Collecting and Examining Invertebrates


It is first important to recognise that all animals have a right to live in their native habitat. If you are going to collect fauna it is important to recognise this and that you should have a good reason to do it. If just curiosity is the criterion, then many invertebrates can be studied in their natural environment. They can be sketched or photographed, and observations should be made with their behaviour and how they use their habitats. If you are unable to identify the animal, then it may be necessary to collect one or a few specimens for identification by specialists. Never collect more specimens than required as you may be causing the local, even total, extinction of that particular species


Collecting invertebrates is usually very easy, and often collectors can make the mistake of over collecting. The first decisions to make are whether it is necessary to collect a particular animal, whether to keep it alive and release it later, or whether to kill and preserve it. It is also important to try not to destroy microhabitats that are essential for the survival of many invertebrates. You should replace items such as logs and rocks in their original positions.


Larger invertebrates can often be identified while they are alive and with the use of good field guides. During our field study we always had handy the Oxford Worms to Wasps which is an excellent illustrated guide to Australia's terrestrial invertebrates by Mark Harvey and Alan Yen. We also acknowledge this book has helped with references for this website.


Smaller invertebrates need to be examined with a magnifying glass or with a microscope, and this usually entails immobilising or killing them. If you have collected several specimens and wish to keep them alive for further study and are unsure of their identity, you should sacrifice and preserve at least one specimen.


In some Australian states like Western Australia, nominated invertebrate species are fully protected and a permit is required for their collection. In WA this information can be obtained from the Department of Conservation and Land Management. In most states, no collecting is permitted in National Parks without a permit, while other regulations apply in the various conservation reserves and in State forest.

br> Specimens are of little scientific value unless accompanied by accurate locality and collection data. A field label, written in pencil or Indian ink (don't use a normal ball point pen) should be written at the time of collection and put inside the container with the specimen. If you are going to print out your labels, it is important to use a laser printer and "bake" the ink on in an oven for half an hour. Information on the label should include the:
-locality, (distance and direction to the nearest town, and of possible, latitude and longitude or grid reference - note a GPS now makes this so easily achievable.)
-Collector's name
-Date of Collection
-Habitat description (in the bark, under a log etc)



Collecting and preserving invertebrates requires a little equipment which ranges from the very simple to the most intricate and expensive. However there are a few standard items that any collector should have:
-A notebook and penicl or indian ink (ball points run in the wet)
-Strong paper to write labels
-Some containers (glass or plastic) with lids to hold specimens.
-Plastic bags
-Forceps
-Paintbrush to pick up delicate specimens
-A pocket knife
-Hand lens, a a garden trowel if digging up litter or soil.



For the Walpole Wilderness Invertebrate Fire Research Project we needed to gain an understanding of the biodiversity of different habitats with different fire regimes to help make decisions for management of areas in the future. For this study we needed to collect and preserve our specimens are regular stages (see "The Study" webpage under "The Project" for how our team went about it). We mainly used a systematic pitfall trapping method.


We had sixteen pit traps per site, with each 90mm cup, one third filled with ethylene glycol and opened for ten days. Eight of these traps were dug into the forest floor and the other eight attached to a log, dug into deep tree butt litter or dug inside a hollow butt. Sometimes we used a wire mesh over to trap to keep out heavy forest litter and bigger vertebrates like frogs and lizards. We also direct searched habitats and collected specimens by hand. However we could have also done our collecting by using an insect net, a beating tray, a sieve or use one of the other multitude of methods available to trap these creatures such as baiting or light trapping.


Note that specimens can be kept in captivity for further observation and breeding. It is important to keep moisture levels high to avoid desiccation, to provide adequate and suitable food, and store them with a suitable habitat in a cage or container.


Preservation

The chemicals involved in killing and preserving specimens can be dangerous and need to be handled with care. Most invertebrate, especially insects and arachnids can be fixed and preserved in 70% ethyl alcohol. This chemical is difficult to obtain due to the necessary stringent laws governing its sale and distribution, so methylated spirits can be used as an alternative. This must be diluted with water or the specimens will become brittle and difficult to work with. Many hard-bodied invertebrates (especiallyinsects) can be killed or anaesthetized in a jar with cottonwool impregnated with ethyl acetate. For our study, after sorting, the specimens were stored in small glass containers containing 70% alcohol or mounted on a insect pin if they are to preserved dry.


"Worms to Wasps" also provides and excellent reference for specific preservation techniques for different invertebrate groups.