What do holly blues eat?

Answered by Tom Adger

Holly blue butterflies, scientifically known as Celastrina argiolus, have specific dietary preferences at different stages of their life cycle. The caterpillars of holly blue butterflies primarily feed on the flower buds of holly and ivy. They have a fascinating way of obtaining their food by boring into the side of the bud and consuming the contents.

During the caterpillar stage, holly blue butterflies rely on the flower buds of holly and ivy as their main source of nourishment. These buds provide the necessary nutrients for their growth and development. As they bore into the buds, they consume the contents, which include the plant tissue and juices. This feeding behavior helps the caterpillars to obtain the energy they need to transform into adult butterflies.

Once the holly blue butterflies complete their metamorphosis and emerge as adults, their diet undergoes a shift. Adult holly blues primarily feed on nectar from various flowers. They have a preference for nectar-rich flowers such as bluebells, primroses, and hawthorns. By feeding on nectar, they obtain the sugars and energy required for their daily activities.

In addition to nectar, holly blue butterflies also have a taste for other food sources. They may feed on tree sap, which provides them with additional nutrients. Tree sap contains sugars and minerals, making it a valuable food source for these butterflies. They can access tree sap by feeding on the sap leaking from tree wounds or by puncturing the bark with their proboscis.

Interestingly, holly blues have been known to exhibit a behavior called “puddling” or “mud-puddling.” This behavior involves gathering on damp soil or mud, where they extract minerals and salts from the moisture. It is thought that these minerals play a role in their reproductive success, so they actively seek out these mineral-rich sources.

Furthermore, holly blue butterflies have been observed feeding on other unconventional food sources. They may occasionally feed on the juice from rotting fruit and even carrion. While these food sources are not their primary diet, they can opportunistically take advantage of them when available.

The diet of holly blue butterflies varies depending on their life stage. Caterpillars primarily feed on the flower buds of holly and ivy, while adult butterflies feed on nectar from various flowers. They may also supplement their diet with tree sap, minerals from damp soil or mud, and occasionally juice from rotting fruit and carrion. By diversifying their diet, holly blue butterflies can obtain the necessary nutrients for their survival and reproduction.