Insect sniffing the way of the future

Insect sniffing the way of the future

Ever since hearing about the potential to use insects as a form on chemical detection, like canines are used for, I have been fascinated by the potential. Imagine going to the airport as your about to go away on holiday, and there are bee’s flying around the place, or people walking around with some wasps in a bottle, trying to find the next terrorist bomb or drug run before it happens.

The article I have chosen to write this post about was “Using insect sniffing for detection” by Glen C. Rains, Jeffery K. Tomberlin and Don Kulasiri.

The first such studies into using insects as a means of detection were developed, like most technologies, in the United States Army in 1963. These studies were aimed at using the innate behaviour of insects to detect the presence of an enemy. Human feeding insects like mosquitos, ticks and lice. These insects have a hardwired behavioural response to changes in CO2 or lactic acid concentrations in the air, which could signal human presence, like an enemy.

Although most insects learn through their natural habitats, or from parents, some can be taught behaviours, or have they modified. A chemical or volatile that is unrecognizable to an insect can be taught to be recognizable by teaching the insect to associate it with food, or a host like for parasitoid wasps. The animals behavioural response when it senses the smell (thinks its sensing food or a host) can then be analysed to find out where or what the chemical is.

 

http://forensicentomology.tamu.edu/pdf/Final_draft_Grains_et_al2008.pdf

There are several different methods that can be used for detection using insects. Free-moving detectors use insects that have been trained to detect a specific substance. These insects will then move towards the source of the substance, and can be tracked using tiny antennae on the insect (usually honeybees).

 

http://forensicentomology.tamu.edu/pdf/Final_draft_Grains_et_al2008.pdf

Another method for using insects for detection is using restrained organisms. These devices use a number of insects trained to detect a specific chemical, and are sometimes combined with some control insects so that the trained insect’s changes in behaviour are more noticeable, and the validity of their detection is augmented. The changes in the insects behaviour are then observed and analysed by webcam, either by entomologists, or computer software currently being developed. There is also another type of detection device which used a voltmeter to detect spikes in the signal from feeding muscles of moths as they start to use these muscles more as they think they have sensed food.

There are numerous advantages for using insects as a bio detection method. Insects can be trained extremely quickly, from within minutes, to only a few days for some honeybees. They can also be trained to be chemical specific. They are extremely cheap to train, especially compared to sniffer dogs, and there is also less controversy towards using insect detectors in potentially toxic environments compared to using dogs. Insects have also been proven to be excellent at detecting chemicals in complex chemical rich environments, and are also more sensitive than dogs in some cases.

There are several problems with using insects for detection. Variability between individual insects could lead to false detections, or varied results. Artificial selection may help to eradicate these over time though. There are also several ethical problems. These detection devices starve the insects before using them as this makes them better at sensing what they think is food. The insects are also kept in restrained positions and in small containers. To the majority of people, these seem of no consequence, as they are ‘only insects’, but to some, myself included (I think), this is quite immoral.

More research is needed in order for these systems to become mainstream; however there is huge potential in them. Future applications for these bio detection systems include fire detection, medical diagnoses, aflatoxin detection in peanuts, grain and milk, illegal drugs, arson and explosives. There are some insects that can already be naturally utilized, such as blow flies and females hide beetles which are adapted in finding decomposing remains like humans. The Jewel beetle Melanophila acuminate can detect smouldering wood from over several miles, which would be a valuable device is detecting wild fires early.

I find this an exciting branch of entomology, and one that has a huge future. I hope you guys found this as interesting as I did.

 

LAND where you want to be,

 

Nick

 

Mosquiiiiiiiiiiiiiiiiiiiiito’s Moving Malaria!

I think you will struggle to find someone in NZ who doesn’t shudder when they are curled up in bed at night and they hear that high pitched whining around their head. Mosquiiiiiiiiiiiiiiiiito! You know it is going to wait until you are sound asleep and then feast on your nutrient rich blood, and there is nothing you can do about it!

