Tooth and Claw: Praying Mantises

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0:56Adam Hart:you're listening to discovery from the bbc world service i'm adam hart and this is tooth and claw the series where i explore our complex and challenging relationships with earth's greatest predators through the people who have spent their lives studying protecting and at times narrowly escaping them.

1:18Adam Hart:Today's predator is immediately recognisable through its bulging eyes and triangular head, but it's most famous for its raptorial front legs, which it uses to grasp, trap and even impale its prey. These insects have been known to predate animals of a size much larger than themselves, including birds, lizards and frogs, which these masters of camouflage ambush. Known to eat their prey alive and at times cannibalistic, they have been considered beings of supernatural powers by ancient civilizations. We are of course talking about the praying mantis. Joining me are Dr. Julio Rivera, an entomologist and researcher at the Université de Montréal in Canada and research associate at the Montreal Insectarium, and Dr.

2:01Adam Hart:Bianca Hredvenstein, a postdoctoral fellow at Northwest University in Pochestrom, who is an expert in the praying mantises of South Africa. Bianca, starting with you, where did praying mantises get their name from? Well, the word mantis is from the Greek, which means soothsayer or prophet. And then, of course, in the entomological side of things, we have two different ways of approaching them. So two different spellings. So because of their posture and the way that they sit in this sort of preying stature. That's why we call them preying mantises. And then some of the entomologists also call them preying with an E instead of an A because of the fact that they are vicious predators.

2:48Adam Hart:And you mentioned that they're vicious predators. What do they actually hunt and how do they go about doing that? So most of them are sit and wait predators. I would probably describe them as being quite opportunistic. So they'll sit and wait for something to fly by or crawl by, and then they'll grab that and eat it. If it's something a bit bigger like a lizard or a bird, same sort of thing applies. They generally go more for insects, but we have had quite a couple of interesting occasions where they have gone for lizards and frogs. And do they ever find themselves as prey from other predators?

3:26Yes. So they're quite the delicious snack I would imagine for birds and then vice versa to their lizards. Sometimes the lizards win. Snakes and any kinds of reptiles and those kind of things.

3:40Adam Hart:Praying mantises have a reputation for eating their prey alive. Do they have any other hunting behaviours that are surprising or intriguing? Yes, they actually fish as well. So they will actually go onto little ponds and things like that. We have lily pads. They'll sit on the lily pad and then they'll hunt the fish that go by, little guppies and things like that. And then I've also had a couple that play dead. So until the food comes by and then they'll actually just spring back to life and catch whatever they want. They can also go for things that would be toxic to other insects such as the monarch butterflies but what the research shows is that they would actually gut the monarch and not eat the gut in which the milkweed is which makes the monarch butterflies toxic so they'll just avoid those parts but there are some bandits that can actually eat poisonous newts as well which is a little lizard and they've got like a specialized intestinal which sort of just I want to say diverges the toxins and it doesn't get absorbed in the mantis so they can eat that.

4:55Adam Hart:And Julio praying mantises have these very distinctive raptorial front legs the ones that make them look like they're praying they're specialized for hunting but how do they actually work? The front legs of the praying mantises are their main hunting weapon. Normally they keep their legs in front of their body, storing energy ready to lash out as soon as a prey item comes within range. What they normally do is stretching their leg forward and grasp the prey item in between two of the main parts of the leg, which is we call the tibia and the femur, which in a human arm will be the equivalent of the hand and the forearm.

5:37So they stretch their legs very fast. They grasp the prey between these two parts, which are further fixed by a number of spines that are covering the surface of these structures. In some species in South America, we discovered that they also have a different strategy. They also use the typical grasping strategy, but these little mantises are able to impale their prey with specialized spines that they have in the front of their front legs. These spines are like arpuns. They have serrations, they are sharp, and they are forward-oriented. It looks very much like Wolverine cloth, you know, the comic character.

6:21They are pretty vicious predators. They just cut everything with their spines as they are picking up snacks with a toothpick. That's how they collect their prey.

