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Tuesday, 6 August 2024

Galling

Germander Speedwell Gall Midge (Jaapiella veronicae)
A number of the Germander Speedwell plants in the garden wear furry little caps these days – a clear sign that they've been attacked by the Germander Speedwell Gall Midge (Jaapiella veronicae). This tiny fly lays its eggs in the terminal bud of Germander Speedwell plants, or occasionally in the terminal buds of other species of speedwell. The presence of the eggs (one or two per plant) changes the development of those terminal leaves; they grow abnormally, becoming deformed, thickened and hairy. And they safely house one or two tiny, reddish-orange midge larvae. These galls are typically the only way most of us will ever know the midges are around. The flies themselves are so small that they're easy to overlook – a mere 2-3 mm (about 1/8-inch) in length. They are bright orange and stand on relatively long, stilt-like legs though, which might help in spotting them. The midge is common throughout the UK, found anywhere that Germander Speedwell grows.

Saturday, 3 August 2024

Six spots

Six-spot Burnet (Zygaena filipendulae)
While we sat working in the office the other day, Mike suddenly said "There's something red out there" and headed for the door. Sure enough, there was something red – a handsome Six-spot Burnet (Zygaena filipendulae), trundling around on Marjoram flowers near the sundial. This day-flying moth is the only burnet moth in the UK with six (rather than five or fewer) spots on its metallic green forewings. Those spots are a warning to potential predators that the moth is toxic; it's full of cyanide. Some of this comes from the food plants that the moth ate as a caterpillar. Preferred larval food plants, such as Common and Greater Bird's-foot Trefoils, are loaded with toxins which the caterpillars can safely metabolise for their own use. And if they can't get enough cyanide from their food sources, they can make their own! Such protection is so important to the moth's survival that males even present "nuptial gifts" of cyanide to females while mating; presumably, this helps to increase the survival rates of any resulting offspring. 

Six-spot Burnets are common and widespread across England, Wales and Ireland, but are mostly coastal in Scotland. Elsewhere, they range across much of Europe, and east into Lebanon and Syria. They flourish in grasslands (particularly those rich in flowers), and can be found from coastal cliffs and sand dunes to roadside verges, meadows and woodland clearings. Adults feed on scabious, knapweeds and thistles, all of which we have on the property; they clearly like Marjoram too. Caterpillars, when they're ready to pupate, build their cocoons high on grass stems. Hopefully our pocket meadow, with its bird's-foot trefoils and abundant grass stems for the caterpillars, plus various food plants for the adults, will prove appealing.