The Case of the Mysterious Mesosa Longicorn Beetle

Entomology Today

A white-clouded longicorn (Mesosa nebulosa) with all of its tiny hairs (pubescence) intact. Photo by Szczepan Ziarko.
By Bekka Brodie

It was a beautiful, sleek, black beetle with long antennae. Immediately, I knew it was different than any other longicorn beetle I had seen, but its identity eluded me.

Bekka Brodie

Solving mysteries may be “elementary” for Sherlock Holmes, but for entomologists, trying to identify an unknown insect requires more than careful examination of trace evidence to reveal information about a mystery insect — especially when there are more than 400,000 different species of beetle worldwide! Identification requires a systematics key, careful examination of the beetle’s habitat, and a review of the scientific literature. And in this case, a team of entomologists from all over the world.

I discovered the mystery beetle while trapping deep in a sub-Mediterranean forest of the Iron Gates Natural Park in Southwest Romania. I had been checking traps for…

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Beetle Trapping Expedition

It was a beautiful, hot, Spring morning, and 3 out of shape committed scientists set out to bait and trap beetles in a mountainous and rugged sub-Mediterranean area of Romania.  Enthusiastic, we were carrying 50 traps, anxious to see what surprises will wait for us in those 50 cups over the next several weeks. We wanted to survey threatened and endangered longicorn beetles that live in the unique habitats that make up the Iron Gates Natural Park (IGNP) but we would have been excited to find even the most common of them all!  This was a brand new territory for us and one that has never been systematically surveyed. We were looking for one beetle in particular, the endangered European Maple Longicorn Beetle (Ropalopus ungaricus), but found more then we ever expected!

Pheromone Factory Line
The “Pheromone Factory Line”, here Gabriel Vanau, Viorel Popescu and I are tying multiple generic pheromone lures together in preparation for deployment in the field. The pheromone lures were provided by David Wakarchuck at Synergy Semiochemicals.  (Yes, we are wearing socks!  The lab is inside someones home… so, no shoes allowed! Next time I will be prepared and bring/wear slippers.) .
Hanging flight intercept traps and recording habitat data.
The pheromone lures are used in combination with flight intercept traps (above) provided by Joseph A. Francese at USDA APHIS.  …Here’s how it works, the pheromones are chemical compounds that transmit a seductive message to the beetles (i.e. “happy hour” or “ladies night”) and attracts members of the same species (often the opposite sex) to the trap location.  The responding beetle flies toward the pheromone message in search of a mate, bumps into the panel, and slides into the white cup below (trapped!).

The pheromones we are using are generic (many species of longicorn beetle produce the same or very similar pheromones) and we hope that they will attract a variety of beetle species (Hanks and Miller 2013, Wickham 2014). The pheromones and traps will help shed light on the diversity and community of beetle species, which is critical since the deciduous forests in Romania are among the last remaining habitat in the European Union suitable for the survival and persistence of a variety of endangered species and because knowledge about them is relatively scarce.  Additionally, the pheromones we are using have yet to be tested in Europe. So, what we find in the trap cups will be a great big surprise (like Christmas morning… but for insect nerds)!

We walked over 3 kilometres setting up traps, up steep mountains and through open fields. The elevation in Eselnita Valley increased from just under 200 meters above sea level to almost 500 meters in less than 1 km!  Within this landscape, there is a temperature inversion causing the Beech trees (which prefer a colder climate and usually grow at higher altitudes) to grow near the valley bottom (200-300 meters), where the river maintains a cooler microclimate.  The higher we climbed, the warmer it got, the Beech trees disappeared and were replaced by Oak trees.  In the open fields (Mala Valley) it is sunny, hot, and full of wildlife, including wild boar, deer, snakes (vipers!), and insects (lots of ticks!).

Vipera_ammodytes ammodytes_VGavril
Baby corn viper posing for the camera, Vipera ammodytes, IGNP, RO [Photo: Viorel Gavril]
Danube Delta,UNESCO,Biosphere Reservation,traditional food,people,landscape,food Danube delta,carp traditional,sturgeons
Danube Delta, UNESCO, Biosphere Reservation [Photo: unknown]
While setting up our traps in Mala Valley, we just about walked into a barbed wire… and looked like we trespassed on someone’s land!  We had to be careful about setting up our traps because we didn’t know if our presence would be welcome, and didn’t know how serious people are about trespassing.  Carefully, we proceeded onto the property in hopes that we would be permitted access to continue our work… And we were greeted with kindness!  We met an old couple, Ion and Veta Jianu, who not only welcomed us, but they gave us coffee and homemade cheese (which became my staple food for the next several weeks), and also gave us permission to trap beetles on their land.  (In fact, Ion greeted me by hand-kissing without making eye contact, which I learned is a traditional way for a gentleman to greet a lady in Eastern Europe!)  Throughout the field season, I would continue to meet Ion every day (no hand-kissing since). Ion spoke no English, but he patiently waited while I strung together a few Romanian words (thanks iPhone data and Google translate!), and we made conversation for hours at a time.  We chatted about the beetles captured, the trees and plants I came across in the woods, our families, and the weather (always up to date with weather conditions in the area, as well as in the town where my in-laws were babysitting my son, at the other end of the country).  I would often bring leaves from trees where I was catching beetles and Ion would teach me the Romanian name of the tree and its traditional use (scythe handle, cane, etc.).  …So, as it turned out, on the other side of that barbed wire was a very good friend!

