Most large beetles, in comparison to flies, wasps and dragonflies seem slow and cumbersome in flight. Perhaps this is due to their forewings being modified into protective covers for the abdomen rather than full aerodynamic partners. Instead, many beetles hold their forewings (called elytra) aloft ahead of their membranous hindwings, contributing to stability and lift at high airspeeds only (note that they often hold them at a high dihedral, which is a stable configuration).
Certain beetles have much more agility in flight, and acheive this by closing their forewings across their abdomens after their hindwings are deployed. If you have ever tried casing down a Trichiotinus flower scarab in flight, you can appreciate their advantage!
Putting all that hindwing under the elytra takes a bit of origami. Compare the folding of the soldier beetle (Rhagonycha fulva, Cantharidae) above with the ladybird below.
Beetles are hyper-diverse, and very prominent in all kinds of ecosystems, so it seems that their (on average) less agile flight has not been a big penalty. The way that they gracefully unfold their wings and reach skyward during takeoff seems somewhat hopeful to me for some reason. And however much their flight performance lacks compared to a housefly, I still remember that almost any beetle can fly a lot better than I can!
This weekend, we began work with a new high speed camera, a Photron SA-5, with a wicked large sensor capable of recording 7500 frames per second at its full 1024 by 1024 pixel square sensor (and higher speeds at lower resolution). This beastly machine is being used by Mike Hrabar and myself to describe some little-understood phenomena around insect locomotion and behavior, which will hopefully be incorporated into a future paper. The rental of this machine is pricy, and the time when our study species is active is small, so in the downtime we have been using it for all kinds of insect imaging for fun and education. I invite you to join me this week for High-Speed Insect Science (just in case the Shark Week Fiasco has got you down).
Let us begin!
Like many insects, adult Hymenoptera have two pairs of wings on the middle and rear segments of their thorax. These wings beat in unison, and are effectively a single pair of aerodynamic surfaces. They are coupled with a tiny row of hooks (hamuli,; a single one of which is a hamulus) on the leading edge of the hindwing which grab a small fold on the trailing edge of the forewing. In the above video of Polistes dominula taking off, note how the wings beat as one unit, connected by the hamuli. For a close up view of hamuli, check out these shots by flickr user Yersinia pestis.
Sometimes the wings become uncoupled, like when the insect moves through vegetation or after a predator attack. The wings may still re-couple, as they do for this Leafcutter (Megachilid) bee during takeoff:
What is interesting to me is how the decoupled wing seems to make the Megachilid lose lift and bank to the left as it falls, something that indicates a severe aerodynamic stall on that side of the insect. The bee recovered and flew away rapidly, and it wasn’t until the video was saved that I managed to see this temporary decoupling. After the shoot, I found a nice retirement spot for this tattered-looking bee:
Large bees, such as this Bombus vosnensenskii also benefit from the large coupled wing area made possible by hamuli. This, combined with their large thoraces bursting with powerful flight muscles, allow these relative giants to power into vertical takeoffs.
Other insect orders also couple their wings with hamuli, such as aphids and male scale insects (Hemiptera), but moths and butterflies use a different structure called a frenulum which hooks into a fold or invagination called a retinaculum.
Hamuli are wonderfully useful structures for the lifestyle of the flying hymenopteran, but they can also be important aids to species identification, as the numbers of hooks may vary between different groups.
Well, I hope you have learned something about wing coupling in Hymenoptera, or at least enjoyed the videos. I will try to get another post ready for tomorrow, depending on what our research schedule is like. Thanks for tuning in!
PS. These are so fun! Here is a shot of a male Polistes dominula making a beautiful takeoff.
Look at this beautiful Platycryptus californicus jumping spider!! She is so nice and plump! She was not always this way. When my labmate Nathan found her she was emaciated and dirty and living on the lab wall. So we fed her some blowflies!
Notice her shrunken abdomen. She is holding her legs clear of her prey while it succumbs to the venom.
Because we have fed her so well, she is now a much more attractive beast.
Anyway, today we started using a really nice high speed camera (for secret science stuff), and I needed to get the hang of working with this beastly machine. I decided a good subject would be this jumper jumping on a calliphorid fly. The videos are below. Please start the video and then immediately click the HD option and view fullscreen, as the default is kind of ugly.
So these videos are not the best in the world, as there is an annoying slowed down flickering from the incandescent light we were using (60 Hz!), but they are pretty cool anyhow. Hopefully I will do better when we get a better light source!
BTW, in both of these instances, the fly escaped. I am not even sure if the spider wanted to catch the fly, as she was already a bit stuffed. I will have to try this again with a hungrier jumper.
Photos from the Honduran Conservation Coalition website.
