Response of a specialist leaf miner insect to the environmental stress of its host plant

The coffee leaf miner, Leucoptera coffeella (Guérin-Mèneville), is one of the main coffee pests ( Coffea spp.) in the Neotropical region. This moth species develops exclusively on leaves of Coffea plants. In this study, we investigated the oviposition preference and performance of L. coffeella in environmentally stressed Coffea arabica L. plants. These plants were exposed to three independent treatments: (a) shade levels (0%, 50%, and 100%), (b) water availability (constant and intermittent irrigation), and (c) the application of phytohormones (salicylic acid, SA; or methyl jasmonate, MeJA). Groups of leaves from these treatments were exposed to individual L. coffeella -mated females, and the number of eggs laid per leaf and the performance in terms of the duration of the immature stages and survival of L. coffeella was recorded. Our results showed that oviposition preference was indistinct among the evaluated treatments. However, leaf miner larvae developed faster under 50% shade level, whereas survival was lower in plants under 100% shade level. Individuals reared on plants under 100% shade level showed slower larval development and smaller adult size. Constant plant irrigation decreased the L. coffeella survival. The application of MeJA delayed larval development, while the application of SA increased adult size. Our results suggest that plant environmental stress should be considered when studying the performance of specialist insect herbivores.