Ion Jianu
Ion Jianu waiting for us to finish our work for the day (Mala Valley, Eselnita, RO)

There are many vulnerable, threatened, and poorly understood beetles in the IGNF.  (I will post stories about many of them in the future.)  However, there is one beetle in particular that we were interested in finding, the endangered European Maple Longicorn Beetle, Ropalopus ungaricus.  This beetle has an endangered IUCN status due to severe destruction Ropalopus_ungaricus_copyright_Petr_Zabranskyof mixed forest habitat for intensive agriculture and urbanization, and because of deficient forest management, and most importantly, the abandonment of traditional land uses (fewer people like Ion and Veta). The Maple Longicorn develops in living and dying Maple trees (Acer spp.) with a preference for pollarded or open trees. Pollarding is a form of traditional forest management in Central and Eastern Europe used to produce more branches and foliage for use as animal feed or firewood. Pollarding also has a side effect of increasing the amount of light that enters the tree canopy, as well as its undergrowth, allowing for optimal conditions Maple Longicorn.

A "wolf beetle" overpowering a longicorn beetle, Hungary, Gerence Highlands. [Photo: Sig]
A “wolf beetle” overpowering a longicorn beetle, Hungary, Gerence Highlands. [Photo: Sig]
Over the next month and a half we checked the traps daily.  We wanted to ensure that none of the beetles were harmed… especially the Maple Longicorn beetle.  We were worried about them getting harmed because we caught more then just beetles responding to pheromones for romance (a mate), we also caught beetles looking for a meal!  We caught hundreds of checker beetles (Clerus mutillarius) daily (about 10-20 per trap)!  The Romanian people I spoke to called these beetles ‘gândacul lup’, or wolf beetles, because they’re amazing hunters and eat everything!    So, we had to check the traps daily to reduce the number of Longicorn beetles that would have been on the “wolves” menu.

After an entire month and a half of hiking 1.5 kilometers of rugged terrain daily, we decided to wrap up the project and take down the traps.  The pheromones were quickly depleting from the heat and we hadn’t caught any new beetles species in a week.  And, although we hadn’t found our target beetle, the endangered Maple Longicorn Beetle (Ropalopus ungaricus), we still had plenty of data for a great story!  (As it turns out it’s so elusive that even the Grigori Antipa Natural History Museum in Bucharest, RO, does not have one in their vast collections).  However, (and quite ironically) on the very last day we captured a similar species of Maple Longicorn beetle (Ropalopus insubricus), a cousin of our target beetle (and featured on the header this post).  So, we are getting closer!  We will be back in August to scope out better habitat to trap for the elusive Maple Longicorn Beetle.

Overall, we managed to collect 40 different species of Longicorn beetles and of those approximately 10 are rare, vulnerable, and threatened beetles.  One species of beetle was unidentified, possibly a new species or invasive species??  Many beetles were captured in specific habitats within our trapping areas or at different times of the day.  I will write more detail about the beetles, their identification, habitat, and behaviour in future posts… So, please stay tuned or “follow” this blog.

In the mean time, for more details on the project, please visit my new page “RO Beetle Project“!

Removing traps from the Eselnita Valley with Akis and Laurentiu Rozylowicz.
Removing traps from the Eselnita Valley with Alexandru Gavrilidis Athanasios (AKA “Akis”) and Laurentiu Rozylowicz [Photo: Laurentiu Rozylowicz).
The spot where the Maple Longicorn Beetle "should be" in the collection at the Antipa...
The blue arrow shows the empty location for the Maple Longicorn Beetle in the collection at the Grigori Antipa Natural History Museum, Bucharest, RO

Citations:

Hanks LM and Millar JG (2013) Field bioassays of cerambycid pheromones reveal widespread parsimony of pheromone structures, enhancement by host plant volatiles, and antagonism by components from heterospecifics. Chemoecology 23:21-44.

Wickham JD, Harrison RD, Lu W, Guo Z, Millar J, Hanks LM, and Chen Y (2014) Generic lures attract cerambycid beetles in a tropical montane rain forest in southern China. Journal of Economic Entomology 107(1):259-267.

Featured imageRopalopus insubricus 

Good night, sleep tight, and don’t let the bed bugs bite!

