Parasitoid Wasp, Blue Velvet Worm and Glowworm Caves of Waitomo

 

Long-tailed Ichneumoid Wasp, linocut, 8" x 8" by Ele Willoughby, 2024

Next up for #InsertAnInvert2023 is my hand-printed lino block print on 8" x 8" Japanese washi paper of Megarhyssa macrurus, the long-tailed ichneumoid wasp or ichneumon wasp. It's a parasitoid wasp and its "long-tail" is in fact it's extremely long ovipositor which you can see looping from its back end into the tree. The wasp uses it to deposit an egg into a tunnel in dead wood bored by its host, the larva of a similarly large species of horntail or wood wasp. Its body is up to 51 mm long and the ovipositor on the female wasps can be 130 mm. It can be found in the eastern US and southern Canada around the Great Lakes. 

Blue Velvet Worm, linocut 8" x 8" by Ele Willoughby, 2024

 

July is Subterranean month, which as it turns out, requires some new art. Here's a sneak peek! I stuck fairly close to the first prompt, simply choosing a different velvet worm, than the one suggested, because the colour is so gorgeous. Hence, my Blue Velvet Worm. Velvet worms (phylum: Onychophora) are named for their velvet-like texture and somewhat wormlike appearance. They are elongate, soft-bodied, many-legged nocturnal animals who spit slime to trap prey, somewhere between worms and arthropods. Like an arthropod their heads have segments but otherwise they have wormlike bodies. They have flexible wormlike skin but like insect skeleton in composition. They have insect-like limbs, but they are unjointed and conical in shape. They look like caterpillars who don't become butterflies. The two extant families of velvet worms are Peripatidae and Peripatopsidae. And amongst the latter there are some in the genus Peripatoides which exhibits lecithotrophic ovoviviparity; that is, mothers in this genus produce and retain yolky eggs in their uteri. The eggs are fertilized internally, and babies develop inside their mother until large enough to be born, in batches of 4–6, as colourless miniatures of the parents! Peripatoides novaezealandiae is a species complex of velvet worms in the genus Peripatoides, found throughout New Zealand. This print is made based on photos of P. aurorbis, but all the Peripatoides novaezealandiae have no morphological characters that distinguish them.

 

Glowworm Caves, linocut in regular and glow-in-the-dark ink, 8" x 8" by Ele Willoughby, 2024

Glowworm Caves, linocut in regular and glow-in-the-dark ink, 8" x 8" by Ele Willoughby, 2024, shot in the dark so you can see how it glows.

 

Third week was troglofauna, or invertebrates who live in caves.  I strayed from the suggested species, because I wanted to illustrate invertebrates I travelled to see, in the glowworm caves of Waitomo. My love of bioluminescence overcame my claustrophobia, and I was proud I ventured into caves, even where it was a tight squeeze.

Glowworm cave photo by by Rap, Raft 'n' Rock, Waitomo

That's me, photo
by Rap, Raft 'n' Rock, Waitomo, May 2010

On the North Island of New Zealand or Aotearoa, there are caves near Waitomo with large populations of Arachnocampa luminosa, a glowworm (insect larvae and adult larviform females that glow through bioluminescence) native to the country.

In the limestone caves, these glowworms, a species of fungus gnat endemic to New Zealand, dot the ceilings with glowing light like blue constellations in the night sky. The larval stage and the imago produce a blue-green bioluminescence. They are found in caves and sheltered banks where humidity is high, hence its Māori name "titiwai", meaning "projected over water." They lay eggs on cave walls and the glowing 3 to 5 mm larva emerge, generally in the spring, and select a site to begin producing its silk nest where it will grow to 30 to 40 mm over several months.

The larva spins silk nests on cave ceilings from where they hang up to 30 threads along which it regularly places small sticky droplets to trap prey like other small Diptera (especially midges), spiders and other non-flying invertebrates. Prey is attracted by the bioluminescence and then sticks to the threads. When prey gets stuck, the larva pulls it up by ingesting the snare and starts feeding on the prey alive.

These are a limited edition reduction lino block print. Each is made with glow in the dark ink, so the 8" x 8" prints themselves glow like the glowworms.

 

Humpback and Barnacle

 

Humpback and Barnacle, linocut, 8" x 8" by Ele Willoughby, 2024

This month is parasite month for #InsertAnInvert2024, so I have been kind of dancing around the prompts and choosing somewhat different species than those suggested, cause, to be quite honest, some of these inverts give me the creeps. For the first two prompts I chose plant rather than animal parasites and reposted art I had previously made: the Dropsophila (fruit fly) and carmine prints. For the third week a shark barnacle was a suggested species, but I decided to look at the whale barnacles.

This hand-printed lino block print with gel plate printed areas is about Coronula diadema, a barnacle which specializes in humpback and some other baleen whales. Each print is 20.3 cm x 20.3 cm (8" x 8") on lovely Japanese mulberry paper and shows the humpback whale swimming above and a close up of the whale below with six barnacles.

