Killing jar
Encyclopedia
A killing jar is a device used by entomologists to kill captured insect
s quickly and with minimum damage. The jar, typically glass, must be hermetically sealable
and usually has a thin layer of hardened plaster of paris on the bottom to absorb the insecticide
. The insecticide will then slowly evaporate, allowing the jar to be used many times before needing to refresh the insecticide. The absorbent plaster of paris layer also prevents the insecticide from sticking to and damaging insects.
The most common insecticides used today in killing jar are ether
, chloroform
and ethyl acetate
. The crushed leaves of the shrub cherry laurel
are very effective, though only for a few hours after fresh collection. In the past, potassium cyanide
or other cyanide compounds were used, but is no longer used due to its extreme toxicity. The potassium cyanide would slowly decompose, releasing hydrogen cyanide.
Killing jars are generally only used on hard-bodied insects. Soft-bodied insects, such as the larval
stage, are generally drowned in ethanol
. The usual method of killing a lepidopteran
is by crushing the thorax
, as the wings generally become damaged in a killing jar.
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s quickly and with minimum damage. The jar, typically glass, must be hermetically sealable
Hermetic seal
A hermetic seal is the quality of being airtight. In common usage, the term often implies being impervious to air or gas. When used technically, it is stated in conjunction with a specific test method and conditions of usage.-Etymology :...
and usually has a thin layer of hardened plaster of paris on the bottom to absorb the insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
. The insecticide will then slowly evaporate, allowing the jar to be used many times before needing to refresh the insecticide. The absorbent plaster of paris layer also prevents the insecticide from sticking to and damaging insects.
The most common insecticides used today in killing jar are ether
Diethyl ether
Diethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...
, chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
and ethyl acetate
Ethyl acetate
Ethyl acetate is the organic compound with the formula CH3COOCH2CH3. This colorless liquid has a characteristic sweet smell and is used in glues, nail polish removers, and cigarettes...
. The crushed leaves of the shrub cherry laurel
Cherry laurel
Prunus laurocerasus, with common names cherry laurel and sometimes called English laurel in North America, is a species in the genus Prunus, native to regions bordering the Black Sea in southwestern Asia and southeastern Europe, from Albania and Bulgaria east through Turkey to the Caucasus...
are very effective, though only for a few hours after fresh collection. In the past, potassium cyanide
Potassium cyanide
Potassium cyanide is an inorganic compound with the formula KCN. This colorless crystalline compound, similar in appearance to sugar, is highly soluble in water. Most KCN is used in gold mining, organic synthesis, and electroplating. Smaller applications include jewelry for chemical gilding and...
or other cyanide compounds were used, but is no longer used due to its extreme toxicity. The potassium cyanide would slowly decompose, releasing hydrogen cyanide.
Killing jars are generally only used on hard-bodied insects. Soft-bodied insects, such as the larval
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
stage, are generally drowned in ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
. The usual method of killing a lepidopteran
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
is by crushing the thorax
Thorax (insect anatomy)
The thorax is the mid section of the insect body. It holds the head, legs, wings and abdomen. It is also called mesosoma in other arthropods....
, as the wings generally become damaged in a killing jar.
External links
- Collecting and Preserving Insects and Mites: Tools and Techniques
- How to Collect and Prepare Forest Insect and Disease Organisms and Plant Specimens for Identification
- A.Tereshkin Killing Jar with pieces of rubber tube for absorption of chloroform.
