Of Mantis and Hummingbird

Updated July 2017.

I was asked to do a short article post on praying mantises and their actions on the environment, with focus more specifically on hummingbirds. To start off the conversation, I would just like to mention that the more specific term for describing most of these insects is actually “mantid.” “Mantid” is derived from the family Mantidae, which is the family of insects most of the common “praying mantises” or mantids belong to. In the past, Mantidae was the only family within the Order Mantodea. However, since then, different groups were split from the family, so “mantis” now is broader of a description. As a side fact, “praying mantis” applies to one species of mantid in the past, the European mantid (Mantis religiosa). However, at this point in time, either “mantis” or “mantid” works for most of our common species since much of them are still within family Mantidae (I personally still prefer mantid. But, basically for this article, mantis and mantid are interchangeable). Okay, that’s the annoying and less important part of the article!!!

To skip to the introductions, statistics, research, etc., you can read under the "What to do when a mantis shows up + killing non-native mantids?" subheading!"

I've also bolded and highlighted important sections of information for easier reading!

Introduction

Now to start off with the bad news: Some mantids can prey upon hummingbirds. They are fierce predatory insects which will feed upon a large variety of food items. Aside from normal insect and arachnid prey (along with other arthropods), mantids have been known to prey upon lizards, snakes, mice and other animals. This tenacity and disposition have led many to regard this insect as sacred. But, for hummingbird lovers, the images strewn across the web of mantids killing and eating hummingbirds right on nectar feeders are potentially too much to bear. However, in reality, such events are actually less common than. As I mentioned quite a few times in the past, the larger introduced species can potentially prey on hummingbirds. However, even for them, the chance is relatively low. The reason as to why such chance is so low, to the point of almost statistical insignificancy, is because of the fact that, in the majority of cases, mantids generally do not attempt to prey upon organisms larger than 1/3 of its body length (it appears one particular exception to this rule is the genus Hierodula, which hosts some of the largest mantids in the world. However, they are only found in Asia so hummingbird lovers can breathe more easily). The largest species of mantids found in North America are the non-native Chinese mantid (Tenodera sinensis) and non-native narrow-winged mantid (Tenodera angustipennis). Both species max out just barely past 4 inches. You do the math (0.333 x 4) and that is smaller than all of our hummingbird species. Recent published research in January of 2017 compiled new data and offered new insight into the capabilities of mantids as predators of avians, with numberical data in observation of predation. Unfortunately, news media sites have successfully stigmatized and sensationalize the article beyond the original premise...

Research on Prey Size (Personal + New Published Information)

I have also personally done experiments with Chinese mantids (T. sinensis) in a captive, laboratory setting to see what size of prey they were willing to capture. In most of the cases, even the large, aggressive females avoided predation on some of the larger insect food items. One particularly large food item given was the obscure bird grasshopper (Schistocerca obscura), which grows to be approximately 2.6 inches in length. Out of the a dozen or so mantids tested, all of them avoided capturing the large grasshopper when another option was available. The tested individuals were most certainly hungry (I avoided feeding them for one week – which perhaps wasn’t long enough). However, despite perceivable hunger, when I offered the Chinese mantids the large bird grasshoppers, they avoided them. To ensure that they were indeed hungry, I offered them adult house crickets (the kind you buy at pet stores to feed tarantulas, lizards and frogs) and they ALL gladly took the smaller prey items without any question. Next, I chose a few of the larger females (4+ inches in size) and re-exposed the large bird grasshoppers into their enclosure. Once again, they avoided them. But, interestingly enough, when I removed the grasshopper for the second time and put in a second house cricket, they took the cricket! While this little experiment isn’t published and not fully backed by published scientific literature, it at least showed that even the big and powerful Chinese mantids would often avoid the large prey items (2.5 inches = greater than 1/3 of their size). The only times I’ve witnessed females (at least in captivity) prey on the large bird grasshoppers was post-egg laying. Egg laying is a very tiring process for the females and many female mantids will die after oviposition, drained of energy. However, at least for captive Chinese mantids, the exhausted and starved females post egg laying attacked, killed and ate the large 2.5 inch bird grasshoppers! This was the only time I’ve witnessed Chinese mantids attack such large prey willingly. The other possible trigger for attacking such large prey would most surely be long-time starvation. As sad as it may seem, urbanization, pesticide use and other factors have caused a great depletion in insect fauna in backyards. Maybe it is this lack of other potential prey items which causes the mantids to go to the extreme of attacking hummingbirds, a prey item significantly larger than what they would normally even attempt to capture. But, whatever the case, I hope this shows that even the introduced species are hesitant on attacking such large items. European mantids, which (Mantis religiosa), are slightly smaller than Chinese mantids also have the potential of hummingbird predation. I honestly haven’t worked with this species before, so I'll rely on published data instead: Only 3 of the 147 analyzed mantis-bird attacks were from European mantids.

