Methods of collecting invertebrates for taxonomic studies in zoology applicable to terrestrial and qaquatic habitats

1. M.Raj
Associate Professor
Dept. of Zoology, Darrang College
Methods for collecting
Invertebrates

2. Methods applicable to terrestrial
habitats

3. Flight Interception Trap
Preservative (ethanol or a soap
solution)

4. Bait Traps

5. Berlese Tullgreen funnel
Method for extracting
invertebrates from soil and leaf
litter.
insect larvae, nematodes,
isopods, slugs, and snails,
as well as arachnid

6. Pitfall traps
Likely invertebrates expected to be trapped include ground-dwelling
spiders ground-dwelling beetles oligochaete annelids, slugs, etc
Preservative
Polypropylene glycol

7. Chemical extraction
A solution of 0.2% formaldehyde is thoroughly applied to the soil of
desired area and the invertebrates emerging out collected. e.g.
earthworms and larva of many flies
Floatation method
Arthropod cuticle can be wetted by various hydrocarbon solvents
such as gasoline. A soil or leaf litter sample is placed in a mixture of
gasoline and water and shaken. The contents are then allowed to
settle. The arthropods will tend to be found in the gasoline layer
(which floats above the water) while soil, leaves, etc. will tend to be
found in the water layer.

8. Canopy Fogging

9. Beat sheet
A typical beat sheet is a square piece of white cotton sheeting with two
dowels that form a diagonal cross. The sheet is placed under the branch
of interest while the branch is shaken or tapped with a stick.

10. Methods applicable to aquatic
habitats

11. Plankton nets
Silk, Organdie, Muslin, Teryline, Nylon, synthetic fibres
Planktons cannot swim against
current

12. Cylinder samplers
Cylinders of known size slowly lowered onto water to collect
crustaceans and planktons

13. Water pumps and hose
 Quantitative plankton sampling.
 A pump with a rotary action and fitted with flexible
inlet and outlet hose pipes is generally used.
 The inlet pipe is graduated to show the depth of the
vertical descent.
 A weight is also tied to the inlet hole of the hose which
makes the pipe easy to sink and keeps it vertically
straight in water.
 This method has certain disadvantages. As the water
flows from all directions into the inlet hole at a
particular depth, the microhabitat occupied by the
plankton cannot be ascertained.

14. Kick nets

15. Rock basket sampling

16. Grabs and Scoops

17. Dredging
Dredging is excavation activity carried out under water. A
fishing dredge is also known as scallop dredge. Oysters,
Crabs, Sea cucumber

18. Methods common to both
terrestrial and aquatic habitats

19. Hand Collecting
 The simplest form of collecting is by hand with
small vials or collecting jars. It is advisable to
carry different sizes of vials in a small bag. The
greatest advantage of this method is that one can
sample a very large number of different habitats
in a short amount of time.

20. Floodlights, Flashlights and
Blacklights
 This is a novel way to capture nocturnal invertebrates.
Nearly half of all invertebrates are active at night. A
flashlight or headlamp is used to attract the insects
which are collected by hand.
 Blacklight traps include a variety of trap types, but
what they all have in common is the "blacklight" or
ultraviolet light (UV) and is used for collecting many
insects that are active and flying at night and are
attracted to UV light.
 Most likely invertebrates to be encountered include
noctuid moths, wolf spiders, fishing spiders, jumping
spiders, miscellaneous unusual beetles, dipterans,
and hemipterans.

21. Yellow pan traps

22. Aerial Net

23. Sweep netting

24. Emergence traps

25. Aspirators and Vacuum devices