How to breed your own insects by Steven Evans
Keeping amphibians in New Zealand
Frogs and other amphibians make really fun and interesting pets. Some of the things like set-up of the tank and making insect traps can be a bit tricky, so get an adult to help you with these. But after set-up, they are fairly easy to keep. This page is really just an introduction to the wonderful world of amphibian care, so have a look at the further reading to find extra information on topics on this page, and to find out about things not discussed on this page, like breeding and outdoor housing. They also provided some of the information for this page!
What kinds of amphibians can I keep as pets in NZ?
Where can I get pet amphibians?
What do I need to keep amphibians?
How long do pet amphibians live for?
Will amphibians eat each other?
What do I feed them?
Make your own insect traps
How to breed insects
How do I keep tadpoles?
What kinds of amphibians can I keep as pets in NZ?
Brown tree frogs (Litoria ewingii), Southern Bell frog (Litoria raniformis), Golden Bell frog (Litoria aurea), axolotls (Ambystoma tigrinum), Fire-bellied newts (Cynops pyrrhogatser and Cynops orientalis). It is against the law to keep any of the native frogs. There are a few people in New Zealand who are allowed to keep native frogs, but these people are native frog specialists who DOC has given a permit to.
You must not release axolotls or newts into the wild, as they are not found naturally in New Zealand and could cause big environmental problems if they become wild. Also, it is important not to let any pet frogs or tadpoles back into the wild, because they can spread diseases that they may have picked up in captivity to other wild frogs.
Where can I get pet amphibians?
Fire-bellied newts and axolotls can only be bought from pet stores, because they don’t live in the wild in New Zealand. Non-native New Zealand frogs can be bought from pet stores or garden centers or collected from the wild as spawn or tadpoles. Tadpoles and spawn are found in still water, so check ponds, wetlands or even farm animal drinking troughs. Be careful where you collect because it is illegal to collect plants or animals from wildlife/national parks or reserves without a permit from DOC. Also, if it is not your land, it is a good idea to ask for permission from the owner.
For Brown Tree frogs, look for small (15-20 eggs) clumps of spawn clinging to vegetation near the water’s edge. Both Bell frogs lay large clumps of spawn in pond weed. Bell frog spawn floats during the first few days after being laid, then becomes submerged just beneath the water surface. It can be really hard to tell different species of tadpoles apart when they are little. A good idea might be to go looking for frogs at night with a torch (make sure you do this with an adult) so that you know which type of frogs your tadpoles came from. See the guide to New Zealand frogs in this site for help with identifying frogs. Normally, though, if you see big tadpoles (more than 5cms long) they will be Bell frog tadpoles. It is best not collect wild adult frogs for keeping in captivity, as they don’t deal well with being put in tanks.
What do I need to keep amphibians?
All amphibians need a closed tank, because frogs and newts can climb glass and axolotls can jump out of the water. Closed tanks also stop live insect food from escaping. Glass or plastic containers make good tanks but at least one of the sides (frogs only) or the top (frogs, newts and axolotls) needs to be made of mesh to let air in. Very fine mesh like muslin or cheesecloth works well because you can keep really small insects like fruit flies from escaping. Size and shape of the tank depends on the size and species and number of amphibians you want to keep. Minimum tank sizes are given here, but your amphibians are likely to be healthier if given a larger tank.
The tanks described here are for indoors. However, the frogs can be kept in outdoor housing (see T.J. Thornton’s book on keeping frogs in NZ). It is best to keep indoor amphibian tanks in quiet areas and out of direct all-day sun.
Brown tree frogs like to climb, so a tall tank is best. For two to three adults, the minimum tank size is 450mm high x 250mm long x 250 mm wide.
Bell frogs aren’t as fussy about the height of the tank because they don’t climb as much. But, they can grow quite large so you will need a fairly large tank. The minimum size for a tank with two small adults is 600mm long x 300mm wide x 300mm high. Larger tanks (900-1200mm long x 450-600mm wide x 450-600mm high) are good for a small group of adults.
