Fatal Attraction: Praying Mantises (A Guest Post)

By Britta Bibbo

We all know the character: an incredibly beautiful woman that seduces the rough-and-tumble action hero, only for him to later find himself chained up over a lava pit with sharks in it! …Or something like that. A “femme fatal” is the idea of a beautiful woman who leads men to their demise. None are more perfect for this role than the female praying mantis. Praying mantis females practice the art of deception through sexual cannibalism. It’s exactly how it sounds: the male is attracted to the female and tries to make some babies, but instead ends up being devoured. Sexual cannibalism hardly seems like a good strategy for keeping the mantis population up, but some argue it’s merely females taking advantage of every scrap of food they can find… even if it’s a loving male.

False garden mantis (Pseudomantis albofimbriata). Image by Donald Hobern from Wikimedia Commons.

When male mantises encounter a female in the wild they only have one thing on the brain, while a female may be more interested in self-preservation. If she hasn’t encountered food for a few days she will be VERY hungry and not all that interested in mating; in many species of mantises it is known that female mantises will eat males, even while having sex! So how do female mantises attract males?

For most insects, females are able to attract males with pheromones, chemicals released from an individual that affect other individuals of the same species. For instance, females can emit pheromones that will be telling of their age, reproductive status, and body condition. Males are able to detect pheromones from great distances and these pheromones play a role in allowing a male to determine how attractive a female could be. Before any sexy time can begin, females have to show that they are open to male advances. Showing a male you’ve never met before that you’re interested can be a difficult task- so females typically emit pheromones that are known as honest signals. These signals accurately convey female interest in mating, as well as her reproductive status, age, and body condition. Because the majority of females are being honest, males don’t have to think twice about their mate’s intentions. This is where female deception comes into play. If a female takes advantage of the lack of male wariness, she could end up with an easy meal. This deception by the females is what scientists know as the Femme Fatale hypothesis. This hypothesis explains that female mantises are naturally selected to deceive male mantises, and exploit them as food. This idea hasn’t had much backing evidence until Dr. Kate Barry of Macquarie University in Sydney, Australia sought to test this hypothesis with the false garden mantis (Pseudomantis albofimbriata).

After considering the test subjects and how the mantises communicate, Kate expected one of three possible outcomes:

1. There will be no pattern between female hunger and male attraction (if female false garden mantises are not femme fatales and false garden mantis pheromones do not communicate feeding-related information).

2. The well-fed females will attract the most males, while hungry females will attract the fewest males (if female false garden mantises are not femme fatales and females are always honest about their quality and willingness to mate).

3. The hungriest females will attract the most males, while well-fed females will still attract some males (if female false garden mantises are femme fatales and females are dishonest about their quality and willingness to mate when they are hungry).

To test her expectations, Kate gathered juvenile mantises that were close to their adult forms to have many male and female mantises that have no previous mating experience. Once the mantises were adults, females were given different feeding regimens to have a range of hunger. Categories included Good (well-fed), Medium (slightly less fed), Poor (hungry), and Very Poor (very, very hungry). Adult mantises were housed in a circular cage that separated each female individually around the edge, while the males were kept in the center.

Diagram of cage experiment was conducted in. Image by Britta Bibbo.

To allow the males to smell the female pheromones, researchers separated males by special walls that the males could not see through, but could still detect the pheromones given off by a female. The number of males on a female’s side of the cage was used to measure how attractive her pheromones were to the males.

The results of this study concluded that pheromones produced by the females that were very hungry were the most attractive to males. Through deception, the hungriest females are seen as sexier than well-fed, healthy females that are willing to mate! This result is surprising; normally females that are well-fed are seen as “sexier” because they have more nutrients available to them, making them more fertile. Hungry females have fewer nutrients available to them, making them less fertile, and therefore not as “sexy”. These hungry female mantises are advertising themselves as well-fed, fertile, and ready to rock when really, they’re not. Simply put, these results show that males are being catfished, and then consumed. Whether hungry females are actively trying to deceive males or if it’s just coincidental still needs to be looked into, but for now, be thankful for a partner who will see you as more than just a piece of meat!

