Effects of early-season insect herbivory on subsequent pathogen infection and ant abundance on wild cotton (Gossypium hirsutum)

1. Plant induced defences play an important role in mediating interactions between insects and pathogens. Yet, the plant traits underlying these effects, the extended consequences for higher trophic levels (i.e. predators), and the implications for plant growth and reproduction have received little attention.
2. Here we asked whether simulated early insect leaf damage on wild cotton (Gossypium hirsutum) affected subsequent damage by insect leaf chewers and pathogenic fungi, as well as ant abundance. To address the mechanisms behind such effects, we measured plant defensive traits induced by early leaf damage to determine which inducible traits might determine the effects on plant-associates. We also evaluated whether early damage influenced plant growth and flower production, and if such effects were mediated by subsequent insect herbivory or pathogen infection.
3. We show that simulated early leaf damage reduced damage by subsequent leaf-chewing insects, increased plant fungal infect...