Forensic en­to­mol­o­gists help solve crimes

By their nat­u­ral in­stinct, in­sects ren­der in­valu­able help to the in­ves­ti­ga­tors.

Alive - - News - ■ by T. Ra­jagopalan

Em­ploy­ing var­i­ous in­sects like bugs and flies to un­ravel crimes of cer­tain types is now a prac­tice adopted by sleuths. This new breed of crime de­tec­tives are called forensic en­to­mol­o­gists who go in search of un­ortho­dox clues.

In­stead of search­ing for mur­der weapons and iden­tity of vic­tims, the sleuths look search­ingly for var­i­ous bugs and flies that are found ev­ery­where and any­where. Based on these creepy crea­tures they pre­dict the time and lo­ca­tion of the crime and also un­err­ingly, in most of the cases, the sus­pect who is re­ally the crim­i­nal who per­pe­trated the crime.

Their work in pre­dicted on one of the an­cient laws of na­ture, that when you per­ish and leave the mor­tal soils you are re­cy­cled into the Earth. Af­ter all, if na­ture didn’t aid in the clear­ance of all that is de­cay­ing and the dead the planet we in­habit would not be a liv­able place.

This ar­du­ous task of clear­ance is partly as­signed to in­sects that come to suc­cour to re­duce the com­plex bi­o­log­i­cal body into sim­pler or­ganic el­e­ments. They are the prime wit­nesses who sup­ply most im­por­tant ev­i­dence about the crime, even ghastly ones.

In­sects, such as bees and wasps, are be­ing trained for de­tec­tion of land­mines. Sci­en­tists in Croa­tia have un­veiled spe­cially-bred colonies of bees that can de­tect buried land­mines three miles away.

The bees are trained by be­ing fed an ir­re­sistible so­lu­tion of sugar mixed with the smell of ex­plo­sives. The idea is that the bees’ keen sense of smell soon as­so­ci­ates the smell of ex­plo­sives with food.

“Even­tu­ally they as­so­ciate the smell of any ex­plo­sives with easy food and will lit­er­ally make a bee­line for them”, said Pro­fes­sor Mateja Janes who trains the bees.

On the other hand, Dutch sci­en­tists have trained a species of wasp with an acute sense of smell to de­tect buried mines. They are also en­deav­our­ing to pro­gramme the in­sects to serve as an early warn­ing sys­tem in bi­o­log­i­cal weapons.

In­ter­est­ingly, the tech­nique for train­ing the in­sects is no dif­fer­ent to that used for dogs each be­ing re­warded when it sniffs out a hid­den ob­ject.

“The wasp is placed in­side a box. The smell of the sub­stance which we need it to de­tect is passed through a hole in the side. Si­mul­ta­ne­ously, an odour­less sugar so­lu­tion is also placed in­side the box to cre­ate the as­so­ci­a­tion be­tween the smell and the food”, Wack­ers ex­plained.

The next process is to re­ward the wasp only when it starts to demon­strate for­ag­ing be­hav­iour in re­ac­tion to the odour in the box. As­ton­ish­ingly the en­tire train­ing process which varies slightly be­tween in­di­vid­ual in­sects can take around one hour com­pared to months for dogs.

The speed of the train­ing makes up

for the fact that a wasp’s life span sel­dom ex­tends be­yond six weeks, whereas a dog’s can see years of ac­tive ser­vice. Sci­en­tists have al­ready sought to pla­cate the man­ner in which the wasp de­tects scents us­ing tech­ni­cal hard­ware.

The chief block­ade for re­searchers has been that un­like dogs the wasp is un­able to bark to draw its han­dler’s at­ten­tion to what it had just “sniffed”. In­stead, the in­sect, barely six cen­time­tres long, rubs its an­ten­nae against the bot­tom of the box.

“Ob­vi­ously sol­diers in bat­tle­field con­di­tions couldn’t be try­ing to gauge the for­ag­ing move­ments of six-cen­time­tre long in­sect”, said Wack­ers. “That’s why af­ter pro­tracted re­search my col­leagues in the US have now suc­cess­fully pro­duced a com­po­nent that func­tions as an alarm and can elec­tron­i­cally reg­is­ter when the wasp has de­tected a mine.”

