These are two of the Cylindera celeripes (swift tiger beetle) larvae that I’m rearing. Note: nobody has ever reared this species before! Nobody has ever even seen its larvae (before now, that is).
These larvae hatched from eggs that were laid by adults I brought back from northwestern Oklahoma last summer. I placed the adults in a small terrarium of native soil – at first just to see if I could keep them alive, and then to see if I could get them to lay eggs. The adults lived for about 4 weeks, and a short time later larval burrows started appearing in the soil. I fed them once or twice a week by placing 2nd instar corn rootworm larvae in the open burrows or dumping Lygus nymphs into the terrarium and letting them catch them naturally. I wasn’t sure this was working, because as the summer progressed I saw fewer and fewer open burrows. By October, there were no open burrows, and I feared none had survived. Nevertheless, I placed the terrarium in a cool (10°C, or 50°F) incubator for the winter and pulled it back out in late March. Within one week ten larvae had reopened their burrows – I believe all but one of them are 3rd instars, which is the last instar before pupation, and since they have awoken they have fed voraciously on 3rd instar fall armyworm larvae, which I dangle above their burrow. I love watching them snatch the armyworm from my forceps and drag the hapless prey down into their burrow. I’ve already preserved examples of the three larval instars and will describe it shortly (although truth be told, the 2nd and 3rd instars are from larvae I found in the field – but that is a post for another day). However, I’m keeping my fingers crossed for the piece de resistance – successfully rearing the species from egg to adult!
Photo Details: Canon MP-E 65mm 1-5X macro lens on Canon 50D, ISO 100, 1/250 sec, f/13-16, MT-24EX flash 1/8 power w/ Sto-Fen diffusers.
Copyright © Ted C. MacRae 2010
Beetles In The Bush 
Aww, how cute.
How long do tiger beetles live in their larval forms? I did not know they lasted so long before reaching adulthood.
One year would be the minimum – larger species and populations in more northern climes tend to take even longer (2-3 years). Cylindera celeripes is one of the so-called “summer” species, meaning that adults emerge and lay eggs during summer, with partially grown larvae overwintering and maturing in the following season(s). Other species have a “spring-fall” life cycle in which sexually immature adults emerge in fall, mess around for awhile, and dig back in for the winter. When spring comes, they emerge as sexually mature adults and lay eggs – the larvae that hatch maybe mature that year but may need another year to complete development. There are some variations on the spring-fall theme.
I suspect the long larval life cycles are a consequence of their reliance upon a sporadic and unpredictable food supply.
Wow! The ‘face’ of the second image is absolutely striking!
Thanks, Javier.
I find it very curious the two eyes more developed in the flat face…
do these larvae have some sort of binocular vision?
I known some points with many adults, but I never saw larvae… I will look more carefully…
If you look carefully, you will see that there are actually four eyes – the second pair are a little smaller than the first and lie between the first pair and the mandibles. They’re a little hidden by debris in these photos.
Tiger beetle larvae have acute focusing abilities and are able to distinguish both the size and distance of moving objects. One study found that objects moving towards their burrow at a height of 10 mm will cause larvae to strike, while the same object approaching from a height of 50 mm will elicit an escape response. I have observed this myself when I feed them – I need to keep the forceps very close to the soil surface as I approach to prevent them from dropping down into the burrow.
Wow, this is so cool! Coincidentally, I just watched disc IV of Life In The Undergrowth and saw how tiger beetle larvae catch preys!
Good luck.
Thanks, Kurt. I haven’t seen that episode – I’ll have to get it.
I think this situation calls for some video of feeding behaviors, Ted. The second image is really spectacular!
hear, hear!
I posted a video last spring of a Cicindela lengi larva snapping an earworm from my forceps – see it here. (Incidentally, I wasn’t sure at the time but later confirmed that the larva did indeed represent that species when it emerged last fall as an adult.)
This is one of the smallest species in North America, so a video of it feeding would be comparatively unimpressive and difficult to capture. However, I have another larva right now that I haven’t talked about that would make a spectacular video – I’ll see what I can do 🙂
Excellent, thanks for the video link. Keep those videos coming!
You’re welcome!
Very cute, peering up like that. I second the call for a video segment!
The popular demand for a video is making me wish I had a Canon EOS 5D Mark II 🙂 Sadly, no way I’m gettin’ that one past the wife!
With larvae that close together, do they ever try to predate on each other?
I do have problems with cannibalism when I place newly collected larvae in containers at the same time and let them run around on their own. I’ve learned to make starter holes and seal the larvae within them to prevent this. Also, if the container is not deep enough then the larvae will tunnel horizontally across the bottom and can encounter each other – this too can result in cannibalism.
In the field, however, I suspect cannibalism is rather rare. Even though larval colonies can be quite dense, it takes movement by a prey-sized object to within about 10-15 mm of the burrow to elicit a strike. Two larvae sitting at the top of their burrows in close approximation probably never actually ‘see’ each other.
Predate on? What ever happened to good old prey on? (Pet peeve: because predate=occur on an earlier date.)
Whew! I scoured my comment several times looking for the dreaded “predate” before finally realizing I was not the source 😉
Oh, that second shot, Ted. Wow! Love it!
I’m looking forward to seeing their progress to adulthood. This is a pretty doggone cool opportunity AFAIC.
And I add my support for the idea of video. That would be awesome. No pressure, but how soon can you start on that? 😉
Thank you, Jason.
Honestly, I’m a little surprised by all the praise for shot #2 – to my mind I didn’t quite nail the focus. I actually debated whether to include it, but I’m glad I did.
Wait until I manage to capture a similar shot of the larva still remaining nameless. A video of it as well would be over the top!
Oh, those eyes!
The eyes have it!
Heh.
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Yeah, I’m famous! 🙂
Super exciting, Ted!
Hey Chris, you gonna come over and see them?