Monthly Archives: October 2012

Earthling Bulletin #10

by Piter Kehoma Boll

The slime mold Physarum polycephalum can “remember” where it has been even without a brain. Photo by Audrey Dussutour extracted from news.nationalgeographic.com

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Unknown whereabouts: the lack of biogeographical references of species

by Piter Kehoma Boll

ResearchBlogging.org Biogeography, as you may know, is the study of the distribution of species or ecosystems through the planet. The knowledge which comes from biogeographical surveys is valuable information for other areas, like ecology, evolutionary biology, geology and paleontology, as well as for conservation purposes. Knowing the distribution of a species may help to determine places of higher priority for conservation, as well as helping to trace an evolutionary pathway or even to determine an ancient geological event.

Despite all this advantages coming from biogeographical studies, many species have a sparse distribution record, or don’t have any at all. That’s more usual concerning “less attractive” groups, like, for example, worms or mosses, which don’t have many researchers interested in them.

I will give here an example among a species I work with. It’s a land planarian, of course; what else could it be? Anyway, the species I’m talking about is called Geoplana marmorata. Here you can see a picture of it:

Geoplana marmorata Schultze & Müller, 1857 from Santa Maria, Rio Grande do Sul, Brazil. Photo by Piter Kehoma boll.

G. marmorata was described in 1857 by Schultze & Müller based on material coming from Blumenau, a city in the state of Santa Catarina, southern Brazil. Later, Graff, in 1899, misidentified it as a variety of Geoplana rufiventris, another species described by Schultze & Müller in the same paper as G. marmorata. This misidentification happened probably due to the specimens examined by Graff being old ones which were kept too much time in a preservative medium, probably ethanol, making them lose their original color as when alive.

About 50 years later, in 1959, C. G. Froehlich corrected this mistake and also expanded its distribution for a new location, Rio do Testo, not that far from Blumenau. In 1967, C. G. Froehlich again expanded its known distribution to include Argentina.

There are no further publications concerning the distribution of G. marmorata, except for a paper by E. M. Froehlich, from 1978, about a Chilean species, G. caleta, which resembles G. marmorata both in external and internal morphology, but the minor differences and the great distance separating both groups seem to point to different species, though probably closely related phylogenetically.

Anyway, so concerning only what’s now found through papers, G. marmorata is only know to happen in Argentina and the Brazilian state of Santa Catarina. Well, here I say that its distribution is far greater.

Despite not being recorded in any species survey in forest remains of Rio Grande do Sul, Brazil’s southernmost state, G. marmorata is indeed found there. We, researchers from Instituto de Pesquisa de Planárias, Unisinos, know this species very well since it is found very frequently in urban environment in the metropolitan area of Porto Alegre, as well as in Santa Maria, a city in the center of the state.

I was kind of shocked as I figured out that there are no publications regarding its presence in Rio Grande do Sul. This just made me wonder about how much scientists know and, as it seems so obvious and natural, they don’t publish it, so retaining essential knowledge, which could be so useful to other researches, simply because of some lack of attention.

This has motivated me to write a paper updating the distribution of land planarian species from Rio Grande do Sul as soon as I have time, based on our protocol records at Instituto de Pesquisa de Planárias. And as a final request, I ask to those who work with research to pay attention to those subjects, so that they don’t get neglected as much.

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References:

Froehlich, C. G. 1959. On Geoplanids from Brazil. Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo, Série Zoologia, 22, 201-265

Froehlich, C. G. 1967. A contribution to the zoogeography of neotropical land planarians. Acta Zoologica Lilloana, 23, 151-162

Froehlich, E. M. 1978. On a collection of Chilean landplanarians Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo, Série Zoologia, 3, 7-80

Graff, L. v. 1899. Monographie der Turbellarien. II. Tricladida Terricola. Engelmann, Leipzig, 574 p.