It’s a aphorism I tell my son before shutting off the lights at bedtime.  My parents said it to me, their parents said it to them, and so on.  We all know the saying, but unlike the boogie-man, goblins, or ghosts, bed bugs (Cimex lectularius) are a real “monster” that could be lurking in your bed and home. What is scary about bed bugs is that anyone can get an infestation (it doesn’t matter if your clean or dirty) and they are almost impossible to get rid of.  Luckily for us there is a new pheromone identified from the bugs frass (insect poop) and cuticle (wax on the insects body) that can be used to monitor and control bed bug outbreaks. We no longer have to worry about the bed bugs bitting and can finally “sleep well”.

Bed bugs have been feeding on humans for 10,000  years!  In fact, Archeologists found 3,550 year old fossilized bed bugs in human dwellings in Egypt (Panagiotakopulu & Buckland 1999).  Bed bugs really began to spread and thrive in America alongside the arrival of the railroad and increased travel. People began moving and distributing the little nightmares from inns and hotels to their homes. However, over the last few decades, bed bugs have been in quiet descent (perhaps due to the use of DDT and other insecticides)… until recently.  Now there are increased reports of bed bug infestations all over North America (in high rise apartments, homes, schools, hospitals, clothing stores, public transit, etc).

They have become a global epidemic not only because adult insects are such good travellers (Wang et al. 2010), spreading throughout public and domestic dwellings, but also because the eggs are hidden well and almost impossible to kill.  The best way to get rid of bed bugs are to throw items in the dryer at a high heat, minimum 120°F/ 48.8°C. Unfortunately, you can’t put everything in the dryer, so many people throw items out or resort to powerful insecticides.

Thanks to scientists (also my friends and colleagues!) at Simon Fraser University we can indeed sleep well at night.  They used state of the art scientific equipment to identify a natural pheromone blend that acts as a chemical hypnosis.  The pheromone blend attracts bed bugs and keeps them in one spot.  Altogether, keeping them out of your bed!

Please watch the video made by my colleague Mike Hrabar that explains and shows exactly how this aggregation pheromone works!  It’s part of the NSERC Science, Action! scholarship competition.  If you enjoyed the video, be sure to share and give him a “like”  in Youtube!

Read the full article:

Gries, R, Britton, R, Holmes, M, Zhai, HM, Draper, J, & Gries, G. 2015.  Bed bug aggregation pheromone finally identified. Angewandte Chemie- International, 54(4):1135-1138.

Citations:

Cohen, J. 2010. They’re Back: A Bed Bug History. History.com.  Retrieved March 9th, 2015, http://www.history.com/news/theyre-back-a-bed-bug-history

Hrabar, M. Bed bug aggregation. [Cover Photo] 2010. Vancouver, BC, Canada.

Panagiotakopulu, E. & Buckland, P.C. 1999. Cimex lectularius L., the common bed bug from Pharaonic Egypt. Antiquity 73. 

Wang, C., Saltzmann, K., Chin, E. Bennett, G.W., & Gibb, T. 2010. Characteristics of Cimex lectularius (Hemiptera: Cimicidae), Infestation and Dispersal in a High-Rise Apartment Building. Journal of Economic Entomology. 103(1): 172-177

Can Ebola be Vectored by Flies?

This is a collaborative post by myself and my colleague, Dan Peach.

Lately, we’ve been inundated with updates about the Ebola outbreak: news, pictures, videos, facts, symptoms and more. This is no surprise, as there are over 14,000 confirmed cases as of November 12, 2014. We’d like to shed some light on the virus and speculate on the natural transmission cycle and the potential for insects, specifically flies such as filth-breeding flies, to act as vectors of the disease – an area which remains a challenge for scientists.

There are four species of Ebola virus – all of which cause disease in vertebrates. It is a hemorrhagic fever belonging to the family filoviridae that was first recognized in Africa in 1976. It is readily transmitted via contact with infected bodily fluids, and can survive on surfaces contaminated by such fluids for at least several hours in dark conditions (Sagripanti et al. 2010). Usually, outbreaks in human populations follow that of outbreaks in chimp or gorilla populations (Leroy et al. 2004, Lahm et al. 2007). This happens (at least partially) because humans consume bush meat and contract the disease. There are normally a few outbreaks every few years in rural Africa, usually 2-4 months after the end of a wet season (Lahm et al. 2007), but the remote locations and small numbers contain them. This time it was different because it got into some of the larger population centres, such as Monrovia, and overwhelmed the healthcare system. For this reason, the 2014 outbreak has become the largest in history.

