What’s that in my spinach?

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A speck on the spinach leaf…

One morning as I was preparing my lunch before school, I noticed something attached to a spinach leaf. It looked like a small tan rounded egg of some sort. Closer inspection revealed something very funny–an aphid mummy! These are the hollowed out exoskeletons of aphids, created by the larva of a parasite that had devoured the aphid’s internal organs. I was familiar with aphid mummies, having seen them many a time on aphid-infested plants outdoors, but to find one on a piece of spinach from the market was worth a good laugh. I tossed it in a vial and headed off to school.

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Aphid mummy on spinach. The only locality information I have is from the packaging, which simply stated “Product of USA”. So this aphid and its associated parasite could be from almost anywhere in the country.

Later that day I decided to get a few shots of the aphid mummy. As I was photographing it I noticed that there was no hole in it, and there was a suspicious-looking dark area inside. What if, despite all odds, there was still life inside? I decided to keep it on the off chance that the parasite might still be inside. Turns out I didn’t have long to wait. The very next day I was excited to spot a 2-mm long wasp walking around in the container. As expected, the aphid mummy now had a large circular hole cut in it where the wasp had emerged. I photographed the wasp and posted it to BugGuide, where Ross Hill quickly determined it as a member of the subfamily Aphidiinae (Hymenoptera: Braconidae), which specialize in parasitizing aphids.

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The resulting aphidiine wasp.

Never doubt that insects are all around us, even in your food!

Rearing North America’s largest moth

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Caterpillar of the cecropia moth, Hyalophora cecropia (Kennebunk, ME)

Almost immediately after finding the northeast’s rarest waterscorpion, my dad alerted me to a “really cool caterpillar” just a few steps away. When he pointed it out to me I was stunned–a cecropia moth caterpillar! An iconic species, Hyalophora cecropia is considered to be the largest moth in North America, with an equally large caterpillar. But they are not just large–they are absolutely beautiful in all stages. Caterpillars are plump green monsters bristling with red, yellow, and blue scoli (knobs with spikes), and the adults are an unbelievable mixture of reds, browns, pinks, and creams, one of the most charismatic moths out there and a perfect example to point to when people say that moths aren’t as beautiful as butterflies. I had only seen three adults in my life and never a caterpillar, so I was pretty dang excited about this one.

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The resulting moth.

After I had taken the caterpillar home and photographed it, I set up an enclosure with lots of food. The ‘pillar was originally on speckled alder, but I found that it would accept maple as well. The next day the leaves were gone, converted into a pile of frass at the bottom of the container, as any self-respecting caterpillar tends to do. This continued for several weeks, with daily replacing of the food and emptying of the waste a necessity for the caterpillar’s survival. Strange as this may sound, I found the frass pellets to be little works of art, intricately marked with lines and spots. Unfortunately I never thought to take a photo. Eventually the caterpillar pupated in a huge baggy cocoon, and into the garage it went to overwinter.

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What a wondrous sight to wake up to!

One lovely day next June, I found that the adult moth had emerged. The first thing I did upon seeing her hanging upside down in the rearing cage might seem a bit odd: I bent down and sniffed her. Something I have experienced with every cecropia moth I have encountered is that they smell very strongly of peanut butter! I initially thought this was just the female’s pheromones, but I have smelled it on males as well. It was a miracle that the caterpillar had not been parasitized by flies or wasps, as many such large caterpillars often are. My moth was a female, as evidenced by her plump abdomen full of eggs and her slender antennae (males have large feathery antennae to detect the pheromones of the female). Cecropia moth adults have no functional mouthparts and only live long enough to reproduce, so the next day my dad and I took her back to where we found the caterpillar and released her deep in the bushes, where she hopefully attracted a male and laid eggs to bring about the next generation of these spectacular insects.

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Detail of the abdomen.

Georgia: Rearing the American Shieldback, Atlanticus americanus

DisclaimerThis has been my first experience keeping any members of this genus.

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Adult male American shieldback, Atlanticus americanus. Reared from nymph collected in Eatonton, GA.

