First Irish Record for the Southern Oak Bush Cricket

Ireland is home to 12 species of breeding orthopterans (grasshoppers and crickets), with five of these being classed as crickets or bush crickets (1). It is only in the last thirty five years that three of these have been recorded, with Pholidoptera griseoaptera, the Dark Bush Cricket, being first recorded as 1983 (2). This trend may be due to the lack of attention that Irish orthopterans have been paid in the past, or may be a phenomenon that has been seen in European dragonflies, that of the spread of certain species from the center of mainland Europe to its peripheries.

Female Southern Oak Bush Cricket, Meconema meridionale

This is most evident in the case of the Southern Oak Bush Cricket, Meconema meridionale. This species was thought to be an exclusively Southern European species, but has extended its range and during the 1990's was to be found in France, Holland and Belgium (3). In 2001 it had reached Britain (4), being discovered in three localities in England from where it has steadily spread. This introduction was though to have been via imported horticultural material and given the strong trade links between Britain and Ireland it is assumed it can only be a short time before M. meridionale reaches Irish shores. And so it has proved to be. On the 9th of November last, I spotted a female adult M. meridionale on a limestone pillar at the entrance to a building on the Western Road in Cork city. The weather at that point had been unseasonably warm and when I first saw it I assumed it was the closely related (and Irish native) the Oak Bush Cricket (Meconema thallasinium), a species often seen close to houses and other buildings. However this individual was lacking in the distinctive long, green wings associated with M. thallasinium and was in fact brachypterous (having abnormally small wings). This is the distinguishing feature of the otherwise almost identical M. meridionale. This may be an errant traveling individual, but the species recent range expansion points to the discovery of a breeding population in Ireland being a very distinct possibility in the not too distant future.

References:

1. Haes and Harding, 1997. Atlas of grasshoppers, crickets and allied insects in Britain and Ireland
2. O'Connor and O'Connor, 1985. Entomologists' Gazette 36 pp. 229-232
   Maclean, 2010. Silent Summer: The State of Wildlife in Britain and Ireland p. 533
   Hawkins, 2001. British Journal of Entomology and Natural History 14 pp. 207-213

Hold On

Common Limpet, Patella vulgata

Probably the most familiar intertidal organism on western European coastlines is the Common Limpet, Patella vulgata. Its conical shell can often be seen in enormous numbers on rocky shore of all degrees of wave action, and numbers are maintained by the relatively long life of certain individuals. Where conditions promote slow growth, some individuals can live up to 17 years of age (1). For a sedate looking animal, often encountered encrusted with algae and barnacles, they are voracious feeders. Although they have been reported to consume a wide variety of micororganisms (2), algae of the intertidal zone is the food of choice. And what a choice; P. vulagata feeds a plethora of different species, including Fucus spp., Ulva spp. and red encrusting algae (1). This is all facilitated by the iron and silica hardened teeth on the radula, which rasp the algae with incredible efficiency. In situations where P. vulagata have been artificially removed form shorelines, Ulva spp. have quickly covered the rocks.

Common Limpet Home Scar

A rocky shore is not for the faint of heart, with waves action dislodging anything not firmly attaced to its surface. Organisms need to be firmly attached to the rock, and P. vulgata is truly a master at this. Depending on where the animal is to be found on the rock face, the shell height will vary. Those at high shore levels have tall shells with a small shell length, while individuals at a low shore levels have shorter but longer shells, which keeps them closer to the rock (1). P. vulgata attaches to their substrate by using a combination of suction and glue like adhesion (3). The specific mode of attachment is dependant on their location at the time. At high tide, when P. vulgata is at its most active feeding, suction is employed. This involves decreasing the pressure under the foot of the animal which forms a tight seal with the substrate. At low tide, when foraging does not occur due to the increase risk of predation, P. vulgata employs a glue-like secretion from its foot which creates a seal that is stronger than that created by suction, however it is more permanent and does not allow movement for foraging. At rest, P. vulgata also employs a home scar, a depression created in the substrate by chemical action and abrasion by the shell of the animal. This is returned to after each foraging excursion as it increases the adhesion power significantly (4).