Fire bellied newts do well in glass fish tanks, where the minimum size for two newts is 600mm long x 300mm wide x 300mm high. They need a lot of water, so ensure the tank you choose is watertight.
Axolotls are totally aquatic, so do well in a fish tank with a large-sized gravel bottom, like what you would give large goldfish. Minimum tank size for two axolotls is 900mm x 380mm x 380mm. The length and width of the tank are more important than the height, because they like to swim around the bottom of the tank, but a minimum water depth of 25cm is needed.
Amphibians are all sensitive to chemicals in water, so tap water is not the best, but you can use it if you get rid of the chlorine in it. You can do this by leaving it overnight in a clean bucket, or you can use dechlorinators (normally used for fish tanks) found in pet stores. It is better to use rainwater if you live in a non-smoggy area, or filtered water. It is a good idea to check the pH of the water if you have newts or axolotls (you can get pH test kits from pet stores). Between 6.5 and 7.4 is best for newts and 7 and 8.5 for axolotls. pH can be changed with products from your pet store. Amphibians need land areas wet too, so keep a spray bottle of water handy to water the tank. The tank doesn’t need to be soaking wet, just spray it once every couple of days so that it looks like there’s just been light rain in your tank. The amount of water needed depends on the species, and is discussed below.
The Bell and Brown tree frogs live mainly on land, but like to bathe, so give them a container of water with a half-submerged rock or branch (do not use manuka or kanuka as this can poison the water) for the frogs to climb easily in and out. Whistling frogs spend a little time in shallower water, so a small “pond” will do. Bell frogs swim more, so will need a bigger and deeper container of water.
Newts do best in tanks that have more water than land because they like to swim a lot. A water depth of around 20cm is best. You don’t need a water filter, but it could be helpful.
Axolotls live completely in water, so simply fill their tank with water to a depth of at least 25cm. You might want to get a fish-tank water filter because it will mean that the water can keep clean for longer. If you don’t have a filter, half to a third of the water needs to be changed every few days.
For how much land to have, a good guide is: frogs need mostly land area in the tank, newts need about half land, and half water, and axolotls need all or mostly water, so the base would be fish gravel on the bottom of the tank, just like for goldfish.
Large round fish gravel makes a good tank base, but make sure the size of the gravel is too large for the axolotls to eat. A good idea for making land for newts would be to put some large rocks into the tank and half fill with water so the top of the rocks stick out of the water. For frogs, soil, leaf litter or sphagnum moss (have a look in garden centres) can be used too. But, soil and leaf litter can contain diseases and pesticides. If you caught your frogs as tadpoles or spawn, you could collect soil or leaves from the same area, as a healthy group of frogs means the soil should be fairly safe.
Plants, rocks and logs
It is important to include plants and logs or rocks for your amphibians to climb and hide under, as it makes life more interesting and being able to hide will make your pets feel safer.
For frogs, plants can be either potted or planted directly in the soil at the bottom of the tank. Plants that like it shady and wet do best in frog tanks. Try ferns, moss, or bog plants. Rocks, logs and dead or live leaves make good hiding and hibernation spots (important if the tank gets cold). Brown tree frogs like to hide in clumps of grass in the wild so may enjoy a small tussock in their tank.
Axolotls and newts have a lot of water in their tanks, so water plants are great (but newts still use land plants, especially moss). There are some cool water plants for fish that are potted in a small plastic basket which you put straight into the water. Axolotls enjoy hollow logs, pieces of plastic drain pipe or hollow fish ornaments to hide and sleep in.
Keep a look out for any fungi growing on logs, leaves or plants, and remove anything that has fungus on it, because it can be harmful to amphibians.
The amphibians you can keep in New Zealand don’t really need any heating. Axolotls and newts shouldn’t need heating if kept at comfortable room temperature. However, frogs kept in a shady place inside may appreciate a fluorescent light or desk lamp directed on the tank during day-time for them to “sunbathe” under. Exposure to light also helps frogs get enough vitamin D3.