One of the areas where the Ebola virus really stands out compared to other pathogenic outbreaks (like measles, whooping cough, smallpox, and the 1918 influenza pandemic) is its reliance on the animal reservoirs. The Ebola virus can be incubated in pigs, primates, antelopes, dogs, and bats. These (or other yet-to-be determined species) can form a reservoir for Ebola to survive if it has been eradicated from the local human population. Viruses like smallpox and measles have no animal reservoirs that we know of. So despite being highly contagious, they’ve been relatively easy to eradicate from human populations because humans are the only organisms one needs to worry about in breaking the chain of transmission.

For a long time fruit bats have been implicated in the transmission of the disease because unlike pigs, primates, antelopes, or dogs, they can be infected with the virus and survive without symptoms (also known as asymptomatic). However, their role in maintaining the virus in nature is under debate.

We would like to bring forth the hypothesis that filth-breeding flies may be responsible for transmitting the disease. There are many kinds of biting and filth-breeding flies, which are quite common around farms, residences, and food establishments (like restaurants or meat-packaging plants). Many of these flies have lapping sucking mouthparts, so they only consume liquids (like bodily fluids resulting from Ebola) and, as they move from food source to food source, they sample and eat food by regurgitating liquid and dropping it on the food to liquefy it. More importantly, because filth-breeding flies are scavengers (on carrion, feces, bodily fluids, and/or decomposing organic material) they could be capable of transmitting diseases to animals, as well as humans.

Another reason we believe filth flies may be responsible for transmitting the disease is because outbreaks in animals (such as gorillas or pigs) usually precede human outbreaks (Leroy et al. 2004, Lahm et al. 2007). While consumption of infected animals has been implicated in many human outbreaks, infected animals or animal carcasses could provide easy, undefended food resources for flies. If these flies then land on human food or on or around an orifice of a human, and deposit infected fluids from a previous meal, the potential may exist for infection. Mosquitoes that feed on an infected animal or human could also potentially transmit the virus.

Ebola is an RNA virus, so the best evidence for insect vectored Ebola would be if insects were found to vector RNA viruses. One study found that house flies could successfully transmit a pathogenic RNA virus from infected pigs to uninfected pigs (Otake et al. 2003). The virus was detected in the house flies up to 6 hours after exposure, plenty of time for a pathogen-carrying fly to expose multiple unexposed hosts.

Finally, many filth flies are exceptional travelers, and individuals have been reported to fly distances of up to 65 km. Therefore having the potential to distribute the Ebola virus both long distances as well as within the immediate vicinity of their feeding and/ breeding site.

There are many many many many flies out there, orders of magnitudes more than any vertebrate deemed responsible for Ebola. Even if a small fraction of the fly populations would be carriers of Ebola, they probably would still be the dominant vector of spreading the disease.

Currently sanitation is the only way to control these flies; there are no effective traps or baits, and pesticides may not be available in developing countries in rural Africa. However there may be hope in monitoring these flies for Ebola by extracting DNA samples. When a fly feeds on tissue or bodily fluids from an animal carcass, it may pick up genetic material from that animal. If the tissue or fluid in that meal is infected with large enough amounts of Ebola, then DNA from Ebola may be present along with animal DNA. This genetic material would likely only be present for a short time before it is degraded by the fly’s digestive system, however, the potential exists to capture flies and survey for the presence of Ebola as well as what they have been feeding on. This would of course also depend on the level of Ebola infection in the tissue consumed. A team of researchers are currently sampling DNA from blow fly meals in southern Guinea to determine whether large mortality events of certain species have occurred in the area (Vogel, G. 2014).

Only after this most recent outbreak have scientists really started to ask the question “what is the role of insects in vectoring the Ebola virus”. In fact, some the most brilliant minds in Medical, Urban, and Veterinary Entomology (MUVE) will be gathering to brainstorm the possibilities this week at the Entomological Society of America. So, it won’t be too long until we have an answer. In the meantime, we’re willing to bet on flies playing an important role.

 

There are many filth-breeding flies, but here are 5 culprits for potential vectors of Ebola virus:

House Fly (Family Muscidae):

House Fly, Unknown sp. (Photo: Sean McCann) House flies are one of the most common fly species around peoples homes and they are distributed all over the world.  They will feed on almost anything from food lying around your home to (especially in warm climates) an open wound or sore.  House flies will lay up to 500 eggs in any decomposing organic material (feces, carrion, garbage).   In warm climates they can complete their life cycle in 7-10 days.  House flies are known vectors of more than 100 pathogens that may cause disease in humans and animals, including typhoid, cholera, bacillary dysentery, tuberculosis, anthrax ophthalmia and infantile diarrhea, as well as parasitic worms
House Fly, Unknown sp. (Photo: Sean McCann) House flies are one of the most common fly species around peoples homes and they are distributed all over the world. They will feed on almost anything from food lying around your home to (especially in warm climates) an open wound or sore. House flies will lay up to 500 eggs in any decomposing organic material (feces, carrion, garbage). In warm climates they can complete their life cycle in 7-10 days. House flies are known vectors of more than 100 pathogens that may cause disease in humans and animals, including typhoid, cholera, bacillary dysentery, tuberculosis, anthrax ophthalmia and infantile diarrhea, as well as parasitic worms

