Sunday, 27 May 2018

Decline and deceit …

Lapwing (Vanellus vanellus)


Also known as the Peewit in imitation of its display calls, its more familiar vernacular name describes its wavering flight. Its black and white appearance and somewhat round-winged shape in flight make it distinctive; even without seeing its splendid crest and beautiful dark green, purple and copper plumage. This once familiar farmland bird has suffered significant declines and is now a Red List species - with changes in farming practices being the main cause of this decline. Targeted conservation work on individual farms in my home county of Sussex have brought notable increases in breeding pairs, but there are not enough of these intensive schemes to make a difference at a landscape and population scale. Success on many nature reserves is at best patchy and any recovery, if it happens, looks likely to be slow.

The above image was taken in the Outer Hebrides in May 2017.

References:

Barfield, C., 2014. Lapwing. The Birds of Sussex. Thetford: British Trust for Ornithology (BTO) Books on behalf of the Sussex Ornithological Society, pp. 243-245.
Pepper, R.T., 1996. Lapwing. Birds of Sussex. Sussex Ornithological Society, pp. 244-246.

Monday, 14 May 2018

Genetic engineering ...

Wood White (Leptidea sinapis)

A pair of L. sinapis (male above) exhibiting courtship behaviour.


Uncovering cryptic biodiversity is essential for understanding evolutionary processes and patterns of ecosystem functioning, as well as for nature conservation. European butterflies are arguably the best-studied group of invertebrates in the world. The discovery, some twenty years ago, of a cryptic species within the Wood White, L. sinapis, was a significant event and, since then, these butterflies have become a model to study speciation. Cryptic species are not separable based on their external morphology but can often be distinguished by dissection of the male and / or female genitalia. In addition, genetic data also supports species level separation.

In the 1940s Williams investigated the identity of the Irish Wood White L. sinapis. From looking at subtle differences between voucher specimens, he came to the conclusion that Irish examples were distinct from those found on mainland Britain and, as such, proposed that the Irish butterfly should be given the status of subspecies, which he named juvernica.

Across Europe, seven species of Leptidea have now been described: sinapisrealijuvernicaduponcheliamurensismorsei and lactea. The last three are essentially Asian species but duponcheli, a butterfly of Eastern Europe and Asia Minor, is found very locally as far west as the South of France. L. sinapis appears quite widespread on the continent as well as occurring in both Britain and Ireland. In the 1970s and 1980s Réali, and later Lorković, undertook research involving dissections of sinapis. They concluded that sinapis was not a single species but was really two cryptic species. Both species looked identical to the naked eye, did not interbreed and only upon dissection of their genitalia were they found to be separable. The new species was named Leptidea reali, Réal’s Wood White.

More recent investigations of museum specimens by Spanish and Russian lepidopterists (Dincă and colleagues) have thrown further light on the identity and distributions of the Wood Whites across Europe, using techniques based on chromosome counts and DNA analysis. Their conclusions are that reali is not in fact a single species but is itself made up of two distinct species - now named reali and juvernica. They are separate entities from sinapis. Therefore, with the benefit of access to museum specimens, what was previously thought to be a single species of Wood White is, in fact, three species - sinapis, reali and juvernica. The Cryptic Wood White, juvernica, is found across Ireland with the exception of the Burren. Current evidence suggests that there is no overlap in distribution between sinapis and juvernica; sinapis being confined to areas of the Burren limestone district in Clare and southeast Galway in the west of Ireland.

More at:

Dincă, V., Lukhtanov, V.A., Talavera, G. and Vila, R. (2011). Unexpected layers of cryptic diversity in wood white Leptidea butterflies. Nature Communications, 2, p. 324, DOI: 10.1038/ncomms1329.
Sachanowicz, K., Wower, A. and Buszko, J. (2011). Past and present distribution of the cryptic species Leptidea sinapis and L. reali (Lepidoptera: Pieridae) in Poland and its implications for the conservation of these butterflies. European Journal of Entomology, 108, pp. 235-242.

Wednesday, 11 April 2018

A case of mistaken identity …

Common argus / Brown blue !!!






When out and about I often hear comment from inexperienced observers on the difficulty in separating the Brown Argus Aricia agestis (Lepidoptera: Lycaenidae) from the ‘brown’ form of the female Common Blue Polyommatus icarus (Lepidoptera: Lycaenidae) in both field and photographic situations.