Example tank set-ups
Brown tree frogs
(Please make note that axolotls should have either no gravel at all or large pebbles as a substrate - too big to be eaten - as gravel or small stones may become impacted in their guts and this is one of the commonest causes of death in captive axolotls - thanks for the reminder from Tayla Adamson).
How long do pet amphibians live?
Captive frogs can live up to 15 years on average. The oldest captive frog recorded is the European Common Toad (Bufo bufo), which lived for 40 years at the London Zoo. Most captive fire-bellied newts live between 10 and 15 years, but could get up to 28 with really good care. Captive axolotls can live for 10 to 16 years. A few captive axolotls have lived for 25 years. So bear in mind if you have a pet amphibian you may be passing it on to your children or your parents to look after when you leave home! The record for a Brown Tree Frog in captivity is 15 years and he will be 16 in 2009!
Will amphibians eat each other?
Yes, amphibians will eat other smaller amphibians. This is why it is not a good idea to keep amphibians of different sizes or species together. The only exception to this is the two species of Bell frog, which can be kept together if the frogs are all the same size. But, be very careful with sizes, because Bell frogs will eat others that are a tiny bit smaller.
What do I feed them?
Amphibians need live food. They will eat any animal as long as it moves and can fit in their mouth. However, some foods suit amphibians better than others. A good rule of thumb for food size is to choose food that is smaller than your pet amphibian’s head. Try to feed your amphibian lots of different foods, as this will help them stay healthy.
There are plenty of insects that make good sources of food. These can be caught from your own garden (or house!). There are some ingenious home-made inventions around for catching flies and moths, and there are few ideas below. You can also have great fun catching insects with butterfly nets for your amphibians. Good ideas for netting insects include scraping the net through long grass, or leaving the outside lights on at night to attract moths, which you can then net. You could also scrape up some leaf litter or compost and put it into your frog’s tank, as these tend to contain lots of edible insects. However, remember there is a risk of adding diseases to your tank when you add leaves or compost. Additionally, you could breed your own insects or buy them from pet stores. The Auckland-based company Biosuppliers Live Insects is worth looking at if you want to buy insects, because they have a wide range of live insects that they can post to you. Have a look at their website (http://www.ak.planet.gen.nz/~bio/) or call/fax them on (09) 4182352.
Very small frogs and newts (<1.5cm) can be fed fruit flies or white worms. Small to medium size (1.5 – 7cm) frogs can be fed flies, waxmoth larvae, slaters and small cockroaches, crickets, locusts, and moths. Good food sources for large frogs (>7cm) include large crickets, locusts, moths and cockroaches.
Axolotls are a little different because they can be fed small chunks of meat as well as live insects (dangle them into the water in front of the axolotl’s mouth). They like food that either moves or smells a lot. Earthworms and oxheart strips are favourites.
Feeding your pet amphibian too much (especially too many waxmoth larvae) will make them fat and unhealthy. Feeding once or twice a week should be enough. It is best not to feed your frogs biting animals like spiders or bees, as they might bite your frog. Also, monarch caterpillars and butterflies and magpie moths and caterpillars are poisonous.
Insect traps - as many frogs need live insects there is always the problem of keeping up with supply and demand. There are a range of excellent and cheap fly traps (that have been tried and tested by NZFROG) that are available by mail order from GreenHand Eco-Products. For more information please contact GreenHand Eco-Products (03-9818859, 0272446474, 72 Chancellor St, Richmond, Christchurch 8013)
How to breed insects (by NZFROG Member Steven Evans)
Raising Feeder Insects
Live feeder insects are readily available in New Zealand, from commercial breeders, either directly or through a pet shop. They also appear from time to time in online auction services. Commercial breeders generally use overnight couriers, but will restrict shipping days, so that the insects will not have to weekend over at a depot. So plan ahead with your ordering.
Insects generally available include;
House and blow flies
Winged and wingless fruit flies
Most of these can be eaten by frogs, depending on their size. Moderation is the key with mealworms and waxworms though. They are slow movers and high in nutrients and fats, so frogs can quickly become overweight. Try to vary your frog's diet, and use these two grubs as supplements, or sparingly when other sources are in short supply.
