Getting fossilised in tree sap seems an odd way for an aquatic insect to meet its maker. Biologists have been left scratching their heads over how it happened. 鈥淢ost previous studies have focused on non-aquatic insects, assuming that most resin solidifies at the tree bark,鈥� says Alexander Schmidt of the Museum of Natural History in Berlin, Germany.
Now a study in Florida鈥檚 swamp forests, led by Schmidt, shows that resin trickles into small pools of water at the base of trees, where it forms a highly effective insect trap.
Schmidt found that resin at the bottom of a pond is probably more of a hazard to insects than resin on tree bark. He says the water delays the process of solidification and 鈥渁mberisation鈥� that is normally driven by oxidation in air. The resin stays stickier for longer under water, so it is more likely to trap insects (Proceedings of the National Academy of Sciences, ). He rejects convoluted explanations of aquatic insects being swept out of the water and into pools of tree sap.
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Underwater resin will not necessarily contain more insects, though. 鈥淭here are many insects flying in the air or living at the tree bark,鈥� says Schmidt. 鈥淎nd the resin outside the water reflects the sunlight, which may attract some insects.鈥�
