Monthly Archives: January 2019

Whose Wednesday: George Evelyn Hutchinson

by Piter Kehoma Boll

Leia em português

Today I will talk about an important figure of 20th Century’s ecology, sometimes described as the father of modern ecology.

George Evelyn Hutchinson was born on 30 January 1903 in Cambridge, England, to Evaline D. Hutchinson, a feminist and writer, and Arthur Hutchinson, a mineralogist. Due to his father’s influence, Hutchinson grew up surrounded by intellectuals and started to show interest in the natural world since the age of 5.

At the age of 8, Hutchinson was sent to Saint Faith’s, a private boys’ school in Cambridge. There, he and some friends organized the Cambridge Junior Natural History Society for field collecting and he began to collect insects, fossils and bird skins. His interest soon focused on water bugs, which he would continue to study for many years.

G. Evelyn Hutchinson in 1935. Credits to Yale University.

In 1917, Hutchinson started to study at Gresham’s School in Norfolk, which had a greater focus on science and history than most of the schools from that time. At the age of 15, he published his first paper about a swimming grasshopper.

From 1921 to 1925, he studied zoology at Cambridge University. There, he was more interested in individual work than in attending classes.

Soon after graduating, at the age of 22, Hutchinson traveled to Italy to work at the Stazione Ecologica in Naples studying the branchial gland of the octopus, as he believed that this gland was their endocrine gland. However, due to an octopus shortage, he was forced to end his research. While still in Italy, he answered an advertisement for a position at the University of Witwatersrand in Johannesburg, South Africa and got accepted. Against his parents’ advice, he moved to Johannesburg in 1926 but was fired after two years because he was considered an incompetent teacher. He was relieved from his duty until the expiration of his contract. He then used his free time to study South African water bugs. This led him to discover limnology, the study of freshwaters, that combined all of his interests. Soon he started to study the chemistry and biology of coastal lakes along with the US biologist Grace Pickford, whom he met at Cambridge.

In South Africa, Hutchinson also befriended Lancelot Hogben, a professor of zoology at the University of Cape Town. Hogben advised Hutchison to apply for a fellowship at Yale to learn with the renowned embryologist Ross Granville Harrison. The deadline had already passed, but Hutchinson applied anyway by transatlantic cable. Luckily, an instructorship became vacant in the Zoology Department of Yale. Due to the recommendation of the arachnologist Alexander Petrunkevitch, Hutchinson got a position as an instructor.

In 1931, Hutchinson married Grace Pickford in Cape Town. The next year, he joined the Yale North India Expedition and traveled to India to study the ecology of high-altitude lakes and compare them with the coastal lakes of South Africa.

In 1933, Hutchison divorced Grace and married his second wife, Margaret Seal, whom he met on a boat returning to England from India. They were married for fifty years, until her death from Alzheimer’s in 1983. In 1985, aged 82, Hutchinson married a much younger woman, the Haitian biologist Anne Twitty Goldsby, who care allowed him to continue traveling and working despite his failing health. She died prematurely in 1990.

Most of Hutchinson’s contributions to limnology are the result of his research at Linsley Pond in Connecticut. He studied chemical stratification, oxygen deficits, productivity and many other biogeochemical aspects. He is also credited as one of the first to use radioisotopes as tracers in field experiments. His ideas led to the development of systems ecology by H. T. Odum, one of his students.

Hutchinson died on 17 May, 1991, in London.

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References:

Slobodkin LB; Slack NG. (1999) George Evelyn Hutchinson: 20th Century ecologist. Endeavour 23(1): 24–30. https://doi.org/10.1016/S0160-9327(99)01182-5

Wikipedia. G. Evelyn Hutchinson. Available at < https://en.wikipedia.org/wiki/G._Evelyn_Hutchinson >. Access on January 29, 2019.

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Friday Fellow: Common Peanut Worm

by Piter Kehoma Boll

Leia em português

Today our fellow is a peculiar marine animal that is also a common food in China and Vietnam. Named Sipunculus nudus, or the common peanut worm, it is a member of the clade Sipuncula, usually called peanut worms.

A dead specimen of Sipunculus nudus found on the Mediterranean coast of France. Photo by Benoit Nabholz.*

As other peanut worms, the common peanut worm has considerably simple anatomy. Its body is consistent of basically two parts, a sac-like trunk and a proboscis, also called the introvert. The introvert is a retractile structure and, when the animal is not feeding, is pulled inside the trunk by a group of muscles. At the end of the introvert, when everted, there is a series of tentacles that takes the food, composed of detritus, into the gut.

The common peanut worm is commonly found burrowed into the substrate in intertidal waters all around the world, with its mouth directed upward. They may reach about 20 cm in length when the introvert is everted, with about 1/4 of this length being composed by the trunk.

As mentioned above, the common peanut worm is used as a food in China, especially in southern regions, and Vietnam. Although the species seems easy to be raised in captivity, currently most, if not all, harvest happens in the wild, which may lead to overexploitation and eventually a serious decrease in the populations.

A bucket full of peanut worms for sale in China. Photo by Wikimedia user Vmenkov.**

Molecular analyses have revealed that, contrary to what is currently considered, Sipunculus nudus is not actually a cosmopolitan species. There are at least four clearly distinct lineages that certainly correspond to four distinct species. Of those, only one is found in waters around Europe, from which the species was originally described. The other three lineages correspond to those found in China and Vietnam (and the one used as food), the Atlantic Coast of the Americas (from Brazil to the USA) and the Pacific Coast of the Americas (around Panama). Let’s hope that soon this taxonomic problem will be solved.

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References:

Du, X., Chen, Z., Deng, Y., Wang, Q. (2009) Comparative analysis of genetic diversity and population structure of Sipunculus nudus as revealed by mitochondrial COI sequences. Biochemical Genetics 47: 884. doi: 10.1007/s10528-009-9291-x

Kawauchi, G. Y., Giribet, G. (2013) Sipunculus nudus Linnaeus, 1766 (Sipuncula): cosmopolitan or a group of pseudo-cryptic species? An integrated molecular and morphological approach. Marine Ecology 35(4): 478–491. doi: 10.1111/maec.12104

Trueman, E. R., & Foster-Smith, R. L. (2009). The mechanism of burrowing of Sipunculus nudus. Journal of Zoology, 179(3), 373–386. doi:10.1111/j.1469-7998.1976.tb02301.x

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*Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

**Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

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Whose Wednesday: Hans Hass

by Piter Kehoma Boll

Leia em português

Today we will move a little forward in time than usual in this section and talk about a 20th century biologist.

Born in Vienna on 23 January 1919, Hans Heinrich Romulus Hass was the son of an attorney and at first followed his steps, studying law. However, in 1938, he met Guy Gilpatric, an American pilot and journalist who was also a diver. They dived together in Riviera, and the activity included underwater hunting and photography. For the next years he continued to dive and switched his interests from law to zoology. He published his first book of underwater photographs, named “Diving to Adventure”, in 1939.

Hans Hass in his natural environment

Hass suffered from Raynaud’s disease, which causes circulation problems, and thus was excused from serving in the German military during World War II. In 1942 he bought the sailing ship Seeteufel and planned to use it in an expedition through the Mediterranean, but was unable to bring it to the Mediterranean during the war. Thus, he rented another ship in Piraeus, Greece, and sailed for several months in the Aegean Sea and the Sea of Crete. In the spring and summer of the next year, he spent several months in the Stazione Zoologica in Naples and Capri, where he collected bryozoans for his thesis. He completed his thesis in February 1944 and became a PhD in Biology by the University of Berlin.

In 1945, Hass married the German actress Hannelore Schroth. They had a son, Hans Hass, Jr., the next year. They divorced in 1950 and in the same year Hass married his second wife, the also actress, as well as underwater diver, Lotte Baierl. They had a daughter named Meta.

Since the beginning of his work with underwater diving, Hass published several books and made many films and documentaries about underwater life, being considered a pioneer in underwater photography, sometimes even credited as the inventor of underwater cameras, and also a developer of new diving technologies. His second wife featured in many of his videos after their marriage.

Hass was a known rival of the French scientist Jacques Cousteau, accusing him of never acknowledging others for their achievements and only focusing on himself.

