All living creatures should be treated with care and respect, handled carefully and kept in a suitable manner.
Woodlice, also known as pillbugs, roly poly and slaters, are terrestrial crustaceans that belong to the order Isopoda. They get their name from often being found in old wood. It is thought there are around 3,500 species in the world and about 35-40 of these can be found in the British Isles.
Woodlice are abundant animals usually found in healthy gardens and greenhouses. They thrive in dark, damp places and love to hide under wood, leaves, bricks and plant pots! Large numbers can often be found in compost heaps where they help to breakdown plant material.
Woodlice are great for studying and are particularly popular when looking at animal habitats, behaviour and movement responses. They are commonly used in choice chamber experiments which demonstrate the type of conditions woodlice prefer. The woodlice change their movement pattern when responding to stimuli such as temperature or food sources in their environment.
We supply with some decaying leaves/humus for the woodlice to feed on, however we advise you use as soon as you can to ensure they are healthy.
Woodlice need damp conditions in order to survive. They absorb water from the air which makes humidity a key condition for their habitat. They are mainly detritivores that feed off dead plant matter, fungi and their own faeces.
If you can't use immediately, keep outside in a sheltered location away from direct sun/rain for a few days. For longer storage we recommend you decant into to a tank of slightly damp soil with leaf litter and rotting wood, then mist as required to ensure humid conditions.
We collect woodlice to order from the Darwin garden in Shropshire and need a few days notice. We can’t collect when the ground is very frozen, and try to avoid posting when the weather is very hot – so please take this into account when ordering! During ‘normal’ weather we dispatch live items Monday – Wednesday to avoid woodlice travelling over the weekend.
Woodlice are commonly mistaken for insects, but they actually have 14 legs and as terrestrial crustaceans are more closely related to lobsters, they even breathe using gills!
They are capable of rolling themselves up into a ball. This is a defence mechanism against predators and desiccation. Their predators include spiders, birds, reptiles and amphibians.
Being native to the UK the woodlice can be released back into the wild after an experiment. We recommend finding a cool shady area with cover such as a hedgerow with leaf litter to set them free.
]]>Drosophila is a genus of flies, belonging to the family Drosophilidae. Drosophila Melanogaster is the most used in research and are often called fruit flies due to their propensity to be found near unripe and rotted fruit.
Drosophila are truly fascinating insects, for example did you know that:
Drosophila media is simple to make, although for ease and speed ready-made media tubes can be purchased as well as instant media. The below recipe makes around 40-50 tubes.
Drosophila Media Recipe:
Add part of the water to the dry ingredients, mix until lump free, add remainder of water. Boil for around 15 minutes stirring occasionally, allow to cool a little then add the Nipagin solution. Decant into specimen tubes whilst still hot (approx. 60°C) then allow to cool.
Once cool, if not using immediately, plug with a plastic stopper and refrigerate, use within 1 week. Before adding flies, dry any condensation using paper towel then add a sprinkling of baker's yeast and a drosophila ladder (optional).
Manchester Fly Facility has some great resources for schools, the fly facts in this blog have been sourced from: http://www.flyfacility.manchester.ac.uk & https://droso4public.wordpress.com/
]]>Flour beetles are small reddish brown beetles around 3-4mm in length that, as the name suggests, live on and in flour. They are often seen as a pest which contaminates stores of flour, bakeries and flour mills are the most vulnerable. There are a few species of flour beetles, the most common of which are the Confused Flour Beetles (Tribolium confusum) and Red Flour Beetle (Tribolium castaneum); Darwin Biological supplies Tribolium confusum. These two beetles look very similar, however only the Red Flour Beetle can fly. Flour beetles are also called ‘Rice Flour Beetles’
Flour beetles are fascinating, they require only a few grains of flour to survive and a single bag of flour could sustain hundred or even thousands of beetles! The most amazing aspect of these animals is that they can survive in such a dry environment – no moisture is required as the beetles manufacture moisture through respiration! Flour beetles have been studied as a model organism since the 1920s for population studies and are an easy classroom animal – especially as they require minimal care so can be left over the school holidays!
