EW BUGS!!

These arthropods were collected in the Witherspoon woods near Princeton, NJ, while conducting a invertebrate diversity assay. The arthropods were preserved in alcohol for two months. We were interested in seeing how they moved, and the form and function of their limbs, so we placed them on slides and looked at them with the foldscope!

The first thing we looked at was a soil centipede (order – Geophylomorpha); we were struck by not just the number of limbs, but their relatively diminutive size compared to the body of the centipede.

We also looked at springtails (order – Entomobryomorpha), which are significantly smaller (less than a millimeter long) and can move very differently than centipedes.

In addition to walking on their legs, when threatened, they use their powerful furcula to catapult them up up and away from danger. The furcula is a forked tail-like appendage that can launch a springtail 15 centimeters into the air – the equivalent of a human jumping over the Eiffel Tower ! (To learn more about springtails, watch this video) . We also were interested in springtails after reading the book “Letters to a Young Scientist,” by E. O. Wilson, in which he describes the acrobatic feats of the tiny bug and its predator the dacetine ant. When the ant snaps its powerful mandibles around the springtail, the springtail simultaneously launches into the air, bringing the ant with it. As Wilson puts it, “If dacetine ants and springtails were the size of lions and antelopes, they would be the joy of wildlife photographers” (Letters to a Young Scientist, 123).

Several other bugs got caught in the centipede’s legs, which gave us a great opportunity to compare the legs of the centipede alongside the legs of the spider. The centipede’s legs appear to be curved, while the spider’s legs bend at a joint.

This experiment brought up many questions for us. What factors are evolutionarily important in shaping the arthropods’ form and function? How do centipedes evade predators? Are there other insects that use furcula-type appendages to escape predators? How can the springtail catapult itself with such force? Don’t YOU wish you had a furcula?

We conducted this project as part of Professor Pringle’s EEB321 class at Princeton University.