The diet of moths varies significantly across species and life stages. Understanding what moths eat requires looking beyond a single food source, as their specific dietary needs are intricately linked to their developmental stage, from the larval form to the adult.
Adult Moth Diets
Adult moths generally consume liquids, using a long, straw-like proboscis. Nectar from flowers is a primary energy source for many species, such as hawk moths, which hover like hummingbirds while feeding. Beyond floral nectar, adult moths also feed on other sugary liquids like tree sap, rotting fruit juices, or honeydew, an excretion from aphids. Some species even obtain nutrients from less conventional sources such as bird droppings or animal dung.
However, a notable number of adult moth species do not feed. These moths, particularly those with short lifespans, rely entirely on energy reserves accumulated during their larval stage. Their brief adult lives are dedicated primarily to reproduction. For example, the Atlas moth has an underdeveloped mouth and lives off reserves for about a week, focusing solely on mating.
Larval Moth Diets
The larval stage, known as a caterpillar, is a period of intense feeding and growth. Most caterpillars are herbivores, primarily consuming plant matter like leaves, stems, roots, and fruits. This feeding is crucial for their development, as they gather substantial energy to transform into adult moths.
Many caterpillar diets are highly specialized, with some species feeding on only one or a few specific host plants. This specialization can be a survival strategy, allowing them to adapt to plant defenses or exploit uncontested food supplies. Caterpillars play a significant role as herbivores within ecosystems, influencing plant populations. Their feeding habits can impact plant health and affect plant defense mechanisms.
Moths with Specialized Diets
Beyond general plant matter, certain moth species exhibit highly specialized diets, often classifying them as household pests. Clothes moth larvae, including webbing and casemaking types, consume natural fibers. These larvae feed on materials like wool, silk, fur, feathers, felt, and leather, which contain keratin, a fibrous protein they can digest. They seek out undisturbed, dark areas such as closets or storage chests for feeding.
Pantry moths, such as the Indianmeal moth, target stored dry goods. Their larvae feed on items including grains, cereals, flour, dried fruits, nuts, and pet food. These moths often enter homes through already infested products. Other specialized diets include larvae that feed on fungi and lichens, such as some tineid moths. Gypsy moth caterpillars, for instance, prefer leaves infected with fungal spores for additional nutrients. While less common, some moth larvae are predatory, consuming other insects or animal products like hooves and horns of dead ungulates.