Blow Fly (Family Calliphoridae):

Blow Fly, Lucilia sericata (Photo: Sean McCann) Blow flies are well-known metallic green and blue flies associated with feces and dead animal carcasses.  They are quite common and well distributed all over the world.  Like the house flies, they will feed on a variety of foods but are especially keen on feces and carrion.  Female blow flies will lay 200 eggs that will quickly hatch and complete their life cycle (egg to adult) in approximately 20 days in warm climates.  Blow flies may be vectors of pathogens, but because of the anti-bacterial, anti-fungal, and anti-viral properties found in their gut they are rarely proven as vectors and are most often causal agents of bacterial infections.  Still, because of their less than socially approved eating habits, I’m keeping them on the list.
Blow Fly, Lucilia sericata (Photo: Sean McCann) Blow flies are well-known metallic green and blue flies associated with feces and dead animal carcasses. They are quite common and well distributed all over the world. Like the house flies, they will feed on a variety of foods but are especially keen on feces and carrion. Female blow flies will lay 200 eggs that will quickly hatch and complete their life cycle (egg to adult) in approximately 20 days in warm climates. Blow flies may be vectors of pathogens, but because of the anti-bacterial, anti-fungal, and anti-viral properties found in their gut they are rarely proven as vectors and are most often causal agents of bacterial infections. Still, because of their less than socially approved eating habits, I’m keeping them on the list.

Flesh fly (Family Sarcophagidae):

Flesh Fly, Unknown sp. (Photo: Sean McCann) Similar to both House flies and Blow Flies, Flesh flies are quite common and also scavengers of feces, carrion and garbage.  Flesh flies are small to medium sized flies with a grey and black striped “back” or thorax, often with a red tipped “butt” or abdomen.  Their entire lefe cycle can be completed quite quickly (as few as 8 days) due to the fact that they live maggots and not eggs. Flesh flies are suspect to transmit pathogens.
Flesh Fly, Unknown sp. (Photo: Sean McCann) Similar to both House flies and Blow Flies, Flesh flies are quite common and also scavengers of feces, carrion and garbage. Flesh flies are small to medium sized flies with a grey and black striped “back” or thorax, often with a red tipped “butt” or abdomen. Their entire lefe cycle can be completed quite quickly (as few as 8 days) due to the fact that they live maggots and not eggs. Flesh flies are suspect to transmit pathogens.

Mosquito (Family (Culicidae):

Mosquito, unknown sp. (Photo: Sean McCann) Mosquitoes take blood meals from a variety of hosts, including humans (depending on the mosquito species). Most diseases they transmit are due to parasites that infect their salivary glands, however, they may transmit Ebola due to a behavior called pre-diuresis in which they excrete excess fluids from their abdomen while taking a blood meal. If they have previously fed on infected blood with high enough concentrations of Ebola in it and then before they have digested their meal excrete this fluid near the orifice of a person there may be a potential for Ebola transmission.
Mosquito, unknown sp. (Photo: Sean McCann) Mosquitoes take blood meals from a variety of hosts, including humans (depending on the mosquito species). Most diseases they transmit are due to parasites that infect their salivary glands, however, they may transmit Ebola due to a behavior called pre-diuresis in which they excrete excess fluids from their abdomen while taking a blood meal. If they have previously fed on infected blood with high enough concentrations of Ebola in it and then before they have digested their meal excrete this fluid near the orifice of a person there may be a potential for Ebola transmission.

Eye Gnat (Family Chloropidae):

Eye Gnat, Liohippelates sp. (Photo: Lyle J. Buss) Eye Gnats are small black flies and are quite common in warmer climates.  Eye Gnats do not bite but are a great nuisance around humans and animals because they feed on fluid from wounds, eyes, nose and sometimes feces.  Gnat flies, like the other flies on our list, will complete their life cycle quickly in warm climates, as few as 7 days.  Eye Gnats in the genus Hippelates can carry the spirochaete pathogen that cases yaws, and may also spread conjunctivitis but, due to their habits, have to potential to spread more.
Eye Gnat, Liohippelates sp. (Photo: Lyle J. Buss) Eye Gnats are small black flies and are quite common in warmer climates. Eye Gnats do not bite but are a great nuisance around humans and animals because they feed on fluid from wounds, eyes, nose and sometimes feces. Gnat flies, like the other flies on our list, will complete their life cycle quickly in warm climates, as few as 7 days. Eye Gnats in the genus Hippelates can carry the spirochaete pathogen that cases yaws, and may also spread conjunctivitis but, due to their habits, have to potential to spread more.

