Complex sentence: The presence of the ants is beneficial to the aphids as the ants deter and remove predators that might feed on the aphids; these include the larvae of the midge "Aphidoletes aphidimyza" and parasitoids which lay their eggs in the aphid nymphs.
Split into simpler sentences: The presence of the ants is beneficial to the aphids as the ants deter and remove predators that might feed on the aphids. These include the larvae of the midge "Aphidoletes aphidimyza" and parasitoids which lay their eggs in the aphid nymphs.