Influence of host quality on larval competition in Drosophila suzukii

 

Drosophila suzukii (commonly referred to as the spotted wing drosophila) is a invasive pest of soft skinned fruits that has been detected throughout the United State., D. suzukii larvae feed on numerous economically important crops, and females preferentially lay their eggs in ripe and ripening fruit rather than rotting fruits like most other Drosophila spp.  We aimed to study the interaction between larval competition and host quality in D. suzukii.  We established that competition can have a negative impact on larval development rate and survivorship. However, we have also recorded that this impact appeared nullified in higher quality substrates. Using this information we infested a known number of eggs (5, 10, 20, and 40) into four different types of diet: raspberry puree (a high quality host), standard fly diet, standard diet with lower amino acid levels, and standard diet with lower carbohydrate levels. We hypothesized that the higher quality substrate would mitigate the negative effects of competition resulting in more rapid development times relative to those in the standard diet. Secondly, we hypothesized that of the lower quality diets the reduced amino acid dishes would result in the slowest development.