A group of katydids that has consistently eluded me throughout the years is the shieldback katydids (subfamily Tettigoniinae). These tend to be large, bulky, dark-colored, and predacious species. For many years, the only one I had ever seen was the Roesel’s katydid, Roeseliana roeselii, an introduced European species found in the northeastern U.S. Almost all other U.S. shieldbacks live in the west, but there is a single widespread eastern genus, Atlanticus, plus a rarely seen southeastern specialty, Hubbelia marginifera (more here). I always wanted to see Atlanticus, as they present a very different image than more typical leafy-looking katydids. My wish was finally fulfilled in August 2014 when I ran across a single old male of Atlanticus testaceus in Delaware. However, I was not able to enjoy his presence long, as he died within a few days. This March, while in Georgia, I was thrilled to find that our campground was brimming with tiny shieldback nymphs, only a few millimeters each! They were abundant in the leaf litter of the forest surrounding Lake Sinclair. I captured as many as I could, but since I had limited space, I was forced to cram them all into a single large container. I knew that these could cannibalize, but hoped that at least some of them would make it back alive.

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Part of the original group of tiny shieldback nymphs. 

My fears were confirmed when I arrived back in Ithaca and sorted out the catch. Out of about 15 originally, only 6 had survived, and those individuals were fat on the meat of their brethren. I immediately separated them out into their own containers to prevent any more cannibalism. They seemed to adjust well to their new quarters and fed avidly on carrots and fish flakes, my standard orthopteran diet.

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One of the baby shieldbacks. 

I learned quickly that the shieldbacks were experts at molting in cramped conditions, unlike most katydids. They molted fine in their original small containers all the way up to their final nymphal instars. By this point, I had discerned an ovipositor on only one individual, meaning that I had 5 male nymphs and 1 female nymph. They were large enough that I began to supplement their diets with live prey (mostly small leafhoppers and moths caught locally), which they actively hunted down and ate. Once each shieldback started showing signs of getting ready to molt, I transferred them to a large container with a standing piece of corkbark for the imaginal molt. This worked perfectly, and although one of the male nymphs died unexpectedly from unknown reasons, all the rest became adults over the course of about a month.

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The largest male nymph, shortly before becoming an adult. 

When the first male nymph became an adult, I was able to key him out to Atlanticus americanus using a paper by Rehn and Hebard (1916). As adults, they became much more aggressive and predatory. Touching their antennae with forceps caused them to leap forward and start biting whatever was in front of them. On several occasions that turned out to be my finger, and I learned that they have powerful bites indeed. Unlike many other predatory animals such as spiders or assassin bugs, shieldbacks have no venom to quickly kill their prey. Instead, they rely on strong, fast bites to incapacitate their quarries. It was interesting to watch their strategies on various insect species. With smaller, weaker animals such as leafhoppers or caterpillars, they would simply grab the insect and start eating. With larger, more active prey, they would grab and attempt to start eating, but as soon as the prey started kicking and struggling to escape, the shieldbacks would systematically move up the body of the prey, biting at intervals until the insect stopped moving. Only then would the predator continue its meal.

In contrast to their dietary habits, I found their songs to be very peaceful and gentle. Two of the males have recently begun to sing. Their call is a series of soft, brief buzzes, repeated about a dozen times. They usually start singing at dusk and continue into the night. Fascinating that such a fierce predator would have such a tranquil voice.

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The single adult female shieldback. 

Reference:

Rehn, J. A., & Hebard, M. (1916). Studies in American Tettigoniidae (Orthoptera). VII. A Revision of the Species of the Genus Atlanticus (Decticinae). Transactions of the American Entomological Society (1890-), 42(1), 33-99.

 

Addendum: I originally wrote this post a few weeks ago and for some reason never got around to actually putting it up on the blog until now. All of my 5 shieldbacks are still alive and well, and the 4 males sing every night. Each tends to spur the others to sing, so that their buzzing becomes blended, and the chorus continues for well over the time span of a single male’s song. I can only imagine what it sounds like right now in their native home of Eatonton, Georgia.

