Wednesday, May 26, 2010

The Blue Ray Limpet

The Blue Ray Limpet, Patella pellucida

The blue ray limpet, Patella pellucida, is named after the striking iridescent blue lines that radiate on the top of the shell. This shimmering, seemingly ephemeral colour is due to diffraction of light by the reflection grating structure of the P. pellucida shell (Shigley and Hurwit, 1999 Optics Express 4 pp. 177-182). This diffraction is common to all molluscan shells but is dependent on the groove density and the surface quality of the shell and is therefore not always visible.

The Blue Ray Limpet, Patella pellucida

P. pellucida is a herbivorous, grazing on Laminaria spp. in the low tide zone. The larvae graze firstly on encrusting corraline algae, later migrating to Laminaria (Kitching, 1987 Advances in Ecological Research 17 pp. 115-186). It is known from the fossil record from the Pliocene era to Recent (Marques da Silva et al., 2006 Palaeogeography, Palaeoclimatology, Palaeoecology 233 pp. 225– 234).

Tuesday, May 25, 2010

The Metal Lover Immortalised in Brass

Thrift, Armeria maritima

Thrift or Sea Pink (Armeria maritima) is a common perennial of cliffs, salt marshes and sandy places as well as inland mountains where its pompoms of pink to purple flowers emerge from April to August. Taxonomically it is a difficult species to put a pin in. Variation in character from one site to another can often be mistaken for seperate taxa (Lauranson et al., 1995 Biochemical Systematics and Ecology 23 pp. 319-329), making it quite a polymorphic species. It shows quite a high tolerance for heavy metal rich soils (Olko et al., 2008 Ecotoxicology and Environmental Safety 69 pp. 209–218) and is recognised as an indicator of copper mineralization. This tolerance of copper rich soils is caused by a combination of morphological and biochemical mechanisms (Neumann et al., 1995 Journal of Plant Physiology 149 pp. 704–717).

1942 Three Penny Coin Showing Thrift Plant, Armeria maritima

It is therefore rather fitting that A. maritima is forever remembered in brass. The threepenny coin issued in Britain during the reign of George VI shows Thrift on the reverse side, a design modified by Percy Metcalfe after sketches by Frances Kitchener. The design bearing the flower on a twelve sided, nickle-brass coin was originally introduced for Edward the VIII in 1937, intending to replace the much smaller silver threepenny coin. Upon his abdication the design was retained for his brother's coinage, being minted (except 1947) from 1937 to his death in 1952 (Leatherhead & District Local History Society Proceedings 2000, Vol 6 No 4 p. 78).

Thursday, May 20, 2010

Most Ancient Among Moths

Micropteryx calthella

The genus Micropteryx belongs to the family of moths Micropterigidae and is one of Irelands oldest Lepidopterans. They have a fossil record from the early Cretaceous (125 million years ago), where individuals recognisable as modern genera are preserved in Lebanese amber (Whalley, 1977 Nature 266 pp. 526). Micropterigidae are scattered world wide, with a concentration of species in the South-West Pacific, and more than half of Micropteryx sepcies found in the Paleartic region (Gibbs, 1983 Geo Journal 7, pp. 505–510).

They are small (c. 5 mm), colourful individuals with metallic sheens of bronze or purple and yellow forewings and are morphologically quite similar to the Lepidopteran sister group the caddisflies (Trichoptera). They are active during the day when they feed on pollen of plants with simple flowers (Schwartz-Tzachor et al., 2006 Flora 201 pp. 370–373), primitive angiosperms (e.g. Zygogynum Baillonii) sedges and fern spores (Thien et al., 1985 Science 227 pp. 540–543). Their ability to feed on pollen is due to their retention of functional mandibles (Powell, 2009, Encyclopedia of Insects (Second Edition) pp. 559-587). Other Lepidopterans either use a probiscus to feed on nectar or lack functional mouth parts and do not feed as adults.

There are four species of Micropterigidae (Ferriss et al. (ed.), 2009 Irish Biodiversity: a Taxonomic Inventory of Fauna), all of the genus Micropteryx, to be found in Ireland. The species pictured is Micropteryx calthella and is often to be seen feeding in the flower parts of the creeping buttercup, Rannunculus repens.

Tuesday, May 18, 2010

Novel Control of the Forest Bug

The Forest Bug, Pentatoma rufipes

The Forest Bug, Pentatoma rufipes, is a pest of nut and fruit trees, particularly hazelnut (AliNiazee, 1998 Annual Review of Entomology 43 pp. 395-419), where its feeding reduces vigor in the plants and facilitates the spread of disease. This is due to the feeding method of P. rufipes, a piercing and sucking motion that removes sap from the host that is characteristic of the Hemiptera.