Citations:

Buss, L. Adult Liohippelates Sp [Photo] 2011. University of Florida. Web. 13 November 2014. http://entnemdept.ufl.edu/creatures/livestock/flies/liohippelates.htm

Getty Images. Digital Image of Ebola Virus [Cover Photo] 2014. New York Post. Web. 16 November 2014. http://nypost.com/2014/09/30/ebola-in-the-usa-texas-patient-has-deadly-disease/ 

Lahm, S., Kombila, M., Swanepoel, R., and Barnes, R. 2007. Morbidity and mortality of wild animals in relation to outbreaks of Ebola haemorrhagic fever in Gabon, 1994-2003. Transactions of the Royal Society of Tropical Medicine and Hygiene 101: 64-78

Leroy, E., Rouquet, P., Formenty, P., Souquière, S., Kilbourne, A., Froment, J-M., Barmejo, M., Smit, S., Karesh, W., Swanepoel, R., Zaki, S., and Rollin, E. 2004. Multiple Ebola transmission events and decline of central African wildlife. Science 303: 387-390

Sagripanti, J-L., Rom, A., and Holland, L. 2010. Persistence in darkness of various alphaviruses, Ebola virus, and Lassa virus deposited on solid surfaces. Archives of Virology 155(12): 2035-2039

Vogel, G. 2014. Are bats spreading Ebola across sub-saharan Africa? Science 344: 140

Acknowledgements:

This post was inspired by my friend Dr. Monica Hughes.  We would like to thank Dr. Carl Lowenberger and Matt Holl for constructive comments.

The Beginning of the End: How Blow Flies find Corpses

In the spirit of Halloween…

“I see dead people”, whispers  Haley Joel Osment in M. Night Shyamalan movie “The Sixth Sense”… and he is very convincing. That’s just a movie, but for blow flies, seeing and smelling dead people, or any decomposing corpse for that matter, is what adult life is all about. Unlike Osment, blow flies want and need to see and smell dead things! They have to be able to find decomposing corpses quickly in order to lay their eggs and propagate their kind. In fact, they are so good at finding dead things that we use their progeny (read maggots and pupae) in forensic sciences for determining time of death (TOD), and ultimately putting criminals behind bars.

Haley Joel Osment in M. Night Shyamalan movie “The Sixth Sense” (Photo: Huffington Post) and blow fly (Photo: Mike Hrabar)

In a recent article published in Entomologia Experimentalis et Applicata, my collegues and I explain how fertile blow flies rapidly locate a recently deceased corpse.  Reproductively mature female blow flies use very low concentrations of dimethyl trisulfide (DMTS) in combination with dark animal pelt mimicking colours (black and reddish brown) to rapidly locate the corpse.

Blow flies lay their eggs on recently deceased animal corpses.  The eggs quickly hatch into maggots which consume and break down the corpse. After approximately 1 week of consuming the rotting flesh, they will leave the corpse and pupate in the soil nearby.  But blow flies aren’t the only organism scavenging the corpse; they face a lot of competition with other insects, bacteria, fungi, and vertebrates.  In order to reduce competition with these organisms, blow flies need to get there first, and they do!  Often, they get there within the first few hours after death!  This means that they can smell a corpse long before our noses can; very intriguing!

Working with one of the first species of blow fly to arrive on the scene, Lucilia sericata, we show that blow flies can detect ‘death’ volatiles, and respond faster to a recently dead and wounded rat carcass than they do to an intact rat carcass.    Our next step was to identify the odour using a variety of lab equipment including a gas chromatograph electro-antennal detector (GC-EAD) which is a fancy name for a process with a easy explanation… the antenna acts as a filter for all the smells and we only identify the odours that excite the antenna.  Using this process we identified 9 compounds that excited the antenna.

Using a series of laboratory and field experiments, we concluded that DMTS was the key compound that attracted flies, but not just any flies… female flies laden with eggs!

Like most insects blow flies use antenna to smell odours and locate resources, like the corpse, but unlike many insects blow flies have huge eyes that take up 70% of their head.  So we paired visual cues with DMTS and found that dark animal pelt mimicking colours accentuate the response of blow flies.

Ultimately these findings will be developed into a lure for trapping blow flies, both industrially and residentially.  But more importantly, the lure can be used to monitor blow flies for the impending Zombie Apocalypse.  Due to the fact that the rotting flesh of zombies is likely similar to the rotting flesh of a recently deceased corpse (although, arguably, my dead experimental rats were far from being undead), Metro Vancouver (one of the safest Canadian cities in case zombies decide to finally take down us humans) will be able to use our lure in a trapping and monitoring system, part of their “Zombie Preparedness Campaign“.