Schultze, M., & Müller, F. 1857. Beiträge zur Kenntnis der Landplanarien. Abhandlungen der Naturforschenden Gesellschaft zu Halle, 4, 61-74

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Friday Fellow: Housefly

by Piter Kehoma Boll

Today we are going to look closer at one of the most widespread insects, the housefly, Musca domestica. There is a good chance that one of them is right now in the same house, perhaps in the same room, as you.

Have you ever wished to be a fly on the wall?

Have you ever wished to be a fly on the wall? Foto by Muhammad Mahdi Karim.*

The housefly originated somewhere in the Middle East, in the Arabian Peninsula or Northeastern Africa, and spread all over the world most likely due to human influence. It is the most common fly species in human residences, measuring 8–12 mm in length as adults, females being slightly larger than males. The thorax and the legs are dark and the abdomen usually light yellow. The eyes are large and red and the antennae are very short.

When mating, a male housefly mounts a female and injects his sperm, the copulation taking from a few seconds to some minutes. The female rarely mates more than once, storing the sperm to use it repeatedly. She lays about 500 eggs in her lifetime, usually in batches of about 100 eggs. Larvae hatch from the eggs within a day and feed on almost any kind of decaying organic material. The larval stage takes from 2 to 5 weeks to be complete, depending on the temperature: the higher the faster.

A housefly larva. Photo by Pavel Krok.*

A housefly larva. Photo by Pavel Krok.*

As houseflies are closely associated with humans and feed on a variety of substances, they are responsible for spreading several diseases, including many bacteria, protozoans, parasitic worms and viruses. Insecticides have been the most common way to control housefly populations, but some strains have become immune to some of the most common inseticides, such as DDT.

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References:

Marquez, J. G.; Krafsur, E. S. 2002. Gene flow among geographically diverse housefly populations (Musca domestica L.): a worldwide survey of mitochondrial diversity. Journal of Heredity, 93 (4): 254–259.

Wikipedia. Housefly. Available at: < https://en.wikipedia.org/wiki/Housefly >. Access on October 11, 2012.

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*GNU FDL
These images are licensed under a GNU Free Documentation License.

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Friday Fellow: Grandidier’s Baobab

by Piter Kehoma Boll

ResearchBlogging.org Let’s expand the universe of Friday Fellow by presenting a plant for the first time! And what could be a better choice to start than the famous Grandidier’s Baobab? Belonging to the species Adansonia grandidieri, this tree is one of the trademarks of Madagascar, being the biggest species of this genus found in the island.

Reaching up to 30 m in height and having a massive trunk only branched at the very top, it has a unique look and is found only at southwestern Madagascar. However, despite being so attractive and famous, it is classified as an endangered species by IUCN Red List, with a declining population threatened by agriculture expansion.

Adansonia grandidieri. Photo by Bernard Gagnon (commons.wikimedia.org/wiki/User:Bgag). Extracted from Wikipedia.

This tree is also heavily exploited, having vitamin C-rich fruits which can be consumed fresh and seeds used to extract oil. Its bark can also be used to make ropes and many trees are found with scars due to the extraction of part of the bark.

Having a fibrous trunk, baoabs are able to deal with drought by apparently storaging water inside them. There are no seed dispersors, which can be due to the extiction of the original dispersor by human activities.

Originally occuring close to temporary water bodies in the dry deciduous forest, today many large trees are found in always dry terrains. This probably is due to human impact that changed the local ecosystem, letting it to become drier than it was. Those areas have no or very poor ability to regenerate and probably will never go back to what they were and, once the old trees die, there will be no more baobabs there.

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Baum, D. A. (1995). A Systematic Revision of Adansonia (Bombacaceae) Annals of the Missouri Botanical Garden, 82, 440-470 DOI: 10.2307/2399893

Wikipedia. Adamsonia grandidieri. Available online at <http://en.wikipedia.org/wiki/Adansonia_grandidieri>. Access on October 02, 2012.

World Conservation Monitoring Centre 1998. Adansonia grandidieri. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1. <www.iucnredlist.org>. Access on October 02, 2012.

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