Rearing Conocephalus gracillimus

Disclaimer: The title of this post is a bit misleading, as my entire experience with this species consists of a single individual which I brought through its imaginal molt only. However, the story is an interesting one, and hopefully what I have learned here may be of use to others trying to rear meadow katydids.

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A last instar male nymph of Conocephalus gracillimus, the Graceful meadow katydid.

This February, I received a shipment of insects from around Fort Lauderdale, FL. In the past I have had no problems with shipments of live insects, but unfortunately, the weather in Ithaca at that time happened to be particularly nasty (-20 degrees F), so the majority of the critters perished en route. Of the 5 animals that survived, only one made it past the first week in captivity. That animal was a small brown meadow katydid nymph, who was missing his right hind leg. For some reason, he seemed unable to jump, despite still having one functional hind leg, and walked everywhere. Given that many of the other creatures that had died were much hardier species (roaches, beetles, spiders), I didn’t have much hope for this guy’s survival. I established him in a container, the setup of which is detailed below:

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The container is an empty couscous container with the lid removed and replaced with a fine mesh, which is held in place by a rubber band.

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Inside the container, there is a substrate of EcoEarth, the Floridian twigs he was shipped with, and two food dishes. One contains small pieces of carrot, the other contains fish flakes for protein. The inhabitant is visible on the far right.

This setup seemed to work for the first couple of weeks. His copious frass indicated that he was feeding well on the carrot slices and fish flakes. I misted the container with water once or twice a day, and replaced the food every couple of days. At this point I was still unsure as to his identity. I knew his tribe (Conocephalini) and given that he appeared to be a last instar nymph with large wing buds, I figured that he had to be in the genus Conocephalus (the only other genera in that tribe would either be much larger or have very reduced wings). Looking through the range maps and descriptions at SINA, I hazarded a guess that he could be C. gracillimus, a Florida endemic species which seemed to match up with the general habitus and color scheme. However, given that he was a nymph, it was too early to be sure. I would have to examine several traits which required him to be an adult male. I hadn’t had much hope for him earlier, but given his success so far, I now began to hope for him to become an adult.

About 3 weeks later, he stopped eating, as evidenced by the fact that no more frass was accumulating on the sides of the container. His wing buds also started to bulge, and his body color started changing slightly. These were all signs that he was due for a molt. I had learned that a humid environment is important for molting, so I replaced the mesh on top of the container with the original lid to reduce water loss. This might have stimulated mold growth, so I removed the uneaten food to avoid that issue. Then I waited. I figured that he would molt at night, as most katydids do, so I checked on him every morning. Nothing happened for a week, and then one day there he was in all his glory as an adult male, with long, elegant wings!

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Conocephalus gracillimus is not a large animal. Here he is perched on the tip of my finger.

Now that he was an adult, I placed the mesh back on top of the container so that I would be able to hear him once he started singing (meadow katydid calls tend to be extremely high-pitched and soft). I photographed him as he was, but since he was still teneral, I did not want to risk damaging him to get a look at his cerci. Judging from his overall appearance, my theory that he was C. gracillimus seemed more and more strong. Interestingly, he was now able to jump, although he could apparently only manage a weak little hop. 2.5 weeks later, his color had changed from the original brownish/pinkish hue to a more green/yellow shade, and his jumping abilities had improved dramatically. I decided to photograph him again, and this time I was able to image his cerci. Running him through the key in a paper by Rehn and Hebard (1915), and comparing images on SINA, I was able to conclusively pin him down as gracillimus, just as I had suspected from the beginning. Concidentally, the very next day he sang for the first time, and his song matched the recording on SINA perfectly.

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Adult male Conocephalus gracillimus, as he appeared while still teneral and then 2.5 weeks later, with his distinctively shaped cerci.

As of today (June 21th, about 4.5 months later!), he is still alive and well. He is very active and calls daily, although it’s very easy to miss due to his extremely quiet song. I wish I had a female so that I could try to breed them, but I don’t think I will be getting down to Florida any time soon. Regardless, I know now that Conocephalus gracillimus make good pets and are quite hardy in captivity should I ever run across this species again.

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Face of Conocephalus gracillimus