The Glue Pistons

For a long time I’ve been wanting to be involved in a recording scheme. Yet I had not quite appreciated the amount of work that is involved in managing what is often a massive collection of records. Over the past few months I’ve been collating the records of springtails (Collembola) from Surrey, which has been a big challenge, even with springtails being one of the least recorded invertebrate groups in the country.

Springtails are often tiny arthropods with six legs. Whether they’re insects or not is up to debate however. Most authorities currently class them as Entognatha, with reference to their internal mouthparts; in contrast to the external mouthparts of insects. However, the other two members of the Entognatha – Protura and Diplura – are just as closely related to springtails as they are to insects.

Another anatomical feature of springtails is the collophore located on the underside of the abdomen, after which they get their scientific name, which means ‘glue piston’. It takes the form of a tube pointing downwards from the ventral side of the first abdominal segment. Originally, it was thought to help to stabilise the animal, although it is now believed to play a part in maintaining the water content of the body.

Springtails get their common name from the furca, a long, forked organ which originates from the end of the abdomen and is often bent under the body. It is used primarily to escape predators, and can fling the springtail at incredible speeds away from danger. However, where and how the animal lands is unpredictable. Some species, such as Ceratophysella bengtssoni, have an inflatable sac on the antennae with which the springtail can adhere to the surface it lands on. Some species have only vestigial furcas or lack one entirely, often in species which live in habitats such as compact soil where the furca would inhibit the movement of the springtail, or those which live near the sea or flowing water, where an unpredictable jump could land them in an even more dangerous situation.

brachy parv (2)

Brachystomella parvula. Springtails can vary greatly in shape, this being one of the stout, pudgy Poduromorphs.

The best literature for identification is the FSC key written by the late Steve Hopkin, A Key to the Collembola (Springtails) of Britain and Ireland. This provides a complete key to all the described species thought to be present in the British Isles and is relatively recent (2007). Otherwise, there are a few good websites that can be found online, such as www.collembola.org, which has many good-quality images.

If anyone finds and identifies any springtails, I’m sure the co-ordinator of the Collembola Recording Scheme, Dr Peter Shaw, would be happy to receive any records. His details can be found here. And if anyone records any from Surrey, I’d love to hear from you so I can add the records to my growing database. You can contact me using the form under the ‘Feedback/Contact’ page on my blog. I’d also be happy to receive any unidentified specimens in need of ID.

willowsia platani 4

Willowsia platani (possibly var. nigromaculata). One of the Entomobryomorphs: comparatively long, slender springtails.

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