…No, but really, BC really does have an emergency zombie preparedness Campaign!  Deal is: If you are ready for zombies, you are ready for the inevitable Megathrust Earthquake, which is due every 70 years or so in the Pacific Rim. Anyway, zombie preparedness is probably one of the things that makes Vancouver one of the best places to live in the Solar System.  I swear I didn’t make any of this stuff up!

Read the full article:

Brodie, B.S., R. Gries, A. Martins, S. Vanlaerhoven, and G. Gries. 2014. Bimodal cue complex signifies suitable oviposition sites to gravid females of the common green bottle fly. Entomologia Experimentalis et applicata. 153(2) 114-127

Citations:

McCann, S. feeding and ovipositing blow flies. [Cover Photo] 2012. Vancouver, BC, Canada.

Blow Flies Spit to Attract Homies

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In hip hop culture, rapping is all in how rhymes are spit to attract a crowd. In blow fly culture, flies also spit to attract crowds. Generally, we wouldn’t think of spitting as attractive but, in a recent article published in Insect Science, my collegues and I explain how blow flies co-opt semiochemicals associated with feeding or “spit” as a resource indicator.  The spit is an “international fly language” attracting flies of the same species and closely related species to lay eggs together.

Blow flies lay eggs together in groups called aggregations on a dead animal carcass (see photo below). In order to find each other, like most insects, they have been thought to rely on pheromones. However, repeated attempts to extract a pheromone failed, invoking doubt whether a pheromone really exists.  Conceivably, the reproductive biology of blow flies may be linked to carrion resources. Simply by regurgitating and feeding on carrion, flies may enhance its attractiveness. These feeding flies may inadvertently attract gravid (flies with eggs) and non-gravid females and even males. Based on their sex, age and reproductive status, flies attracted to a resource may then obtain meal, find a mate, or lay eggs.

Egg-laying aggregation of blow flies, Lucilia sericata (Family: Calliphoridae) on rat carrion.  (Photo by Sean McCann)
Egg-laying aggregation of blow flies, Lucilia sericata (Family: Calliphoridae) on rat carrion. (Photo: Sean McCann)

If flies were to aggregate on a carrion resource in response to feeding flies rather than ovipositing flies, then the semiochemical cue(s) may be present in the vomitus or salivary secretions of flies. As early as 1955, Dethier noted that fed-on food was more attractive to blow flies than non-fed on food. Even if the flies do not signal themselves, their salivary secretions may contain enzymes and microorganisms that initiate the breakdown process of the carcass (Dethier, 1955; Telford et al., 2012).

Working with two species of blow fly, Lucilia sericata and Phormia regina, we show that female blow flies of varying reproductive stages present on an oviposition site enhance its attractiveness to fellow female blow flies.  We conclude that their is not an oviposition pheromone, but rather female flies co-opt semiochemicals associated with feeding flies of varying reproductive stages as resource indicators.

The digestive fluid, such as spit, is in addition to other strategies flies use to improve the resource and increase benefits of their offspring. House flies (Diptera: Muscidae), for example, preferentially lay eggs near freshly deposited eggs of their same species. The maggots warm and moisten the resource and prevent fungi from taking over. Similarly, aggregated oviposition by blow flies increases the fitness of their offspring because, with large numbers of maggots, relatively fewer are eaton by predators. Additionally, these maggots develop quickly by sharing digestive fluids and taking advantage of elevated temperatures.

So, it’s beneficial for flies to be “Rollin’ with their Homies”.  I’d spit you a rhyme if I could but, for the flies, it’s just simply all in the spit (not the rhyme)!

Read the full article:

Brodie, B.S., W.H.L. Wong, S. Vanlaerhoven, and G. Gries.  2014. Is aggregated oviposition by the blow flies Lucilia sericata and Phormia regina (Diptera: Calliphoridae) really pheromone-mediated? Insect Science. DOI: 10.1111/1744-7917.12160

Citations:

Dethier V.G. (1955) Mode of action of sugar-baited fly traps. Journal of Economic Entomology, 48, 235–239.

Telford, G., Brown, A.P., Rich, A., English, J.S.C. and Pritchard, D.I. (2012) Wound debridement potential of glycosidases of the wound-healing maggot, Lucilia sericata. Medical and Veterinary Entomology, 26, 291–299.

Blow flies spitting on rat carcass.
Blow flies “spitting” on animal carcass. (Photo: Sean McCann)

Insect Flight

Flight has always intrigued and inspired human beings.  Since antiquity we created stories, myths, and legends about flight, and flying is arguably one of humanity’s greatest achievements…  Since flight became a reality in 1903 with the Kitty Hawk we continue to aspire better, faster and more efficient aviation, to the most recent “Flying car”. (No, not Doc Brown’s time travel car from “Back to the Future” or “Chitty Chitty Bang Bang” but a real flying car!  You can reserve one here.)  So it is no wonder that we are enthralled and are continuing to learn about flight from insects and birds.  Insects, my “bread and butter”, were the first to evolve flight and, as such, have long since perfected the ability long before us!  As usual, we may have a lot to learn insects!

