34 Million Years of Wasps

An ancient wasp fossil has shown that winning designs are sometimes best left
alone.<
Evolution has not altered the wasp in 34 million years, scientists have
discovered.<
Three fossil specimens, the oldest examples of their species known, were
discovered on the Isle of Wight in the 1920s but wrongly labelled as ants.<
A new study of the fossils, housed at the Natural History Museum in London, has
now confirmed their true origins.<
Dr Steve Compton, from the University of Leeds, who led the research, said:
``What makes this fossil fascinating is not just its age, but that it is so
similar to the modern species.<
``This means that the complex relationship that exists today between the fig
wasps and their host trees developed more than 34 million years ago and has
remained unchanged since then.''<
Fig wasps are highly specialised and attach themselves to individual tree
species, which rely on them to spread their pollen.<
Each of the 800 or so modern species of fig tree is pollinated by just one or
two species of wasp that ignore other fig trees.<
The wasps measure just 1.5 millimetres in length. They have body shapes
designed to help gain access to flowers hidden out of sight within the green
``fruits''. Although figs are thought of as fruits they are technically synconia
- closed plant structures containing large numbers of tiny flowers.<
Modern fig wasps carry the pollen they collect in special pockets beneath their
bodies.<
Using advanced microscopy techniques, Dr Compton's team was able to identify
pollen pockets on the wasp fossils, and even grains of fig pollen within them.<
This showed that 34 million years ago the wasps were carrying out active
pollination in the same way they do today.<
Further evidence from analysis of the insect's ovipositor, or egg-laying organ,
suggested that the wasp and its host fig tree had been evolving together for
millions of years.<
``Although we often think of the world as constantly changing, what this fossil
gives us is an example of something remaining unchanged for tens of millions of
years - something which in biology we call 'stasis','' said Dr Compton.<
The research is published online in the Royal Society journal Biology Letters.<