Although I have always been one of those people, I have always been thankful that as a New Zealander, I do not have to worry about being infected by such life threatening diseases as malaria. Having been to malaria infested countries, seen the damage and worry it causes people, I was naturally interested in how these wee critters work and cause so much damage. The article I have chosen to help me in my quest for knowledge is “Mosquito ecology and control of malaria” by H. Charles and J. Godfray.

A huge amount of the world’s most infectious diseases are transmitted by insects, and in particular mosquitos (Family: Culicidae). Although this article focuses on malaria, as does this blog post, mosquito are also vectors for other fatal and well known human pathogens such as Yellow fever, the West Nile virus, the Rift Valley fever,  the Ross River fever, as well as numerous animal diseases. The most widely known and damaging of these is malaria, which is vectored by the genus Anopheles and infects approximately 200 million people per year and causes between 06-1.2 million deaths per year.

Although there are 40 known genus of mosquito, the only one which transmits malaria is the Anopheles, and out of the 500 species of Anopheles, only 70 are known to transmit malaria competently between humans.  The basic mosquito biology is similar between all mosquito genus and species. Females merge from their larval life stage and mate immediately. They then need a blood meal in order for their eggs to mature, however they can obtain energy from nectar. The Anopheles genus of mosquito feed from several different host species, however the 70 species that do transmit competently between humans show a preference towards feeding on humans, hence the reason they are successful transmitters. Some species even seem to have evolved to hunt and feed around buildings or other likely locations where they will find people.

http://www.myhealthnewsdaily.com/2998-best-insect-repellents.html

After having a feed on human blood, the mosquitos are heavy and struggle to fly, so rest to aid with digestion. This is why you often see mosquitos resting on the walls of houses. Once digested and the eggs have matured, the mosquito flies to its aquatic breeding site where it will oviposit its eggs.

The actual malaria disease is caused by the genus Plasmodium which is a single celled eukaryote in the phylum of Apicomplexa. The species which is most prolific in causing the damage to humans is Plasmodium falciparum however Plasmodium vivax is also capable of such illness. The pathogen enters into the human body when the mosquito pierces into the bloodstream to feed. It then colonises the liver and divides, ruptures the cell it is in and enters the blood stream where it infects red blood cells. Once it is in a red blood cell, it then begins to multiply again and can infect other red blood cells. These red blood cells spread around the body and cause the disease symptoms.

Some of the Plasmodium which has entered the red blood cells takes on a different developmental approach. It undergoes meiosis and male and female gametes are produced, which can then be taken up by mosquitos when they feed on the blood of the infected victim. These male and female gametes can then ‘mate’ in the mosquitos gut, making that new mosquito a vector for malaria.

The malaria pathogen is well protected from the host’s immune system as it spends the majority of its lifetime inside the host’s cells. Malaria can be removed by the spleen of humans, so it has developed a defence against this. It produces proteins which bind the infected red blood cells to capillary walls, which is a major cause of the disease symptoms of malaria. Humans can however produce some immunity to malaria and adults in highly infected regions generally have some immunity to it.

http://novatravelclinic.com/wp-content/uploads/2010/12/malaria-map.png

After looking into how malaria occurs and the complex adaptations and relationships that surround it, it is hard to see how an effective vaccine will be developed. The relationship between the mosquito, the malaria pathogen and the human immune system is highly complex and the pathogen well evolved. With advances in technology and knowledge, and an increase in funding from uninfected western countries, hopefully we will see a vaccine in our lifetimes.

So next time you hear that high pitched whining around your head, be thankful that you don’t have to worry about a tiny protist infecting you, and let the wee mosquito enjoy its meal in peace!

LAND where you want to be,

Nick

ColeopterYUM

Insects as a food source? Why not? We rape and pillage nearly everything else on the planet. Insects are fast growing, have a high fecundity, some are multivoltine, convert feed efficiently, have low space requirements and are possibly delicious. They could be the answer to a sustainable food source for the earths growing population.

