Keep an eye out for Holly Blue, an April speciality
THE spell of dry, mild, settled weather that we enjoyed last week brought some relief to these strange times of confinement that we are living in. The fine weather saw many people avail of the welcome opportunity to get out of the house and to tend whatever gardens they are lucky enough to have.
Those who were out of doors, obeying, of course, the essential recommendation to stay within the confines of their properties, cannot have failed to notice that butterflies are on the wing again.
Some Small Tortoiseshells and the stunningly colourful Peacocks were out earlier this year, but the month of April brought a rise in numbers and the emergence of other species such as Holly Blue, Orange Tip, Green-veined White and Speckled Wood.
The Holly Blue is an April speciality and is commonly found in gardens, so it is one to watch out for at present. The clue to its identification is in its name: it is a pale blue in colour and it normally cannot be confused with any other species as it is the only blue butterfly that we have that usually flies in April.
The Holly Blue is a widespread species in Ireland but is not particularly common; it is far less abundant than our most numerous blue butterfly: the Common Blue, that normally emerges towards the end of May. The only other blue butterfly recorded on our shores is the tiny Small Blue, a rare and very local insect that normally emerges in June.
Apart from time of emergence, the Holly Blue is distinguished from the Common Blue by both the presence of black dots and the absence of orange spots on its underwings.
The other part of the Holly Blue’s name refers to the fact that at this time of year the freshly emerged females congregate around Holly bushes to lay their eggs singly in very precisely-defined locations: the bases of unopened female flower buds. While Holly is a plant of choice for the woodlouse-like caterpillars to feed on, the females will also lay on Ivy later in the year.
Holly Blue numbers are known to be increasing and the species is steadily expanding its range northwards. However, its colonisation of new territories is happening in fits and starts with numbers regularly fluctuating wildly from year to year. Maybe this year will be a good year for them? Do watch out for them and report any sightings to https://records.biodiversityireland. ie/record/butterflies#7/53.455/-8.016.