June 7, 2011

What are those red things?

So I was talking to a friend and she asks, "Do you know what these bright red things are?"  Yes, in fact this does happen to me ALL the time (I'm glad I love being an entomologist so I can answer this questions).  Fortunately, I knew the answer and could provide some "mostly" (I will explain this further in a later section) accurate information about the "critter" in question.

I'm guessing you know what's coming next.  A lot of information about the "critter" and you would be correct.  But before I go any further, I want to direct your attention to the label section below my blog.  I have decided to label blogs that are specific to arthropod identification, biology, and ecology as AFRAID BugZ.  ARAID stands for Angela's Fabulously Reliable Arthropod Information Document (unless someone can help me come up with a better abbreviation) and BugZ just because I wanted to do so. So when you see this as a label you know I'm providing specific information on the "critter" in question.

Alrighty then..... so what was that "red thing?"

Phylum Arthropoda (arthropods = "jointed foot")
Class Arachnida (Spiders & mites)
Order Acari (Ticks & Mites; largest order of arachnids)
Family Trobidiidae
Scientific Name: Trombidium sp. (short for species if you are new to the blog)
Common Names: Red Velvet Mite, Trombidiid Mite, Chiggar (yes, yes I'm going to talk about this {my sort of mistake you see}), Red Bugs, and Harvest Mite



I'm sure you have seen these tiny red dots running around on stones and sidewalks near soils particularly in the springtime.  These mites are considered to be one of the largest and that is because you can see them with your naked eye whereas most mites require a microscope in order to be seen.


Red Velvet Mite
Identification: Bright red color (seriously- this is the best description one of my references provided; I do admit that it is accurate but rather unhelpful particularly when you think of how many insects are bright red in color) and velvety (unfortunately, you really need to observe them under a microscope to see this characteristic); has 6  (larva) or 8 (adult) legs

Life History:

The adults lay eggs in the vegetation.  Larvae will emerge from the egg and crawl through the vegetation looking for a suitable host.  After a suitable host is obtained, the larvae will since their mouth parts into the outer layer of skin and excrete saliva into the epidermis (skin).  This saliva will help digest the underlying tissues which the larvae will feed on for a few days and then drop off. 


I bet you are asking yourself, "What is a parasitic form and what is a free-living form?" Have no fear I'm going to explain it to you.

Parasitic form is parasitic on arthropods and "related organisms." Please click to read more and see pictures of this aspect of their life history:  Water Mites on Arthropods 

Chiggers is a relatively common name used to describe parasitic arthropod life-stages, forms, which are annoying and/or pests to man. Okay- so my friend asked if the "red things" bite humans and if they are okay in gardens.  My responses were no and yes.  However, in my research I have found that there are some species in this family which attack humans, however, they considered to be uncommon. So, I'm wrong on the biting part but I have suggestions for prevention below.  I'm told that these chigger bites are quite irritating and appear unsightly.

Free-living forms are quite abundant in soil where populations are estimated to be several million/acre of land. The adults primarily eat insect eggs and are considered soil insects.  Soil insects provide a variety of garden benefits such as soil aeration due to tunneling activities and adding to the organic content by leaving their excretia (insect pee and poop) and dead bodies in the soil.  There are many soil insects which are harmful for gardens and plants but I do not include the that information here since it is not relative to the red velvet mite.

Pest Management:  so the adults are not pests but if the larvae are of the "chigger" variety then they would be considered a pest particularly if they find you "tasty." I'm not one of these unfortunate souls but I will offer my recommendations for prevention. First of all, for those of you who like to kill everything which looks like a creepy crawler I have very "bad" news for you....... Mites are difficult to kill.  Sorry, these are just the facts I'm reporting here.

So no killing methods today- we have repellents (these repeal the insects; think skunk spray and you have the right idea). There are two recommended repellents and they are dimethyl phthalate and diethyltoulamide otherwise known as DEET.  Dimethyl phthalate is commonly used in cosmetics such as hairspray, deodorant, and perfumes.  Chigger bites tend to be around areas where clothing is tight (bra lines, socks, waistband, etc.); I rarely get bitten but I also rarely wear socks or jeans when I'm working outside so you might try changing your clothing and applying some repellents.  However, if you do get bitten by chiggers try using a tincture of benzyl benzoate. Benzyl benzoate can be found in several flowers so you might take a look at that link if you are interested in preparing your own tincture. Yes, I could do a blog on tincture preparation, however, I have never tried it myself I just have instructions on how to prepare it.

I hope you find this information useful and happy gardening, weeding, insect watching, bird watching, whatever you do outdoors!

1 comment:

  1. PERFECT! We just started our first little packet of seeds on our new property. Russian red kale and we got these little guys on the freshly chicken pecked and pooped on soil that we had raked up for the little bed that the kale is in. I am so grateful to have found your blog and am able to rest assured that they are helping and not hurting. I am glad we did not go for the dish soap in a spray bottle or something. Thank you

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