Natural Enemies of True Fruit Flies (Tephritidae) - USDA - aphis

Jeffrey N. L. Stibick
Conservation of Predators and Parasites
Small mammals which are known or observed to feed on fruit fly life
stages can be protected by not destroying their habitat or reducing
their numbers through hunting.
Insect Predation
There is apparently an inverse relationship between vertebrate and
invertebrate predation levels. Pupal predation by vertebrates
increases as small mammal density increases, but invertebrate
predation decreases (Cook, et al., 1995).
See Thomas (1995), who stated that ants, rove beetles, and spiders
were found to prey on Mexican fruit fly larvae which have left the host
fruit and have not reached the shelter of a pupariation site. The
predation rate was estimated to be 1-5%. Honey ants were recorded
as being incidental predators. Rove beetles were deliberate predators
during summer months.
However, pupae and emerging adults were subject to attack by salticid
spiders, an insectivorous ant, Pheidole sp. and especially exotic fire
ants, Solenopsis invicta, which were effective predators.
Approximately 29.5% of the fruit fly population was destroyed (70.5%
survival). This factor was most effective in the summer.
Ants may attack fruit fly last instar larvae on the ground as the latter
look for a place to pupate. Ant numbers may be increased by spraying
hosts with surcose; by encouraging benign (to hosts), host dwelling
honey-dew producing aphids; by providing food for ants during fruit
fly off season periods, or even by transporting ant nests into an area
on a small scale (Weseloh, 1994).
Similar results are known for other species of fruit fly. Ants
(unspecified spp.) are responsible for 10% of the mortality of the
soil-inhabitating stages of Bactrocera tryoni in Australia (Bateman,
1968). In Hawaii, Pheidole megacephala attacks Bactrocera dorsalis
larvae in fallen fruit, causing 36% mortality (Newell and Haramoto,
1968).
The interaction of ant species and prey may be summarized by stating
that ant species occurring in an area are important agents in the
regulation of pests and the rate of control varies spatially (ground,
bush, tree) and temporally (winter, spring, summer, fall) within that
area, depending on which species of ant is dominant. The dominance
pattern is typically a mosaic of territories, as ant colonies partition the
area in accordance with habitat requirements and competitive abilities
(generalized from Thomas, 1995). Ant colonies may be encouraged in
commercial areas by as little use of insecticides as is possible and
covering the soil in a grass sward (Bateman, 1968).
02/2004-01 Natural Enemies of True Fruit Flies 3-63
PPQ