The economic impact of insects can be positive or negative, depending on the species. For example, insect pests that inflict costly property damage obviously have a negative economic impact on homeowners. Some insect pest species in Massachusetts that are economically significant for causing property damage include eastern subterranean termites, black carpenter ants, and several wood-boring beetle species. The eastern subterranean termite is the most economically damaging insect pest species in the country, as they inflict more than one billion dollars in structural damages annually in the US. Insects like bees and wasps are responsible for pollinating crops and wild vegetation, making them economically beneficial insects. Some insects are exploited for profit, such as silkworms, which are raised on an industrial scale to produce silk fabrics. European honey bees raised in US apiaries produce billions of dollars worth of honey annually, and as it turns out, certain ant species obtain honey in a similar way.

Aphids are small insects that possess needle-like mouthparts that they use to penetrate plant stems and roots in order to suck out sweet-tasting nectar. More than 1,350 aphid species have been documented in the US, a minority of which are considered major agricultural and yard pests due to their habit of feeding on the internal fluids of cultivated plants, resulting in costly plant damage. Aphids harm plants by sapping them of their internal fluids, and they often coat plant leaves with their sugary excrement, known as honeydew. Honeydew on leaves becomes moldy and inhibits photosynthesis, resulting in plant death. Since ants generally love sugar-rich food sources, ants follow aphids around in order to feed on honeydew.

Many ant species in the Acanthomyops subgenus rely on honeydew as their sole food source, and several ant pest species like black garden ants and black carpenter ants are often found infesting houseplants along with aphids. Ants can induce aphids into secreting honeydew by using their antennae to caress certain parts of an aphid’s body, a process known as “milking.” In order to protect their source of honeydew, ants protect aphids from predators, even going as far as to dig cavities in the soil in order to provide aphids with a hiding spot. Eliminating aphid infestations in houseplants is usually relatively easy, but infestations become more complicated when aphids are accompanied by ant pests. Ants behave the same way toward other honeydew-secreting plant pests, such as scales and mealybugs. In order to eliminate a dual infestation of ants and aphids from houseplants, ants must be exterminated first.

Have you ever found both ants and aphids in your house plants?