As for our native mantids, such as the ever common Carolina mantid (Stagmomantis Carolina) of the East or the California mantid (Stagmomantis californica) of the West, they are even smaller. If you want the numbers, California mantids reach about 2.5 inches in size while Carolina mantids reach about 2.2 inches in size. Recent research showed rare instances of native Carolina mantis predation on hummingbirds, along with similar Stagmomantis limbata of the West (Nyffeler, Maxwell, Remsen Jr. 2017). However, native mantids also provide their fair share of pest control, just like your neighborhood Chimney Swifts, American Robins, and Barn Swallows. We would never advocate for you to kill a Blue Jay, a Roadrunner, or an American Robin, so we will never advocate for the killing of a native mantis species either! Think of native mantid attacks on hummingbirds as shark attacks on humans - it has the slim chance of happening but the probability is exceptionally low (even though the media always seems to overplay the numbers both in news and in entertainment).

So what if a mantid shows up on your porch or hummingbird feeder? Well, mantids are attracted to lights because lights often attract vast quantities of insects, allowing the mantid to potentially get a meal. The same is for a hummingbird feeder. I am sure at this point that most people know that insects are not hesitant about drinking from the same sugary water as the birds. If you are worried, feel free to move feeders around or move the mantid away from the feeder using either your hands or a broomstick. Mantids can give a moderately painful pinch with their modified raptoral forelimbs. However, they are not venomous and aren’t dangerous to people. As long as you let the mantid “walk” onto you, it won’t try to grab you. The only instances of aggressive bluffing would be if you grab the mantid or bother it for too long. You can always negate the problem of getting pinched simply by using a stick or some other object. Gently “pick up” the mantid with the stick and move it elsewhere. If you do not want to hurt the mantid, do NOT bash it down from the feeder. Mantids, especially adult females, have very fragile abdomens and can get easily injured by physical trauma.

Mantid Identification

I would like to make this short section in showing some of you how to ID a few of the more common mantid species found in the United States. IMPORTANT NOTE: Many of our mantid species range from different shades greens to different shades of browns, even WITHIN THE SAME SPECIES. The difference is often attributed to factors such as humidity, temperature, food availability (?) and perhaps also genetics (?).

>Chinese Mantid (Tenodera sinensis) – Non-Native Species:

This is our largest species of mantid, sometimes growing past 4 inches in length. Chinese mantids were introduced to North America from Asia. Males are generally slimmer and thinner than the stocky females. Males also tend to be smaller. Key ID traits for this species are large size and green costal margin of the wings. Note that Chinese mantids can be different greens or browns, but the green costal “wing stripe” is almost always present. Adults have wings while juveniles don’t have wings. Adult males are powerful fliers while adult females tend to be more placid in terms of movement and flight. Likewise, adult females often cannot fly due to their abdomens being full of eggs. Females are the ones that feed on hummingbirds; males are too weak to do so. Found throughout much of North America. There is also the narrow-winged mantid (T. angustipennis) which is very similar to the Chinese mantid, but more restricted. One way to separate the Chinese from narrow-winged is by looking at the spots in the anterior of the forelimbs. Chinese would have yellow and narrow-winged would have orange. Aside from that, the two species are generally very similar in behavior. The narrow-winged is also another mantid introduced from Asia. The "invasive-ness" of Chinese mantids have been largely debated with proponents from both ends of the spectrum. At least one source, Snyderand Evans 2006, suggested the warranting of the Chinese mantis as "invasive."

