1. INSECTS & THEIR FEEDING…
• Insects feed very specifically on their host.
• They recognize their host through
morphological, phenological, and chemical
traits.
2. PHYTOPHAGOUS INSECT
vs.
DIVERSITY
• The phytophagous insects undergo dramatic
changes and they tend to be more diversified
than their non-phytophagous sisters.
• The most likely driver is that they diversify
through host shifts followed by evolution of
new species.
3. USE OF PLANT TRAIT SPACE
DURING HAD-
THE GAPE & PINCH MODEL
4. INSECT- HOST PLANT
• All plant species vary intra specifically for
numerous morphological, phenological, and
chemical traits.
• This variation defines a set of phenotypes that
are available for attack by a phytophagous
insect searching its environment for suitable
hosts.
5. INSECT FEEDING - PATTERN
• The total area available for a specific insect to
feed on is its “available trait space”.
• The area or rather the plants on which an
insect has fed is called its “attacked trait
space”.
6. Continued…
• The relationship between available and
attacked trait spaces will depend upon the
preference, performance of the insect.
• The “attacked trait space” either represents
the common preference of hosts by the
insects or the sum total of the distinct
preferences of host by different insects.
9. • STAGE 1:Single-Host Specialists and the Importance
of host choice errors:
Host shift occurs when a few insect individuals
start attacking the ‘wrong’(novel) plants.
ADJACENT ERROR HYPOTHESIS.
16. GAPE & PINCH MODEL-
NOMENCLATURE
• The overall conceptual model suggests a pair of
attacked trait spaces that begin close together, move
apart, and then move back together like pincers.
• This movement underlies the terminology “gape-
and-pinch” model of trait-space use.
17. REFERENCES…
• RESEARCH ARTICLE: Use of Host-Plant Trait Space by
Phytophagous Insects during Host-Associated
Differentiation: The Gape-and-Pinch Model, Stephen
B. Heard, Hindawi Publishing Corporation,
International Journal of Ecology,Volume 2012,
Article ID 192345, 15 pages
doi:10.1155/2012/192345.
• www.wikipedia.com
• Host-Plant Selection by Phytophagous Insects By
Elizabeth A. Bernays, Reginald F. Chapman