Literature Cited:

Barry, K. (2014). Sexual deception in a cannibalistic mating system? Testing the Femme Fatale hypothesis Proceedings of the Royal Society B: Biological Sciences, 282 (1800), 20141428-20141428 DOI: 10.1098/rspb.2014.1428

Infidelity in Nature: a Lion’s Story (A Guest Post)

By Devin Zingsheim

When people think of mating, especially in the case of humans, they often think of one man marrying and mating with a single female. While this provides a nice image of mating, it is not always true. In the case of humans, both males and females may stray from this image and mate with other individuals. For example, a female in a relationship may become attracted to and mate with someone she finds exciting, like a rebel. These exciting individuals are the outsiders because they exist outside the female’s main relationship. But this is only in the human species - Could this observation hold true in another species, like lions?


Photo taken by Devin Zingsheim
at the Wisconsin Wild Cat Sanctuary.

As most people know, lions live in groups of animals, called prides. Prides often consist of between one and three dominant males and several females. Females of one pride typically do not co-mingle with members of other prides. This fact means that typically in a pride, the dominant males do all the mating and father all of the cubs born into their pride. However, as with humans, could there also be exceptions in lions?

Martha Lyke of Northeastern Illinois University, Jean Dubach of the Wildlife Genetics Lab at Loyola University Medical Center, and Michael Briggs of the African Predator Conservation Research Organization investigated breeding behavior in lions. These researchers noticed that field observations recorded females of prides residing in the Etosha National Park in Namibia interacting with outsider males. Outsider males can be from other prides or they can be rebels without a pride. This is unique because past studies focusing on lions of the Serengeti revealed that females seldom interact with other prides. These observations led the researchers to three main hypotheses. First, they thought that this mingling with outside males could lead to mating and eventually births. They also thought that females might mate with more than one male, potentially leading to cub siblings with different fathers. Lastly they thought prides with fewer males would be at greater risk for these illegitimate births because the male is not around enough to drive the outsider males away.


Image of Africa with the location of Namibia highlighted.
 “Location Namibia AU Africa” by Alvaro1984 18 –
Own works. Licensed under Public Domain via Commons.

To find the answers to the three questions the researchers had, they set up a study in Etosha National Park. This national park has a program in which every lion that resides in the park is branded for monitoring. At the beginning of the study, the researchers took observations of every lion spotted and its interactions with other lions. Lions that were observed spending a lot of time with one another in a territory were considered a pride. This then allowed the researchers to identify when and if females interacted with outsider males. After identifying prides, the researchers gathered blood and tissue samples for analysis. DNA analysis indicated the parents of any cubs within the prides.

Observations led to the identification of 11 prides containing 102 lions. Prides on average contained 10 individuals and had a roughly 2:1 adult female to male sex ratio. Surprisingly, only 55% of the 164 DNA samples collected came from the 11 identified prides and a whopping 41% of cubs sampled were illegitimate and had outsider males as their fathers. Interestingly, the researchers found that these cubs fathered by non-pride males came from only five of the prides, four of which had an unusually high female to male sex ratio. Additionally, the researchers also found four cases where litters of cubs had different fathers!

These results provide a lot of new and interesting insights into the sexual behavior of lions. Evidence was found to support all three of the researchers’ hypothesis. They found that females do give birth to young whose fathers are not part of the pride and that mixed paternity does occur in this population. They also found that prides with fewer males did have cubs born to males from outside the pride. This might be due to the fact that there are fewer pride males around to protect and drive away outside males. Additionally, with fewer males around, females may want to seek out other males to ensure they get to reproduce. This study has found evidence that there may be a lot more to sexual behavior in lions than meets the eyes. It has shown that, like human females, lionesses may be tempted to run off and mate with that exciting rebel outsider male.


Works cited

Lyke, M., Dubach, J., & Briggs, M. (2013). A molecular analysis of African lion (Panthera leo) mating structure and extra-group paternity in Etosha National Park Molecular Ecology, 22 (10), 2787-2796 DOI: 10.1111/mec.12279