During a recent visit from Louis Deharveng and Anne Bedo, Collembola taxonomists from the Natural History Museum in Paris, France and molecular Biologist David Porco and PhD student Charlene Janion took part in survey to determine what species of Collombola occur at Grootbos as this is one of the largest remaining patches of Milkwood forest in the Western Cape.
The following information was very kindly supplied to us by Charlene Janion!
The Springtails of Grootbos
Collembola or springtails are small, primitive wingless invertebrates, usually 1 - 2 mm in size, and are among the most abundant and widespread invertebrates in the world. Some scientists believe that springtails are actually more closely related to crustaceans than to insects. The oldest fossil of Collembola (Rhyniella praecursor) is about 400 million years old and was found in Scotland, and is also the oldest insect fossil known to date.
Collembola have the following characteristics in common:
- They have a spring, or furca, they use for jumping, thus to move around with. Some species that live in caves or in soil have lost the use of their furcas, so it has become vestigial or is absent;
- They have a ventral tube, which is important in water balance.
Collembola occur in all habitat types (mostly in soil and litter) from the Arctic to the Antarctic, and are generally more abundant in tropical regions. Collembola play an important role in ecosystem functioning, by actively breaking down leaf litter, soil formation and are also prey to spiders, predatory mites, and even lizards and frogs. Worldwide, about 7500 species have been described.
Until recently, very little research has been done on these little invertebrates in South Africa. Together with the Natural History Museum in Paris, the DST-NRF Centre for Excellence for Invasion Biology, Stellenbosch University, is running a project investigating the Collembola diversity in the fynbos. We are working with several experts in the field of Collembola taxonomy, soil ecology and molecular biology in order to fully understand this very diverse group and several new species have been discovered so far.
During a recent visit from from Louis Deharveng and Anne Bedos, Collembola taxonomists from the Natural History Museum in Paris, France, we were very interested to see what species of Collembola occur at Grootbos, as this is one of the largest remaining patches of Milkwood forest in the Western Cape. Molecular Biologist, David Porco, and PhD student, Charlene Janion, also took part in the survey.
Sampling sites
During our visit to Grootbos, we spend the day walking through the fynbos and the Milkwood forest, searching for Collembola. They are known to mostly occur in leaf litter and soil, but also found on the fynbos vegetation, especially the Ericaceae (Erica family). We also take leaf litter samples back to the laboratory, where the Collembola are extracted (using Berlese funnels), and the diversity and abundance is incredible!
Both the forest and the fynbos yielded interesting soil fauna, which is currently under study. More than 40 species of spingtails (Collembola) were collected, of which at least 15 are new to science!
Seira, the most diversified springtail genus of the Western Cape, was very abundant in the forest and in the fynbos, on the vegetation but also in the forest litter. We recognized 6 species differing by color and pattern and overall morphology. All were of large size Collembola (i.e. at least 2mm in adult). This makes Grootbos the richest site sampled so far for this genus in Africa. The fauna collected at the forest edge included a remarkable species from a genus only known so far by one species represented by 3 specimens from Madagascar. Several body parts of this species are strongly modified, including the mouth, suggesting a special ecology which remains enigmatic.
The litter fauna, though not rich, included several valuable species new to science. What was unexpectedly diverse was the fauna of deep sandy soil. Species adapted to this habitat have a very small size (usually less than 0.6 mm) and reduced appendages. The unique sample analysed so far contained 8 such species. Three of them belong to general that are recorded for the first time from South Africa!
We also sampled some moss, which are known to host specialized fauna often able to cope with xeric (dry) conditions. Our most interesting finding was Cryptopygus with extremely reduced jumping apparatus, and a set of characters on antennae and on legs so original that even its placement in Cryptopygus is questionable!
We would sincerely like to thank Grootbos management for allowing us to sample in the forest, especially to Sean Ingles for his interest and hospitality! We really appreciate it, and hope to be back soon. This research is funded by the NRF and SA-France grant.
Check out these excellent websites for more information on Collembola and the Centre for Invation Biology:
www.sun.ac.za/cib
www.collembola.org
www.stevehopkin.co.za
Thanks for supplying us with the article, Charlene! We look forward to learning more about the Grootbos Collembola!