As with other beetles, flour beetles go through complete metamorphosis, from egg to larva to pupa to adult. This transition can be studied by students who can analyse, draw and label the various stages and body parts observed. One way of doing this is to provide each student with a single larvae in a small vial with a little flour, students can then record the changes on a regular basis.
Flour beetles, in particular their larvae, are also used as a feeder insect for dart frogs. The adult beetles secrete defensive quinones which taste bitter to frogs, these secretions also cause odours and are a skin irritant.
Flour beetles lay 2-10 eggs per day which hatch in 6-14 days depending on temperature. The tiny eggs are white and sticky, becoming quickly coated with flour camouflaging them. A female may lay between 300 and 600 in a lifetime.
Once hatched, the cream-coloured larvae pass through numerous moults over a period of weeks before they reach 6mm. After the larval stage, they pupate for around 2 weeks before emerging as adults. In favourable conditions the entire lifecycle can be completed in a month. Adult flour beetles live for around 1-2 years.
Flour beetles, Tribolium Confusum, are easy to grow and breed. Simply place the culture you receive in a container with whole wheat flour (fine), white flour and baker’s yeast in a ratio of 4:4:1. There is no need to provide water! The media only needs to be around 5cm deep. They are fascinating creatures which burrow through the flour; we recommend you keep them in a clear plastic box/tank to allow you to fully observe them, roughly shoebox sized is perfect. Now sit back and relax!
As flour beetles can turn cannibalistic you should aim to avoid overcrowding. When culture is becoming crowded harvest a large scoop of your stock culture and transfer to a fresh container.
The best way of removing the beetles and larvae from the flour is to use a small sieve or tea strainer. Scoop some of the media and tap to remove the flour. If you only want larvae, place the sieve back on the surface of the media and allow the adults to climb back out.
If you no longer wish to keep flour beetles or have bred too many you can dispose of them in your general waste bin. Take care however that no flour escapes as it may contain microscopic eggs and cause an unwanted infestation. For this reason, we suggest bagging the culture before disposal and thoroughly cleaning the container. Do not keep flour beetles anywhere near sources of grain or flour, for example in a kitchen.
References: “Flour Beetles.” Science and Children, vol. 25, no. 5, 1988, pp. 36–37. JSTOR
]]>Locusts are a great insect for students to study and dissect as they go through an incomplete metamorphosis as they change from hoppers to adult locusts with wings. They go through 5 instars, or stages, shedding their skin as they grow.
Not only are the live locusts fascinating but locust dissection allows students to fully understand the locust respiratory system including air sacs, spiracles and trachea. To euthanise, see section further down this post, alternatively you can buy preserved locusts.
The easiest way to keep locusts is using a readymade plastic vivarium available cheaply online. They do not need any ‘bedding’ and keeping the base of the tank clear will help you keep it clean. Put a dry stick in the tank for the locusts to climb and fledge on.
Ideally keep locusts between 30-32° during the day and 26-28°C overnight. Heat mats and heat lamps can be purchased from online reptile stores as can simple vivariums. If you struggle to maintain these temperatures locusts will be fine at a constant 27°C, however their development may be slowed.
Locusts need to be fed daily with ‘leafy greens’ such as cabbage, grass, broccoli leaves etc. In addition, provide a small dish (such as a petri dish or jam jar lid) filled with bran and one with moist cotton wool. Each day remove any waste (including shed skin) and uneaten food then replenish food/water. Any dead locusts must be removed immediately to avoid the spread of disease.
Once the adults have reached maturity they will begin mating, it is only at this point that suitable laying media should be provided.
First obtain a 4” tall jam jar and fill with silver sand up to the top. Pour this sand into an old saucepan and repeatedly wash the sand under the tap until the water runs clear, it usually takes 3 or 4 washes. Once the sand is clean place the pan on the hob or boiling ring and heat the sand until dry, stirring occasionally. The sand will be very hot so ensure no one touches either it or the pan during this process. Allow the now sterile sand to cool naturally.
Once cool, weigh the sand and add 15% in weight of water, for example if the sand weighs 100g add 15g of water. Mix thoroughly and then using a teaspoon transfer this damp sand into the jam jar. Do not compact the sand, but equally ensure there are no large air gaps. Sprinkling the sand in and tapping the jar can help achieve this. Fill the sand to the very top of the jar, you will have some left over.
