Wednesday, March 16, 2011

Death of the Tadpole

Common Frog Tadpoles, Rana temporaria
It is the time of year for spawning by the Common Frog, Rana temporaria. Through out Ireland eggs are being laid that will become frogs in about 16 weeks time. However, making its way there is a tough journey for R. temporaria. Many are taken, as food by birds and large fish while some, like a large number of tadpoles I spotted recently, may not even make it that far. I discovered a large number of recently hatched (only about 7 days old) R. temporaria tadpoles in a large amount of mucus that must have been the remains of the egg casings alongside a marsh pond.
Dead Tadpole and Egg-Mass
The tadpoles were a good two feet away from the water and may have been laid during recent heavy rains. However there has been little such rain in the past few days that must have lead to water levels dropping, stranding the egg masses. When I discovered them, ice was present on their surface from the previous night, probably speeding their death.
Common Frog Tadpoles, Rana temporaria
Tadpoles of R. temporaria are quite resilient, so it was a shame to find so many of them ending up like this. Loman (1) has shown that stress on tadpoles, such as drying of habitats leads to an early metamorphosis. Such an adaptive response as this means the stresses on the tadpoles must have been severe.
Common Frog Tadpoles, Rana temporaria
In Ireland R. temporaria was considered a recent introduction, possible from Norman time c. 1000 years ago (2). This was due to the lack of archaeological evidence to support its arrival by natural colonisation. However, a phylogeographic study of R. temporaria in Europe published in 2009 (3) provided evidence that the Common Frog is native to Ireland, having survived the most recent glaciation periods to affect the country, possibly in a refuge in the South West of the country. Many of the frog haplotypes from Ireland were monophyletic groups that are unique to the country. Other groups were found that are more closely related to those found in the west of continental Europe and it is thought that these were introduced by human actions (or possibly across a land bridge with Britain). In fact Smith (4) states that in 1696 a Fellow of Trinity College Dublin moving common frogs from England to Dublin.

  1.   Loman 1999, Amphibia-Reptilia 20 pp. 421-430
  2.   Sterry 2004, Collins Complete Guide to Irish Wildlife p. 94
  3.   Teacher et al. 2009, Heredity 102 pp. 490–496
  4.   Smith 1964, The British Amphibians and Reptiles 3rd edn.

Monday, March 14, 2011

Anti-HIV Drugs from King Alfred's Cakes

King Alfred the Great has a lot to answer for. Bothering those poor Danes for one, when all they had in mind was a bit of pillaging. And improving the literacy of the Anglo Saxons for another. One point point where he is undoubtedly blameless though is the legend of him burning some poor woman's cakes. The story goes while fleeing Vikings, he took refuge in the house of cowherd. His wife bade him watch over bread she had cooking on the hearth, but the king was preoccupied with other things and allowed the cakes to burn. While this story dates from 300 years after his reign (1) and is therefore dubious to say the least, it does lend a picaresque name to the fungus Daldinia concentrica: King Alfred's Cakes.
King Alfred's Cakes, Daldinia concentrica
One look at this inedible ascomycete is enough to understand where the name comes from. Its shiny black, tough looking outer surface is suprisingly brittle, showing concentric rings from previous years' growth in cross section (2). It can be seen all year round on dead and dying tree braches, Ash in particular (although in some areas, such as Scotland it is found more on birch(3)), growing up to 5 cm in diameter.
King Alfred's Cakes, Daldinia concentrica
D. concentrica has proved itself rich in unique secondary metabolites (4). In one study alone, Quang et al. (5) discovered four new compunds as well as isolating eleven known compounds. One of the more intriguing metabolites produced by the fungus is a lactone called Concentricolide, first isolated in 2006 (6). This was shown to have anti-HIV-1 properties by blocking binding of infected T helper cells with healthy cells, preventing the killing of the healthy cells. This significant inhibitory effect on the cytopathy caused by HIV-1 is very promising and the recent synthesis of Concentricolide (7) as well as an approved patent (8) for its use bodes well for its role in treating this disease.

  1. Smyth 1995, King Alfred the Great
  2. Sterry 2004, Collins Complete Guide to Irish Wildlife p. 288
  3. Whalley and Watling 1982, Transactions of the British Mycological Society 78 pp. 47-53
  4. Qin et al. 2006, Helvetica Chimica Acta 89 pp. 450-455
  5. Quang et al. 2002, Journal of Natural Products 65 pp. 1869-1874
  6. Qin et al. 2006, Helvetica Chimica Acta 89 pp. 127-133
  7. Fang and Liu 2009, Heterocycles 78 pp. 2107-2113
  8. Liu et al. 2010, Kunming Institute of Botany, Concentricolide and its Derivatives, Process for Preparing Them, Pharmaceutical Composition Comprising the Same and its Use, Patent Number US 7,659,308 B2

Thursday, March 10, 2011

The First Record of the Red Lily Beetle in the Republic of Ireland?

Red Lili Beetle, Liloceris lilii
During a recent gardening spurt in Cork City, I discovered a red beetle, slowly making its way across the disturbed soil. Thinking it was a nice example of a Cardinal Beetle, I took a few photos and set the little chap on his way. However, later on when I viewed the photos in more detail, I realised it was not the a Cardinal Beetle at all: the elytra were too round and shiny. It turned out that I had happened upon a Red Lily Beetle (Liloceris lilii). This was not surprising at first as the bed in which I found the beetle had some of its favourite food of lilies growing in it.
And yet it was surprising in another way because (as far as I can make out) there has been no recorded sighting of L. lilii in the Republic of Ireland. Anderson (1) states that the first recorded sighting of L. lilii on the island of Ireland was in a garden in Belfast in 2002. Furthermore, he states on the website (2) that no recorded sightings of L. lilii in the Republic exist, however it is more than likely to be present.
L. lilii is distributed throughout Europe where it feeds on lilies and fritillaries, often doing considerable damage, especially in Britain and Holland (3). Overwintering adults emerge from overwintering to feed on emergent lilies. Eggs are layed on the underside of leaves in April, with larvae pupating to emerge in early summer when they too feed on lilies.

  1. Anderson and Bell 2002, Coleopterist 11 p. 90
  3. Kenis et al. 2003 1st International Symposium on Biological Control of Arthropods 1pp. 416-419