Plant‐mediated effects of host plant density on a specialist herbivore of Solanum carolinense

摘要: Host plant density can affect insect herbivore oviposition behaviour, which can, in turn, both and populations. Because clear generalisations about effects on remain elusive, a better understanding of underlying mechanisms is needed. One such mechanism plant-mediated (i.e. changes traits with density), are often suggested but rarely isolated experimentally. In an experiment directly manipulating host (Solanum carolinense) the field, by specialist (Leptinotarsa juncta) declined as increased. A greenhouse cage removing neighbour plants before introducing L. juncta females. Oviposition increased, supporting importance this system. To determine whether food quality contributed to effects, larval growth rates were measured leaves from field- greenhouse-grown plants. In field experiments, rate was not significantly affected density. It concluded that contribute to, do completely explain, strong influence experiment. These results suggest considering may help explain variability responses density.