An insect, is made up of three segments: head (first and, hopefully, obvious section), thorax (middle section), and abdomen (last section).  Internally, the thorax is chuckfull of muscles, making it is the “engine” responsible for locomotion via legs and wings.  Even though legs are intriguing and have many adaptations as well, this post focuses on insect wings, their evolution and variation.  To be honest, I’ve chosen this topic to show off all the high speed videos my colleagues, Mike Hrabar and Sean McCann, have taken in the Gries lab… they are SO amazing!  You will be mesmerized!  I promise.  (I may show some of my own soon… still holding out for possible publication.)

There are four theories regarding wing evolution, plus my Laymen explanation, (1) Paranotal process, or wings developed from projections (or bumps) on thorax, (2) Epicoxal, or wings developed from abdominal gills (i.e. mayflies and nymphs), (3) Endite-exite, or wings developed from gill branches on the leg, (4) Paranota plus leg gene recruitment, or wings developed from projections on the thorax aided by hereditary genes from legs which were transfered to the projection producing muscles needed for flight.  I’ve been taught that the “paranotal process theory” is the most widely accepted, with matching fossil records from cockroach relatives that indicate the paranotal lobes were originally a mechanism that allowed the insect to glide down from treetops. However, I’m beginning to be convinced of “paranota plus leg gene recruitment theory” because it is in agreement with the fossil records and the most recent genetic studies.

Inspired by X.
Inspired by “The Backyard Arthropod Project“. Figure shows wing evolution theories, (1) Paranotal process, (2) Epicoxal, (3) Endite-exite, and (4) Paranota plus leg gene recruitment.

SO, insects were the first to evolve flight!  Having two pairs of wings, they have faced problems with drag and turbulence when their wings beet together.  We face these same problems when engineering flight devices, but, unlike us, insects have evolved many ways to overcome this issue and stabilize their motion. Consequently, these adaptations are fundamental in identifying and classifying insects into groups.

Dragonflies and Damselflies have two pairs of wings that are approximately the same size and shape with many veins throughout.  This group of insects has developed a reversed (or alternated) wingbeat that can clearly observed in this slow motion video (Valevids, 2010).

Similarly, this alternated wingbeat can be seen in Lacewings (Order Neuroptera).

Flies (Order Diptera) have 1 pair of large functional wings and a pair of reduced hind wings called a halteres.  Although small, they have a important role in flight, and are used for orientation and balance.  Look closely for the halteres in the below video of a hoverfly (Family Syrphidae), they look like tiny little drumsticks behind the first pair of wings.  You can see them beet in an alternate pattern with the first and large wings.

Most beetles (Order Coleoptera) have a hardend first pair of wings, called elytra.  Making only the second pair of wings functional for flight.  These second pair of wings are folded longitudinally (lengthwise) and transversely (across) under the elytra.  There is a spring mechanism, in addition to abdominal movements, that keep the wings folded and in place.

Butterflies and moths have two functional pairs of wings that are covered in scales, arranged like shingles giving them their beautiful appearance.  This group has a very unique way of dealing with drag, called wing coupling.  In the video below,the cabbage looper (Family Noctuidae) is shows frenate coupling, where a well-developed hair (called a frenulum) on the hind wing catches with the forewing (called retinaculum). During flight, you will notice both pairs of wing appear “together”.

Another great example of wing coupling is in bees and wasps (Order Hymenoptera).  They have hooks (called hamuli) along the top margin of the hind wing that catchinto the fold of the front wing.  The number of hamuli are quite variable among this order, some only have a few and the larges wasps have many.  You can see both pairs of wings work together in the below slow motion video of a Polistes (Family Vespidae) take off.  One unique adaptation in this family of wasp is that the hind wing is longitudinally (lengthwise) folded under the forewing at rest.  In this video you can see the hindwing unfold from the forewing and spread open for flight.

Scientists study insect (and, more recently, hummingbird) flight for their potential application in advanced engineering, robotics, and aviation.  The problems that insects have had to overcome, such as turbulence, stabilization, and maneuverability, are the same we continue to face as we endeavour faster and more efficient crafts.  We still have a lot to learn from insects!!

Citations:

McCann, S. Dragonfly in Flight. [Cover Photo] 2012. Flickr, Vancouver, BC, Canada. Web. 08 Aug. 2014. <https://www.flickr.com/photos/deadmike/7604870044/in/photolist-fctMDR-fctMJP-cA1WV3-fctMXP-8Ya1k-aeu2QA-arHaS/&gt;.

ValeVids. “Dragonfly action in slow motion.” YouTube. YouTube, May 31, 2010. Web. August 3, 2014.