The blue present in female P. icarus is highly variable, with individuals ranging from almost completely blue through to almost, though extremely rarely, completely brown. In icarus some degree of blue scaling is typically present on the body, around the bases of the wings, and along the hindwing margins. It is this ‘brown’ form that causes the most confusion. A. agestis has no blue scales but may, in certain light, give off a bluish-green sheen from the upperside of its wings and the hairs found on the thorax and abdomen. Upperside diagnostic features include (i) the prominent dark discoidal spot normally found in the centre of the forewings of agestis, which, if visible, is usually much reduced in icarus, (ii) typically strongly marked orange lunules along the wing edges in agestis, and (iii), the outer margin fringes of the wings which generally appear as a light two-tone fringe in icarus typically appearing more whitish in agestis. A small dark extension of the venation into the border fringe is also characteristically present in agestis and, where present in icarus, typically much reduced.

Differentiating icarus and agestis from their undersides can be more problematic and here we need to resort to the pattern of spots. We have two main distinguishing features and a third less obvious. These are (i) icarus has a spot on the underside of the forewing that is absent in agestis, though this is not always visible if the wings are not fully open, and (ii), two of the spots on the leading edge of the hindwing are relatively-close in agestis, almost forming a figure of eight, but are more spaced apart in icarus. This second feature is particularly useful if the full underside of the forewing isn't visible. A third guide to determination, as per the upperside, is that the outer margin fringes of the wings which generally appear as a light two-tone fringe in icarus typically appear whitish in agestis; the small dark extension of the venation in agestis is also typically present.

Finally, and one mistake that many people make, is jumping to conclusions and thinking they have a brown ‘female’ icarus without first checking the abdominal length and form. If the specimen clearly shows an abdominal structure that is male, long and slender and extending just beyond the wing margin, as opposed to being more rounded and pointed in form and typically not extending beyond the hindwing margin, then it can’t possibly be a ‘brown’ female icarus.

The above images (top to bottom) show (i) a female agestis upperside, (ii) a female ‘brown’ icarus upperside, (iii) a strongly blue form female icarus, (iv) female agestis underside, and (v), a female icarus underside.

More at:

Tuesday, 27 February 2018

Getting your eye in …

Alder Goblet (Ciboria caucus)




Found solitary or in small groups on the fallen male catkins of the Common Alder Alnus glutinosa or willows, C. caucus is a widespread species though one that is easily overlooked due to its small size and wet habitat.

References:

Phillips, R. (2006). Mushrooms. London: Pan Macmillan, p. 369, fig. f.
Sterry, P. and Hughes. B. (2009). Collins Complete Guide to British Mushrooms and Toadstools. London: HarperCollins, p. 326, fig. p. 327.

Wednesday, 21 February 2018

Auricularia ...

Jelly Ear (Auricularia auricula-judae)


The gelatinous and often ear-shaped A. auricula-judae (Auriculariales: Auriculariaceae) is a widespread and common species. It can be found on living or dead branches of a wide variety of hardwoods but especially those of Sambucus nigra, the Black Elder. The above example, one of a small group, was recently photographed at Ebernoe Common in West Sussex.

References:

Buczacki, S., Shields, C. and Ovenden, D. (2012). Collins Fungi Guide: The most complete field guide to the mushrooms and toadstools of Britain & Ireland. London: HarperCollins, p. 592, fig. p. 595.
Kibby, G. (2017). Mushrooms and Toadstools of Great Britain & Europe, Volume 1, pp. 100-101.
O’Reilly, P. (2016). Fascinated by Fungi – exploring the majesty and mystery, facts and fantasy of the quirkiest kingdom on earth. Llandysul: First Nature, p. 298.
Sterry, P. and Hughes. B. (2009). Collins Complete Guide to British Mushrooms and Toadstools. London: HarperCollins, p. 290, fig. p. 291.

Sunday, 18 February 2018

Signs of spring …

Spring Hazelcup (Encoelia furfuracea)




Although widespread, E. furfuracea (Helotiales: Sclerotiniaceae) is generally regarded as an uncommon find in Britain. This irregularly shaped cup fungus can be found during the winter and spring. Typically clustered in small groups on the dead wood of Common Hazel Corylus avellana it has occasionally been recorded on Common Alder Alnus glutinosa.

References:

Sterry, P. and Hughes. B. (2009). Collins Complete Guide to British Mushrooms and Toadstools. London: HarperCollins, p. 308, fig. p. 309.

Wednesday, 14 February 2018

Little brown jobs …

Cortinarius pratensis




There are just fourteen records for Cortinarius pratensis currently listed on the FRDBI database [February, 2018]. The above specimens were located in a West Sussex sand dune system during a detailed search of the area in December 2017. My thanks to Nick Aplin of the Sussex Fungus Group for confirming their identification. It’s a fairly nondescript brown toadstool but certainly one to look out for if you enjoy little brown jobs …

References:

Edwards, A. and Leech, T. (2017). Evidence for an interesting association between Cortinarius pratensis (Section Dermocybe) and Sand Sedge, Carex arenaria. Field Mycology, 18(3), pp. 78-81.