If you are looking to breed your own insects, then you may have to purchase a starter culture. Be careful to check that they are not accompanied by mites, or visible fungus or mould, that might affect your chances of success. Generally bigger insects/larvae are better, as you will have your breeding age stock sooner.
We have been successful in breeding many of these insects in a New Zealand home environment, and hope to offer you our tried methods, to improve your chances of breeding success. Other set-up options and methods are available, through online searches and elsewhere.
Our first and foremost advice to you would be;
Keep it simple, until you have experienced success and then you can experiment with other foods or further nutrients.
Start with one type of insect at a time.
Be patient. Cultures may take quite a while (2 months or so) to become established. But with appropriate maintenance, patience and perseverance, you could potentially end up with an unlimited supply of insects or larvae for your frog.
Mealworms (commonly referred to as mealies) are the larvae of the Darkling Beetle (Family: Tenebrionidae). Crop farmers would consider them a pest, as will parents if they get into your flour, other grains or cereals.
They are probably the easiest and most hygienic feeder insect to start with.
What you need:
A container with firm fitting lid. Ideally you want about 3, but one is fine to start with. A container of about 10 litres capacity, with walls at least 100mm high is adequate.
Small piece of fly screen, or off-cut of fine net curtain material.
Layers mash (about $1/kg) available from many supermarkets, pet shops and stock food agents. It is usually sold in bags of 10kg or greater and is given to young chickens as it is high in nutrient, and finely ground.
Packet of bran from the supermarket.
A moisture source e.g. piece of pip fruit or vegetable e.g. small piece of lettuce, carrot etc (thawed frozen vegetables are ok). Not water as the mealworms will drown. Also nothing that will go moldy
What to do:
Cut a hole in the lid for ventilation, and tape (PVC/insulation tape works well) or glue over the piece of fly screen or net curtain. Ventilation is crucial, as without it the mash may go mouldy, and destroy the eggs or mealworm culture.
Pour a 30mm or thereabouts layer of mash, and a cup or so of bran into the container. Add a moisture source as above. You will need to add a fresh source of moisture each day. Keep an eye on how much they’re eating, and adjust the amount accordingly. Too much and the mash may become damp and moldy. Too little and they may start to die or eat each other.
Add a starter culture of mealworms (usually sold in pottles of about 150). They often arrive in a container of bran, and will eat it, so just add that too. Check for mites etc first, as you don’t want these in the culture.
Put the lid on and put the container somewhere out of the sun. Preferably a dry warm cupboard.
What you will see:
The mealworms will move through the layers mash, eating it as they go. Over time, they will outgrow their skin and need to shed it. They will come up and lie on the surface to do this. Note, that If there is a build-up of these skins, just sweep them to a corner of the container, with a piece of material or paper and dispose of them. The new skin will be a pale creamy white colour but will darken as it dries.
Eventually, as each mealworm has grown enough, it will lie almost motionless on the surface and stay there. It will shed its last mealworm skin, and emerge as a creamy white pupa.
You will need to remove pupae (which will wriggle with touch) to another container. Pupae are defenceless, and left with either mealworms or beetles, may become food for them. An ice-cream container or similar with ventilation holes is fine.
After about 2 weeks (dependent on temperature) you may be able to see some pronounced adult features on the front side of the pupa e.g. darkening around the head, and to the antennae and legs. Shortly afterwards the adult beetle will emerge.
The beetle will have a pale brown head and creamy white body. It will gradually darken over the following days, as its exoskeleton hardens, to brown and then black.
The beetle will eat the same food as the mealworms, so put it in a container with mash, bran and a moisture source as before. They also like to have somewhere to hide, so give them a piece of hessian/jute or similar, or a piece of light plastic (preferably dark coloured i.e. not clear) to hide under.
Provided they have food, moisture and other beetles, they will proceed to mate and lay eggs. They lay their eggs directly into the mash.
Be patient. It will be some time (could be several weeks) before newly hatched mealworms are noticeable. You may run your finger through the mash, and see a slight shifting of the powder as it covers back over, or see pin sized holes in a piece of lettuce, or turn a piece of carrot and see the tiny worms feeding on the underside.
