Locusts are arguably the most notorious pests in history, directly affecting the livelihood of 1 in 10 people worldwide. These fascinating insects exhibit dramatic phenotypic plasticity in response to environmental fluctuation, changing from shy and cryptic 'solitarious' forms to brightly-colored and swarming 'gregarious' forms. How do these swarms form? What triggers this phenotypic switch? I will discuss how the experience of locust females influences the phenotype of her offspring, and how the 'gregarizing factor' underlying this maternal effect was isolated, purified, and partially characterized. Finally, I present field and laboratory data suggesting that swarm formation (and this gregarizing factor) affects locust immune function.
