DOI: 10.5061/dryad.4xgxd25jg
title: Resistance assays of Drosophila suzukii populations from seven locations in Michigan and one location in Oregon

description: Host-parasitoid interactions are tied in coevolutionary arms races where
 parasitoids continuously have to evolve increased virulence as hosts
 evolve increased resistance. Over time geographic structure in virulence
 and resistance can arise because of spatial and temporal differences in
 parasitoid communities, in the strength of reciprocal selection pressures,
 in genetic variation in local populations, and as trade-offs are balanced
 between defense and fitness traits. It is crucial to understand how
 invasion changes the coevolutionary dynamics of host-parasitoid
 interactions to successfully implement biological control programs against
 invasive insect hosts. We investigated spatial and temporal variation in
 resistance of the invasive Drosophila suzukii in seven geographically
 distinct populations in Michigan and of one population from Oregon against
 a newly approved biocontrol agent, the larval parasitoid Ganaspis
 brasiliensis. We found regional and temporal variation in resistance
 (encapsulation rates of parasitoid eggs) of D. suzukii populations that
 ranged from 11– 48%. The northernmost site with the lowest encapsulation
 rate had the highest rate of parasitism suggesting that parasitoids may be
 able to detect the defensive capacities of their hosts and adjust attack
 rates accordingly. The lowest encapsulation rates at the northernmost and
 thus coldest site suggest a negative effect of temperature on resistance.
 Large regional differences in resistance of D. suzukii populations can
 render the ensuing biocontrol program more variable and less predictable,
 and release strategies may need to be altered at sites where flies have
 high resistance to accelerate biocontrol.  
description: <em>Drosophila suzukii</em> was collected from seven
 locations in Michigan and one location in Oregon. Field collected flies
 were reared in the laboratory for one generation and then assayed for
 resistance to parasitism by <em>Ganaspis
 brasiliensis</em>.
description: # Resistance assays of Drosophila suzukii populations from seven locations
 in Michigan and one location in Oregon
 [https://doi.org/10.5061/dryad.4xgxd25jg](https://doi.org/10.5061/dryad.4xgxd25jg) ## Description of the data and file structure Second tab in an Excel file titled Istas_Szucs_DATA_for_dryad.xlsx contains the data. * Column A: Location where D. suzukii was collected from, as shown in Figure 1 of the manuscript. N = North, W = West, SW = Southwest, WC = West Central, C = Central, EC = East Central, and E = East. OR = Oregon. *  Column B: the sample type used to collect D. suzukii was either a banana trap, the collection of managed fruit, or unmanaged/wild fruit * Column C: the month of the sampling, either Aug or Sept 2022 * Column D: the 5 replications for each location*month*sample treatment combinations. * Column E: the number of larvae that was parasitized of the 10 larvae offered for each parasitoid female for each replicate * Column F: the proportion of larvae parasitized of the 10 larvae offered for parasitism. * Column G: the number of parasitoid eggs that were encapsulated in D. suzukii larvae that had been parasitized. * Column H: the proportion of D. suzukii larvae that were parasitized and encapsulated parasitoid eggs. Calculated by dividing the number of encapsulated eggs by the number of parasitized flies. * Column I: the number of D. suzukii larvae offered for each parasitoid female in each replicate.