Place the jar in with the sexually mature adults, you will know once an egg pod has been laid as there will be a white foam ‘plug’. Females can spend a long time laying so it is likely you will see the pod laid.
Once you are sure you have a pod laid remove the jar from the tank. Tap it lightly its side to remove the top 1-2cm of sand – the pods will now be protruding. Punch a few small holes in the jar lid (a dissecting needle works well) and screw onto the jar. Place this jar somewhere warm (around 28°C) and write the date(s) you believe the eggs were laid. Each locust pod will contain between 50 and 100 eggs.
The time for locust eggs to hatch will vary depending on temperature but 10-14 days is normal. From day 9 onwards check at least daily for the presence of nymphs or ‘hoppers’, remove the lid to air the sand periodically (if no hoppers). Once your eggs have begun hatching place the jar in a clean tank, (always disinfect using bleach before/after use) and add a dish of water and a dish of bran as well as some leafy greens. Before removing the jam jar lid ensure that the tank is escape-proof, you may need to use a piece of fine mesh, tissue paper or muslin. Remove the jam jar lid and quickly seal the tank, the hoppers will now live up to their name!
Provided you have left them plenty of food and water you will not need to reopen the tank for a few days – at this point remove the jar of sand and discard the contents, the sand cannot be reused. Whilst the hoppers are in their first instar it is best to limit the number of times you have to open the tank. Once they are large enough, remove any mesh/muslin. And voila, you have successfully bred locusts!
As locusts are non-native it is illegal to release them into the wild, instead euthanise humanely by placing in a freezer for 24hrs then decapitating or exposing to Diethyl ether (in an airtight tub) for around 8 hours to ensure death.
To preserve locusts for dissection at a later date, submerge them in a preserving fluid comprising 70% alcohol, 25% water and 5% glycerol. Over time the liquid will discolour, at this point decant locusts into to fresh preservative.
Ready to purchase locusts? Click here!
Any questions? Please contact us.
]]>Vinegar eel, or Turbatrix aceti, are non-parasitic nematodes which thrive in unpasteurised apple cider vinegar, feeding on the bacteria which creates the vinegar. They grow to a maximum of 2mm long, so can just be seen with the naked eye, and have a virtually transparent body. Vinegar eels go through 6 stages of development (egg, 4 larval stages and adult), taking 5 weeks to reach maturity and living for a total of around 10 months.
Vinegar eels are often bred as a live food for fish fry, but in a school context it is their transparent body that makes them a fascinating creature to study. Using a stereo microscope digestion can be observed - vinegar eels are among the lowest group of animals to possess a complete digestive tract.
The other reason for studying vinegar eels is that under a stereo microscope developing larvae can be observed inside the female. Females can give birth up to 40 live young at a time every 8-10 days.
The vinegar eel cultures supplied by Darwin Biological can be studied immediately and do not need any special care. They should have their lid loosened to allow airflow and kept out of direct sunlight. The culture will be fine for a week, if you intend to keep it longer it should be sub-cultured as below.
Mix unpasteurised apple cider vinegar with distilled/deionised water in approximately a 3:2 ratio. It is essential that the apple cider vinegar is unpasteurised, often bottles will state that that they contain ‘the mother’, this is ideal. Pour this mixture into a clean jar or bottle and add a slice of raw apple; for school use a 250ml container is likely to be sufficient.
Cover loosely to avoid contaminants whilst allowing air flow. Keep the cultures at room temperature and out of direct sunlight. Write the date of the culture on the jar.
Subculture every 3 months by preparing a jar 2/3rds full of fresh water/vinegar then gently pouring 1/3 of the original culture in and adding a fresh slice of apple.
Vinegar eels naturally gather near the surface of the vinegar as this is where the highest concentration of oxygen is. This can be used to your advantage allowing you to gently pipette the vinegar at the top to collect the vinegar eels and place a drop on a cavity slide or petri dish for viewing under a stereo microscope.
Vinegar eels are not dangerous so can be washed down the sink with plenty of water, alternatively, feed to young fish or autoclave to kill.
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