Amara aulica is a ground beetle, a member of the Carabidae family, commonly found across various habitats in Europe and Asia. These beetles are typically small to medium-sized, ranging from 6 to 10 millimeters in length, and possess an elongated, oval body with a shiny exoskeleton that can vary from black to dark brown. They are primarily nocturnal, emerging during the night to engage in various activities, including searching for food.
Main Dietary Components
Amara aulica exhibits an omnivorous diet, consuming both plant matter and small invertebrates. A significant portion of its diet consists of seeds, making it an important predator of various plant seeds, including those from cruciferous plants like Capsella bursa-pastoris and Stellaria media. This ground beetle also consumes seeds from other plant species such as Artemisia vulgaris, Tripleurospermum inodorum, Urtica dioica, and Cirsium arvense. Beyond seeds, Amara aulica also preys on small insects and other invertebrates. These include aphids, caterpillars, and the larvae of other insects, as well as mites and worms. In addition to living organisms, their diet can also include fungi and dead organic matter.
Seasonal and Life Stage Dietary Shifts
The diet of Amara aulica can vary depending on its life stage and the availability of food throughout the seasons. While adult beetles are omnivorous, their larvae often exhibit a more specialized diet. Amara aulica larvae are known to be carnivorous, primarily feeding on small insects, their larvae, eggs, aphids, and mite juveniles. However, larvae can also consume seeds and may even depend on them for successful development, demonstrating a degree of omnivory.
The feeding niche of the larvae expands as they mature through their instars. This flexibility allows the species to utilize different food resources as they become available. Some ground beetle species, including those in the Amara genus, are known to shift their diet seasonally, alternating between insect prey and weed seeds to exploit abundant resources at different times of the year. This adaptability ensures their survival.
Foraging Strategies
Amara aulica employs specific strategies to locate and consume its diverse diet. As a nocturnal species, it primarily forages under the cover of darkness, emerging from hiding places to search for food. The beetles are adept at finding food through random searching, but they can also use chemical cues to locate specific food sources, particularly seeds. They are known to forage for seeds directly on the ground.
When consuming seeds, Amara aulica utilizes its powerful mandibles, which are adapted for handling and breaking apart the hard outer coats of seeds. These beetles may also climb plants to feed on ripening seeds. The foraging behavior of Amara aulica can also be influenced by environmental factors, such as the perceived risk of predation, which may lead them to increase their mobility while searching for food.