We tend to move the beetles to a new container once a month, so that the mash doesn’t become over-populated. A typical container can have several thousand mealworms in it of various sizes. Just place a piece of carrot in with the eggs and replace it as it dries out, checking each time that there are no small mealworms on it first.
Important: Allow a good number of mealworms from each new culture, to mature into beetles, so that they can replace the others as they die off. Try to separate some off for this purpose, before we start feeding out mealworms to our frogs. The beetles are the future of your mealworm culture.
Provided that the lid is secure, and there is nothing to climb on, neither the beetles nor mealworms should be able to get out. They can’t climb glass or plastic without support.
Troubleshooting and Extra
Once you are established, you may want to try other feeds or supplements. To do this, place a piece of hessian/jute (about 80x60mm) on the top of the mash and tip a small amount of you chosen feed onto it. They will either eat it or they wont. Try one at a time.
If the pupae are kept too warm or get dried out, they may die, or the beetles that emerge, may be deformed and have a short unproductive life.
Remember to remove any dead insects to avoid the chance of decay contamination.
Just as warmth can speed up the life cycle, placing the container in a cool place can slow it down.
One possible treatment for mites, is to place the leaves of a herb plant called Wormwood, on the mash. Wormwood has a repellent effect on some insects, and may work. Its botanical name is Artemisia absinthium, and it’s a member of the tarragon family of herbs.
Breeding Black Field Crickets (Family: Gryllidae)
This large cricket is thought to be a native, but also occupies Australia. They are a dark brown to black colour and have wings. In the wild they live in holes in the ground, and feed at night on grass, leaves, flowers and seeds. In captivity their appetite has been found to be quite broad.
The male has two spikes off the rear of its abdomen and the female has three. The centre one on the female is the ovipositor, for laying eggs. The wing tips being quite pointed, can be confused as an ovipositor, to the unfamiliar eye.
Crickets do not tolerate humidity and accordingly do not travel well in the summer, when they may arrive stressed and having eaten the legs off their fellow travellers. We’ve had batches arrive with losses of up to 80% because of this. Cooler months might therefore be better for ordering starter batches.
They do not need a substrate, so don’t put soil in your container. You want to keep maintenance to a minimum, so that you don’t unnecessarily stress them.
What you need:
Large container with firm fitting lid, probably at least 20 litre capacity.
Medium sized container with lid - at least 10 litre capacity.
Small tub type container at least 60mm high with a lid
2 x 12 egg, cartons
2 litre milk bottle caps
Piece of flyscreen or fine net curtain material off-cut
Coarse River sand -sold at hardware stores for mixing concrete or through pet shops
Coir/coco peat - coconut husk - sold at garden stores etc as hanging basket liner
Small dry branches.
What to do:
Cut a hole in the lid of both the large and medium containers for ventilation, and tape (PVC/insulation tape or similar) or glue over the holes, a piece of flyscreen or fine curtain net. Ventilation is critical, as humidity and mould can be fatal to crickets.
With the egg carton lid closed, cut across the centre of the carton, so each end has 6 egg slots. You should end up with two open and two closed ends. Place the cartons in the large container for the crickets to hide in.
Cut and place two pieces of coir (see above), in the bottom of the small lidded container. Soak with water and leave to absorb. Pour off excess water. Top up container with sand so that the combined height of the coir and sand is about 40-50mm. With lid off, place in the large container. This is what the crickets will lay their eggs in. It should be kept damp (coir enables free draining) but not wet. Don’t overly firm down the sand, as it needs to stay relatively loose.
In the milk bottle lids, place the food for your crickets. You can give them small amounts of budgie seeds, bran, cornmeal, dried grass, and a couple of tiny cat biscuits. Try to change these feeders about twice a week, so that it doesn’t get soiled or moldy. They eat very little of it, so just check and top-up if necessary in between times. Small pieces of pip-fruit of carrot etc can also be given. Again you don’t want this to go moldy.
