Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2017 Mar 9;17:72. doi: 10.1186/s12862-017-0916-0

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s). 2017

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

PMC Copyright notice

Fig. 1 — Two models explaining the formation of spatially non-overlapping (or near non-overlapping) ecotypes. Under the sympatric host-shift model (a) insects from a population (Eco 1) shift to a novel host-plant (Host 2) and become a new ecotype (Eco 2). Note that the lack of competition [13] on the novel host-plant is often invoked to explain why such shifts occur (see introduction). After the host-shift occurs the new ecotype expands into the distribution range of the novel host (Host 2). Under the allopatric host-shift model (b) insects from a population (Eco 1) disperse into a region where its ancestral host-plant is absent (Host 1). It is then forced to use an alternative host-plant (Host 2). It adapts to the novel host-plant and becomes a new ecotype (Eco 2). While the allopatric host-shift model can occur when host-plant distribution ranges are completely non-overlapping or partially non-overlapping, the sympatric host-shift model can only occur when host-plants have partially overlapping distribution ranges. Note that we do not attempt to cover all possible models. See, for example, the more complex specialisation oscillation hypothesis [69]