Inter-populational differences in the response to dietary restriction: evidence for medfly (Ceratitis capitata) ecotypes on Hawaii

The medfly is a globally distributed invasive species. Each of the global populations exhibit adaptive traits to the environmental conditions of the region they occur. To determine if similar adaptations can arise when populations are in close proximity, but experiencing different environmental conditions, we performed a common garden experiment on two wild populations of medfly on the island of Hawaii. The two populations occurred within 35 km of each other, but one population originated from an agricultural environment with a cultivated host (Coffea arabica), while the other was from an area of native forest with an introduced host occuring at a low density (Solanum pseudocapsicum). The F₁ generation from each population was subjected to high quality and low quality dietary conditions, with responses measured as changes in life expectancy. Overall, the poor quality diet was associated with a reduction in life expectancy, but the forest population had a greater tolerance to the poor dietary conditions. The population from the forest ecosystem appears to have life history traits that allow it to better tolerate periods of poor dietary conditions, while the population from the agricultural ecosystem lacks the adaptation.