After the wet (part 2)

Having recently raised a Bright-line Brown-eye moth Lacanobia oleracea from a pupa rescued from our storm-damaged fence panels, this morning I awoke to find another new arrival in the hatchery, a Brimstone moth Opisthograptis luteolata - not to be confused with the Brimstone butterfly Gonepteryx rhamni.

Brimstone moth Opisthograptis luteolata.

This species feeds on a range of shrubs and small trees - although none of its more common host plants grow in our garden, there are plenty nearby and the overlapping fence-panels must have provided effective overwintering shelter until it blew down. Adults are usually found from April to October so this one was only a few days early.

Portrait of the Brimstone moth Opisthograptis luteolata.

Empty cocoon and pupal case of Opisthograptis luteolata.The pupa was inside the cocoon which is usually a rounded elliptical/oval shape - here it is squared off and has flat sides due to being formed between flat fence panels.

Blisters in the dry

As spring has indiced some rapid plant growth, I was doing some weeding in our small gravel/alpine garden, including pulling a few unwanted hairy bitter-cress Cardamine hirsuta that were bullying my less-aggressive plants. During this, I noticed some white blisterlike structures on the underside of many of the leaves - not leaf-mines, but something more fungal. A quick look in Ellis & Ellis (1997) told me it was, as I suspected, the 'brassica white rust' Albugo candida.

Albugo candida on Cardamine hirsuta

Close-up of A. candida on C. hirsuta - the widest part of the leaf here = 6.5mm. The leaf margin also shows some small bristles - despite the common and scientific names, C. hirsuta isn't very hairy, or hirsuite.

C. hirsuta is very similar to wavy bitter-cress C. flexuosa but the flowers only have 4 stamens (6 in C. flexuosa) and C. hirsuta tends to be found in drier locations. In this case the plant identification isn't hugely important as A. candida is found on a range of Brassicaceae, but many microfungi have a more specialised and narrow relationship with their host plant/s so (as with galls and leaf miners) it is usually essential to identify the plant.

C. hirsuta flower with 4 stamens.

Although A. candida is generally called a fungus or microfungus, technically it is a fungus-like 'water mould', one of a group of plant pathogens in the class Oomycetes of the phylum Heterokontophyta within the kingdom Chromalveolata (i.e. not the kingdom Fungi). The taxonomy is still a matter of debate (there are several competing versions and research is ongoing) but they are more closely related to photosynthetic organisms such as brown algae and diatoms. The class also includes some serious plant diseases such as late potato blight (Phytophthora infestans, cause - socio-economic factors aside - of the Irish potato famine of the 1840s) and sudden oak death (P. ramorum).

Reference

Ellis, M.B. & Ellis, J.P. (1997). Microfungi on Land Plants: An Identification Handbook (2nd ed.). Richmond, Slough.

After the wet

It seems that our several months of almost incessant rain has finally come to an end, and spring is happening. Although I expect that some species will have suffered due to flooding (water vole burrows, soil-hibernating invertebrates...), some are starting to appear. So here's a quick non-technical introduction to a couple of garden-dwelling moths that have made themselves known to me recently.

A mature larva of the Old Lady moth Mormo maura. Note the bright orange spiracles along the side, and the black marks in the rear half. Approx 60mm long.

Head of larva of Mormo maura - note the shiny, speckled head capsule with ocelli (simple eyes) and small antennae

M. maura is a common species and I have previously seen adults in our garden, including one roosting in a shed. Ivy (Hedera helix) is one of its main food plants and we have plenty of that so it is not a surprise to see this species.

A couple of months ago, a series of storms destroyed many garden fences (not to mention causing widespread flooding) in the UK and while clearing up the debris, I found several pupae that had been dislodged. Most were put in our 'bug hotel' but a few were taken indoors to be hatched. One of these emerged a couple of days ago and proved to another common species, the Bright-line Brown-eye Lacanobia oleracea. It feeds on a wide range of woody and herbaceous plants and again is no surprise, but did provide some photo opportunities prior to release.

L. oleracea - the bright line is along the rear edge of the wings, the brown eye refers to the kidney-spots in this species.

Close-up of the wings showing the scale-patterns.

Side view showing the hairy and tufted thorax.

Portrait!