Found in Europe, today’s Friday Fellow is a nice day-flying moth with beautiful colors and toxic compounds. Scientifically known as Zygaena filipendulae, its common name is six-spot burnet, burnet being the common name of moths in the genus Zygaena and six-spot referring to the six red spots in each of the front wings. Those spots contrast beautifully with the dark blue or green metalic background of the wings, giving it some sort of mystical look, don’t you think?
The colors say “I’m not edible”. Photo by Vlad Proklov.*
As a caterpillar, the six-spot burnet feeds on leguminous plants, especially trefoils, and has a very different appearance, as usually in lepidopterans. It is yellow to greenish-yellow and has two rows of black spots running on the dorsum.
A chubby yellow caterpillar. Photo by Harald Süpfle.**
The plants used as food by the caterpillar contain cyanogenic glucosides, substances that are stored individually and produce toxic hydrogen cyanide when in contact with each other. This is used as a defense mechanism by the plant, but the caterpillar ingests and stores such compounds to use for its own defense. It has also been shown that the caterpillar is able to produce these cyanogenic glucosides by itself, thus not relying solely on the portion ingested with the food. Most of the compounds, however, are lost during the metamorphosis, so that the adults are much less toxic than the caterpillars.
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References:
Zagrobelny, M., Bak, S., Olsen, C., & Møller, B. (2007). Intimate roles for cyanogenic glucosides in the life cycle of Zygaena filipendulae (Lepidoptera, Zygaenidae) Insect Biochemistry and Molecular Biology, 37 (11), 1189-1197 DOI: 10.1016/j.ibmb.2007.07.008
Wikipedia. Six-spot burnet. Available at: < https://en.wikipedia.org/wiki/Six-spot_burnet >. Access on August 1, 2016.
Here is a list of species described from August 11 to August 20. It certainly does not include all described species. Most information comes from the journals Mycokeys, Phytokeys, Zookeys, Phytotaxa, Zootaxa, International Journal of Systematic and Evolutionary Microbiology, and Systematic and Applied Microbiology, as well as journals restricted to certain taxa.
Today’s Friday Fellow is a creeping (but not creepy) plant with nice deep blue flowers shaped like a human female genitalia.
Yeah, you read that right. Its scientific name is Clitoria ternatea, the genus name being a direct reference to a woman’s clitoris due to the shape of the flowers. Its common names include Asian pigeonwings, bluebellvine, blue pea, butterfly pea, cordofan pea and many others.
Almost pornographic. Photo by N. Aditya Madhav.*
Native from tropical Asia, the Asian Pigeonwing has been introduced worldwide in tropical regions. Its seeds are edible when tender and the flowers may be used to make a nice blue infusion called “clitoria tea” or “butterfly pea tea”. It is a plant used in Ayurvedic medicine to improve mental health.
A nice blue tea to improve your memory. Photo by Tanya May.*
In fact, some studies have shown that it may indeed be benefitial for memory improvement, at least in rats, and has also anti-inflammatory, analgesic and antipyretic properties, especially from root extracts. Once more traditional medicine was a good guide for pharmacological research.
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References:
Devi, B., Boominathan, R., & Mandal, S. (2003). Anti-inflammatory, analgesic and antipyretic properties of Clitoria ternatea root Fitoterapia, 74 (4), 345-349 DOI: 10.1016/S0367-326X(03)00057-1
Taranalli, A., & Cheeramkuzhy, T. (2011). Influence of Clitoria Ternatea Extracts on Memory and Central Cholinergic Activity in Rats Pharmaceutical Biology, 38 (1), 51-56 DOI: 10.1076/1388-0209(200001)3811-BFT051
Wikipedia. Clitoria ternatea. Available at: < https://en.wikipedia.org/wiki/Clitoria_ternatea >. Access on August 1, 2016.
Certainly the most widespread, adaptable and well-known honey-producing bee is Apis melifera, commonly known as honeybee for obvious reasons. But there are a lot of other honey makers all over the world. Today I’m going to present you the most popular native bee in South America, Tetragonisca angustula, commonly known as jataí in Brazil and yateí, angelita, mariola and many other names in the Spanish-speaking countries.
Jataí bees at the entrance of their hive. Photo by Bernard Dupont.*
Found from southern Mexico to southern Brazil and northern Argentina, the jataí bee is a very small stingless bee that easily thrives in urban areas. Measuring about 4–5 mm, they build their nests in natural cavities of trees and sometimes in abandoned ant and termite nests or even in walls of human constructions.
Because it is a native species in the Neotropics, and therefore an important pollinator agent, and because it lacks a sting, being thus harmless to humans and domestic animals, the Jataí bee is an attractive species for domestication. In fact, the jataí bee is the only native stingless bee with a considerable large community of beekeepers maintaining hives. As the hives are small and harmless, they can also be used as effective pollinators of some plants, such as strawberries, inside greenhouses.
