originally written by Jedediah and updated by Stacy Griffith
Need to identify a bug? Place it in a cup of water so you can take a clear photo of it or use a magnifying glass to inspect it.
Insects have six legs and three body parts that are usually clearly visible, the head, the thorax (the breast) and the abdomen. Most of them have wings, although those might not be clearly visible, some insects can hide them in a sort of pouch on their back (like earwigs) and some insects have no wings at all. The vast majority of insects that you might find in your crabitat are beneficial, harmless or a nuisance at most. Usually you can get rid of them by doing a deep clean.
Common insects are:
Booklice aka Paperlice
Very often described as walking grains of sand, booklice are tiny and usually white to grey in colour. They are often hard to get rid of, probably because they can live in the rest of the house, too and quickly return to the crabitat where they find ideal conditions. They are harmless and even beneficial because they feed on mold and fungi.
Interesting fact: there are no male booklice, the females “clone” themselves, they are all more or less genetically identical.
Springtails are white, brown, green red, yellow or grey and very small, no bigger than 1/8 inch. They can hurl themselves in the air with a fork like tail they hold under their body, but they have no wings. Springtails are often found in flower pots and they need a humid atmosphere to survive, so the crabitat is ideal for them. They are beneficial because they will feed on crab poop, leftover food and other decaying material, they are excellent cleaners.
Interesting fact: Springtails are among the oldest insect species, they have been around for at least 400 million years.
Fruit flies or Drosophila
You probably know them, these are the flies that turn up whenever a piece of fruit is left for too long. The most common species is Drosophila melanogaster, around 2 mm in size, usually red eyes and a brownish colour (other species are a bit bigger or smaller, up to 4 mm). They feed on decaying fruit and breed rapidly (two weeks between generations) and can become a nuisance in the crabitat, although they are not harmful. To get rid of them, place a glass with wine, beer or fruit juice mixed with vinegar and a drop of dish liquid next to the crabitat, the flies will drown in the liquid. It’s best to stop feeding fruit for that time so that the larvae won’t find any food.
Interesting fact: Fruit flies mutate easily and you can breed really weird flies in a short time (no wings, small wings, white eyes, no eyes ect.)
Humpbacked Flies or Phorid Flies
Photos of Phorid Flies
This article states that Phorid flies do indeed infest many small invertebrates including hermit crabs: http://bugguide.net/node/view/14163
Excerpt from this page:
“Other Common Names
Humpbacked Flies, Coffin Flies
Explanation of Names
Phoridae Curtis 1833
Scuttle Flies: refers to their habit of running quickly in short bursts, followed by short pauses; Coffin Flies: larvae can be a pest in mausoleums, entering coffins and feeding on the bodies inside
376 described species in 50 genera in North America (half of the fauna are Megaselia), >4,200 described species in >300 genera total(1), and many times that number undescribed(2)
Adult 1-7 mm (many 2-4 mm)
Tiny black, brown, or yellowish flies with a humped back, a low small head, and dark eyes; costal vein extends only about halfway along anterior wing margin; two strong longitudinal veins anteriorly (in costal area), and 4-5 weak veins posteriorly, not connected by cross-veins; hind femora enlarged and flattened, and hind legs long; antennae appear 1-segmented
The way of life of most species is unknown. A few common, synanthropic species, especially Megaselia scalaris, Dohrniphora cornuta, Megaselia rufipes, and Puliciphora borinquenensis, live in almost any type of decaying organic material. Larvae of D. cornuta often build up to huge populations when sewer pipes break and nutrient-rich water soaks into the soil; adults emerge in swarms through drain pipes in affected houses. The most commonly noticed species of phorid is M. scalaris, which is found in a number of filth-fly situations, and also infests nearly every type of invertebrate and small vertebrate cultures, such as insect zoos, tarantulas, lizards, snakes, hermit crabs, etc.
Most species, however, are probably specialized scavengers, predators, parasitoids, and even true parasites. Many Megaselia species are found in fungi, some feeding on the fungus (including a few commercially important pests), others probably feeding on sciarid larvae. Many species are found in buried carrion, away from competition from blow flies and other agressive species. One such species, the coffin fly, is found commonly on buried human bodies. Small invertebrate carrion, such as snails, slug, and dead insects, are also breeding sites for phorids. Species of the genus Anevrina are found in the burrows of mammals, probably as scavengers.
Many species are associated with ants, as commensals in ant nests or as parasitoids. The largest group of ant-parasitoids, Apocephalus, are known as ant-decapitating flies because they develop inside the ant’s head, and some species cause the ant’s head to fall off, sometimes before the rest of the body stops moving. Most North American Apocephalus attack ants in the genera Camponotus and Pheidole, but other hosts are used here and elsewhere. Another ant-parasitoid genus is Pseudacteon, whose South American species are being used in attempts to biologically control imported fire ants (since the native Pseudacteon are not doing the job!).
Other parasitoid genera attack millipedes (phorid genus Myriophora), fireflies and cantharid beetles (some Apocephalus), bees (some other Apocephalus), scale insects, beetles, and probably many other hosts we do not know about.
Some phorids have wingless or short-winged females. Some of these are commensals or parasitoids associated with ants, others are scavengers that are apparently not associated with ants.