Hass died on 16 June 2013 in Vienna and was survived by this wife and daughter.

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References:

Wikipedia. Hans Hass. Available at < https://en.wikipedia.org/wiki/Hans_Hass >. Access on 22 January 2019.

Encyclopaedia Britannica. Hans Heinrich Romulus Hass. Available at < https://www.britannica.com/biography/Hans-Hass >. Access on 22 January 2019.

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Friday Fellow: Green mold

by Piter Kehoma Boll

At least once in your life you probably saw a rotting orange with greenish and white mould growing on its peel. This unfortunate condition is caused by the species that I am going to present today.

Penicillium digitatum growing on an orange. Photo by Alison Northup.*

Known popularly as the green mold or green rot, its scientific name is Penicillium digitatum, being closely related to a similar, but slightly bluer mold that also attacks oranges, the blue mold Penicillium italicum. As a member of the genus Penicillium, this fungus is also related to Penicillium chrysogenum, the main source of penicillin, and to several fungi used to produce cheese such as Camembert (by Penicillium camemberti), Gorgonzola (by Penicillium glaucum) and Roquefort (by Penicillium roqueforti).

Infecting exclusively fruits of species in the genus Citrus, the green mold grows and feeds on the fruit’s peel, being the main source of post-harvest decay and thus of major economic concern. The optimal temperature for the development of the green mold is 20-25 °C, although it is able to grow in a range of temperatures going from 6 °C to 37 °C. The spores of the green mold are unable to germinate at the surface of the fruits, though, and they need a fissure on the peel to start growing. However, the storage and transportation of the fruits is enough to create small fissures that are rapidly filled by the growing mycelium.

Conidiophores (spore-producing structures) of Penicillium digitatum as seen with a magnification of 40 times. Photo by Wikimedia user Ninjatacoshell.**

The green mold is known to produce ethylene, an organic gas that is a plant hormone leading to fruit ripening. It is likely that this fungus synthesizes it to induce the ripening of citrus fruits, thus increasing the substrate for its development.

Currently, the main methods used to avoid the spoilage of citrus fruits by P. digitatum include the aplication of fungicides, sometimes in massive amounts. However, as such fungicides can lead to serious environmental and health issues, and sometimes increase the public rejection, there is a demand for the development of less aggressive and more environmentally friendly options.

The genome of the green mold has been recently sequenced, being the second species of Penicillium to be sequenced (after P. chrysogenum), as well as the first main plant pathogenic fungus to have its whole genome analyzed.

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References:

Chou, T. W., & Yang, S. F. (1973). The biogenesis of ethylene in Penicillium digitatum. Archives of Biochemistry and Biophysics, 157(1), 73–82. doi:10.1016/0003-9861(73)90391-3

Marcet-Houben, M., Ballester, A.-R., Fuente, B., Harries, E., Marcos, J. F., González-Candelas, L., & Gabaldón, T. (2012) Genome sequence of the necrotrophic fungus Penicillium digitatum, the main postharvest pathogen of citrus. BMC Genomics, 13, 646. doi: 10.1186/1471-2164-13-646

Plaza, P., Usall, J., Teixidó, N., & Viñas, I. (2003) Effect of water activity and temperature on germination and growth of Penicillium digitatum, P. italicum and Geotrichum candidum. Journal of Applied Microbiology, 94(4), 549–554. doi: 10.1046/j.1365-2672.2003.01909.x

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*Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 International License.

**Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

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Your mother loves you more when she loves your father… if you are a fish

by Piter Kehoma Boll

Sexual selection is a frequent subject of my posts here but they are usually focused on how females and males behave regarding each other. However, there is a third element that results from their interactions: the children.

Females tend to select the best males to be the father of their children because they are interested in having a healthy and strong offspring with better chances of surviving. But what happens when a female has no choice but to mate with a low-quality male? Will she take care of their children the same way?

A recent study conducted with the Honduran red point cichlid, Amatitlania siquia, investigated this question. This fish species is native from Central America and, as usually between cichlids, a female and a male form a bond and take care of their eggs and young together.

