Thermotolerance and place memory in adult Drosophila are independent of natural variation at the foraging locus.

Natural polymorphisms at the foraging (for) gene influence several behaviors. However, it is seldom clear how different for alleles could be selected. In one case, Drosophila with the rover allele (for(r)) have higher locomotor activity in the presence of food than animals with the sitter allele (for(s)), suggesting a complementary feeding strategy. There are, in addition, differences between for(r) and for(s) Drosophila in some tests of short-term memory (for(r) animals generally perform at higher levels) and thermotolerance (for(s) larvae are more resistant to the effects of high-temperature). We asked whether there could be a direct compensating advantages in adult for(s) flies that could maintain the natural for variants. First, are adult for(s) flies more thermotolerant? Second, do for(r) flies have a higher short-term place memory? Third, as an alternative, might for(s) flies have higher place memory? Our results do not confirm these possibilities. Thus, a thermotolerance advantage of for(s) flies does not compensate for a potential for(r) short-term memory advantage; for(r) flies do not have a universal advantage in short-term memory; and for(s) flies do not have an advantage in place memory that could compensate for for(r) advantages in other learning contexts.