Considered of high quality, the honey produced by jataí bees is more expensive than that of common honeybees. In some places the price of jataí honey may be as much as ten times the price of honey produced by common honeybees. Just as the honey and propolis of common honeybees, jataí honey and propolis have antibacterial acitivity. People from communities in which the consuption of jataí honey is a common practice believe that it has medicinal properties, but actually there is no scientific evidence that jataí honey differs from the honey of common honeybees regarding this aspect.
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References:
Malagodi-Braga, K. S., Kleinert, A. M. P. (2004). Could Tetragonisca angustula Latreille (Apinae, Meliponinni) be effective as strawberry pollinator in greenhouses? Australian Journal of Agricultural Research, 55 (7), 771-774. DOI: 10.1071/AR03240
Miorin, P., Levy Junior, N., Custodio, A., Bretz, W., & Marcucci, M. (2003). Antibacterial activity of honey and propolis from Apis mellifera and Tetragonisca angustula against Staphylococcus aureus. Journal of Applied Microbiology, 95 (5), 913-920 DOI: 10.1046/j.1365-2672.2003.02050.x
Sawaya, A., Cunha, I., Marcucci, M., de Oliveira Rodrigues, R., & Eberlin, M. (2006). Brazilian Propolis of Tetragonisca angustula and Apis mellifera. Apidologie, 37 (3), 398-407 DOI: 10.1051/apido:2006011
Wikipedia. Tetragonisca angustula. Available at: < https://en.wikipedia.org/wiki/Tetragonisca_angustula >. Access on August 1, 2016.
Here is a list of species described from August 1 to August 10. It certainly does not include all described species. Most information comes from the journals Mycokeys, Phytokeys, Zookeys, Phytotaxa, Zootaxa, International Journal of Systematic and Evolutionary Microbiology, and Systematic and Applied Microbiology, as well as journals restricted to certain taxa.
What if the cure for cancer has been living in your garden all this time and you have been trying to get rid of it because it is an annoying weed?
I cannot assure you that the answer lies in today’s Friday Fellow, but it certainly has a good potential. Its name is Bidens pilosa, commonly known as beggar’s tick, beggar ticks, black jack, cobbler’s pegs or Spanish needle.
Not extravagant, but discrete. This is Bidens pilosa. Photo by Wibowo Djatmiko.*
Native from the Americas, where it grows in open fields and forest glades, the beggar’s tick is now found worldwide, from Eurasia and Africa to Australia and the Pacific Islands. At first it does not call much attention while growing among other weeds. It grows up to 1.8 m tall and has small discrete flowers in a daisy-like head, with a handful of white ray florets and a small disc of yellow florets.
The problem with this fellow happens when you have to pass among them after the flowers have turned into fruits.
The terrible evil infructescence of the beggar’s tick. Photo by Wibowo Djatmiko.*
The fruits of the beggar’s tick are small, stiff, dry rods with about 2–4 small heavily barbed awns at the end. They are arranged in spherical infructescences are are eager to stick on any passing animal. The small barbed awns catch onto fur and clothes and the fruits are easily dispersed to other areas. It is a classical example of zoochory, i.e., seed dispersal by animals. If you live in an area where this plant is common, you most likely have had the experience of finding your clothes full of those prickling seeds, especially after playing, working or simply walking through a field.
But the beggar’s tick is much more than a dull and annoying weed. In Subsaharan Africa, it is one of the most widely eaten plants. Its leaves are edible when cooked, but have a strong and unpleasant taste.
Furthermore, the beggar’s tick is used in traditional medicine in South America and several studies have found out that it is indeed a powerful medicine. Extracts from the plant have shown several medicinal properties, including:
Antibacterial and antifungal activity
Antimalarial activity
Anti-herpes simplex activity
Ability to reduce tumoral and leukemic cells
Immunosuppressive and anti-inflammatory effects
If this were not enough, the beggar’s tick has the ability to bioacumulate cadmium in its tissues, so that it can be used to depollute cadmium-contaminated soils.
The next time you find your clothes full of beggar’s ticks, remember that it is more, much more, than simply an annoying weed.