Also know that Chinese mantids may also be completely green like the one pictured here (Image by Patrick Murray):

http://bugguide.net/node/view/887682/bgimage

>European Mantid (Mantis religiosa) – Non-Native Species:

This is a medium to large sized mantid species introduced from Europe. Color ranges from a tannish-cream color to a grey-black to a rich green. European mantids are interesting because they have a very conspicuous eyespot on each of the anterior part of their forelimbs. Adult males are strong fliers while females, like Chinese mantid females, become grounded often due to having to carry lots of eggs. Found throughout much of North America.

The European mantis is the third-most likely culprit of hummingbird predation after the Chinese and bordered mantis. Nyffeler, Maxwell, Remsen Jr. 2017's analysis revealed about 3 out of 147 accounts of mantis-bird predation were from European mantises (Nyffeler, Maxwell, Remsen Jr. 2017). I should note that the 3 accounts were from the United States.

Here is a very clear and incredible image of a mating pair of European mantids by Brandon Woo on BugGuide (Copyrighted by and credited to Brandon Woo and used with permission here):

Another great image showing the eyespots on this species' legs (Image also by Brandon Woo): http://bugguide.net/node/view/1132182/bgimage

Green Colored Female By Mathew L. Brust (Copyrighted and used with permission): http://bugguide.net/node/view/1116877#1995564

>Carolina Mantid (Stagmomantis carolina) – Native Species:

The Carolina mantid is one of the most common native mantids in North America, especially in the East. According to BugGuide, the range of this species is: “New Jersey south to Florida; west to Utah, Arizona, Texas, and through Mexico to Central America. Recently found in New York as well, perhaps extending its range.” Males are slim, have full wings, are very small and are strong fliers. Females do not have fully formed flight wings. Their wings only reach to about 2/3 of their abdomen, which makes females unable to fly. There is great variation in coloration from brown to green. Max size is about 2.2 inches.

Here’s a mostly brown adult female. Notice how short her wings are:

Wonderful image of a male here by Robert Lord Zimlich: http://bugguide.net/node/view/222984

>California Mantid (Stagmomantis californica) – Native Species:

This species is very similar morphologically to the Carolina mantid. Its colors also range from green to brown. Adult males are strong fliers but females have shortened wings and cannot fly. Max size is about 2.5 inches or so according to BugGuide. Also from BugGuide: Their range is “Texas, Colorado, west to California. Within that state, southern California: arid and desert regions, north into Central Valley.”

Photo of adult female below by Ray Bruun (Copyrighted and used with permission). Link to original: http://bugguide.net/node/view/827944/bgimage

Extra image of two females, one green one brown, by David J. Ferguson on BugGuide: http://bugguide.net/node/view/457959/bgimage

>Bordered Mantid or Arizona Bordered Mantid (Stagmomantis limbata) – Native Species:

I actually do not know much about this species. So, according to BugGuide: “Moderately large Mantid. Facial plate (below and between antennae) about twice as wide as long (as for genus), eyes not as protruding as in Carolina Mantid. Females most often fairly plain green (often yellowish abdomen), but sometimes gray, or light brown, with dark spot in middle of tegmina. Tegmina do not completely cover wide abdomen. Hind wings checkered or striped yellow. Blue upper lip more pronounced in females, brighter in green forms and darker in brown forms.

Males slender, long-winged, variable in color but most often green and brown with sides of folded tegmina green and top brownish (may be solid gray, brown, green, or any combination of these). Abdomen without prominent dark spots on top. Wings transparent, usually with cloudy brownish spots on outer half.”

Range according to BG: “Texas to southern California, north into Colorado and Utah, south into Mexico.”

Nyffeler, Maxwell, Remsen Jr. 2017's discovered at native mantid species such as S. limbata had 10 instances of hummingbird predation out of the 147 accounts of mantis-bird predation (note this is mantis-bird predation and includes species from the Old World and not JUST hummingbirds). This may suggest the capability of female S. limbata as a native species capable of capturing hummingbirds at higher numbers than most other native mantis species. However, this number is still less the percentages by the non-native Chinese mantis (25/147). Since this is a native species, like any native predator, your best option to maintain a good environment for bird is to not actually cull S. limbata.

