摘要：
Aims This systematic review highlights the relative support and implications of the attractant-decoy and repellent-plant hypotheses, discussing important linkages between these theories and the opportunity for novel integration into ecological and applied research.
Methods An extensive systematic review of the current literature on the attractant-decoy and repellent-plant hypotheses was done to describe the following attributes of the research to date: (i) the geographic extent (country and biome) of studies on this topic, (ii) the scope of experimental designs used, (iii) the level of support for these hypotheses with respect to the breadth of ecological niches tested, (iv) the level of support for these hypotheses with respect to the classes of herbivores examined and, lastly, (v) the ecological impact or purpose of these studies. Herein, we summarize important research gaps in the empirical literature on this topic and identify novel opportunities for critical linkages between ecological and applied theories.
Important findings A total of 37% of experiments testing these two associated hypotheses were done in North America, frequently in either temperate broadleaf (26% of studies) or taiga ecosystems (15% of studies). The majority of these studies involved experimental manipulations such as removing and transplanting vegetation and either tracked or excluded mammalian herbivores. Ecological implications were primarily examined (59% of studies), but there were also implications described for agriculture and commercial forestry in 22% of studies. The repellent-plant hypothesis was well supported in many ecological systems, particularly for mammalian herbivores, but the attractant-decoy hypothesis has been less frequently tested, thereby representing an important research gap. Insect herbivores were under-represented in all categories except in applied contexts such as commercial forestry and agriculture. There is a clear need for studies to connect these two ecological hypotheses with the management of agriculture and restoration efforts in many ecosystems. Research on the co-evolution and facilitation between palatable and unpalatable plants also represents another novel area of future study.