Control of this pest is currently reliant on insecticides such as cabosulfan. However this particular pesticide has been shown to have mutagenic properties (Giri et al., 2002 Mutation Research 519 pp. 75–82) while others can destroy relationships in a community by affecting non target organisms (Elzen, 2001 Journal of Economic Entomology 94 pp. 55-59).

Neupert et al. (2009, Peptides 30 pp. 483–488) propose an intriguing alternative. Neuropeptides that mimic those in P. rufipes could be synthesised with the aim of disrupting the organisms reproductive success. Key to this strategy is further study of the P. rufipes peptide sequence, or peptidome.

To this end, Neupert's study isolated products of two previously unobserved neuropeptide genes (allatotropin-related peptide and tachykinin-related peptides) using MALDI ToF mass spectrometry from the ventral nerve chord and antennal lobes respectively.

Tuesday, May 11, 2010

Bryzoans, Past and Present

Four colonies of a marine bryzoan on Laminaria

Sea mats, ectoprocts or bryzoans are to be found all along the Irish coast, most commonly seen as skeletal remains attached to Laminaria washed up on the midshore line. This mineralized skeleton consists of an extracellular secretion of calcium carbonate crystals set in an organic matrix. There are clear similarities between bryozoan skeletons with the shells of brachiopods and molluscs in the calcareous composition of the skeleton, the morphology of the crystallites, and the mode of secretion (Taylor, 2005 Encyclopedia of Geology pp. 310-321).

The earliest known bryozoans are reported in the Paltodus deltifer Conodont Zone of late Tremadocian age (487 – 478 million years ago) (Zhang et al., 2009 Palaeoworld 18 pp. 67–73). All three classes of bryzoans are represented in Ireland; the marine classes Stenolaemata, with 27 species, and Gymnolaemata, with 171 species, and the freshwater Phylactolaemata, with 8 species (Ferriss et al. (ed.), 2009 Irish Biodiversity: a Taxonomic Inventory of Fauna).

The specimens pictured were both found on the same seashore but are separated by millennia.

A Fenestrate fossil bryozoan in limestone

Friday, May 7, 2010

The Lesser Periwinkle

A guest post by Ken.

During a short walk in Knaresborough, in North Yorkshire, I discovered a wonderful looking plant. It was the Lesser Periwinkle (Vinca minor). This plant is a member of the periwinkle family Apocynaceae, which are creeping woody shrubs with opposite, evergreen, oval untoothed leaves and have corollas with 5 spreading lobes, twisted in bud. The other member of the family is the Greater Periwinkle (V. major) and although very similar to V. minor, the calyx-teeth on the Greater Periwinkle are hairy and the leaves are oval rather than lanceolate. (Rose, Francis et. al. The Wild Flower Key; Revised edition, 2006, p.352).

The Lesser Periwinkle - Vinca minor

The alkaloid vincamine from this Lesser Periwinkle is used in the production of the synthetic compound vinpocetine. This is a potent neuroprotective agent. It is used in neurological practice, particularly in cerebrovascular diseases such as ischemic stroke. The drugs main pharmacological and physiological actions are not fully understood. Recent studies have shown that Vinpocetine contributes to a regional redistribution of cerebral blood flow in such a way that relatively more blood reaches the brain structures which show a high uptake of radiolabelled vinpocetine. The chemical can also regionally modify the utilisation of glucose in the brain and this effect is more pronounced in the affected hemisphere. These effects of vinpocetine suggest that, through direct CNS effects, the drug can usefully contribute to the restoration of physiological conditions in stroke patients. (Geza Szilagyi, Zoltan Nagy, Laszlo Balkay, Istvan Boros, Miklos Emri, Szabolcs Lehel, Terez Marian, Tamas Molnar, Szabolcs Szakall, Lajos Tron, Daniel Bereczki, Laszlo Csiba, Istvan Fekete, Levente Kerenyi, Laszlo Galuska, Jozsef Varga, Peter Bonoczk, Adam Vas, Balazs Gulyas, Effects of vinpocetine on the redistribution of cerebral blood flow and glucose metabolism in chronic ischemic stroke patients: a PET study, Journal of the Neurological Sciences, Volumes 229-230, Vascular Dementia, 15 March 2005, Pages 275-284).

One did a spot of rowing that day too. Icelandic volcanic ash clouds prevented me from flying. Still, at least I got to see another beautiful plant.