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References:
Brandão, M., Krettli, A., Soares, L., Nery, C., & Marinuzzi, H. (1997). Antimalarial activity of extracts and fractions from Bidens pilosa and other Bidens species (Asteraceae) correlated with the presence of acetylene and flavonoid compounds Journal of Ethnopharmacology, 57 (2), 131-138 DOI: 10.1016/S0378-8741(97)00060-3
Chang, J., Chiang, L., Chen, C., Liu, L., Wang, K., & Lin, C. (2001). Antileukemic Activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb. The American Journal of Chinese Medicine, 29 (02), 303-312 DOI: 10.1142/S0192415X01000320
Chiang, L., Chang, J., Chen, C., Ng, L., & Lin, C. (2003). Anti-Herpes Simplex Virus Activity of Bidens pilosa and Houttuynia cordata The American Journal of Chinese Medicine, 31 (03), 355-362 DOI: 10.1142/S0192415X03001090
Deba, F., Xuan, T., Yasuda, M., & Tawata, S. (2008). Chemical composition and antioxidant, antibacterial and antifungal activities of the essential oils from Bidens pilosa Linn. var. Radiata Food Control, 19 (4), 346-352 DOI: 10.1016/j.foodcont.2007.04.011
Kviecinski, M., Felipe, K., Schoenfelder, T., de Lemos Wiese, L., Rossi, M., Gonçalez, E., Felicio, J., Filho, D., & Pedrosa, R. (2008). Study of the antitumor potential of Bidens pilosa (Asteraceae) used in Brazilian folk medicine Journal of Ethnopharmacology, 117 (1), 69-75 DOI: 10.1016/j.jep.2008.01.017
Oliveira, F., Andrade-Neto, V., Krettli, A., & Brandão, M. (2004). New evidences of antimalarial activity of Bidens pilosa roots extract correlated with polyacetylene and flavonoids Journal of Ethnopharmacology, 93 (1), 39-42 DOI: 10.1016/j.jep.2004.03.026
Pereira, R., Ibrahim, T., Lucchetti, L., da Silva, A., & de Moraes, V. (1999). Immunosuppressive and anti-inflammatory effects of methanolic extract and the polyacetylene isolated from Bidens pilosa L. Immunopharmacology, 43 (1), 31-37 DOI: 10.1016/S0162-3109(99)00039-9
Sun, Y., Zhou, Q., Wang, L., & Liu, W. (2009). Cadmium tolerance and accumulation characteristics of Bidens pilosa L. as a potential Cd-hyperaccumulator Journal of Hazardous Materials, 161 (2-3), 808-814 DOI: 10.1016/j.jhazmat.2008.04.030
Wikipedia. Bidens pilosa. Available at < https://en.wikipedia.org/wiki/Bidens_pilosa >. Access on July 31, 2016.
Everyone with some sort of knowledge on evolution has heard of sexual conflict, how males and females have different interests during reproduction, and sexual selection, i.e., how one sex can influence the evolution of the other.
Sexual organisms are almost always defined by the presence of two sexes: male and female. The male sex is the one that produces the smaller gamete (sexual cell) and the female sex is the one that produces the larger gamete. The male gamete is usually produced in large quantities because as it is small, it is cheaper to produce. On the other hand, the female gamete is produced in small quantities, because its large size makes it an expensive gamete.
A classical image of a male gamete (sperm) reaching a female gamete (egg) during fertilization. See the astonishing difference in size.
As one can clearly see, the female puts a lot more resources in the production of a single descendant than a male does. As a result, females are usually very choosy regarding who will have the honor to fertilize her eggs. Males need to prove that they are worth the paternity, and female choice, through generations, increase male features that they judge attractive. A classic example is the peacock.
The peacock is one of the most famous examples of how sexual selection can drive the evolution of dioecious species. Photo by Oliver Pohlmann.
There are a lot of exceptions, of course, most of them driven by the social environment of the species or due to an unusual natural environment which may increase male investment. But all of this stuff refers to dioecious species, i.e., species in which male and females are separate organisms. But what happens if you are part of a hermaphroditic species, therefore being male and female at the same time? Do you simply mate with anyone? Is everyone versatile every time they get laid?
Well, there is a lot of diversity in these organisms, but all the principles of sexual conflict are still valid. Even if you are male and female at the same time, you still have the desire to fertilize as many eggs as possible with your cheap sperm while choosing carefully who is worth fertilizing your own eggs. The main problem is that anyone else wants the same.
“Come on, darling. Let me fertilize you.” “Will you let me fertilize you too?” Photo by Jangle1969, Wikimedia user.*
Imagine that you are a hermaphrodite with a handful of expensive eggs and lots of cheap sperm. You are willing to mate and you go on a hunt. Eventually, you find another individual with the same intentions. You look at each other in the eyes, get closer and start a conversation. Let’s assume that you didn’t find the other one very attractive to be the father of your children, but you want to be the father of their children.
“So, what are your preferences?” you ask.
“Right now, I wanna be the male” the other one answers.
“Damn!”, you think. Both of you want the same thing. You guys want to play the same sexual role, so there’s a conflict of interests, or, as it is called, a “gender conflict”. In this case, regarding sexual behavior in biology, the word gender refers to the role you play during sex. Who will be the man in the relationship?