We have 2-3 water crystals (optional - used by gardeners to hold water in planter pots) in another milk bottle lid to provide moisture, and usually put a small piece (30mm square) of paper towel over it and drip water onto that. Do not put in a container of water as the crickets (particularly small ones) may drown.
What you will notice.
Crickets will hide in and underneath the egg cartons and come out to feed, and to attract a mate. They will scurry away when approached.
The male will make a loud shrill sound with his wings to attract a mate. While not unpleasant, you might want to put the container somewhere it won’t be heard.
The female will insert her needle-like ovipositor, into the sand to lay her eggs, so don‘t press the sand down too firmly.
Once a week or so, take the sand container out and place the lid on loosely. Put it into the medium sized container for hatching (the adults may eat the young if left with them). Place a fresh sand container with the adults. After 3-4 weeks start checking daily, to see if the young crickets have hatched. With the lid on the sand should stay moist.
The medium container should now be set up, in the same way as the larger adult container, but leave food out until the young crickets have hatched.
Newly hatched crickets are only 2-4mm long and will eat the same foods as the adults. Moisture is important. A damp section of paper towel moistened twice a day or so is best, as any more and they could easily drown. Without moisture though, they will quickly die.
Young crickets can climb plastic so make sure the lid is secure.
As time passes the young crickets will need to shed their skins. Initially they can do this on the egg cartons, but after a while, they will need to hang from a branch, so make sure it is in the container for them.
Adult crickets manage well, and breed at a comfortable indoor temperature of around 18-20 degrees plus, without need of additional heating or light. Provided this is achievable, then no further resources are needed. If however temperatures get into the high 20’s or 30’s and humidity increases the crickets can become agitated and/or die. They will slow down too if the temperature drops below the mid-teens.
Build your stocks, and make sure you are replacing the adult population, as they die off, before feeding insects to your frogs.
To collect the crickets, place the open end of the egg container into a plastic bag and give it a light shake. The crickets should drop into the bag. Calcium or other supplemental powders, can be added to the bag, to coat the crickets before you feed them to your frogs.
Breeding Migratory Locust (Short-horned Grasshoppers - Family: Acrididae)
We are currently growing our colony and instructions will be added shortly.......
How do I keep tadpoles?
Tadpoles can be kept in an ordinary fish bowl, with some oxygen weed and stones for them to hide under. The NZ Litoria tadpoles don’t seem to be as fussy as some species of tadpole about having lots of oxygen in the water, but an air pump or oxygen weed can be used to boost oxygen levels. The water needs to be changed regularly before it gets yellow.
NZ non-native tadpoles naturally eat plants. They can be fed lettuce, fish food rabbit chow or fish algae wafers. If feeding them lettuce, either use organic lettuce or wash the leaves before putting in the tank to get rid of pesticides. You can freeze your tadpole’s lettuce if you want to keep it for a long time. Remember if using flakes, the tadpole’s water needs to be changed more regularly as the food disintegrates. Try to give your tadpole a varied diet. Water needs to be changed before it starts to become yellow. It is best to use aged filtered water, as compounds in tap water can be harmful to tadpoles. To make this, simply leave a container of filtered water overnight.
Anstis, M. (2002) Tadpoles of South-eastern Australia: A Guide with Keys. Reed New Holland, Australia.
A useful guide for telling the tadpoles of non-native New Zealand frogs apart. Also has a section on keeping tadpoles.
Rowlands, R.P.V. (2005) New Zealand Geckos: A Guide to Captive Maintenance and Breeding. EcoPrint, New Zealand.
This book is about keeping geckos, but has excellent ideas for catching and breeding live food suitable for reptiles and amphibians.
Thornton, T.J. (1999) Keeping frogs in New Zealand: A Guide to the Maintenance of Captive Frogs. TJ’s Books, New Zealand.
Thornton, T.J. (1999) Keeping Axolotls: A Guide to the Captive Maintenance and Breeding. TJ’s Books, New Zealand.
Thornton, T.J. (1999) Keeping Fire-bellied Newts: A Guide to the Maintenance and Breeding of Fire-bellied Newts. TJ’s Books, New Zealand.