6:32Adam Hart:What size are we talking about here? In my mind, this is something quite massive, but of course, it's happening at a very small insect scale. What size are the mantises and what size is the prey that they're impaling? The impaling mantises are very small. We're talking about maybe two, three centimetres. So the prey that they normally catch are also very small and usually soft-bodied. because let's remember that insects' exoskeleton is pretty hard and tough. So it's really hard to pierce. So these particular perimantises have evolved the ability to catch very small, soft-bodied prey that usually live in the same habitat.

7:08We are talking about epiphytic vegetation, moss, lichen, where there's a lot of moisture. These small insects can survive without having extensive exoskeleton, enough to absorb water.

7:20Adam Hart:So their soft bodies let the mantises there use this impaling tactic quite effectively. Exactly, exactly. And are mantises solitary hunters or do they work together? We've seen lots of group hunting predators on tooth and claw, but I'm guessing these are mostly working on their own. Yeah, prey mantises are solitary insects. They don't like to share. You normally find them along, hunting along among the vegetation. And how do they interact with other mantises? Do they get along or do they tend to look at each other as prey? Prey mantises are cannibalistic. Sometimes they will not make a distinction between other prey mantises, whether they are from their species or a different species.

8:01If they have a chance, they will catch another mantis. And sometimes, even if a female prey mantises ran into one of their babies, she would also eat it. So after they lay their eggs, they stay on guard for a little while. but natural selection has favoured the behaviour of abandoning the eggs before hatching. So the baby will not face the threat of a hungry mother. So they normally try to avoid each other, except, of course, when the mating season arrives, they become more tolerant. But still, in that particular moment, males normally are quite cautious because they don't want to be caught by a hungry female.

8:46Adam Hart:and Bianca you've researched the benefits of having mantises in agricultural settings how can their efficiency as predators be beneficial to us as humans I think the best thing about the praying mantises is the fact that they are generalist predators I'm sure you get a couple of species that are specialists and will only hunt like soft-bodied things but most of them actually will eat anything that comes their way. So any kind of moth or larvae or anything like that. And in the agricultural setting, that's a very positive thing when it comes to pest control because it means that they're not going to sit around and wait for a specific thing.

9:29They'll go and catch all the pests that you need them to eat so they don't affect your crops. So praying mantids can be used as biological control. It does, however, also mean that they will eat other beneficial things like earwigs and that kind of thing. So they're indiscriminate in that regard, but it is a positive because they also eat all of the pests, not just one in particular.

9:55Adam Hart:And have farmers embraced the praying mantis as a biological control, having seen your research? Not in all areas. We still have some work to do in convincing all of them. But in St. Helena Island, it's like off the coast of Angola, one of the South African mantids has become invasive there. It's called the springbok mantis, like our rugby team. The farmers actually protested because the government is looking at ways to eradicate this invasive species because it's, ecologically speaking, not great to have invasive species but the farmers actually protested against this because they love these mantids in their agricultural fields because they're doing this great biological control and and actually taking care of the pests for them which obviously is great in terms of their yields and and that kind of thing.

10:48Adam Hart:Bianca we've covered a lot of very large and very dangerous predators on tooth and claw. Praying mantises a little bit smaller than than some of the ones we've featured but are they ever a threat to people? No not really I think the the worst you'll come off with is a slight bite and having been bitten by a relatively larger size species mantis it really just feels like a pinch so maybe draw a little bit of blood but nothing in compared to the other creatures you've had on tooth and claw. Now Julian I think I'm right in saying that praying mantises are bounded to their habitats because of their camouflage specializations.

11:28Adam Hart:Can you tell us a little bit about this and their different body configurations? Yes, Prairie mantises, even though most people are familiar with the typical look of the green, plain-looking Prairie mantises, like Mantis religiosa, which is a very common species in Europe, Prairie mantises actually show extensive variation in their body configuration and all the associated behaviors. Prairie mentheses in general are mostly recognized as leaf mimics, meaning they are green and their wings are shaped like leaves, for example. But there are other species that imitate, you name it, dead leaves, lichen, sticks, rocks, bark.

