A guide to mites

Poxicator · #1 (**permalink**) 03-10-2009, 01:41 AM

MITES
abridged from Nick Lear's, (zoologist) posts

DO NOT WORRY ABOUT MITES!!! The hysteria about mites all seems to stem from Stanley Schultz (The Tarantula Keeper’s Guide) and has just been repeated; how/why he formed such a distorted view I’ve no idea. A lot probably has to do with their rapid appearance on the corpse of a dead T – but, they are like vultures, literally smelling death and within hours appearing out of nowhere (dormant eggs and individuals hatch/emerge) in their masses to scavenge/feed on the corpse.
The vast majority of mites you will come across will be detritivores/scavengers or predators and should be encouraged, if you’re very lucky you’ll get some parasitic ones (marvel at, and observe them!!!). An overabundance of one particular type just indicates that something has caused the population to get out of balance – just try and correct it; dry the soil out a bit, remove dead feeders, etc. DO NOT PANIC!!! Don’t replace the substrate (maybe scoop-out any particularly large concentrations), don’t try to remove mites from your T – such actions are FAR more stressful/damaging to your T than any minor irritation a few thousand mites may cause.

Mites are detritivorous’ eating any dead organic matter that they can eek a living out of. If there’s not much ‘preferred’ food around like dead prey items, faeces, rotting vegetable matter, etc. they will subsist on the organic particles in the soil/substrate. They WILL be in the cleanest of enclosures in their 100’s/1,000’s. They have the capacity to reproduce rapidly and in great numbers and do so when there is ample ‘preferred food’ around – this is when you notice them; their populations have now reached 10-100,000’s +! They do NO harm to your T but are unsightly – if you want to reduce (notice I don’t say ‘get rid of them’!) their numbers to acceptable levels dry the enclosure out a bit and be a bit more ‘house proud’ removing dead food, waste food boluses, etc. Within a few weeks the population will have crashed back down to the ‘normal’ unnoticeable levels.

Where did they come from?
Mites are hitchikers, they'll attach themselves to a host knowing they'll soon arrive at a new food source. The most likely introduction is from your feeder insects but eggs can remain dormant for long periods. Therefore the answer of removing them is very apparent - provide a source of food and they'll leave the host to feed. I've personally tried to remove mites from feeder insects by placing dead locusts or very wilted lettuce in the tubs. Obviously this will encourage the population to increase but it will also free your feeder insects from mites. A water source will make a great new home for the mites. Its then merely a matter of removing the crickets into another enclosure and the problem is vastly reduced.

The type of mite usually found on crickets is Sancassania sp. during their phoretic (hitchhiking) stage. These mites have an interesting life history… Eggs are laid randomly in/on the soil/substrate, these hatch into 6-legged prelarvae which feed on fungi/mold, these molt into larger larvae which subsequently molt into 8-legged protonymphs. Now depending upon conditions and food availability they either molt into tritonymphs (if food is plentiful and conditions good) or molt into deutonymphs (if food is scarce or conditions poor). At the tritonymph stage the diet switches to nematodes and other microscopic soil inhabitants. The deutonymph stage is a non-feeding/dispersal stage; they search-out anything large enough that walks by and hitch a lift on them. The deutonymphs stay attached to their ‘vector’ for an indeterminate length of time eventually dropping off. Once they’ve dropped off, if conditions are favourable they molt into tritonymphs and continue their life-cycle (eating nematodes, etc.) and eventually molting into adults and breeding. If conditions are not favourable they go into a kind of suspended animation and remain dormant until condition become favourable again – in fact what they do is kind of prepare to molt into tritonymphs but instead the old skin hardens and dries around them forming a protective shell/cyst, they then molt directly into adults when conditions are OK again.
For crickets the deutonymph stage can be real problem; they clog-up the mouth parts preventing feeding and block spiracles preventing breathing. With a severe infestation crickets die of starvation or suffocation. If a T eats an infected cricket the deutonymphs will transfer to the T but they are not such a problem for the T. They tend to accumulate in-between and around the chelicerae and spread to the soft membranes around the carapace and base of legs. B’cos of the way Ts feed they cannot prevent it from feeding and b’cos T have better mobility when it comes to self-grooming their book-lung openings I’ve so far never seen any around the booklungs. [I think it unlikely that they would ever enter the book lungs anyway.] They are probably an irritation to Ts but NOT harmful. I think it is more stressful for the T trying to remove them – they will drop off naturally and are not feeding on the T, merely hitching a ride. You obviously wouldn’t go deliberately feeding a heavily infested cricket to a T but I certainly don’t worry about them when I do see them on Ts.
You’ll encounter other types of mites in T enclosures but none of them are likely to be a problem. Indeed many species such as the ‘cricket mite’ may be your best insurance against nematodes.

Sterilise your substrate?
If you want to sterilise substrate you need to do it properly… It needs to be damp for a start, NOT dry. When I’ve done so in the past I’ve put about 2-3 litres of damp coir in a bowl and microwaved for about 10 mins; taken it out then stirred/mixed it up and put back in for another 5 minutes. Then take out and put clingfilm over the bowl and leave to cool – it is this, trapping steam that penetrates throughout that ensures that it is sterilised rather than the microwaves
However, I don’t bother sterilising substrate anymore – anecdotal observations over the past couple of years is that such sterile substrate suffer far more ‘out of control’ infestations of mites, mould, etc, than a ‘living’ substrate. The substrate in all of my containers contain a range of mites (detritivours, fungus eaters, and predatory), springtails and tropical woodlice. When I rehouse a spider I always seed the new container with a few spoonfuls of the old substrate. My reasoning is that a balance will be reached much quicker if you introduced a population of predators and prey rather than with a sterile substrate that WILL be rapidly colonised by airborne mite eggs/deutonymphs, fungal spores, etc. which can then grow/reproduce out of control and unchecked by predators.

Cleaner inverts
Tropical woodlice and springtails make excellent additions to moist substrates and will compete with mites for the same food. As they are far quicker than mites you'll notice a reduction in mites as the food available to them decreases. Its also rumoured that they eat or attack the mite eggs. These are the dustmen of your substrate, cleaning up uneaten food, moulds and fungus but they require a level of moisture to live and breathe. You can use woodlice found in your garden but these must be quarantined for a fortnight before introducing into your enclosure. This will help to flush out any unwanted elements that could be detrimental to your tarantula if eaten. The woodlice and springtails will be self sufficient and self regulating so no need to worry about population explosions.

Types of mites
There are two broad classes of parasitic mites – protelean and non-protelean. Protelean mites are highly evolved and are only parasitic during part of their lifecycle (usually the larval stage); non-protelean mites are rather primitive and are thought to be parasitic at every stage.

Common examples of protelean mites are Leptus spp., nicely shown in the second photo (the red mites on the opilione) in this thread Arachnoboards - Powered by vBulletin. Note their size/body shape and more interestingly how they are attached/feeding. They are attached only by their mouths! Once they bite they secrete a type of glue that welds their mouth to the host – to detach they molt. You may conceivably find the odd such mite on a T as they are very cosmopolitan in their choice of host. They can attach almost anywhere where they can’t be rubbed off by the host – their mouth parts are highly specialised and are capable of drilling through the toughest cuticle, they are however usually found on the softer membranes (=why waste energy). They are nothing to worry about though – the ‘damage’ they’d do in terms of loss of hemolymph is minimal (unless on a very tiny sling) and there is no hope of them proliferating as they have rather complex lifecycles where pre-larvae and adults have different habits/lifestyles that are not likely to be available in captivity (many spp. are aquatic at other stages).

Non-protelean mites of the genus Ljunghia are the ONLY species that have been recorded from Ts (at least in the ‘scientific’ literature). They are however very uncommon and their complete life-cycle is not known. They are relatively primitive parasites – they attach to their host by clinging on with their legs and their mouth is held in place by tiny pincers that ‘lock’. They are only capable of piercing the thinnest cuticle and if dislodged whilst feeding will die as their mouthparts are effectively ripped-off. They therefore attach to a very specific zone – the zone that splits when a T molts, hence they remain in place. These could potentially proliferate in captivity but their complete life-history is unknown and not understood – Alex Fain* failed to keep them alive in captivity so to did Barry O’Connor (@Michigan, pers. comm.) who finally obtained an infested T about 10 years ago after 30 years of looking! So, if you do ever find parasitic mites on a T and manage to breed/maintain them you are VERY lucky and there are specialists out there who would love to know your secrets!

There are two completely different morphologies that characterise parasitic mites. Firstly, the mobile stage – these look comparatively long-legged and have small triangular shaped bodies which look dull due to closely packed bristles. [They look quite similar to the predatory mite 'Hypoaspis miles'.] These really bomb-around, scuttling all-over the host looking for a suitable place to settle-down and feed (it takes them several days to decide upon a spot). The feeding stage is completely different – they are not like some vertebrate mites that feed then move on, feed again, etc. Once they’ve selected a place to feed they ‘lock on’ and remain totally static and rooted to that spot, feeding until they molt; with the non-protelean mites the mouth parts are imbedded in the cuticle locked in place by tiny pincers and they hold-on tight with their legs, with the protelean mites they literally glue themselves to the host by the mouth and then let go with their legs. Such feeding mites are huge and shiny looking; just like minature blown-up balloons (ranging from pear to sausage shaped). To remove a feeding mite you’d have to tug at it with forceps – it wont come off easily – and you risk ripping the exoskeleton of the T in trying to do so. A good rule of thumb would be if you can remove the mites easily manually then they’re harmless and you’re wasting your time; if they’re too fast for you to remove or stuck fast you shouldn’t be trying to remove them anyway!

Hopefully this information provides a good insight into mites, of which there are over 13,000 species and aleviates some fears. Keeping your enclosure clean is the best preventative, drying your enclosure out is the easiest control method, but never expect to permanently eradicate. Remember, a good balance of living organisms creates the best environment and reflects what's found in natural habitats.

invertasnakes · #2 (**permalink**) 03-10-2009, 01:43 AM

Awesome post mate.

STICKY STICKY STICKY!!!!!!

Slinkies mum · #3 (**permalink**) 03-10-2009, 03:15 AM

Quote:

Originally Posted by invertasnakes

awesome post mate.

Sticky sticky sticky!!!!!!

agreed!!!!

ph0bia · #4 (**permalink**) 03-10-2009, 08:37 AM

That's brilliant, Pete. I'm tempted to copy that into a .pdf and add it as an "Extra" in the caresheets topic (with your consent?). I was thinking to start adding more than just caresheets there, but husbandry advice too.

Absolutely brilliant post, will help many, many people here.

STICKY THIS NOW O' GREAT AND POWERFUL MODERATOR

khaostim666 · #5 (**permalink**) 03-10-2009, 08:54 AM

As above STICKY

Simon M · #6 (**permalink**) 03-10-2009, 09:10 AM

Nice one! Will hopefully put mites to bed!!

garlicpickle · #7 (**permalink**) 03-10-2009, 10:00 AM

Sticky please

kazzz32 · #8 (**permalink**) 03-10-2009, 10:10 AM

Great info, thank you.

AshMashMash · #9 (**permalink**) 03-10-2009, 10:48 AM

Quote:

Originally Posted by ph0bia

STICKY THIS NOW O' GREAT AND POWERFUL MODERATOR

You know they're not like the all-seeing gods? Press the report button or PM someone and recommend it for sticky.

Personally, it's "tl;dr" for me, but I am sure it's good

spicewwfc · #10 (**permalink**) 03-10-2009, 12:07 PM

Very informative. This will put an end to a lot of needless panicking.
STICKY!!!

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