Astigmatina

Astigmatine Mite

Astigmatina

Astigmatina, also known as astigmatine mites, dust mites, grain mites, fur mites, and feather mites are an order of mites that have been around for about 389 million years and live within our soils and even have evolved to be able to survive in our households [3]. They can be found in many different areas of the world from forests to deserts and even inside other organisms as parasites and mutualistic relationships. It is also to note that Astigmatine mites are a subset of Oribatida.

Abundance and Diversity

Astigmatine mites can be found worldwide (excluding polar regions) and are one of the more uncommon mites found in soil. They are often found in numbers of 10,000-16,000 individuals per square meter [5]. Astigmatine mites prefer moist soil and habitats which is why they can be found in different environments like forests, deserts, freshwaters, oceans, agroecosystems following harvest, manures, and are commonly found in households [5]. These mites have adapted throughout their time to better themselves in specific niches; astigmatine mites have been known to be found infesting stored foods and animal feed for both household pets and agricultural animals [3]. It is also important to note that these mites are a very hardy class of mites and while they prefer to live in moist high temperature zones they can easily adapt to extremes like living in deserts in a more dry climate [5]. While these oribatid mites have lived on Earth for hundreds of millions of years, it wasn’t until the 18th century when scientists began studying the mites later called feather mites in birds to more recent years where the mites have been studied for their role in agriculture and effects on allergies in humans.

Scientific Classification

Taxonomy

Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Subclass:	Acari
Superorder:	Acariformes
Order:	Sarcoptiformes

Biology

Astigmatine mites are one of the less common classes of mites, with the Oribatided mites being the largest of the mites. The astigmatine mites have roughly 4500 identified species and another 90,000-180,000 additional estimated species yet to be identified [1]. They are soft bodies mites that are white to brown in color [2]. Astigmatine mites have an average size of 0.15mm to 2mm depending on the species [2]. At the larval stage they have six legs and as they mature and reach their adult stage, they develop eight legs and a 2 segmented chelicerae (mouth part similar to that of arachnids) [3].

Life Cycle

Astigmatine mites are an egg laying species of mites that reproduce sexually. These mites go through a number of different stages in life in which each stage they develop new features to help with their survival and reproduction. The first stage is the egg stage where the larvae is developed then they move to the second stage, the Hexapod Larva stage, at this stage they develop six legs and begin feeding until they molt and begin their third stage. In the third stage, the Protonymph stage, they develop eight legs and their first pair of genital papillae (reproductive organs) and become very active feeders. The fourth stage, the Deutonymph stage, is not found in all astigmatine mites but in many; this stage is when the mite will find a host in an animal or insect to call home. The fifth stage, the Tritonymph stage, is the stage in which they grow a second pair of genital papillae. The final stage, the Adult stage, is when the mite has fully developed its reproductive system and reproduce with male and female mites to then begin the life cycle all over again by laying eggs [3].

Feeding Habits

Astigmatine mites are a very diverse group of mites that feed on a variety of different food sources. Many feed on fungi, plants, and algae but other more specific feeders will find hosts to feed off of and infest the nests of insects, mammals, feathers of birds, gills of fish where others feed on animal waste and dead animals. When these mites find hosts they have the potential of causing very serious diseases or minor inconveniences like allergies towards the mites [1].

Impacts on Soil

Astigmatine mites, similar to many other mites, contribute to feeding on and breaking down organic material in soil and depositing nutrients back into the soil. They help decompose matter and release necessary components back into the soil to create rich soils. While they can cause harm to crop and harvested materials, they still play an important role in regulating soil health [6].

References

[1] Astigmata - an overview | ScienceDirect Topics. (n.d.). . https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/astigmata.

[2] Astigmatina. 2024, November 5. . https://en.wikipedia.org/wiki/Astigmatina

[3] Astigmatina (Astigmata, Acaridida). (n.d.). . https://idtools.org/id/invasive_mite/Invasive_Mite_Identification/key/Major_Mite_taxa/Media/Html/Astigmatina.htm.

[4] Coleman, D. C., D. A. Crossley Jr., D. C. Coleman, and D. A. Crossley Jr. 2004. Fundamentals of Soil Ecology. Elsevier Science & Technology, Chantilly, UNITED STATES. https://ebookcentral-proquest-com.gate.lib.buffalo.edu/lib/buffalo/reader.action?docID=288744&ppg=70

[5] Lagerlöf, J., and O. Andrén. 1988. Abundance and activity of soil mites (Acari) in four cropping systems. Pedobiologia 32:129–146. https://www.sciencedirect.com/science/article/pii/S0031405623002251

[6] Soil Mite - an overview | ScienceDirect Topics. (n.d.). . https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil-mite.