12:13Some other imitate different species like there's wasp mimics, there's ant mimics, beetle mimics. Prairie mentheses are very good at evolving different strategies for camouflage and predation, especially the females. So there's a strong sexual demorphism in praying mantises, meaning males and females tend to look slightly different. So in females, they have evolved all sorts of strategies to sit within the vegetation and remain invisible. That not only involves looking similar to the surrounding, but also blending in terms of coloration and contrast, the textures of the body, and also behavior.

12:56They are quite static. They don't move that much. Females are quite sedentary. Also because if they reveal their position to a predator, there's not much they can do. They cannot fly. Normally, females have short wings, which they have co-opted for camouflage. The wings have been incorporated into the camouflage strategy, and sometimes it's completely suppressed because they don't need to fly. On the other hand, they have also evolved large abdomens, right? So they can lay more eggs and sacrifice flying. But males do fly, and that's the main way they locate females when they are releasing pheromones during the mating season.

13:33But they are particularly in tropical areas overlooked by collectors and entomologists, which you can spend hours and days in a particular location and not seeing a single praying mantises. They are there, but you cannot see them.

13:48Adam Hart:And Bianca, we've heard there about the camouflage of praying mantises, but is it just the adults that are camouflaged, or is there some interesting things going on with their eggs as well? We have, it's called the false flower mantis here in South Africa. Their eggs sort of, it sort of looks like a shell, but it's very small. And this is very similar to some of the thorn trees in the area where they are found or where they inhabit. There's actually been some ideas going around saying that they are specifically making their eggs look like this shape to mimic the thorns and to obviously keep them safe and keep predators away from the eggs and try and camouflage the eggs as well.

14:38Prep for a busy week with Whole Foods Market. Start your day with fully cooked breakfast sausages from Amy Lu, 365 brand frozen waffles with no bleached flours, and of course Whole Foods Market eggs, which are all cage-free or better. In the evening, bring home a build-your-own family meal that feeds four for just$35. Choose one entree and two sides. Shop smarter, not harder, at Whole Foods Market. Get more with BBC Podcasts, wherever you listen. Be the first to listen to your favourite shows like Evil Genius, Good Bad Billionaire and You're Dead to Me with a subscription to BBC Podcasts Premium on Apple Podcasts.

15:17You can also enjoy a range of our podcasts ad-free with an Amazon Music subscription.

15:26Adam Hart:You're listening to Discovery from the BBC World Service. I'm Adam Hart and this is Tooth & Claw. Joining us are Praying Mantis experts Dr Julio Rivera and Dr Bianca Hevenstein. One thing that really stands out to me when I look at praying mantises are their prominent big eyes and triangular heads. They look quite anthropomorphic, like you could make eye contact with them. So I can understand why people have historically found them quite intriguing. What we're going to do now is to turn to the cultural importance of the praying mantis. And Bianca, this has formed part of your research. Can you tell us about some of the folklore about these insects from around the world?

16:00They actually have a quite ancient history with people. and if you go and look at some of the cultural values it's spread across the world it started in greece where mantis were actually put on little coins that are very very valuable at this point in time it's called the ancient drachma there's also quite a couple of folklore or myths in africa of course so some of the indigenous people such as the koi and the san believe that the mantis is for example a sort of deity and if you ask it questions it will give you advice so they'll ask something like they've lost their cattle and then if the mantis points in a direction with its front legs then they'll take it as the cattle's in that direction or some of them actually believe that they are shapeshifters and tricksters but that they also were the ones that created the first antelope.

17:02So we recently found some cave drawings in the Karua area of South Africa, which actually depicts a praying mantis as well, because they were so important to the sand people. But this goes beyond Africa. And sometimes it's good omens, sometimes not so great. So in Japan, particularly, they had a haircutting demon that looked a lot like a praying mantis. and that was responsible for cutting people's hair, which was a symbol of their status in those years. But except for this haircutting demon, they are a symbol of power and cunning. It has also inspired some blade designs, so they make these beautiful samurai swords.

17:49They actually have pictures of praying mantids on them because of the symbolism. And then in China, it actually, they have two fighting styles or types of martial arts that are based on the praying mantis. It's different in the north than it is to the south. And then when we look at a place like Egypt, the praying mantis has had great significant cultural influence there. And they are featured in the Book of the Dead. So it's believed that the praying mantas actually is a guide to the afterlife and that they are also involved in the opening of the mouth ceremony, which actually allows people who have passed on to eat and drink in the afterlife.

