Heterozygous and homozygous larvae show strongly reduced encapsulation of eggs of the avirulent wasp L. clavipes compared to that seen in wild-type larvae. Heterozygous larvae also have a significantly reduced ability to encapsulate the eggs of the avirulent wasp avirulent Aphaereta sp. Only approximately one-third of heterozygous larvae exposed to either L. clavipes or Aphaereta sp. develop into adult flies.

The total number of hemocytes and the number of circulating lamellocytes per larvae is increased in heterozygotes exposed to L. clavipes compared to wild-type larvae exposed to L. clavipes.

Plasmatocytes migrate to and surround the wasp egg in heterozygous larvae as occurs in wild-type larvae following infection. Following this, lamellocytes surround the wasp egg in the mutant larvae, but they fail to form a consolidated layer. Pieces of melanised tissue are often seen floating in the hemocoel.

Homozygotes show a reduction in mean and maximum lifespan and show reduced locomotor activity compared to controls.

Homozygous adults are recovered only when the mutants are isolated as first instar larvae and allowed to develop at low density in the absence of wild-type larvae. under these conditions, approximately two-thirds of the mutants eclose while the remaining third appear to die throughout larval development. Mutant adults that emerge have a normal external morphology.

Homozygous males produce normal levels of mobile sperm, but are sterile. Females mated to homozygous males do not contain any sperm within the spermathecae, suggesting that the sterility of homozygous males is due to a failure of the males to mate.

Homozygous adults show more than a 95% reduction in movement compared with control flies.

Homozygous males and females have a severely reduced life span compared to both wild-type and heterozygous flies; homozygous males have a mean life span of 12.8 days (50% survival) and a maximum life span of 16.7 days (10% survival), while homozygous females have a mean life span of 13.9 days and a maximum life span of 21.3 days (wild-type values are a mean life span of 75.1 days and maximum life span of 80.1 days for males and a mean life span of 76.7 days and maximum life span of 84.1 days for females).

Homozygous adults show more than 50% reduction in the separation of the β lobes of the mushroom body, with full fusion of the lobes being seen in 40% of cases.