Where did the springtails of Svalbard come from?

It is generally believed that few, if any, invertebrates survived the last glacial maximum in Svalbard.  Rather that the fauna observed today is a result of immigration during the last 10,000 years after the ice began to retreat.  A recent article in the scientific journal Insects considers the current distribution of the Collembola in the Arctic and supports this idea. Link to the article

Collembola, the springtails

There are approximately 60 species of Collembola recorded from Svalbard.  All are small six-legged invertebrates looking like small insects and less than 3mm in length.  Many species live in the soil but some, such as the large yellow Megaphorura species, can be seen under rocks, especially under birdcliffs.  New species are being continually added to the list from Svalbard.  The last being found in Adventdalen in 2008.  Collembola are important in decomposition and nutrient cycling processes.  They are best known for their springing ability, hence the common name of springtails or spretthaler.  This organ, the furca, is an escape mechanism enabling the animal to propel itself into the air if threatened by a predator.  Landing is not all that graceful.  Once airborne the animal has no control over its direction and is usually rotating rapidly.

 

 

<i>Lepidocyrtus lignorum</i> collected in Bjørndalen (also showing <i>Folsomia quadrioculata, Hypogastrura</I> sp. as well as oribatid and prostigmatid mites)A beautiful photograph of <i>Isotoma anglicana</i>. The springing organ, the furca, can be seen partially extended and pointing straight down. In life the furca lies flat along the underside of the organ. Should a rapid escape be required the furca can be released pressing down on the ground and flipping the animal into the air.

<i>Megaphorura arctica</i> (<i>Onychiurus arcticus</i>). A favourite amongst researchers as it is a) amongst the largest species of Collembola and b) is one of the few to not have a furca and hence cannot jump away. <i>Megaphorura arctica</I> and eggs under a rock in Hornsund. August 2008.

<i>Ceratophysella</I>


 

Examples of typical Collembola to be found in Svalbard.

Left, <i>Agrenia bidenticulata</I>. Right, <i>Ceratophysella longispina</I> Left, <i>Desoria neglecta</I>. Right <i>Desoria olivacea</I>. Left, <i>Sminthurides malmgreni</I> (dark red), <i>Arrhopalites pricipalis</I> (pink, long subdivided antennae). Right, <i>Sminthurinus concolor</I> Left, <i>Folsomia quadrioculata</I> (above), <i>F. sexoculata</I> (below). Right, <i>Protaphoirura macfadyeni</I> (slim), <i>Oliagphorura groenlandica</I> (pear-shaped). Left, <i>Tetracanthella arctica</I> (4 big anal spines). Right, <i>Hypogastrura viatica</I>, Left, <i>Desoria tshernovi</I>. Right, <i>Agrenia bidenticulata</I> Left, <i>Friesea quinquespinosa</I>. Right, <i>Parisotoma notabilis</I>