They look very much like fruit flies, but if you take a closer look, you can see a hump. Apart from that, they can be recognized by the way they run around: very fast, always stopping after a short distance and very reluctant to fly. Humpbacked flies are the only insects that have been found in crabitats that can be harmful to the crabs, at least I haven’t heard of any other. The adults and larvae can feed on almost anything including flesh, so if a crab has an open wound the larvae are able to get into the wound and eat the crab from the inside out. Some species are able to lay their eggs into healthy animals, but those are parasites of a certain species and as far as I know, no phorid fly preys on land hermit crabs specifically. To get rid of them, do a deep clean, bake or boil everything, bathe the crabs and I recommend keeping the crabs in an ISO tank that’s easy to clean for six weeks to make sure there are no eggs or larvae left. Clean the ISO every week (change substrate and hiding places, boil or bake the hiding places you want to use again) and make sure the food doesn’t spoil.
Interesting fact: Phorid flies have been known to survive by eating shoe polish – you somehow have to admire a bug that’s so adaptive
http://ohioline.osu.edu/hyg-fact/2000/2144.html (dead link)
Fungus gnats are small (2.5 mm), black flies. Both the adults and the larvae feed on decaying and living plant matter, the adults eat pollen, too, and they are harmless to the crabs, but can become a pest when they multiply too much. To get rid of them, you can use yellow sticky traps. Those are sticky on both sides and can be attached to the lid of the crabitat where the crabs cannot reach them.
Silverfish and Firebrats
Those are rarely found in crabitats, but I will include them anyway. Silverfish are often found in bathrooms, firebrats need a high temperature to breed and are sometimes found in bakeries and other warm places. Both look similar, 1/3 to ¾ inches long and carrot shaped without wings. Silverfish are silver in colour and really look a bit like fish. Firebrats are hairy and often have dark grey stripes on their body. Both feed on almost anything at all, including cereals, fish food ect. They are harmless and won’t breed in the crabitat because it’s too humid and too cool for the firebrats and probably too hot for the silverfish, so they will disappear eventually. They mostly get into crabitats by chance.
Interesting fact: Both can survive and even thrive on a steady diet of wallpaper, tissue paper or similar things. Like springtails, they have been around for a very long time.
There are more insects that can be found in your crabitat, especially small flies and other tiny insects living in the soil, but those are the species that people have found very often and that were positively identified. If you find something else, try to take a picture of make a drawing so that the bug can be identified.
Arachnids are such bugs as spiders, scorpions, mites and other bugs related to spiders. They have two body parts, the thorax and the abdomen, no wings or antenna and eight legs.
There are thousands of species of mites and it’s extremely hard to identify them. They come in all colours (white, grey, black, brown, bright red etc.) and many sizes. Only comparatively few species are harmful for the crabs. The rule of thumb is: if you find them in the food dish or the rest of the crabitat, they are probably harmless. If you find them on the crab, especially on the joints, the abdomen or the mouth parts, they are predatory and harmful.
Interesting fact: Some mites feed on pollen and hitch rides with hummingbirds, racing up the beak and then down again into a new flower. Others hitch rides with flying insects to reach new plants and some not only hitch a ride, but also suck the haemolymph (insect blood) on the insect that’s carrying them. Many species change their dietary habits depending on their age.
Click on the links at the bottom to see pictures of mites hitching rides with insects:
Other mite pictures:
Bookscorpion or Pseudoscorpions
A rare guest in crabitats that sometimes comes with moss or leaf litter is the bookscorpion. They look like tiny (1-4 mm) scorpions, but have no tail and are absolutely harmless unless you are a springtail or a fruit fly.
Interesting fact: One species, Chelifer cancroides, does live in books and this species gave the whole order its name. They dance with each other during mating and they build a small nest from grains of sand, moss and silk. The females produce a nourishing substance for their babies, so in a sense they nurse their babies.
Other bugs you might find
Woodlice, also called pillbugs, sowbugs or rolypolys, are the only crustaceans that live permanently on land without any contact to water. They need a humid atmosphere to breathe, that’s why they are sometimes found in crabitats. Woodlice are harmless and feed on decaying plant matter. They are often used as tank cleaners with reptiles, phasmids and other animals.
http://www.geocities.com/CapeCanaveral/Hangar/7649/wlice.htm (DEAD LINK)
Millipedes and Centipedes
Both belong to the Subphylum Myrapodia (this means “numerous feet”) of the Phyllum Arthropoda (“joint-legged”), which insects, arachnids and crustaceans belong to, too. Millipedes (“with a thousand feet”) have two legs on either side per body segment, centipedes (“with a hundred feet”) only one. They sometimes turn up in crabitats and come from moss, leaf litter or with live plants. Millipedes are vegetarians that feed on decaying plant matter, centipedes are predators. The centipedes you might find in your crabitat are very small and are no danger to the crabs.
Interesting fact: Millipede males of some species can breed only after every second molt.
Bugs that help getting rid of other bugs
You can purchase predatory mites or insects that will feed on some bugs in your crabitat and then die when they find no more prey. This is a efficient and absolutely crab-safe method to get rid of bugs, without stressing the crabs by doing deep cleans ect.
Here’s one website that offers such bugs: