Collecting setting and preserving Insects

INSECTA Methods of collecting, Preserving and Pinning : 

INSECTA Methods of collecting, Preserving and Pinning Dr.Vinod Khanna Zoological Survey of India Dehra Dun <drvkhanna51@gmail.com>

Slide 2: 

The Class Arthropoda, which includes insects, spiders, mites, and their relatives, is without question the most successful group of organisms on earth. Insects alone account for nearly 73% of all fauna known to science.

How do you identify Insects : 

How do you identify Insects The insects are the Class of Arthropods with their body INCISED into three parts The head The Thorax and The Abdomen Three pair of legs Head with a pair of antennae, compound eyes or ocelli

Collecting Insects : 

Collecting Insects Specialized sampling by the experts Random Sampling by amateurs

Slide 5: 

In the first the collector actively searches out the insects, using nets, aspirators, beating sheets, or whatever apparatus suits his or her particular needs. In the second, the collector participates passively and permits traps to do the work. While picking up insects by hand is simple and sometimes effective, their size, mobility, and the possibility of being bitten or stung usually dictates that various kinds of equipment and special methods are needed.

Collecting Nets : 

Collecting Nets Collecting nets come in three basic forms: Aerial, designed especially for collecting butterflies and other flying insects .Both the bag and handle are relatively lightweight. Sweeping: The sweeping net is similar to the aerial net but is stronger and has a more durable bag to withstand being dragged through dense vegetation. Aquatic. Aquatic nets are used for gathering insects from water and are usually made of metal screening or heavy scrim with a canvas band affixed to a metal rim. A metal handle is advisable because wooden ones may deteriorate after repeated wetting.

Slide 7: 

The insect collecting net is the basic tool of the insect collector. The net should be light and the handle made from an aluminum pipe, a sturdy do-well stick. The length may vary between 50-120 cm. A metal opening or hoop, no less than 30 cm in diameter, can be made from heavy steel wire, about 5 mm in diameter. The net bag should be about 90 cm deep tapered at the bottom, and made from nylon mosquito netting which does not disintegrate or tear easily. Around the hoop the net should be reinforced with strong binding material. The ends should be left open so that the metal ring can be passed through the binding. Insect Net for dry collection

Transferring the collection to Killing Jars : 

Transferring the collection to Killing Jars Once an insect is caught in the net, the handle is given a quick twist to fold the bag and prevent escape. The insect is then transferred into a suitable container or a killing jar. General collecting can be done by sweeping the net back and forth through foliage and grasses. Sweeping results in the collection of a mixture of insects that may be removed by hand, forceps or an aspirator. Another way of dealing with the sweep-net catch is to shake the contents of the net to the bottom and invert the net into a killing bottle. Insects can then be sorted later. This technique may result in the excessive collection of unwanted specimens, which may be released back in the original habitat.

Dip net for wet collection : 

Dip net for wet collection The dip net is used to collect aquatic insect. It has a shorter bag and a fairly long handle. Some are designed with a flat side opposite the handle to allow the net to scrape along the bottom of a pool. The contents of the dip net can be emptied into a shallow white plastic tray of water and the required insects can then be sorted easily. Surplus insects should be returned to the habitat from which they were collected.

Beating tray : 

Beating tray The object of beating is to capture crawling insects that do not fly readily. The beating tray can be made from strong white cloth, rectangular or square, about 100cm x 60cm, with pockets at the corners into which the ends of two diagonal bracing sticks are fitted. The tray is held beneath the branches of trees and shrubs and the branches beaten with a strong stick. The insects are dislodged and fall into the beating tray. The specimens are then collected by hand, forceps or aspirator. With the sticks removed, the beating tray can be rolled into a neat parcel for easy transport.

Aspirator : 

Aspirator Is a device for collecting small delicate insects directly from the ground, foliage, or from the beating tray. An aspirator bottle consists of a bottle (7cm x 2,5cm) fitted with a rubber stopper. Two holes are drilled through the stopper to take two pieces of hard plastic tubing, each about 7cm long and about 5mm in diameter. One piece of tubing is pushed through each hole in the stopper, with at least 2cm showing below and above the stopper. The end of one of the pieces, which will be inside the bottom when the stopper is inserted, should be covered with a piece of mosquito netting to prevent insects being sucked into the mouth of the collector. A rubber tube 30-45cm is attached to both plastic tubes on the outside of the stopper. To use the aspirator, air is drawn through the apparatus by sucking on the rubber tube with the mosquito netting. The insect is sucked into the chamber through the other tube that is pointed towards the insect.

Camel hair brushes : 

Camel hair brushes Delicate insects that are best stored or preserved in alcohol can be picked up on the tip of a fine brush moistened with alcohol and then transferred to a glass vial containing alcohol.

Forceps : 

Forceps The best forceps are those with prongs that are rounded The prongs should make contact at the tips only, so that an insect can be gripped firmly without slipping out. Soft stamp collectors forceps are useful for soft-bodied insects

Killing bottles : 

Killing bottles Once insect has been captured, it should be killed quickly by placing the specimen in a killing bottle moistened with a killing agent. e.g. ethyl acetate or Carbon Tetra Chloride or Benzene. Only one or two drops are needed to charge the jar with vapour sufficiently concentrated to effect rapid death. Excess ethyl acetate causes condensation on the inner walls of the jar that will wet and discolor specimens. Any wide-mouthed glass jar can be used with a simple modification. Cover the bottom of the jar with a thin layer of sawdust. A sheet of paper, cut to the shape of the jar, is placed on top of the sawdust, which is then covered with a mixture of plaster of Paris and water to a depth of about 10mm. The plaster of Paris is made by adding powdered plaster of Paris to water, little by little, stirring continuously, until the mixture has the consistency of relaxing box thick cream. It is then poured into the middle of the paper in the jar and allowed to spread out to the sides. The jar is then placed outside in the shade to allow the contents to dry completely. Bottles and jars of different sizes can be prepared in the same way. It is advisable to have at least three killing jars – one for grasshoppers which kick and dribble, one for moths which shed scales all over the jar, and the third for other insects. Never put delicate insects like butterflies with hard insects like beetles into the same jar.

Field storage box : 

Field storage box A box or tin containing layers of soft tissue paper, cut size, which fit snugly into the corners of the box. When the first batch of insects is ready to be taken from the killing jar, the top layers are removed in order to start at the bottom of the box. The dead insects are emptied onto the bottom layer and a data label is placed with them. The rest of the tissue paper layers are then placed on top. The same procedure is followed with the second batch of insects; each batch must be separated from the previous one by a layer of tissue. Each layer must receive its own data label and specimens from separate localities should not be put together. The insects should be pinned before they dry out, but if that is not possible they could be placed in a relaxing box for a day or two.

Relaxing box : 

Relaxing box A relaxing box is a dampened air tight box with a drop of ethyl acetate to prevent fungal infection

Paper data labels and pencil : 

Paper data labels and pencil Each specimen must eventually be labeled with the information relating to its capture. The basic information required for every specimen should include the following: locality, date of capture and the name and initials of the collector. A grid reference would also be useful for more accurate location. The label information must be recorded in the field; never trust your memory when it comes to label data. Specimens from different localities and dates should always be kept separate from one another and labeled separately. It is often useful to have additional information, like host plant, found under rock, trapping methods etc. Writing in the field is important and it is best to use a HB pencil for this. BallPoint type pens are usually not satisfactory

Collecting bag : 

Collecting bag A canvas bag with partitions for sorting items is useful, and should be slung from the shoulder by means of a strap to leave the hands free. The following items usually are included in the general collector's bag: Forceps. Fine, lightweight forceps are recommended Vials containing alcohol or other preservatives. Killing bottles of various sizes .Small boxes or containers for storing specimens after their removal from killing bottles. These may be made of cardboard, plastic, or metal and should be partly filled with soft tissue or cloth to keep specimens from rolling about. Do not use cotton because specimens become entangled in the fibres and may become virtually impossible to extricate without damage. Small envelops for temporary storage of delicate specimens and/or gel caps for tiny specimens. One or more aspirators. Absorbent tissue for use in killing bottles and aspirators. Notebook and writing equipment for jotting down notes and label data. A strong knife for opening galls, seedpods, twigs, etc and a pair of scissors for cutting labels. A small, fine brush (camel's hair is best) for picking up minute specimens. Bags for storing plant material, rearing material, or Berlese samples A hand lens.

TRAPS : 

TRAPS Light trapping The most obvious attractant for night-flying insects is light. Portable low-voltage fluorescent lamps that operate from a car battery . The bulbs emit light on wavelengths different from those of ordinary incandescent bulbs and tend to be more attractive to insects. Funnel trap The trap consists of a light source, with a funnel at the bottom down in which the insects fall, after striking the lamp, into a killing jar or dark box from which they cannot escape Sheet trap This trap consists of a light source and a big white sheet.The sheet is hung between two trees, with the light placed in front of it. Insects attracted to the lamp will settle on the sheet while others will settle nearby. Make sure the sheet is also spread on the ground to catch insects that fall. Collect the insects from the sheet with an aspirator, a vial, or a small net. In the field a small generator might be needed for the light.

Bait Trapping : 

Bait Trapping Meat trap: Meat is a good attractant for some flies and beetles. The trap consists of a small bucket filled three quarters with water and a detergent. The detergent helps to break the surface tension of the water, and prevents the insects from escaping. A smaller paper cup is used for the meat bait. Place the cup with meat bait in the water, with stone or something heavy inside to prevent it from falling over in the water, the bucket is lowered into a hole in the ground, and placed level with the surface. To protect the trap from small mammals, place a rock on top of a flat piece of metal, at an angle, so that insect can get in. They will be attracted to the smell of the rotting meat, fall into the soapy water and drown. Sugar trap: The same method can be used for a trap using sugar instead of meat, but the bucket should be hung from a tree. Mix banana, sugar water, brewers yeast and an alcohol like beer as bait. Various orders of insects will be attracted to the sweet, rotting smell. The traps can be checked regularly, but should be left for at least two days to mature before they are replaced.

Killing and Preservation : 

Killing and Preservation Liquid Agents for Killing and Preserving Ethanol or ethyl alcohol mixed with water (70 to 80 percent alcohol) is usually the best general killing and preserving agent. Parasitic Hymenoptera are best killed and preserved in 95 percent alcohol. Adult bees should not be collected in alcohol because their usually abundant body hairs become badly matted. Soft- bodied insects, such as aphids and thrips, small flies, and mites, become stiff and distorted if preserved in 95 percent alcohol and should be preserved in alcohol of a lower concentration. Adult moths, butterflies, mosquitoes, moth flies, and other groups with scales and long, fine hairs on the wings or body may be worthless if collected in alcohol regardless of the concentration. Formalin (formaldehyde) solutions should not be used because the tissues become excessively hardened and the specimens then become difficult to handle. Larvae of most insects should be collected in alcohol and subsequently killed in boiling water to "fix" their proteins and prevent them from turning black. Large specimens or small specimens that have been crowded into one vial should be transferred to fresh alcohol within a day or two to reduce the danger of diluting the alcohol with body fluids. If the alcohol becomes too diluted, the specimens will begin to decompose. Thrips and most mites are best collected in an alcohol glycerin-acetic acid (AGA) solution, and for many larvae a kerosene-acetic acid-dioxane (KAAD) solution is preferred. Larvae and most soft-bodied adult insects and mites can be kept almost indefinitely in liquid preservatives; however, for a permanent collection, mites, aphids, thrips, whiteflies, fleas, and lice usually are mounted on microscope slides. Many insects collected in alcohol are later pinned for placement in a permanent collection. Hard bodied insects such as beetles can be pinned directly after removal from alcohol.

Dry preservation : 

Dry preservation For dry preservation will covers most general collecting equipment. Pins: Stainless steel entomological pins 3.8cm long come in various thicknesses. The most useful pins are a no.5 (large insects) a no.3 (medium) and a no. 1 or 2 for small insects. Steels\ minutens: These are minute headless pins used for small insects like mosquitoes and midgets. Polyporous pith: Used for staging small insects mounted on minutens. Usually purchase in strips which may be cut to size. Points, cards, glue: A small card or card triangles on which to mount small insects may also be used. Use a soluble glue to stick the insects to the card or onto the bent point of a card triangle. Setting board: A setting board is used to hold the wings in position while the insects are drying. A simple board can be made from polystyrene foam, cork or wood. Pinning block: A pinning block allows insects and labels to be positioned at standard heights on the pin. The cheapest and easiest way to make the block is to use wood. .Storage box: Large glass-topped drawers in cabinets, or Temporary wooden boxes with lids and bottoms made from polystyrene foam or cork are a good alternative. The box should be airtight, to keep the fumes of any repellent in, and to keep pest insects out. Dry-stored specimens must be labeled with complete collection data in or on each container Some insects, such as small beetles, should be glued to points directly from the layers for permanent preservation, but if they are to be pinned or otherwise treated, they must be relaxed. Papering: Although pinning specimens when they are fresh is preferable, the storage method known as papering has long been used successfully for larger specimens of Lepidoptera, Trichoptera, Neuroptera, Odonata, and some other groups. It is a traditional way of storing unmounted butterflies and is satisfactory for some moths, although moths too often will have their relatively soft bodies flattened, legs or palpi broken, and the vestiture of the body partly rubbed off. To save space in most large collections, file Odonata permanently in clear plastic envelopes instead of pinning them. Papering consists of placing specimens with the wings folded together dorsally (upper sides together) in folded triangles or in small rectangular envelopes of glassine paper, which are the translucent envelopes. Glassine envelopes have become almost universally used in recent years because of the obvious advantages of transparency and ready availability.

