“Red mite” is a common term for various small, reddish arthropods. These tiny creatures, often barely visible, belong to diverse mite species. Despite similar appearances, their diets and habitats vary significantly. Understanding their specific consumption helps identify them and their potential impact.
Blood-Feasting Red Mites
Some red mites are obligate blood feeders, with the poultry red mite (Dermanyssus gallinae) being a prominent example. These mites primarily feed on bird blood, especially chickens, posing a significant concern in poultry farming. They are nocturnal, emerging from coop crevices at night to feed on resting birds. Before feeding, they appear grayish-brown, turning distinctly red after engorging on blood.
Poultry red mites possess specialized mouthparts for piercing host skin and drawing blood. While birds are their primary hosts, they can bite humans and other mammals, though they typically do not complete their feeding cycle on these incidental hosts. Human bites can cause itching, skin irritation, and dermatitis, but mites do not remain on human skin for extended periods.
Severe infestations in poultry can lead to anemia, reduced egg production, and even death in young birds due to significant blood loss. Their rapid life cycle allows populations to grow quickly. These mites hide during the day in dark areas, making them difficult to detect until their population is substantial.
Plant-Sap Feeding Red Mites
Many common red mites are plant feeders, drawing nutrients from plant sap. Spider mites, such as the two-spotted spider mite (Tetranychus urticae), are widespread examples. These mites feed by piercing individual plant cells, typically on leaves, and extracting chlorophyll and cell contents. This feeding causes visible damage like tiny pale spots or stippling. Heavy infestations can lead to bronzing, yellowing, and premature leaf drop.
Spider mites have a broad host range, affecting hundreds of plant species including many vegetables, fruits, and ornamental plants. They use stylet-like mouthparts to penetrate plant cells and extract nutrients. The European red mite (Panonychus ulmi) is another plant-feeding species that primarily infests fruit trees like apples, pears, plums, and cherries. Its feeding causes a characteristic bronzing of leaves due to the removal of cell contents.
Clover mites (Bryobia praetiosa) are also common plant feeders, primarily consuming sap from grasses, clover, and other turf plants. They insert their mouthparts into plant tissues to suck out juices. These mites often appear around homes, especially in spring, as they migrate from lawns onto building surfaces. While they do not bite humans, crushing them can leave a reddish stain, which is due to their body pigments, not blood.
Specialized Diets and Habitats
A red mite’s diet is intrinsically linked to its habitat, dictating where and how it lives. For instance, some predatory mites, which can appear reddish, feed on other mites or small insects and their eggs, distinguishing them from plant or blood feeders. These beneficial mites, such as species within the genus Balaustium (often called red velvet mites or concrete mites), are predators of soft-bodied arthropods and insect eggs. Some Balaustium species are also known to feed on pollen, algae, and fungal spores.
Other predatory mites, like Zetzellia mali, specifically target spider mites and rust mites, including the eggs of European red mites. Similarly, Phytoseiulus persimilis is a bright reddish-orange predatory mite that feeds exclusively on plant-feeding spider mites, particularly those that produce abundant silk. The presence of these predatory mites is often tied to environments where their prey is abundant, such as in orchards or gardens.