I was inspired to delve into the exquisite world of insect cuisine and explore it after watching numerous accounts of a personal hero: Bear Grylls, gorging himself on squirming insects. Bear seems like a man who knows how to keep himself alive, and insects seem to keep him going. The article that I found and interested me into entomophagy (the consumption of insects) was “Nutritional composition and safety aspects of edible insects” by Birgit A. Rumpold and Oliver K. Schlu¨ ter.

 

http://importfood.com/thai_insects.html 

Entomophagy has been a part of life for numerous cultures around the world for thousands of years as insects are regarded as being highly nutritious and full of protein and energy. One study showed that consuming 100g of caterpillar gives you 76% of your daily intake of protein and nearly 100% of your daily intake of vitamins. The energy intake was very similar to that of normal consumable meats.

 From the different orders of insects, the average contents of insects are proteins and fats, followed by fibre, nitrogen-free extract and ash.

As can be seen from figure 1 above, proteins make up the majority of the composition of insects. The average protein contents of insects range from 35.34% for Isoptera to 61.32% for Orthoptera. For 100grams of most mainstream sources of protein around today like meats and beans, insects trump them with a higher protein content. In a trial with rats fed with crickets (orthoptera), and rats fed on soy beans, it was shown that the insects were a better source of amino acids than the soy beans. A similar study was also done on chickens showing similar results.

Fats also make up a high composition of insects. The fatty acids in insects are similar to those found in fish and poultry, and also have low cholesterol contents.

 Research has shown that although insects are low in calcium and potassium, they are good potential sources of micronutrients like copper, iron, magnesium, manganese, phosphorus selenium and zinc. The levels of the micronutrients in edible insects could also be controlled by the type of feed provided for the insects.

 Besides providing just minerals, insects can also be a valuable source of vitamins. It has been shown that 100g of insect dry matter is rich in riboflavin, pantothenic acid and biotin, and also folic acid which are all essential vitamins for humans. Some vitamins like vitamin A, C and niacin were not at efficient levels in 100g of insect dry matter. In contrast to this however, it has been shown that an insect tea contained 15.04mg of vitamin C per 100g. The Food and Agricultural Organisation of America recommend 45mg of vitamin C per day for an adult, so 300mL of insect tea covers this, which is just over the size of a normal cup of tea. Mmmmm… Edible insects can provide important sources of vitamins, although insects do need to be selected for specific vitamins. The vitamin content of insects could also be selected via the insects feed.

Eating insects may not be all fun and games however! Just like other edible plants and animals, caution does need to be applied to the consumption of some insect species. Some insects contain allergens and other toxins which would be detrimental to human health if consumed. An example of this is the African silkworm. It was recently shown that the silkworms contain a heat resistant thiaminase that has been responsible for seasonal ataxic syndrome cases due to a thiamine deficiency in Nigeria over the last 40 years. Insects, like shellfish, can also cause allergic reactions in people when consumed. Like other consumable plants and animals, there is always the risk of food poisoning and poor food preparation causing illness to the consumer. Insects that are harvested from the wild may contain traces of pesticides in them which could be harmful for human health; however this may be rectified by controlled feeding of artificially raised insects.
http://itthing.com/strange-weird-meals-made-with-insects

It can be concluded that edible insects are a potential food source for the earths growing human populations of the coming years. They are high in energy, proteins, and fats and contain valuable minerals and vitamins. A huge advantage of them is that their composition can be manipulated by their feed matter, allowing for an easy way to get much needed substances and minerals into populations of humans in need of them specifically. More research is needed into how to raise and manipulate compositions and also on insect’s storage and preparation for eating. Before this goes too far though, the cultural issue of consuming insects needs to be overcome by today’s fickle minded and squeamish steak and potato eating humanoids.

Thanks for reading my blog guys. The link to the article is below and is well worth a read. It also has a list of all known edible insects’ species in the world, so get out there and start sampling them!

 

http://onlinelibrary.wiley.com/doi/10.1002/mnfr.201200735/abstract;jsessionid=0E8226C75C3F01C10ABB12C3F29397A7.d03t03

 

LAND where you want to be!

 

Nick