Can heat and resource availability affect the pest status of African crickets?

Climatic changes, even transient events such as heatwaves, can markedly affect crop-insect interactions. Some insects might be favored or hampered in their development, but less clearcut interactions owing to changes in their needs or in agroecosystem resource availability, including in uncultivated surrounding areas, may mediate insect-crop interactions. In Tanzania, sudden and transient devastation of vegetable fields by crickets — which are usually considered as minor pests — raised this question. In this study, we sought to gain insight into whether sudden increased temperature and alternative food availability could affect the pest status of Gryllidae spp. Feeding damage on cabbage plants was measured under three temperatures in mesocosoms in climatic chambers. Tomato fruits were provided as an alternative food source. We demonstrated that Gryllidae spp. were able to feed on young cabbage, and that the damage level increased with temperature when no alternative food was available. Unexpectedly, the presence of alternative food increases feeding on the young cabbages. This case study highlighted how increased temperature could drive increased pest damage, raising concerns about climatic events that may substantially affect plant production in Africa through the interacting effects with insect herbivory.