Thursday, July 1, 2010

Masters of Camouflage


Grasshoppers hatch in May, from eggs that have spent the winter buried in the soil, down among the grass roots, and by mid-June their nymphs have grown and passed through three moults. At this stage they resemble miniature adults but don’t have functional wings, so their best defensive strategy is to remain motionless. If they are disturbed they use their long hind legs to hop, but never very far. Only when they undergo their final moult will they develop full-sized wings and then they can leap and glide away out of danger, but for now camouflage is their salvation. At this stage they are silent, unable to produce the chirrups that they use as courtship signals and which become part of the soundtrack of summer on hot August days.

In this view you can see the partially formed wings of the nymph. The grasshopper song - stridulation - is produced by pegs on the legs rubbing against the hard edge of the wing - so grasshoppers can't begin singing until their wings are fully formed.

2 comments:

  1. Being a Physics person, I never knew the delights of biology. I am discovering them now by reading your posts. Thank you!

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  2. Thanks lotusleaf, I think there is some interesting physics in grasshoppers' adaptations!

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