Tag Archives: pheromones

Pheromones rally locust swarms, but they could also be used against them

Swarm of locusts near Satrokala, Madagascar in 2014. Credit: Wikimedia Commons.

The world is almost exclusively preoccupied with the COVID-19 pandemic right now. But that doesn’t mean other plagues are sitting idle. Africa and the Middle East are experiencing an intensification in locust swarms driven by climate change. Billions of such insects travel in unison, stripping hundreds of square kilometers of vegetation at a time, threatening the livelihoods of local farmers and undermining food security.

Right now, the most effective way to fight locust outbreaks is by mass aerial sprays of pesticides. However, many countries lack the financial resources and infrastructure required to mount a long-range pest management strategy. This is why governments plagued by locusts are left scrambling for solutions — but the findings of a new study might be just what they were waiting for.

Writing in the journal Nature, researchers led by Le Kang of the Chinese Academy of Sciences in Beijing, have identified the pheromones that migratory locusts release and detect in order to swell their numbers.

The organic compound called 4-vinylanisole (4VA) is released by the migratory locust (Locustia migratoria), the most widely distributed and one of the most dangerous species of locust.

When four or more locusts congregate, they begin to release these pheromones, attracting others to the field. According to Kang and colleagues, the chemicals are detected by sensory receptors found in the locusts’ antennae.

When this olfactory receptor, known as OR35, was lacking in genetically enginered locusts, the insects were far less attracted to the pheromones.

Immediately, the researchers came up with two strategies for dismantling locust swarms. Spraying 4VA chemicals over certain areas might attract swarms in a pesticide trap. Alternatively, chemicals that disrupt the activity of the pheromones could prevent the locusts from aggregating or migrating to certain areas close to food crops.

These strategies would have to be verified by further research. One thing’s for certain, millions of people desperately depend on a solution.

Locusts have caused famines and widespread destruction since the time of Egyptian pharaohs. However, in recent times, the pests have become more and more aggressive. According to the U.N. Food and Agriculture Organization, desert locust swarms could threaten the livelihoods of 10% of the world’s population if current trends continue unabated.

The most vulnerable areas to locust invasions are East African countries, as well as those in Southwest Asia and the Middle East, including Yemen, Saudi Arabia, and Iran.

India and Pakistan are currently facing their worst locust outbreaks in the last 25 years. Ten of billions of the flying critters congregate and devour vegetation over hundreds of square miles in less than 24 hours. In Kenya, such swarms were reported to be 25 miles long by 37 miles wide.

The upsurge in locusts has been linked to extreme weather events fueled by climate change. Particularly, these last couple of years have caused wet conditions to persist, creating the ideal breeding conditions for the pests. Once they congregate, locusts can expand their swarms 20-fold every three months.

In other words, the insect swarms grow exponentially in numbers, which is why disrupting their chemical signaling before they have the chance to swell out of control may be the secret weapon against locusts we’ve been all waiting for.

Pheromones can keep your pets from ‘fighting like cats and dogs’

Credit: Pixabay.

Many times, bringing a new pet home when another pet was already accommodated beforehand is an invitation for trouble. This is more so true when cats and dogs are forced to interact in the household. A new study, however, suggests that pet owners can broker peace between felines and canines by employing calming pheromones.

In the UK, 7% of households own both cats and dogs. According to Daniel Mills, an animal behavior scientist at the University of Lincoln in the UK, the inherent tension between cats and dogs can potentially cause lots of stress to both pets on a day-to-day basis.

“Many cat and dog owners report that their animals are comfortable in each other’s company, but where this isn’t the case, a poor relationship between a resident cat and dog can have serious consequences for the welfare of individual animals. There may be an unacceptable level of social stress or restricted access to key resources such as food, water or suitable toilet areas. There will also be increased stress for the remainder of the family (both human and animal), and potential risks of injury due to conflict,” the researcher said in a statement.

Mills and colleagues are the first to explore the use of pheromones in order to improve the relationship between two species living in the same household.

Over six weeks, the researchers placed Feliway Friends, a pheromone with soothing effect for cats, and Adaptil, another pheromone that calms dogs, inside households where both cats and dogs interacted.

Both products significantly decreased the number of conflicts and other undesirable interactions between the two species. Examples of such interactions include the dog chasing the cat, cat hiding from the dog, or the dog and cat engaging in a staring match. In fact, Adaptil led to an increase in the number of desirable interactions, such as friendly greetings between cats and dogs or relaxing time spent together in the same room.

According to the researchers, unsolvable conflict between dogs and cats living in the same household is one of the main reasons why pets are taken to shelters for rehoming.

The most surprising part of the study was that the dog pheromones led to the most increase in desirable interactions. Capricious felines, whose comfortability is known to have a stronger influence on the quality of cat-dog interactions, had a less sensitive response to the calming pheromones than dogs.

“While it might be expected that Feliway Friends would be more effective in multi-species homes given the apparently stronger contribution of the cat’s comfortability to the quality of the cat-dog relationship, this did not appear to be the case. Our results might be explained by the behavior of the dog being the primary determinant of the cat’s quality of interaction with it,” said Dr. Miriam Prior, co-author of the study.

“We would like to investigate this further to really tease out the effects of these pheromone products individually and also to investigate their use in combination with each other. We suggest that Adaptil may have had such a beneficial effect because a more relaxed dog may be less likely to disturb the cat (e.g. by chasing it), resulting in a cat that is less stressed and more willing to form some form of social bond with the dog.”

The findings appeared in the journal Frontiers in Veterinary Science.

pig love

Do pheromone perfumes work? Love at first scent is not that easy

With Valentine’s Day just around the corner, some of you might be tempted to employ some of those spray-on pheromone products. I won’t give names, but you must have seen the ads – they’re all over TV and the internet. Odorless pheromones are secreted by many animals to attract mates, and while synthesized versions have been shown to work for bees and other insects, the human nose and brain for that matter is a whole different thing.