Photo of female below by Bob Beatson (Copyrighted but used with permission). Original Here: http://bugguide.net/node/view/467594

Comparison with Carolina mantid (Photo by Jennifer Thompson): http://bugguide.net/node/view/1128330/bgimage

>Mediterranean Mantid (Iris oratoria) – Non-Native Species

From BugGuide: “May be distinguished from Mantis religiosa and other mantids of similar general size and shape by the red-orange spot on the ventral side on the fourth (second to last) abdominal segment; also, its cerci are shorter than those of M. religiosa.”

Size: About 2.6 inches max.

Range: According to the BG map, it appears to be common more in California and the Southwest. However, this species’ range is thought to be expanding

For more information and images about the Mediterranean mantid, please visit here: http://bugguide.net/node/view/71486

There are about twenty different species of mantid here in North America north of Mexico. The majority are too small to be of danger to hummingbirds so I won’t go too much into detail. But, if you are interested, here are a few other species if you want to check them out:

Grizzled Mantid: http://bugguide.net/node/view/11677

Ground Mantid: http://bugguide.net/node/view/35587

Little Yucatan Mantid: http://bugguide.net/node/view/4819

Arizona Unicorn Mantid: http://bugguide.net/node/view/22607

Grasshopper Mantids: http://bugguide.net/node/view/34939

Bottom line, mantises are predators. Predators will hunt and predators will kill to survive. Sometimes, native species may target large items as well. However, it is important for us as humans to keep a certain distance and respect their behaviors. In many instances, it is best to not intervene.

Mantid Eggsacs

Mantid eggsacs, also known as ootheca are small to medium sized masses of eggs. Females often lay in the fall and die by the first frost in temperate areas. The eggs will survive the winter to hatch next spring and summer. In more tropical and hot areas, mantids may be found year round and females may actually guard their eggsacs. The foamy, papery outer structures keep the mantids warm and also prevent easy access to predators. Each eggsac can have dozens to hundreds of eggs in separated compartments.

California mantid eggsac: http://bugguide.net/node/view/588607/bgimage

European mantid eggsac: http://bugguide.net/node/view/154902

Chinese mantid eggsac: http://bugguide.net/node/view/1016946/bgimage

Carolina mantid eggsac: http://bugguide.net/node/view/233403

What to do when a mantis shows up + killing non-native mantises?

So these questions come up a lot: What do I do when a mantis "stakes out" my feeder? If I do find a mantis in my yard should I kill it to "protect" hummingbirds?

If I find a mantis in my yard should I kill it to "protect" hummingbirds?

Your first step is to make sure it is a non-native species. You can use the images above to help you or browse through BugGuide to try and ID it yourself. Additionally, you can feel free to message an image of your mantis friend to Chao (the guy who wrote this article and is an admin on Hummingbird Academy) and he will give you the answer.

If you can confirm your mantis is a native species, you can still relocate it away from your feeders. But as mentioned above, DO NOT KILL NATIVE MANTIS SPECIES. Native mantis species are vital organisms within the local ecosystem and provide a priceless amount of pest control. In addition, native species fulfill a unique ecological niche both in maintaining local insect populations AND being food themselves for birds. If you find a native mantis species, your best bet is to LEAVE IT BE, though you can relocate if you want, and DO NOT KILL.

However, if you are sure it is indeed a non-native species, whether you want to kill it is up to you. I will weigh out some pros and cons of non-native mantids.

- Pros: Non-native mantids still feed on a wide variety of insects, including many species of native and non-native insects which can become pests (Japanese beetles, cucumber beetles, squash bugs, etc). Likewise, in many urban environments depleted of predatory arthropods, non-native mantids partially fill these gaps and provided a percentage of biological control.

- Cons: Non-native mantids (and mantids in general) can become double-edged swords, feeding not only on animals we consider pests, but also on animals we consider beneficial. In other words, they will prey on butterflies and bees just as readily as squash bugs and flower beetles (the same can be said for native species, though, but they are supposed to be here). Likewise, non-native species such as the European and Chinese have a higher chance of preying on hummingbirds.

So ultimately, I would not suggest killing ANY native mantis species. As for non-natives, I am a little less against culling, but feel free to weigh in everything mentioned above before doing so.

What do I do when a mantis "stakes out" my feeder?

