And the war continues

The war between plant eating insects and plants continues. Plants have lots of defense mechanisms, but then insects evolve counter strategies, and so the war continues. When a female insect lays a clutch of eggs in the bark of a shrub, one plant strategy is to respond to the injury, however minor, with localized cambial growth increasing the diameter of the twig beneath the injury. This may not sound like much of a defense until to realize the insect eggs can get crushed in the process, slowly crushed, but crushed. Now biologists have found out that leaf beetles have evolved a behavioral counter measure. Female leaf beetles try to lay their eggs near other clutches of leaf beetle eggs. Now this may sound like putting too many eggs in one basket, but clustered oviposition sites can so damage the bark that the twig beyond dies thereby eliminating the growth response defense. So more leaf beetle larvae will hatch when their mothers oviposited in clusters than alone. And that's the bottom line of evolution: differential survival.