18:36The Egyptians were really quite fascinated. They were fascinated in general by insects, but the praying mantis in particular, so much so that in the 19th dynasty, there was a pharaoh that reigned. And when they checked out his tomb a couple of years later, like in the 2000s, they actually found a little clay coffin with a mantis that was wrapped in linen, almost like it was sort of mummified. But it also goes into the modern era. So there's monster movies that have praying mantises in them, as well as the Marvel comic books actually have a character called Mantis. mantis. So this cultural importance of the praying mantis is one of the things that we've been looking at to try and increase their conservation.

19:26Because if people feel connected to an insect, then they tend to be more forthcoming and more willing to participate in their conservation.

19:36Adam Hart:And has any of that folklore played any part in your life? Yes. So my grandmother had a farm outside Potchip Sturm. She used to tell me when I was little and I went to go visit, if we get a praying mantis, she would always say, oh, this one brings so much peace. So it was actually quite interesting that I ended up working with them. And Julia, how about in South America where you largely work? Is there any folklore associated with mantises there? Yes, there is this one in particular that I really love in some parts of Argentina, in the area of Misiones, which is sort of a tropical forest. The indigenous communities there, they have a name for the praying mantises.

20:21They call them Mboise. And Mboise in their language means the mother of snakes. For a long time, these mantises were known as the mother of snakes, but there wasn't really a comprehension of why it would have that name. It turns out that there's a worm that is a very common parasite in that area called the nematomorpha, and they are internal parasites of praying mantis. This worm makes its way into the praying mantis' abdominal cavity, and there it grows for several weeks feeding off the fat tissue. And when the worm is mature and ready to mate, it has to go back to water because these are aquatic worms.

21:06Mantises are not aquatic insects. So the worm has quite a challenge to go back to water to complete its life cycle. So what it does is take mental control of the praying mantis to make it look for water. When the mantis finds water, it jumps into it and immediately the worms leave the body of the mantis through the anal area. And indigenous people from that area were very familiar with that particular association. To their eyes, what they are seeing is a praying mantis giving birth to a snake in the water. And that's where the name comes from, the mother of snakes.

21:44Adam Hart:And are there any other misconceptions about the praying mantis that you've come across? Yes, a typical and very persistent misconception is the sexual cannibalism of females. You know, sometimes I talk to people and most people know what a perimentee is, but some don't. When you bring this particular fact to the conversation, yeah, you know, this instance that the female is the male when they are mating. Oh, yes, I know exactly what you're talking about. So the sexual cannibalistic behavior of females is well known for prairie mantises, but it's not widespread in the group. It has been observed in a few species and has received a lot of bad press through history.

22:26But I would like to tell to your audience that that's not the case. Most prairie mantises do not kill the male during mating. It has been observed in some species that live in temporary regions, like in Europe, for example. The mantis religiosa is a well-known species that does that, but it certainly is not across the board. Another interesting aspect of praying mantises, and most people don't realize this, is that their closest living relatives are cockroaches. When you look at a cockroach and a praying mantis under the microscope and you conduct more detailed anatomical comparisons, you can realise that they are very similar indeed.

23:11In fact, they both also lay eggs in this... They form this structure called the egg case or othika, where they encase their eggs for protection. So it's a very unique feature among insects and is a testimony of their close relationship.

23:28Adam Hart:Now on tooth and claw, we often consider the impact of climate change on our predators. Bianca, do you see any climate change affecting the praying mantis? So there has been some studies and most of it has related to a desynchronisation. So because mantids are insects and are very susceptible to temperature changes, they also use temperature as a guide for when it's time to mature and when to lay eggs and and that kind of thing so as the temperature changes there has been this desynchronization where mantids would think that it's still summertime and lay eggs and the little ones would hatch and then there'd be a cold front coming in because it's actually winter which then kills off all the small nymphs.

24:19So this is the kind of thing that will happen with continuing climate change. On the other side of things, it's also with an increase in temperature, it should theoretically mean that they should go through their life cycle a bit quicker. But yeah, we're still investigating that.