References:

1. Fish and Fish, 2011. A Student's Guide to the Seashore pp. 205-206
2. Jenkins and Hartnol, 2001. Journal of Experimental Marine Biology and Ecology 30 pp. 123-139
3. Smith, 1992. Journal of Experimental Marine Biology and Ecology 1600 pp. 205-220
4. Smith, 1991. Journal of Experimental Biology 161 pp. 151-169

Punk Moth

Pale Tussock Moth Larva, Calliteara pudibunda

With its bleached-blonde mohawk, running halfway down its yellow and black body and a shocking-red spike of tail hair, the larvae of the Pale Tussock Moth (Calliteara pudibunda) is nothing if not an attentions seeker. Yet its wildly flamboyant appearance serves an important role for the caterpillar. Its long body hairs will cause irritation upon handling, and in some cases can cause severe damage to human skin (1). It is therefore avoided by most predators, a fate that the less hirsute adults are unfortunate to avoid, being food for a variety of birds. It is found throughout Europe, and is most common in the south and west of Ireland (2).

Pale Tussock Moth Larva, Calliteara pudibunda

C. pudibunda is a polyhpagous insect, feeding on a range of plants including including hops, birch, elm, flowering cherry, hazel, hornbeam, oak, poplar, pussy willow and walnut (3). Beech is a particular favourite and large numbers have been known to occur that put immense stress on commercial beech plantations. Commercial, monocultural forests such as these are remarkable only for their lack of invertebrate biodiversity due to their lack of floral diversity (4), so lack of competition is partly responsible for such outbreaks. However, the introduction of only a small number of other tree species has been shown to reduce the numbers of C. pudibunda significantly (5). Chemical volatiles emitted from Norway Spruce grown in co-culture with beech will mask the signals that attract egg laying females to the host beech trees. Such inhibition has lead to a 25% reduction in numbers of C. pudibunda in commercial forests.

References:

1. Backshall, 2007. Venom: Poisonous Animals in the Natural World p 49
2. Sterry, 2004. Collins Complete Guide to Irish Wildlife p. 112
3. Alford, 2012. Pests of Ornamental Trees, Shrubs and Flowers p. 320
4. Christensen and Jens Emborg, 1996. Forest Ecology and Management 85 pp. 47-51
5. Heiermann and Schütz, 2008. Forest Ecology and Management 255 p. 1161-1166

Blog Awards Ireland Finals

From left to right: Sally from Register 365, John from 21stcenturynaturalist (me), Nicola from The Sequin Cinderella and Steve from Register 365.

 A great night was had by all at the finals of the Blog Awards Ireland on Saturday the 13th last in the Osprey Hotel in Naas. Unfortunately 21stcenturynaturalist didn't take home any prizes, but the Science/Education awards went to the truly excellent Science Calling!, a most deserved winner. Congratulations to Maria Delaney on a blog that always excites and educates me.

Foreground, from left to right:  Nicola from The Sequin Cinderella, John from 21stcenturynaturalist (me), and Steve from Register 365.

Best Blog was awarded to Wise Words, while Best Blog Post (presented by the wonderful people at Register 365) went to Head Rambles for "A friendship of a lifetime". A full list of winners is available here.

Oxtongue in the City

Bristly Oxtongue, Picris echioides

Urban, and for that matter suburban, landscapes are often thought of as ever changing, ever moving. The commonly held opinion is that building works, cleaning and development in such areas make dynamic habitats that only the most adaptable and durable organisms can make anything close to a permanent home in. Rural habitats, which seem to experience less human interference other than agriculture, should be far more suitable for a larger range of organisms. And generally these two statements can be held to be broadly true. However, as always, there are a few delightful anomalies.

Bristly Oxtongue, Picris echioides

Bristly Oxtongue (Picris echioides) is a large and often quite branched annual or biennial of dry, disturbed ground (1). A common plant in southern England and Wales (2), it is of rare and local occurence in Ireland, being found only with any frequency in the South and South-East (1), and is considered to be nationally rare (3). Such low frequency may be explained by its status as an introduced species, being a native of the Mediterranean (4). P. echioides certainly earns its common name, Bristly Oxtongue as it is is covered in bristles arising from small white blisters all over the plant. In the past the leaves were boiled and eaten (2), possible for medical reasons as there is anecdotal evidence that it has an effect on stomach complaints (5). There may be some truth in this, as the aerial parts of the plant contains sesquiterpene lactones, some of which are seemingly unique to P. echioides (6). Its flowers, which from a distance resemble a number of other yellow Asteracea, reveal upon inspection the most wonderfully delicate sepals.