If you are finding praying mantises that are hanging out near your feeders, the best thing to do is relocate it if you are worried. Take a broom and gently get the insect to climb onto the broom then move it elsewhere. You can also use your hands to get the mantis to crawl onto them (as long as you don't threaten/grab the mantis, it will not bite or pinch you with its forelimbs). I guess I should also say that mantises in North America are poisonous or venomous, so don't worry about that.

99% of the time the mantis is drawn onto the feeder because the sugar water attracts bees, flies, and other insects which sip nectar rather than because of the hummingbirds themselves. In the wild, mantises will sometimes perch near flowers to wait out prey (kind of like crocodiles waiting in/near rivers for antelope to come for a drink).

Keeping feeders in easy viewing distance and checking regularly, especially around August to October in most temperate areas (and probably July to November in subtropical areas) will drastically decrease predation chances.

Other tips/Information

Because the large majority of nurseries sell eggsacs of the introduced European and Chinese mantis for "biological pest control" rather than native species, we as individuals to use their judgment before purchasing and releasing insects for the aforementioned reasons. Theoretically however, because European and Chinese mantids have already established populations in the United States, their release is likely to be less environmentally harmful than spraying pesticides. Likewise, according to the 2017 study, the species of hummingbird most commonly predated by mantids is the Ruby-throated Hummingbird which breeds in Eastern North America. BUT, despite the prevalence of introduce mantids in eastern North America, the population of Ruby-throated Hummingbird actually increased while the east was being inundated by non-native mantid introductions...

Last Word

I hope everyone learned a little bit about mantids and their dispositions and got a small amount more eased about their predation on hummingbirds. Likewise, I hope everyone perhaps gained more knowledge about different common species of mantids here in North America. While potentially menacing to hummingbirds, mantids are mostly insectivores, preying upon hundreds of different insects in the environment. Cooperatively, predatory insects (like mantids) and arachnids (like garden spiders) consume a much higher amount of insects than all the birds combined. While it is important to have bird diversity, we cannot stray away from recognizing that insects play an even more integral part to the balance, diversity and ecology of our planet. Finally, it is essential for us to comprehend that mantids, specifically native species, are crucial aspects of any habitat, natural, suburban or urban, and should not be extirpated simply for the (even more) exceptionally small and insignificant probability that they prey on hummingbirds. Remember, organisms like bears and sharks are known to kill people. But, just because they have the potential to harm us does not mean we should eradicate them from the forests and oceans. Bald eagles and Cooper’s hawks eliminate large numbers of birds from various habitats every year. A single Cooper’s hawk will kill more birds in a month than what a mantid could even attempt at a lifetime. Yet, why are we so disturbed and disgusted by the rare chance that a mantid captures a hummingbird? It is all simply organismal disparity, which occurs for all of us, even me. If we see a Cooper’s hawk in our yard, we would not be killing the hawk for the reason that it has the potential to harm the birds in our neighborhood. The same is said for mantids, especially native species.

Ultimately, there are much bigger threats to wildlife we as a birding community need to address rather than the continuous dwelling on the, once again minute, potential of mantids’ hummingbird predation.

To quote a friend: "The only reason this [seeming increase in predation of hummingbirds by mantids] has been happening is because people are giving them a new opportunity, and as any animal will do, take advantage of something that benefits their survival. Bees, wasps, and flies also visit the feeders, and are more likely the intended target instead of the hummingbirds. The amount of hummingbirds eaten by any mantid is infinitesimal compared to the number of birds slaughtered by feral cats." So the next time you see a mantid chilling on a hummingbird feeder, there’s no need to instantly picture the worst case scenario.

Source:

I HIGHLY suggest everyone read through the original article below rather than rely purely on "sensational" media websites.

Nyffeler M, Maxwell MR, Remsen Jr., JV (2017) Bird Predation By Praying Mantises: A Global Perspective. The Wilson Journal of Ornithology, 129, 331-344.

For those interested, here's a very basic Chinese mantid mini-documentary I made awhile ago. Note: It does show the mantids eating other insects close up, so if that disturbs you, I suggest you not watch it. There aren't any images or footage of mantids eating hummingbirds in this, so rest easily!

#bugs #birds #mantis #mantid #prayingmantis #hummingbirds #species #insects