Train­ing given

While the bees and wasps could be im­parted train­ing to de­tect ex­plo­sives and mines no such train­ing is given for the de­tec­tion of a mur­der sus­pect in case of man­slaugh­ter. Na­ture it­self makes them de­tect the sus­pect as also the time of the com­mit­tal of the crime.

It works like this. A dead crea­ture is a rich source of fod­der. Once they ar­rive they con­vert it their home. They set­tle, mate, breed, lay eggs, hatch into lar­vae, pupa, meta­mor­phose into the adult in­sect and the cy­cle be­gins all over again.

Each stage of the cy­cle is pre­cisely timed. It is the tim­ing that car­ries the in­for­ma­tion which the forensic en­to­mol­ogy re­quires and utilises in solv­ing the crime mys­tery.

En­to­mol­ogy is science of study of in­sects. In­ter alia, en­to­mol­ogy de­tails the com­plex and elab­o­rate life-cy­cle of an in­sect. In­sects are very par­tic­u­lar about their breed­ing con­di­tions. They need the ex­act amount of sun­shine and a per­fect tem­per­a­ture, in­doors or out­doors.

It is this fac­tor that comes to the aid of the forensic en­to­mol­o­gists. By glanc­ing at the var­i­ous in­sects and the dif­fer­ent stages that they are in, they can with ex­ac­ti­tude calculate the time, tem­per­a­ture and lo­ca­tion of the crime.

In­sect pop­u­la­tion varies widely from re­gion to re­gion as also from sea­son to sea­son. In USA and Canada where the map­ping of in­sect pop­u­la­tion has been car­ried out ex­ten­sively for var­i­ous sea­sons, forensic en­to­mol­o­gists are called to ten­der ev­i­dence in cases of crimes.

The pi­o­neer of this field is Dr Gail An­der­son of the Si­mon Fraser Univer­sity. She and her stu­dents not only help solve mur­ders but they are also ac­tive in nail­ing the poach­ers.

Up­wards a cen­tury ago, it was Dr Berg­eret d’Ar­bots who founded the gen­era of forensic en­to­mol­ogy when he was called upon to ex­am­ine the body of a child, ruth­lessly killed and in­terred in a house in 1840. While all con­ven­tional clues pointed to­wards the cur­rent ten­ants as the per­pe­tra­tors of this hor­ren­dous crime, Dr d’Ar­bots proved oth­er­wise.

By mak­ing an in-depth study of the var­i­ous in­sect pop­u­la­tions around the body, he let out vir­tu­ally ir­refutable ev­i­dence in­di­cat­ing that the ghastly crime was ex­e­cuted months ago when there was an­other house­hold dwelling in the same house. The kind of in­sects in­di­cated the tem­per­a­ture and sea­son of the crime.

Stud­ies on bees

Today Dr Gail An­der­son em­ploys the same meth­ods of study­ing in­sect pop­u­la­tion around the scene of the crime. Her most re­cent suc­cess has been a com­plex case of bear poach­ing in Man­i­toba, Canada.

Here al­beit the au­thor­i­ties ap­pre­hended a hand­ful of sus­pects they couldn’t find any stolen bear parts on their person. The petrol of­fi­cer, how­ever found a type of Blow fly on the bod­ies of the dead bear cubs and sent the sam­ple to Dr An­der­son. Dr An­der­son knew the pe­riod that the eggs of this in­sect needed to hatch.

Based on her stud­ies she ar­rived at a time for the crime that per­fectly matched the time for the crime when the ve­hi­cle of the sus­pects was no­ticed in that area. The sus­pects were found guilty on re­lent­less ques­tion­ing and were con­victed for the il­le­gal poach­ing of the bear parts.

Her tremen­dous achieve­ment in this unique case brought her recog­ni­tion from the World Wildlife Fund, the Cana­dian Wildlife Ser­vice and var­i­ous other agen­cies in­volved in pro­tec­tion of an­i­mals.

Forensic an­thro­pol­ogy is an ap­pli­ca­tion of ex­pert knowl­edge

and anal­y­sis about skele­tal anatomy.

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