A couple of Amatitlania siquia. Photo extracted from nvcweb.nl

The researchers placed a female in an aquarium with transparent walls in which she was able to visually analyze two males, one placed in a chamber to the left and another in a chamber to the right. One of the males was larger than the other, both being larger than the female. After 48 hours, the female was placed randomly with either the larger or the smaller male for them to mate.

The results indicate that females produce similar egg clutches and take care of the eggs in equal amounts when mated with either larger or smaller males. However, after the eggs hatch and the larvae develop to the fry stage, the female spends more time caring for them if their father is the larger one.

They don’t seem very excited to waste their time with low-quality children. Afterall, they may meet that handsome big fish again in the future.

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References:

Robart AR, Sinervo B (2019) Females increase parental care, but not fecundity, when mated to high-quality males in a biparental fish. Animal Behavior 148: 9–18. https://doi.org/10.1016/j.anbehav.2018.11.012

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Whose Wednesday: Antonio José Cavanilles

by Piter Kehoma Boll

Leia em Português

Today we celebrate the birthday of one of the most important Spanish naturalists of the 18th century.

Antonio José Cavanilles y Palop was born on 16 January 1745 in Valencia, Spain. He studied at the University of Valencia and obtained a master’s degree in Philosphy in 1765 and a doctorate in Theology in 1766. In 1772 he was ordained priest.

Portrait of Antonio José Cavanilles by Mariano Salvador Maella.

Dedicated to teaching, Cavanilles moved to Paris in 1777 to become the instructor of the children of the Duke of Infantado. There, he was introduced to botany by André Thouin and Antoine Laurent de Jussieu and became one of the first Spanish scientists to adopt the taxonomic system introduced by Linnaeus.

Cavanilles returned to Spain in 1789 due to the conflicts caused by the French Revolution. From 1790 on, he started a scheme with a Parisian bookseller, Jean-Baptiste Fournier, that introduced many forbidden books into Spain, including the Encyclopédie, which aimed to secularize learning, separating it from religious ideas.

Back in Spain, Cavanilles also increased his dedication to botany. He described many plant species from the Americas brought to Europe by Spanish expeditions. Among the several new genera described by him, we can mention the well-known Dahlia and Stevia.

In 1801, Cavanilles became director of the Royal Botanical Garden of Madrid and remained at this post until his death in 1804.

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References:

Caballer, N. (2011) El ‘correo’ de la Ilustración. El país. Available at < https://elpais.com/diario/2011/12/27/cvalenciana/1325017091_850215.html >. Access on 14 January 2019.

Wikipedia (in Spanish). Antonio José de Cavanilles. Available at < https://es.wikipedia.org/wiki/Antonio_Jos%C3%A9_de_Cavanilles >. Access on 14 January 2019.

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Species in Progress: Upper- and lower-class butterflies don’t get along

by Piter Kehoma Boll

Leia em português

Speciation, i.e., the split of one species into two or more, usually happens when two populations become spatially isolated from each other. This separation can happen in many different ways, and sometimes a simple ecological preference can cause it.

Archaeoprepona demophon in Colombia. Photo by iNaturalist user dengland81.*

This is what happens with a Neotropical butterfly, the banded king shoemaker Archaeoprepona demophon. Found in tropical forests from Mexico to the Northern portions of South America, this butterfly feeds on rotten fruits.

Many other butterflies feed on rotten fruits as well. Inside the forest, they usually occur only in the understory, close to the forest floor, or only in the canopy, among the tree crowns. Archaeoprepona demophon is an exception, living both in the understory and in the canopy.

A recent study, however, found out that the populations living in the understory and in the canopy are genetically distinct, indicating that they do not interbreed. The vertical distance between both populations is of about 20 m, but the degree of divergence is as high as that found between populations living in different locations about 1500 km apart.

It seems that once you ascend to the top of the forest community, you are not willing to keep in touch with the lower classes anymore. If the environmental conditions that keep this separation continue in the future, understory and canopy populations may become different species.

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Reference:

Nice CC, Fordyce JA, Bell KL, Forister ML, Gompert Z, & DeVries PJ (2019). Vertical differentiation in tropical forest butterflies: a novel mechanism generating insect diversity? Biology Letters 15: 20180723.
https://doi.org/10.1098/rsbl.2018.0723

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*Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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