Bristly Oxtongue, Picris echioides

As it is such a scarce plant, it was with great surprise that I received most welcome correspondnace from one Mr. Pat Dunne of Cork city outlining not one, but two locations for this flower in the city. The first is on the docks of the river Lee, near to the city center. At once this area was a very busy access point for the various industries within the city, but with their disappearance or relocation the docks have become less used and this undisturbed habitat has seemingly proved ideal for P. echioides. Similarly, the second site (located in the city suburb of Ballyphehane) is a small section of waste ground in a now disused factory. While this site was in the past tended when the factory was operational, this no longer seems to be the case, which is, again, a boon for the plant. So while cities as a whole may be never ceasing monuments to progress, there are parts of them that remain refreshingly static and a refuge for wonderful organisms.

References:

1. Sterry, 2004. Collins Complete Guide to Irish Wildlife p. 252
2. Philips, 1977. Wild Flowers of Britain p. 94
3. O'Mahony, 2009. Wild Flowers of Cork City and County p. 73
4. Preston et al., 2002. New Atlas of the British and Irish Flora p. 928
5. Hooper, 1817. A New Medical Dictionary p. 629
6. Marco et al., 1992. Phytochemistry 31 pp. 2163-2164

A Sighting of the Kidney Spotted Ladybird from Cork

Kidney Spotted Ladybird, Chilocorus renipustulatus

Ireland is home to 18 species of ladybirds, 15 of which are considered resident here (1). All of these species are also present in Britain along with 8 more (2), so it is therefore feasible to think that some of these 'extra' species may appear from time to time in Ireland as migrants. Nonetheless, I was still quite surprised to see an individual Kidney Spotted Ladybird (Chilocorus renipustulatus) on branch of some low growing willow in an unused quarry about 18 km from Cork city center on the 19th of September last. C. renipustulatus is not recorded as being present in Ireland, even though it is of common occurence in England (though less so in Wales and very rare in Scotland). 

Kidney Spotted Ladybird, Chilocorus renipustulatus

The ladybird possessed the characteristic domed elytra which were rimmed at their edges and demonstrated defensive behaviour typical of C. renipustulatus, namely clamping tightly against the surface of the branch it had been moving along. The site at which the ladybird was spotted is quite close to a large ferry port, which may account for its presence there. It may also, however, be a symptom of global warming that has lead to an increase in the numbers of species of dragonfly found in Ireland.

Kidney Spotted Ladybird, Chilocorus renipustulatus

References:

1. http://www.habitas.org.uk/ladybirds/
2. http://www.ladybird-survey.org/default.aspx

A Flying Swimmer

Rhantus sp. Predatory Diving Beetle

A wet, wet, wet summer has given way to a pleasingly dry Autumn here in Ireland, with some of the southern counties experiencing their driest September in 26 years. This has lead to some water bodies which remained swollen throughout the year to finally experience something of a drought. Some of the more temporary examples have began to dry up and with this disappearing of certain bodies, so the predatory diving beetles, the Dytiscidae, take to the wing in search of new hunting grounds. Voracious hunters, they are found in a variety of fresh water habitats such as streams, ditches, canals and lakes, although usually in shallow water (1). Their prey are quite varied, consisting of a wide number of invertebrate larvae as well as tadpoles and worm species (2), and are excellent swimmers with large back legs perfectly adapted to pursue these prey in the water. These are lined with hairs that spread out when the leg is drawn back (in a rowing motion) and then lie flat when the leg is pushed forward, reducing drag (3). Drag is further reduced by the shape of the of the beetle's body which is streamlined for rapid movement through the water. This is tempered somewhat with the need for stability, giving Dytiscids excellent maneuverability.

Rhantus sp. Predatory Beetle

Its something of a shock therefore to see these masters of the waterways barreling through the air with all the grace of a carelessly tossed stone. Moving to new territories, Dytiscids fly with a refreshing directness, generally only halted by the water they come seeking (the individual pictured just managed to avoid me on its approach flight). The fact that many species are of considerable size (up to 4 cm long) makes seeing them a little alarming. This propensity towards large size is linked to reduction of drag in the water, with larger bodies animals experiencing much less drag than their smaller relatives (3). Ireland is home to quite a number of Dytiscidae, with 86 species being recorded here (4).

References:

1. McGavin, 2005. Insects and Spiders of Britain and Europe pp. 86-87
2. Aditya and Saha, 2006. Limnologica - Ecology and Management of Inland Waters 36 pp. 251-257
3. Nachtigall, 2009. In Encyclopedia of Insects pp. 972-975
4. Ferriss et al., 2009. Irish Biodiversity: a taxonomic inventory of fauna p. 98