I received an email last night from Mark Bonta, a researcher with the Honduran Conservation Coalition, alerting me to some big news from Honduras! A nest of the Red-throated Caracara was found by Isidro Zuniga, a researcher with the coalition in the pine forests of Olancho province. This is a sparsely-populated region of dense forests and rugged mountains which is filled with a multitude of fascinating plants, animals and habitats. You can read the press release from this morning here.
This is big news for raptor biology in general, as it is only the fifth Ibycter americanus nest found by researchers in the world, and the very first from Central America! Not only that, but on a personal note, it means that there are actually other researchers taking up study of my very favourite bird. The Red-throated Caracara was only recently re-discovered in Honduras, by Narish and Jenner in 2004*, also from Olancho. This could mean that there is a stable population of this species in these pine forests, and gives some hope for its continued persistence. For too long this species been neglected by science, despite its fascinating biology, and the fact that it has been nearly extirpated from much of Central America. Now, with sightings in Nicaragua, and this recent discovery in Honduras, I think there is cause for hope for research into the conservation issues for these birds.
In fact, in the press release, the Honduran Conservation Coalition, in partnership with the Peregrine Fund and others state that this is the start of a concerted research effort. The preliminary information is a but a teaser of things to come, and when these data become available they will add greatly to the known biology of the species.
So far, we know that Mr. Zuniga spent six weeks observing the nest, recording prey deliveries and nestling care. The nest was in a pine tree, although from the video it is unclear whether the nest is constructed by the birds or is just a platform on a broken tree (the two nests we have found in French Guiana used a bromeliad as a nesting platform, with no nest material brought by the adults). Only a single chick was being reared, which accords well with our findings in French Guiana.
The nests we found in French Guiana were in large epiphytic bromeliads, which are in short supply in the pine forests of Olancho. What could they be nesting on?
There is also some video of the nest, with footage of adults and the young bird.
I am really excited by these findings, and I eagerly look forward to learning more. How many adults brought prey? What was the nest made of? What kinds of wasps were they preying on? What types of fruits, if any would they find in the pine forests?
All these questions will no doubt be answered in time, and as always, I will be eager to learn more about this awesome bird!
*Narish AJ., Jenner T (2004) Notes on the Red-throated Caracara, Ibycter americanus in Honduras. Cotinga 22: 100.
Remember those photos of the Red-throated Caracaras in Nicaragua from last week? Here is the video of one of the birds, making alarm calls and holding a piece of a Polybia brood comb. This video comes from Pablo Elizondo, director of the Costa Rica Bird Observatories, who was with Mandred Bienert when they encountered the birds. I strongly suspect this bird is engaged in brood care, as the tail feathers are extremely worn, as if it is spending considerable time in a nest.
During our 2009 field season, Tanya Jones (my field assitant in 2009-2010) was drying some Astrocaryum seeds to take as samples on a shelf in our carbet. The problem was, they kept disappearing. Tanya thought I had been taking them*, but I had done no such thing.
So we set up a video trap to catch the culprit:
Mystery solved! So the lesson is, when you need to dry Astrocaryum, make sure they are in a protected location.
*I admit, I did like smashing them and trying to eat the flesh…don’t bother, it is very hard!
Update! Pierre-Michel Forget (the king of tropical forest seed dispersal specialists!) has directed my attention to a cool paper that describes the phenomenon we are seeing here, namely scatterhoarding by a Spiny Rat (Proechimys spp.). Check it out here!
Remember the Acuchi eating Astrocaryum? This time, a much larger rodent comes for some fallen Jackfruit (which incidentally smells like Juicy Fruit gum!).
This is a Lowland Paca (Cuniculus paca). They are some of the largest rodents in these forests, other than the massive Capybaras. This was filmed Feb 27, 2011 at the Inselberg Camp of the Nouragues Reserve in French Guiana.
The jackfruits are not native to these forests, but several were planted upon the establishment of the station (there are also some mango and citrus trees within the camp).
In lieu of a more substantive post this week, I must resort to some footage of a Red Acouchi (Myoprocta exilis) coming to some Astrocaryumseeds. This I took in March of 2011 while testing out a DVR which I was going to use on the caracaras. Having this equipment on hand during the our field seasons was a cool opportunity to get some footage of interesting animals (as well as providing large portions of our data). In future posts I will put up some more of these jungle camera-trapping clips, as I think they can be fun and informative.
We had a representative of High Speed imaging Inc. in the lab today to demonstrate some high speed cameras…So what did we record? Some blowflies of course!
Check out how these awesome flies take off:
We have used high speed cameras before, but this one was pretty impressive. This video was recorded at 4000 frames per second, and is slowed down to 30, so it is about 133 times slower than real life. No wonder they are so hard to catch!
