Mvl^97f mutants exhibit an iron-deficient phenotype, but display comparable levels of copper, manganese and zinc to wild-type controls. A dietary supplement of 1 mmol/l CuSO[[4]] leads to a decrease in total body iron, yet these flies accumulate iron to similar levels as controls.

Mvl^97f mutants accumulate less iron in ferritin than controls, except when fed on an iron-enriched food. There is a decrease in iron-loaded ferritin content following dietary copper supplementation in Mvl^97f flies.

Dietary iron accumulates primarily in the anterior midgut and copper in the diet reduces iron content of the middle midgut. Intestines from Mvl^97f homozygotes show severely reduced iron content in the middle midgut. Dietary iron fails to rescue iron storage in this region, whereas in the anterior midgut ferritin induction and iron accumulation are normal. The addition of copper to the diet reduces iron content in Mvl^97f intestines to below levels of histochemical detection.

There is a 4-log reduction in viral titers of flies that are infected with Sindbis virus in Mvl^97f mutants compared with heterozygous or wild-type controls, while vesicular stomatitis virus (VSV) infection is unaffected.

Mvl^97f flies show no significant changes in pigmentation or cuticle morphology under basal, copper-limited, or copper-excessive conditions.

Mvl^97f flies show a strong sensitivity to excess copper, with significant reduced viability at 1 mmol 1[-1] Cu and essentially no survival at 2 mmol 1[-1] Cu.

Under limiting Cu conditions Mvl^97f females demonstrate reduced viability, but males are unaffected.

The pupae of Mvl^97f larvae raised on basal food show 40% lower iron levels than controls. Copper, Zinc and Manganese levels are not significantly lower. Larvae raised under copper-limited conditions show significantly reduced copper levels in both Mvl^97f and control pupae.

Mvl^97f larvae raised under basal conditions and exposed to 6 mmol 1[-] copper for a 24 hour period as adults show dramatically higher levels of copper. These flies also contain significantly more manganese and zinc than controls, and iron levels are restored.

Mvl^97f flies show defects in a feeding preference assay; only 30% of the Mvl^97f flies preferentially choose sucrose (in a choice between agar containing 1 mmol l^-1 sucrose and control agar) in contrast to 90% of normal flies.

Mutants do not discriminate between tastes, showing no preference for sugar supplemented medium, unlike wild type flies. Addition of Mn²⁺ and Fe²⁺ reverses the mutant phenotype in a dose-dependent manner. Addition of Ca²⁺, Mg²⁺, or Zn²⁺ fails to revert the phenotype. Metal ions are not required for correct development to the nervous system components involved in taste perception: transfer of newly eclosed adults onto Mn²⁺ Fe²⁺ supplemented medium does not rescue the mutant taste phenotype. Mn²⁺ and Fe²⁺ are implicated in a signal transduction pathway underlying taste perception.

Heterozygotes and homozygotes show a reduced preference for several sugars and an increased acceptance of low concentrations of sodium chloride, though homozygotes show a significantly stronger phenotype. Homozygotes show a shift in the threshold of acceptance of sucrose, fructose and trehalose, as measured in the feeding preference test and the proboscis extension test. Higher concentrations of stimulus are required to elicit a maximal behavioral response.