Mammals of all sorts use olfactory signals to indicate willingness to copulate, define territory, mark their young, and signal aggressive intent. These processes can be seen in many animals used as models for human systems, including rats, monkeys (both Old World and New World), hamsters and mice. The fact that pheromones are important biological signals in a plethora of other species indicates that the possibility of human pheromones should not be discarded lightly. But this doesn’t mean those $100 bottles for 1/6  of an ounce actually work. Reactions is back this week with a great debunking on commercial pheromones. In short: no, these don’t work! Save your money for a nice dinner. You’ll have to impress your date the hard way.

This male mouse has left brownish scent marks by depositing pheromone-rich urine on a fence separating his territory from those of other mice. (c) Doug Cornwall, University of Utah

Promiscuous female mice breed sexier male offspring. Research may help conservation efforts

University of Utah researchers found that female mice that live in a competitive social environment and choose to mate casually with multiple partners give birth to males who are much more attractive to female mice, at the cost of a dramatic cut in life expectancy however. You only have one life, says the sexy male mouse.

The research is a fantastic example of epigenitics at work –  how parents’ environment modifies their offspring’s genes; in other words, not only do parents’ gene count, but also a great contribution in the overall offspring genetic mark-up depends on the environment.

“If your sons are particularly sexy, and mate more than they would otherwise, it’s helping get your genes more efficiently into the next generation,” says biology professor Wayne Potts, senior author of the new study.

“Only recently have we started to understand that environmental conditions experienced by parents can influence the characteristics of their offspring. This study is one of the first to show this kind of ‘epigenetic’ process working in a way that increases the mating success of sons.”

A promiscuous family

Typically, lab mice breeding is skewed from the animals’ natural conditions. Domesticated mice are generally monogamous and hardly touch each other in the cage – go figure.   “In nature, mice must seek out and choose their own mates – a process that is eliminated in standard lab breeding conditions,” says   University of Utah doctoral student Adam C. Nelson.

This male mouse has left brownish scent marks by depositing pheromone-rich urine on a fence separating his territory from those of other mice. (c) Doug Cornwall, University of Utah

This male mouse has left brownish scent marks by depositing pheromone-rich urine on a fence separating his territory from those of other mice. (c) Doug Cornwall, University of Utah

To simulate seminatural conditions, the researchers bred mice in a  22-foot-by-13.5-foot enclosure (mice barn),  divided by wire mesh fencing into six sections or territories which were easy to cross in and out by the mice. However, some of these territories were made more appealing than others, as they had more food, water or a more spacious nest box. So, the mice had to compete with each other – almost like in natural conditions. As a measure of control, the mice which were introduced descended from wild mice and were bred for 10 consecutive generations  in domesticated conditions: in cages with assigned mates.

Prospective parents first lived in one of two environments: the promiscuous mouse barn or monogamous cages. They were removed after eight weeks and bred in cages in four combinations: mother and father from promiscuous environment; both from monogamous environment; mother from promiscuous environment and father from monogamous environment; and vice versa.

Regardless of the father’s origin, the researchers found that females which came from promiscuous environments gave birth to sons which  produced more pheromones than sons of monogamous, domesticated moms.  More than just a classy perfume, mice pheromones are a sex magnet and the stronger the scent, the harder it is for females to resist the call. Hey, guys, stop looking for deodorants online now – it doesn’t work for humans that way.

Back to pheromones. Yes, lady mice love these, understandably: the more the male’s scent is saturated with  pheromones produced in mouse urine and other glands the more the said male with mate. Apparently, male mice who came from promiscuous parents produced 31 percent more major urinary proteins or “sexy” pheromones  than male mice from caged monogamous parents. Previous research established that male mice with promiscuous parents actually produce about one-third more progeny than sons of monogamous parents.

It’s clear that the social life of female mice has a great impact on their male offspring, something that is described through epigenetic inheritance. In epigenetic inheritance, however, genes aren’t mutated, instead genes are either activated or expressed. So, epigenetics deals with gene modification and a common mechanism is methylation , a change that reduces a gene’s production of a protein.  In the new study, Nelson and co-authors looked at a pheromone gene named Mup11. They found that methylation of the gene was twice as high in sons of monogamous, domesticated mice than it was in sons of promiscuous, social mice. So the sons of the promiscuous mice were able to produce more pheromone.

Sexy to die for

This illustration depicts how the researchers liken the way mouse pheromones act much like a male peacock’s tail to attract mates. Illustration by Sarah Bush, University of Utah

This illustration depicts how the researchers liken the way mouse pheromones act much like a male peacock’s tail to attract mates. Illustration by Sarah Bush, University of Utah

You win some, you lose some. Apparently, those enhanced pheromones come at a huge price tag, though. n. Only 48 percent of them lived to the end of the experiment, compared with 80 percent of the male mice whose parents lived monogamously in cages.

“Production of pheromones is outrageously expensive,” says biology professor Wayne Potts, senior author of the new study.  “A single mouse’s investment in pheromone production compares with the investment that 10 male peacocks make in the production of their tails, which also are used to attract females.”

Besides gaining insights in mice sex habits and practices, the University of Utah preset research has some important practical applications. Through a better understanding of how pheromones work and how these influence mating, scientists, workers or volunteers associated with conservation efforts may improve their success with captive-breeding programs. It might be better, for instance, than forcing pandas to watch panda porn in hope they might get aroused and actually get off their lazy butts to mate.

“It’s amazing how often reintroduction of captive-breed endangered species fails – it’s estimated to be as high as 89 percent,” says Potts. “Domestication stimulates epigenetic mechanisms that make animals less fit for nature.”