Liquid Preservation : 

Liquid Preservation Ethanol and isopropanol mixed with water -a mixture of 75% alcohol to 25% water is used. Labels placed in alcohol. Paper should be high quality rag or linen and acid-free. The ink should contain vegetable gum (such as India inks) as these seem to withstand the constant exposure to the alcohol the best. Typewritten labels and computer generated (laser printed) labels are generally unacceptable. The best system is still professionally printed labels. Shell vials plugged by cotton or with polyethylene stoppers are recommended. Avoid stoppers made from cork, rubber, or neoprene, as they tend to degrade and/or leach chemicals into the alcohol. Shell vials are preferred over necked vials as it is easier to remove the specimen and the chance of damage is reduced. Each vial should be individually labeled with complete collection data. The shell vials are kept in wide mouthed, gasketed bailtop jars with straight sides. Avoid metal screw caps, Bakelite lids, greased glass, and ground glass as they may rust, warp, crack, leak, or allow the alcohol to evaporate. Generally it is recommended that each jar contain between 10 and 40 vials. Avoid glass-glass contact by placing a folded paper towel in the bottom of each jar. Keep vials upright within jars. Each jar should be filled with alcohol to just below the level of the gasket. If material is going to be stored for long periods of time, the jars should be checked periodically and the alcohol topped off. Labels may also be placed on the outside of the jars to indicate the enclosed contents. Light is the chief enemy of alcohol preserved material, and as a result, jars should be stored inside cabinets. Fire safety is always an important consideration when storing or working with alcohol collections. Concentrations of vapors can be very hazardous so care should be taken that work areas are properly ventilated and that there is no source of open flame nearby. In larger collections, special cabinets, exits, and other precautions may be necessary to meet the fire code.

Mounting Specimens : 

Mounting Specimens Specimens are mounted so that they may be handled and examined with the greatest convenience and with the least possible damage. Well-mounted specimens enhance the value of a collection; Their value for research may depend to a great extent on how well they are prepared. Equipment typically needed to mount specimens includes forceps, a pinning block, pins, paper points, scissors, glue, and specimen holder.

Preparing Dry Specimens for Mounting : 

Preparing Dry Specimens for Mounting Any dry insect that is to be pinned must be relaxed, that is, remoistened enough to soften so that it will not break when the pin is inserted or so that parts of the specimen may be rearranged or repositioned. The dried insects are put in desiccators for relaxing. The desiccators contains a solution made of one part of Phenol, Two part of Benzene and a small quantity of Naphthalene Powder. Insects, especially Lepidoptera,that are to have their wings spread should be relaxed even if they have been killed for only a short time.

Direct Pinning : 

Direct Pinning

Slide 29: 

A. Winged Insects 1. Insects with 4 - wings ( 2 pairs ) ………………………2 Insects with 2 – wings ( 1 pair ) True flies ……...Order Diptera 2. Wings covered with scales, Butterflies & Moths ……..Order Lepidoptera Wings without scales …………………………...3 3. Only hind wings used for flight,fore wings partly or wholly horny. Used as covers of hind wings …………………………...4 Both pairs of wings membranous and used for flight ………..7 4. Mouth parts tube-like adapted for piercing & sucking ……..Order Hemiptera Mouth parts adapted for biting and chewing ………………………….5 5. Wing venation of the fore and hind wings similar. Forewings stiffer and serves as covers (Grass hoppers) ………Order Orthoptera Fore wings without veins, modified into hard covers of Hind wings Order Hemiptera 6. Fore wings without short Tip of the abdomen With forceps ( Earwigs ) ……Order Dermaptera Fore wings nearly always long,covering abdomen, enclosing hind wings ( Beetles ) ………Order Coleoptera

Slide 30: 

7. Wings narrow without veins,fringed with long hairs Small insects ( Thrips ) .…Order Thysonoptera Wings fully developed ………..………………...8 8. Hind wings much smaller than fore wings ………………………….9 Hind wings similar in size to fore wings …………………………12 9. Abdomen with 2 or 3 long taillike appendages ..Order Ephemeroptera Abdomen without tail-like appendages ……………..……….10 10. Wings hairy ( Caddisflies ) …Order Trichoptera Wings not hairy ..…………………….11 11. Body size less than 6 mm, tarsi 2-3 segmented ..….Order Psocoptera Body often large, wasp/beelike, Tarsi 4-5 segmented ...Order Hymenoptera 12. Tarsi 3 – 4 segmented ..…………………….12 Tarsi 5 segmented ……..……………….15 13. Wings with a few cross veins,Hind wings greatly expanded Posteriorly ……Order Plecoptera Wings usually with several cross veins. Fore and Hind wings very much similar in size …………..…………14 14. Small insects with long antennae, wings folded flat all over the body………Order Isoptera Large insects, short antennae, wings held away from the body when at rest ……...Order Odonata 15. Mouth parts beak shaped …Order Mecoptera Mouth parts short ....Order Neuroptera

Slide 31: 

THANKS Dr.Vinod Khanna Zoological Survey of India Dehra Dun