Are adaptation costs necessary to build up a local adaptation pattern?

Area of Science:

• Ecology
• Evolutionary Biology
• Arthropod Biology

Background:

• Ecological specialization is common in plant-feeding arthropods.
• Host range limitations are often attributed to trade-offs preventing adaptation to multiple hosts.
• Local adaptation, indicated by negative correlations in performance across hosts, suggests such trade-offs.

Purpose of the Study:

• To experimentally investigate the causal link between local adaptation and trade-offs in spider mites.
• To determine if adaptation to novel hosts leads to decreased performance on ancestral or alternative hosts.

Main Methods:

• Experimental evolution of spider mites on cucumber, tomato, and pepper.
• Assessing performance on different hosts after 15 and 25 generations.
• Conducting mate choice experiments to assess reproductive isolation.

Main Results:

• Spider mites rapidly adapted to novel hosts within 15 generations.
• A pattern of local adaptation was observed, with lines performing better on their evolved host.
• No costs of adaptation were detected; performance on novel hosts did not decrease on ancestral hosts.
• Reproductive isolation between adapted lines was unlikely.

Conclusions:

• Performance and preference do not appear to limit host range in this spider mite species.
• The evolution of local adaptation does not necessitate the evolution of adaptation costs.