The Coronula diadema name comes from its barrel and crown-like shape, which can grow to 5 cm (2") tall and 6 cm (2.4") in diameter. They are common to abundant on humpback whales. Barnacles are actually crustaceans, and C. diadema has 6 plates and a hexagonal opening on top, protected with a pair of opercular valves. The hermaphrodite parasites cluster together in order to breed. The barnacles use the whales as host, and the whales may in turn use the barnacles as a sort of armour and to inflict more damage when fighting in mating battles or against predators. So theirs is a likely a mutually beneficial relationship and are considered commensals.

Joseph Fourier and the Sinusoids

Joseph Fourier, linocut, 11" x 14", by Ele Willoughby, 2024

Sometimes people ask to commission a scientist portrait of someone I had already considered portraying. I don't think you can study physics for as long as I did and not think about Joseph Fourier. So when asked to make his portrait, I had a plan in mind.

French mathematician and physicist Jean-Baptiste Joseph Fourier (1768-1830) is best remembered for his work Fourier series, Fourier transforms, Fourier’s law of conduction, Fourier analysis and harmonic analysis and their use to solve heat transfer problems. He is also often credited with proposing the greenhouse effect as early as 1824.

Born in Auxerre, a son of a tailor, he was orphaned at age nine. Recommended to the Bishop of Auxerre, he was educated by the Benedictine Order of the Convent of St. Mark. Being a commoner he could not seek a commission in the scientific corps of the army but took a military lectureship in mathematics. He took a prominent part in promoting the French Revolution in his district. Nonetheless he was briefly imprisoned by the Terror. In 1795 he was appointed to the École Normale and later succeeded Lagrange at the École Polytechnique. After accompanying Napoleon as a scientific adviser on his Egyptian expedition in 1798 he was appointed secretary of the Institut d’Egypte, where he organized workshops for the French to make munitions, wrote several papers for the Egyptian Institute (now Cairo Institute). He returned to France in 1801 after the British victories, to resume work at the École Polytechnique but Napoleon appointed him Prefect of the Department of Isère in Grenoble. In Grenoble he began to experiment on the propagation of heat, and contributed to the comprehensive catalogue Description de l’Égype.

In 1820 he published his theorem on polynomial real roots, that a polynomial with real coefficients has a real root between any two consecutive zeros of its derivative. (This is technically a corollary of a theorem published by Budan in 1807 and 1811, also now known as Fourier’s theorem). In 1822 he succeeded Delambre as Permanent Secretary of the French Academy of Sciences, and he published his heat flow research in his Théorie analytique de la chaleur (The Analytical Theory of Heat) which included his important claim that any function of a variable, continuous or discontinuous, can be expanded in a series of sines of multiples of the variable. The idea is true (with some conditions, later discovered by Dirichlet) and a breakthrough. This is the foundation for what we call the Fourier transform, an invaluable tool in math, physics and engineering. During the 1820s he realized that the Earth, at its distance from the Sun should be colder is it is only heated by solar radiation. He wrongly thought Earth has must then receive significant radiation from interstellar space but he did consider the correct answer that the atmosphere acts as an insulator. He referred to experiments by Saussure who measured temperature in a vase with several inset panes of glass, who noted that the inner chambers (under more glass) become hotter. Fourier noted that if the atmosphere makes a layer like the glass in the vase we would get the same effect on Earth (though he noted that Saussure’s experiment did not account for the convection we get in the atmosphere). This is now recognized as the first conception of what we know as the greenhouse effect.

He became a foreign member of the Royal Swedish Academy of Science in 1830. He experienced heart aneurysms in both Egypt and Grenoble and died 16 May 1830. He was buried in Père Lachaise Cemetary in Paris in a tomb with an Egyptian motif and his name is one of 72 inscribed on the Eiffel Tower.

My portrait (inspired by the portrait by Boilly) alludes to Fourier decomposition: the sine waves sum to the violet waveform framing him. With an infinite series of sines, his very outline, as a function of x (the horizontal axis across the page) could be made. Likewise the circles in the background are another visualization of building up an image of Fourier himself from sine waves. If you trace the perimeter of a circle on a continuously advancing sheet of paper you produce a sine wave. (Mathematicians and physicists often use this equivalency to think of a real sinusoid as the real part of a complex function where a vector formed by by its real and imaginary parts traces a circle around the origin). So a simplified function tracing the main lines in Bouilly’s portrait can be produced by the sum of sine waves produced by tracing the series of these epicycle circles. 

There are a lot of great tutorials about this online, but a particular shout out to 3Blue1Brown on YouTube who not only has an excellent series of videos (it's everything you ever wanted to know about Fourier series but were afraid to ask) but he's also specifically made animations of producing a path that approximates Bouilly's portrait with rotating vectors or Fourier epicycles here.