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Spider making its web.

Imaginative Insects Formed From Resin and Brass by Hiroshi Shinno

Japanese artist Hiroshi Shinno builds hyperrealistic sculptures of insects that don’t exist, perfect forms of imaginative species that look as if they were built from vibrant leaves and delicate flower petals. Even these aspects of the creatures are false, as each leaf or petal was cast from resin and painted with acrylic paint before being placed on the model’s brass base.

In addition to building these fantastical works, Shinno also sketches the initial ideas for his imaginative creatures in an Insect Diary on his website. You can see more of the Kyoto-born artist’s insect-based sculptures and 3D work on his Tumblr. (via Lustik)

> thisiscolossal.com

bigpseudopsisfan

Beautiful

It’s been a few years

I really let this lapse. Well, I’m updating now. Closing up my field season now that we’re getting frost on the ground. Luckily my lab populations seem solid for now (seeing larvae from my beetles).

Been a while

I think I’ll keep updating this blog, even though the Manduca project is done. Might help keep me on track (I’d lose my own head if it wasn’t stitched on).

Looking back

Our experiment, as with many experiments in zoology, has been geared at gaining a better understanding of organic systems. The insect endocrine system, while differing in its effects and capacity for whole-body change, has its parallels with our own. Insects are hardy and able to survive invasive procedures of brain removal and transplanting that would be too dangerous or unethical to be attempted on vertebrates (4). Testing the effects of removing key components may lead to the discovery of alternate sources of chemical signals in the insect body.

4. Wigglesworth, V. B. 1936. The function of the corpus allatum in the growth and reproduction of Rhodnius prolixus (Hemiptera). Quart. J. Micr. Sci 79: 91-121.

As for our difficulties, many replicates may be needed in order to eliminate the individual responses of our test organisms. Ideally, we would try to simulate the natural diet and environment of our test species as closely as possible in order to gain a more precise understanding of how these systems work. Unfortunately for us, Manduca aren’t very hygienic organisms in a small environment. Frass, bacteria, and fungi are a constant concern, so that the containers had to be cleaned every two days. As it stands, our experimental design appears to have allowed the Manduca to survive until the point of pupation and possibly beyond.

My ligated Manduca had passed its critical period, so it is appropriate based on our background to see a full molt occurring. I haven’t come across any test Manduca so far that appear to have the front-only molt pattern expected of the pre-critical ligation, but our experiments will continue.

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Week 4 (2/15/16)

I placed one of the Manduca in a dark container over the weekend, as it had exhibited wandering behavior. Since then, it’s heartbeat has become much more visible on the dorsal integument and its head has become slightly translucent. The stumpy prolegs have become much less firm in shape, a possible sign of internal changes. I assume that this is a precursor to the final molt.

The other Manduca is still eating, though its pulse is also becoming visible. It may be ready for the wandering phase within the next day or so.

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Week 3 (2/12/16)

The Manduca appear about the same. Looking at the mealworm that was ligated as a practice exercise, there doesn’t appear to have been any development on either end of the tie. Based on what I have seen of other student’s specimens, I would have expected at least one molt of the forward segment. The rear end looks a little larger, but there is no discarded cuticle in the container.

It should be noted that there have been a few reports of molting hormone being produced in isolated abdomens in this species as well as others (3). It is unlikely that this is a perfect substitute, but it may explain our failure to see any significant differences between the fore and posterior segments after several weeks.

Hsiao, T., Hsiao, C., and J. De Wilde. 1975. Moulting hormone production in the isolated larval abdomen of the Colorado beetle. Nature, 255, 727-728.

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2/10/16

They appear to be eating much more than previously noted. Given their size, I assume it is still around the same rate, though I must note the duration between molts.

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Week 3 (2/9/16)

Both Manduca have been very agitated since the ligation, though they continue to eat. It may be necessary to separate them soon due to wandering-stage aggression.

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Week 3 (2/8/16)

Both Manduca appear to have molted over the weekend. The ligations don’t appear to have stayed in place. I have replaced them, but it will be anyone’s guess whether or not we will see the predicted partial molt.

Ligating behind the thorax and before the abdomen should allow us to see a clear division in molt activity for each ligated caterpillar. A tight ligation will cut off chemical signals from the brain as well as the prothoracic gland. We would expect to see slower development in the separated portion (2).

Most early insect ligation experiments noted the effects of ligating behind the brain before or after a critical period. Ligating before the critical period would inhibit development, while ligating after this period would have little effect on development. Timing is key in these experiments in order to correctly influence the development of a chosen instar.

Safranek, L., Squire, C., and C. Williams. 1986. Precocious termination of diapause in neck- and abdomen-ligated pupal preparations of the tobacco hornworm, Manduca sexta. Biol. Bull, 171, 126-134.

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Week 2 (2/5/16)

There hasn’t been much change since the last few inspections. Both of our subjects remain at the fourth instar. The non-ligated Manduca appears non-responsive during care and maintenance. This could be a sign that they will be advancing to the fifth instar over the weekend. Unfortunately, I will not be around.

