Dene Park - as the weather turned!

After teaching and a bit of admin this afternoon I got up to Dene Park as the supposed last sun of this short Indian summer faded to give way to grey cloud and the threat of rain. There was quite a strong breeze as well, so I had little thought on insects or birds today. And so it turned out, although I did hear a buzzard, Buteo buteo, calling plaintively on the Western side of the woods.

I spent a bit of time as we went round scanning for the commoner galls mainly on the herbaceous plants but I also had a look on the hazel, oak, blackthorn and sallow.

One of the herbaceous plants I found was figwort, Scrophularia nodosa, now in full fruit. The fruit is a two celled capsule, slightly glossily dark and now splitting open, with even the hard dry sepals at the base of the fruit now discarded:

Figwort is really quite a common plant in woods and hedgerows, scattered and not very obvious in the undergrowth at the side of the path at first glance, but with flowers that are beautiful on close inspection, and notably square stems (although this is a characteristic of the family Scrophulariaceae in this case, and not indicative of membership of the Lamiaceae or dead nettle family). Scrophularia is in fact the type genus of the family, which also includes Buddleija, Mullein and Foxgloves, to mention a few.

The mine I first noticed on the figwort is probably Amauromyza verbasci (Bouche, 1847), a common Dipteran mine on Buddleija, Verbascum and Scrophularia as far north as the Midlands. It is a variable blotch mine, starting off sinouous at first, then a large patch of a mine, with pupation occurring outside the mine and the large frass grains noted to be left well dispersed throughout the mine, as shown here.

This is one of the few mines supposed to be found on Scrophularia, but here is a picture of one that doesn't seem to be covered by the on-line web-site I normally consult - it looks a bit like a Phyllonorycter in its general size and shape between two veins, however I suppose it could just be another example of Amauromyza.

There were a lot of creeping buttercup, Ranunculus repens, leaves visible alongside the track. The leaves were looking particularly fresh (there has been a little rain, and a lot of dew!) and I even saw one flower out, looking a beautiful fresh golden yellow, but with an extra small petal added on the normal five. This extra petal is certainly not an unknown phenomenon, and may be induced perhaps by unfavourable conditions such as the current cooler temperatures or even possibly the shorter days.

On many of the leaves of the numerous buttercup plants there were coarse white spots. These looked coarser (larger) than the white spots normally caused by leaf-hoppers, and reminded me of the feeding marks caused by certain species of fly adults, members of the Agromyzidae group, whose larvae cause annoying serpentine mines in the leaves of cultivated chrysanthemums. And there were at least some, although not many, serpentine mines in the leaves of these buttercups! Other leaf mines in the Agromyzidae group could be blotch shaped, rather than serpentine.

There are several species of Phytomyza, a genus of fly known to be associated with larval serpentine mines, found on buttercup leaves. The commonest appears to be Phytomyza ranunculi, and pictures of these leafmines on the internet, do indeed look similar to my sightings, with the expected feeding marks shown as well. So, I think this is the most likely identification, of both the mines and the very numerous feeding marks, abundant throughout the woods. However there are perhaps other possibilities, and my photographs were too fuzzy to show the detail of the tunnel's contents required to absolutely separate the species! In particular Phytomyza ranunculivora is similar-looking so is a possible alternative ID, although it hasn't been found in R. repens in the UK as yet. However on the balance of probability, I am reasonably sure that its Phytomyza ranunculi!

There was also evidence of mining on the hogweed, Heracleum sphondylium, leaves, and I think this might possibly be Phytomyza spondylii, quite common throughout the UK. However I'm not considering this ID anywhere near as certain as the one above! One factor that has been difficult to determine is the scale of the mine in the picture in relation to the size of the suspected species.

This is another picture, but the scale and dimensions of the mine might seem different?

There were also some possible viral symptoms on some of the hogweed leaves, which might be classified as "speckly vein clearing" perhaps?

Agromyzid-like feeding marks were also seen on Hedge Woundwort, Stachys sylvatica, Selfheal, Prunella vulgaris, and a Speedwell, a Veronica species, but no associated larva mines were noticed in the limited time available.

These very different feeding marks on the leaflets of Bramble, Rubus species look very much like feeding damage by capsid bugs, which are often referred to as "cigarette burns" because of the brown edged raggedy holes, caused by the poisonous saliva released from the bugs' stylets as they are feeding. All three leaflets of this one leaf were very heavily damaged. Odd though that this damage should be so concentrated on these particular leaflets, but not noticed on any others?

On a hazel, Corylus avellana, by the Scambles at the far side of the wood, there was a folded-over leaf edge, which when opened revealed a small caterpillar, which I think must have been a Tortricoid type caterpillar, related to, or in, the genus Tortrix, typically web-spinners and leaf-rollers.

Overall of course the woods are continuing to look more and more autumnal day by day, with the seedheads of willowherb, Epilobium, ready to disperse their seeds all along the sides of the tracks...

...and the heads of Common Knapweeds, Centaurea nigra scattered around, with their delicately sculptured two layers of scaly bracts: