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Questions and Answers

This page contains answers to questions which I found interesting enough to answer - send me email if you want to test my interest levels...

 

Can anyone help with this urgent enquiry?
- Please reply care of

I am researcher of the National Institute for Agricultural Technology. We are having problems with isopods in soybean crops under no tillage systems. We would greatly appreciate receiving information about isopods as agricultural or horticultural pests or related information, as soon as possible. Thanks a lot in advance.
- Eduardo Trumper

 

Would you please be able to tell me what the difference between kinesis and taxis. Thanks - Johanna

A taxis is a directional response to a stimulus - towards or away from the stimulus eg woodlice move directly away from bright light.

A kinesis is a non-directional (ie not towards or away from the stimulus) response to a stimulus - this means the response is usually shown as in increase or decrease in activity level - eg woodlice move faster in low humidity  conditions (and move slower in higher humidity conditions)

 

I was wondering how are young cared for what do they look like? Also what kind of body parts or regions do they have? Thanks
- Acidmama

The young are raised in a brood pouch located on the lower side of the abdomen in female woodlice. After hatching they spend a few days in the brood pouch before escaping into the external habitat.

It is reported that at first they only have 6 segments in their thoracic region and only 6 pairs of legs. After their first moult the segments number increases to 7 and after the 2nd moult the number of legs increases to 7 pairs. (Sutton, (1980), Woodlice)

I have raised young woodlice in plastic 1.5 litre ice cream container. I added a few dried leaves, a small amount of soil litter (about 1-2 tablespoons), some pieces of bark and twigs, a few teaspoons of water, a couple of pieces of carrot and some potato (about 1-2 cubic cm of food in total).

When the young were born they move into the soil where they remain hidden from view. When they next become visible they are white in color and about 1mm long. After 3 weeks they are about 2-3 mm long and a light tan color.

I think the secret is to make sure that you get a gravid (pregnant) female - you can recognize this condition by turning them upside down and looking for a yellowish swollen region on the under side of the thorax.

Make sure that the habitat is kept damp so they don't get desiccated. Check them each day and remove any dead ones. If you keep a regular check then you will also see them moulting and will sometimes find half an empty exoskeleton (they only moult half their exoskeleton at a time)

 

Please could you send me any information you have on woodlice, especially their turn alternation patterns and why this occurs.
- Dave

Remember that woodlice generally lack any cuticle on their exoskeleton and are therefore likely to become dehydrated relatively readily when they are in hot and/or dry conditions.

If a woodlouse is travelling across an open dry (or hot, or low humidity) region then it would be in its best interests to minimise the amount of time it spends in those conditions - if there were no obstacles then all it would need to do is to travel in a straight line until it reached the other side.

If the woodlouse meets an obstacle then things are not so easy - if it had a rule that it always turned left at an obstacle then it would end up going around in circles. By showing a short term alternation of direction of turning then it is more likely to travel in a relatively straight line - of course the best strategy and the best distance for alternation to operate over will vary with the density of the obstacles in the environment - the greater the number of obstacles then the greater the more likely it is that alternation will result in the woodlouse travelling in a relatively straight line across the area. You might like to think about what could happen if alternation always occured even if it happened a long time after the last turn....


Hi, I was just wondering, how fast do slaters reproduce?
-
Py

Woodlice probably only mate once a year (in spring). The female woodlice (at least for Porcellio scaber and Armadillidium valgare) are able to store sperm for some time and so may be able to produce a 2nd brood without having to mate a second time.

After fertilisation of the eggs has occurred they are released into the brood pouch which appears as a yellowish growth on the lower side of the thoracic region. The eggs develop over about a 4 week period. Towards the end of this time the young hatch. They will remain in the brood pouch for a few days after which they will crawl out between the plates of the brood pouch. If you drop a gravid female into water this may stimulate liberation of the young.

Just out of interest, are you planning to observe development of the young? If so then there is a description of such an experiment in Sutton's book "Woodlice", published by Pergamon on page 115. My edition is dated 1980.

1) What do woodlice eat?
2) Why do they like the dark?
3) Do they have any preference to light intensity and why?
    - Steven

The answers to all these are mentioned or implied on my woodlouse pages so this will be brief
1) Mostly plant matter. They can survive just by eating paper and digesting
the cellulose in that - not ideal though
2) Dark areas are cool and tend to be more humid. Both of these factors
will result in reduced water loss and therefore increased chances of
survival in the terrestrial habitat. They have no waterproof cuticle to
reduce water loss so this behvioural adaptation will help prevent desiccation.
3) There preference does seem to change depending on the conditions in
which they have been previously. Woodlice which are water saturated from
living in high humidity conditions don't always show the same preference
for dark conditions shown by woodlice which have come from drier
conditions. So the answer is yes but it depends on the conditions they have
been living in.

I am studying the behavior of woodlice. I would like to see whether woodlice 'learn' a route through a maze and therefore complete the maze faster in subsequent runs. I would be very grateful if you could E-mail me any information that could be useful
-    Anthea

I only know of one other student who carried out research on this topic. She found that most of the woodlice that she used did not show any signs of learning a route through a simple maze.

From observations that I have made in the course of other maze experiments it often appears that woodlice are remembering a route - but if new woodlice are used they also tend to follow the same route used by the 1st woodlice. It seems likely that they are following an odour trail or gradient. They may also/instead by responding to some other environmetal variable (eg temperature or light intensity). This means that your experiment should be carried out in such a way so as to eliminate external stimuli and also to remove any odour traces from previous runs of the experiment. Also remember that previous forced turns may cause an alternation response so if the woodlouse is kept in a flask between runs then its direction of movement may be enough to influence which way they turn if they are given a free choice turn instead of a forced turn when they are 1st introduced into the maze.

We have several of these Pill bugs getting into our house. What can I do to stop this? Should the house be treated out side as well as in, and what can we use to do so? Thank You - Greg C.

To prevent entry of woodlice you need two things:

  1. Make sure there is no vegetation or dead plant matter near the house

  2. Make sure that the house is kept dry. Woodlice can't survive for long in dry conditions. You may need to make sure that water is not getting under the house (foundations or basement) from a leaking pipe or other source.

  3. You could try poisoning them.Patrick Dale suggests in his book (A Houseful of Strangers) that a good bait can be made by mixing the following:
        200g of bran
        200g blood and bone manure
        200g maldison at 50% concentration
        Mix with enough water so it is just damp
        Place in heaps under shelter near where the woodlice are found

Some URLs with more information about controlling woodlice are:
http://www.uky.edu/Agriculture/Entomology/entfacts/trees/ef439.htm
http://www.ianr.unl.edu/pubs/Insects/g342.htm
http://ohioline.osu.edu/hyg-fact/2000/2072.html

References

    Sutton, S.L. (1980) Woodlice.Pergamon Press, Oxford
    Dale, P.S. (1992) A Houseful of Strangers: living with the common creatures of the New Zealand house and garden, Harper Collins, Auckland (New Zealand)

 

 

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