QEII pond, though the larvae can eat rushes too.

The adults emerge in Spring after overwintering in the soil as pupae. They are black and hairy, about 8mm long, and have smoky grey wings (though they don’t fly much).

In April and May, a female will lay her eggs inside the base of an iris leaf near the thicker middle, cutting a slit with the tiny saw on her ovipositor. The larvae, which hatch in late May and June, grow to around 25mm.

The larvae are browny-grey with black heads and white spots along their bodies. Munching first on the edges of the leaves, in a group

 they can devour whole leaves, but the plants will recover next year.

Come July and they will crawl into the ground and make their cocoons to stay safe until next year.

Links to further information and images

Royal Horticultural Society

Naturespot 

 

 

 

Red Campion

The Summer Woods by Mary Hewitt (1866)

….. I cannot tell you half the sights

Of beauty you may see, 

The bursts of golden sunshine, 

And many a shady tree.

 

There, lightly swung, in bowery glades

The honeysuckles twine; 

There blooms the rose-red campion, 

And the dark-blue columbine.

Seeds of the perennial (or biennial) were sown at the QEII Nature Reserve, and are coming into flower this month. These plants are already growing tall, over 50cm, and will stay in bloom for ages, until October. Each flower has five deeply-notched, pink petals that emerge from a pot-like calyx.

The scientific name is Silene dioica; the species name, dioica, means that male (on the left in the images below) and female flowers (on the right) are on separate plants.

The female flowers are a bit sticky so that they capture the pollen from visiting insects, and this is what the genus name, Silene, refers to, the sticky foam.

 

The stems and leaves are hairy and slightly tacky too, which is why the plant is sometimes called ‘red catchfly’, but the gluey hairs are really there to stop ants and other insects crawling up to steal nectar and pollen. All the more then for the welcome pollinators, the bees, butterflies (like Brimstones, Green-veined Whites and Orange-tips), hoverflies and moths. Campion and Lychnis moths lay their eggs in the flower heads, the caterpillars eventually feeding on the ripening seeds.

The plant is a source of natural soap, saponin. Maybe this helps in forming the flowers’ frothy pollen traps? Traditionally, the root, which has lots of saponin, was simmered in water and the soapy extract used for washing clothes.

Links to further information and images

Woodland Trust

Bug Woman – Adventures in London

Organic roofs