Astigs
Astigmata
Classification
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Subclass: Acari
- Superorder: Acariformes
- Order: Astigmata
Pronunciation
How to pronounce Astigmata: //æsˈtɪɡmətə//
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Images
Summary
Astigmata is a diverse clade of mites characterized primarily by their soft bodies, lack of stigmata, and diverse ecological roles ranging from pests in human environments to beneficial organisms in agricultural ecosystems.
Physical Characteristics
Astigmatan mites are usually soft-bodied and range from white to brownish in color, measuring between 0.15 mm to 2.00 mm in length. They typically lack stigmatal openings, peritremes, or prodorsal sensilla. The mouthparts are usually exposed, with a pair of chelicerae that are 2-segmented and chelate-dentate in shape. Larvae have six legs, while nymphs and adults have eight legs. Their genital opening varies based on life stage.
Identification Tips
Look for soft-bodied mites that lack the typical stigmata found in other mite groups. Examination of their color and size, along with the number of legs at different life stages, can help in identification.
Habitat
Astigmatina are found in a variety of habitats, including decaying plant tissue, dung, mud, tree holes, mammalian nests, human houses, stored foods, and in association with vertebrates and insects.
Distribution
Astigmata are found worldwide, although specific distribution can vary significantly by family or ecological association.
Diet
Many Astigmatina are detritivorous, feeding on decaying organic material, while others can be herbivorous or parasitic, feeding on animal exudates, bacteria, fungi, and algae.
Life Cycle
Astigmatan life cycles typically involve a series of stages, beginning with eggs, followed by larvae (6 legs), nymphs (8 legs), and adults (8 legs). Some nymphs have heteromorphic stages, particularly deutonymphs, which are adapted for dispersal or survival in challenging environments.
Reproduction
Males have a postcoxal aedeagus, and females possess a bursa copulatrix for sperm reception, with varied structures for reproduction in different taxa.
Ecosystem Role
Astigmatan mites play important roles in various ecosystems as decomposers, parasites of pests, and as part of the soil food web.
Economic Impact
Certain species are pests in homes and stored products, contributing to allergies. Parasitic species are known to cause scabies and mange. However, some species are beneficial, such as Hemisarcotes that help manage plant pests like scale insects.
Health Concerns
Parasitic astigmatans can cause skin conditions such as scabies and zoonotic diseases.
Collecting Methods
- Light traps
- Soil sampling
- Nest sampling from bees and other animals
- Dust sampling from indoor environments
Preservation Methods
- Ethanol preservation
- Freezing for preserving morphological features
Evolution
Astigmata represents an important evolutionary clade of mites that have adapted to numerous ecological niches, moving away from the soil-dwelling lifestyle of their oribatid ancestors.
Similar Taxa
Misconceptions
Astigmata are often confused with other mite groups; however, they lack stigmatal openings, distinguishing them from many other mites.
Tags
- mites
- Astigmata
- arachnids
- pest management
- ecology