Plant‐mediated interactions among above‐ground and below‐ground life stages of a root‐feeding weevil

Abstract

1. Interactions among herbivores mediated by plant responses to herbivore injury may have large impacts on herbivore population densities. Responses may persist for weeks after injury and may affect not only the initial (inducing) herbivore, but also herbivores that are spatially or temporally separated from the initial attacker. 2. In many plant–insect interactions, multiple life stages of the insect may be associated with the same plant, and these various stages may interact indirectly with one another via induced responses. The rice water weevil (RWW), Lissorhoptrus oryzophilus, a serious global pest of rice, is one such insect. A series of experiments were performed with root‐feeding larvae and leaf‐feeding adults of the RWW using three conventional rice varieties. 3. The first objective of this study was to test whether RWW adult feeding on rice leaves resulted in altered oviposition by subsequent adults. The hypothesis for the first objective was that RWW adult feeding would decrease plant suitability, resulting in reduced oviposition by subsequent adults. 4. The second objective was to test whether injury by RWW larvae to rice roots resulted in altered oviposition by subsequent adults. The hypothesis for the second objective was that below‐ground RWW larval feeding would decrease plant suitability of rice to above‐ground RWW adults, resulting in decreased oviposition. 5. Results provided inconsistent support for the first hypothesis, indicating that responses differed among combinations of variety and injury level. Conversely, consistent support for the second hypothesis was found, indicating that larval feeding on roots decreased suitability of rice plants for oviposition.

Leafminer attack accelerates the development of soil‐dwelling conspecific pupae via plant‐mediated changes in belowground volatiles

“…Many herbivorous species complete their life cycle in different organs of the host plant, for example adults feeding on shoots and conspecific larvae feeding on roots. Initial leaf herbivory by adults can elicit systemic plant responses in the roots that facilitate or inhibit subsequent larval performance (Erwin et al ., 2014 ; Huang et al ., 2014 ; Kraus & Stout, 2019 ). While the impact of herbivory‐induced plant defence responses on different plant‐feeding life stages of conspecific and heterospecific herbivores have been studied extensively, little is known about their influence on nonfeeding life stages such as the pupal stage.…”

Leafminer attack induces plant-mediated facilitation of conspecific pupae in the soil

“…For instance, many herbivorous species complete their life cycle in different organs of the host plant, e.g., adults feeding on shoots and conspecific larvae feeding on roots. Initial leaf herbivory by adults can elicit systemic plant responses in the roots that facilitate or inhibit subsequent larval performance (Erwin et al, 2014;Huang et al, 2014;Kraus & Stout, 2019). While the impact of herbivory-induced plant defense responses on different plant-feeding life stages of conspecific and heterospecific herbivores have been studied extensively, little is known about their influence on non-feeding life stages such as the pupal stage.…”