Saturday, April 4, 2009

Hebrew Character ( Orthosia gothica) and Common Quaker (Orthosia munda)

I am an amateur naturalist trying to identify everything that lives in my garden.

Photo 1 shows two more moths I caught (for the record, on 26th March) in my recently- constructed moth trap.

I didn't know the species of either at first but from my copy of Moths (Waring, Townsend and Lewington, British Wildlife Publishing) it's clear I've found (left) a Common Quaker (Orthosia cerasi) and (right) a Hebrew Character (Orthosia gothica).

I should easily identify them in future: the two, kidney-shaped wing spots of the Common Quaker and the black shapes on the wings of the Hebrew Character are very characteristic.

The Hebrew Character gets its name from the resemblance of its black wing markings to the letters (characters) of the Hebrew alphabet.

I was puzzled by the origin of the name 'Common Quaker' but then came across an article from the Times newspaper 2003, describing an interview with the naturalist Peter Marran. It seems that many of the common names for British moths were made up by members of the The Aurelian Society - one of world's first entomological societies, established in London in the 1760's. According to the article, Quaker's of the time wore (quotes) "subfusc attire" (i.e. dusky or drab clothes). This inspired the naming of not one but three British moths: The Powdered -, The Twin Spot- and (our moth here) The Common Quaker.

Adult of both the Hebrew Character and the Common Quaker feed on the nectar from sallow catkins whilst their caterpillars will eat a range of plants including Oak, Birch and Hawthorn.

An interesting feature of the Hebrew Character I learnt from reading Michael Majerus' book Moths (The New Naturalist Library) is that it displays high latitude melanism; In Northern Scotland, a form of the Hebrew Character - specifically Orthosia gothica f. gothicina - is found that lacks the black colour to the 'Hebrew letters' on its wings. Some other moths, notably the Scalloped Hazel and the Ingrailed Clay, also shows a distinct form at high latitudes. Why? Because, high latitudes impose some unique selective pressures on the moths that live there: firstly there may be issues of thermal regulation (having dark or pale wings will effect how easily a moth heats up or cools down); secondly the low angle of the sun creates softer lighting conditions that may mean birds can more easily pick out camouflage patterns that might work well elsewhere; thirdly, at high latitude in summer the sun does not set - a challenge for the camouflage of normally night flying moths. Low latitude moths that want to 'make the transition' to high latitudes are therefore faced with the need to adapt their colourings or suffer the consequences. A wonderful example of evolutionary change.


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Rev Philomena Cocks said...

Sir, your article is most enlightening but I am forced to protest at your brutish use of the precious colon. That monarch of punctuation must be employed with the most frugal parsimony for it to retain its proper potency. An amateur naturlist you may be: an expert on the colon you are not.
Your servant, Rev Philomena Cocks