Why are most herbivorous insects so specialized? How do generalists and specialists differ ecologically? And what sensory and cognitive processes determine which host species an insect recognizes and uses? We review sensory cues involved at different stages of interaction with host plants and outline a unified scheme of insect–host interaction mechanisms. Generalist species may be best understood as specialized organisms with a longer tail of secondary host species that they accept to a lessening extent. Secondary hosts have fewer attractive cues, and hence a lower probability of meeting the stimulation threshold required for egg laying. We then discuss the alternative theories of co-evolution and sequential evolution used to explain the diversification of insect herbivores. We conclude that ‘escape and radiate’ co-evolution rests on unrealistic assumptions and empirical evidence favours sequential evolution of plants and herbivores, and the unique life cycles of insect herbivores may sufficiently explain their extreme diversity within the animal kingdom. We also outline a new speciation-oriented hypothesis to explain why specialists are far more diverse than generalists. Generalists tend to have large, contiguous distributions and therefore lower speciation rates. Natural selection in novel environments may also result in narrowing of the host range more often than broadening, further increasing specialist diversity.
ABSTRACT
PUBLICATION RECORD
- Publication year
2022
- Venue
Biological Journal of the Linnean Society
- Publication date
2022-07-04
- Fields of study
Not labeled
- Identifiers
- External record
- Source metadata
Semantic Scholar
CITATION MAP
EXTRACTION MAP
CLAIMS
- No claims are published for this paper.
CONCEPTS
- No concepts are published for this paper.
REFERENCES
Showing 1-96 of 96 references · Page 1 of 1
CITED BY
Showing 1-23 of 23 citing papers · Page 1 of 1