For a quick look at what the final instar will look like, skip to the end of this video.

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Week 2 (2/1/16)

Our two caterpillars appear to have molted at some point over the weekend. Both are larger and their spur is noticeably shorter relative to their body size. The other eggs have still failed to hatch. Both individuals possess white slanted bands on their lateral abdomen. This appears to be the fourth instar, so I may attempt ligation and see what occurs.

Two of the hormonal factors that regulate larval development have been at work here. A sudden increase and decrease in ecdysone levels leads to the production of a new integument and the discarding of the old. Juvenile hormone is responsible for inhibiting development into the adult stage until the immature insect has reached the end of the appropriate instar (life stage). Our Manduca will have to go through another molt before they are ready to begin the pupation process.

I found a helpful summary for basic insect endocrinology from a general entomology course at NC State University. My thanks to Professor Meyer.

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Week 1 (Thurs 1/28/16)

No new behaviors seen yesterday. Dropping by to check on the sole Manduca revealed the presence of another hatched individual. The shade of the remaining eggs appears more brown than previously seen, so I am not expecting to obtain more than my existing pair. It looks like both are around the same size, placing them both at second instar.

I wonder if Manduca will eat neighboring eggs that fail to hatch? Given that our specimens only have a small space to explore, they should come across the eggs as they chew their way through the food block. Something interesting to keep an eye out for, even if it is not a behavior that would likely take place in nature.

Week 1 (1/25/16)

One of the Manduca has hatched. It is alternately working away at the food block and resting in place. My Manduca spends a lot of time resting on the side of the container, which may make sense for an organism that spends lots of time hanging from the edge of leaves. This appears to be the 1st instar, but research suggests that it may have reached the second instar by size alone, as it is now close to 1 centimeter long. The body is a very light shade of green and still only somewhat opaque. There are no signs yet of the white lateral markings that exemplify the mature larval form of this species.

The long black spur at the end of its abdomen appears disproportionate to its size, reaching nearly half the length of its body. While threatening, it does not appear very effective at actually being used as a deterrent. Looking into this a little, it appears that toxicity is the hornworms major defense (1). It would be interesting to see how being reared on a diet devoid of this chemical may affect aspects of the larval life history besides defense mechanisms. While most likely irrelevant for the purposes of our study on hormone regulation of development, it is worthwhile making a note of this in case nicotine content contributes to signaling for key processes in other areas.

1. Kumar, P., Pandit, S., Steppuhn, A., and I. Baldwin. 2014. Natural history-driven, plant-mediated RNAi-based study reveals CYP6B46′s role in a nicotine-mediated antipredator herbivory defense. PNAS, 111:4, 1245-1252, do: 10.1073/pnas.131484111

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Week 0 (Friday)

I received some hornworms (Manduca sexta) to rear today as part of a project. 4 Manduca eggs currently rest on a food block in the containment jar. Each egg is light green, oval, and around 1-2 mm long. I am unfamiliar with the egg-laying habits of their adult moth form, but the proximity of the eggs leads me to believe that they were removed from a cluster. They should hatch in a few days if conditions in their container are favorable.

For a sense of scale, the square of artificial diet on which these eggs are located measures 2.5-3 cm on each side.

Manduca are usually fairly voracious herbivores on various plants in the wild. The artificial diet we use contains all the needed nutrients (I assume) as well as preservatives to prevent decay and possibly inhibit the growth of toxic fungi and bacteria.

I’ve placed my container in our department’s Insectarium rather than transport them outside and risk the cold. I imagine that they’ll do better in regulated heat than at my desk. The insectarium’s lights are always on, so I hope that the day-night cycle isn’t key for their development.

Now for a better look at what we have and what we’re hoping to see by next week

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Week 0 (Tuesday)

As part of my Insect Physiology course, I will be performing ligations on individuals of Manduca sexta (Lepidoptera:Sphingidae) , also known as the tobacco hornworm. For those of you interested in pursuing this type of experiment, Manduca are fairly common in gardens in Illinois.

Insect development, like that of humans and other animals, is heavily controlled by hormones. Cues from the insect’s environment trigger changes to the natural developmental equilibrium, allowing the insect to mature over time.

As practice, the class performed test ligations on Tenebrio larvae, more commonly known as mealworms, as well as diminutive fly larvae. I will be interested to see how the mealworm’s development goes. It seems very distressed and quickly made itself scarce in its container.

By placing a tight restriction between the brain and the abdomen (rear part of the insect), we intend to disrupt the flow of hormones between the anterior and posterior sections of the insect. If all goes well, we will see partial pupation in our Tenebrio as well as our Manduca. Due to the periodic nature of insect hormone release, the Manduca ligations will wait until after the molt from the 3rd to 4th instars.

This 2015 point of view article by Karel Sláma provides some historical background on the subject of insect endocrinology

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