In face of this conflict, this hermaphrodite’s dilemma, you both have to find a solution. There are four possible outcomes:
1. You insist on being the male and your partner agrees to play the female against their will. You win, the other one loses. 2. Your partner insists on being the male and you agree to play the female against your will. The other one wins, you lose. 3. Both of you insist on being the male. Sex doesn’t happen and both of you go home without having got laid. 4. Both of you agree to play both roles. Sex happens and you successfully deliver your sperm but is forced to accept the other guy’s sperm too.
The worst for you is not being able to deliver your sperm, as you wished. So 2 and 3 are the worst outcomes. 1 is the better outcome for you, but how will you convince your partner to be the loser? So, the best solution for everyone is 4. Both are neither fully happy nor fully frustrated.
Earthworms use the 69 position to exchange sperm. Photo by Beentree, Wikimedia user.*
But is this the end? Not necessarily. The most stable mating behavior in a population is indeed to agree to play both roles, but things can go on after you kiss your mate goodbye. Now you have to deal with post-copulatory selection.
You have had sex, you delivered your sperm, but received sperm in return. A low-quality sperm in your opinion. You won’t let that fertilize your eggs, will you? Of course not! So, as soon as your partner is out of sight, you simply spit the sperm out before it reaches your eggs! He will never know.
A pair of flatworms, Macrostomumlignano, mating. See how the white one, in the end, bends over itself and sucks the other guy’s sperm out of the female pore in order to get rid of it. Image extracted from Schärer et al. (2004) [see references].
So you cheated your partner! You agreed to receive their sperm in exchange of your own, but then you discarded it as soon as your partner went away. You rule! Right? But… wait! What if they did the same? What if your sperm was discarded too?
You cannot risk that. That would be worse than not having get laid in the first place because you would have wasted energy and sperm for nothing! But how can you assure that the sperm remains where it is supposed to be?
One strategy is to include some stiff bristles on your sperm cells so that they stick on the inner wall of the female cavity and cannot be removed. The sperm cells function like thorns or spines that go in easily but are very hard to be pulled back. That’s what some flatworms do.
Two strategies used by species of Macrostomum to force the partner to have your sperm. (A) A species in which two individuals share sperm, but later may try to get rid of the partner’s sperm, have evolved sperm cells with bristles that hold the sperm in the female cavity. (B) Other species have evolved a more aggressive behavior, in which they inject sperm in the partner using a stylet (penis) with a sharp end able to pierce the body. In this case, there is no need to have bristled sperm cells. Image extracted from Shärer et al. (2011) [see references].
Other species evolved a more aggressive approach. They armed their penises with a sharp point that pierces the partner’s body, forcing it to take the sperm. The sperm is injected in the partner’s tissues and swims towards the eggs.
Both strategies may look like wonderful solutions for the male, but remember that they are hermaphrodites, so that everything can be used against themselves! And that’s the big hermaphrodite’s dilemma or the ultimate hermaphrodite’s paradox. They are constantly trying to outrun themselves.
Anthes, N., Putz, A., & Michiels, N. (2006). Hermaphrodite sex role preferences: the role of partner body size, mating history and female fitness in the sea slug Chelidonura sandrana. Behavioral Ecology and Sociobiology, 60 (3), 359-367 DOI: 10.1007/s00265-006-0173-5
Janicke, T., Marie-Orleach, L., De Mulder, K., Berezikov, E., Ladurner, P., Vizoso, D., & Schärer, L. (2013). SEX ALLOCATION ADJUSTMENT TO MATING GROUP SIZE IN A SIMULTANEOUS HERMAPHRODITE Evolution, 67 (11), 3233-3242 DOI: 10.1111/evo.12189
Leonard, J. (1990). The Hermaphrodite’s Dilemma Journal of Theoretical Biology, 147 (3), 361-371 DOI: 10.1016/S0022-5193(05)80493-X
Leonard, J., & Lukowiak, K. (1991). Sex and the simultaneous hermaphrodite: testing models of male-female conflict in a sea slug, Navanax intermis (Opisthobranchia) Animal Behaviour, 41 (2), 255-266 DOI: 10.1016/S0003-3472(05)80477-4
Marie-Orleach, L., Janicke, T., & Schärer, L. (2013). Effects of mating status on copulatory and postcopulatory behaviour in a simultaneous hermaphrodite Animal Behaviour, 85 (2), 453-461 DOI: 10.1016/j.anbehav.2012.12.007
Schärer, L., Joss, G., & Sandner, P. (2004). Mating behaviour of the marine turbellarian Macrostomum sp.: these worms suck Marine Biology, 145 (2) DOI: 10.1007/s00227-004-1314-x
Schärer, L., Littlewood, D., Waeschenbach, A., Yoshida, W., & Vizoso, D. (2011). Mating behavior and the evolution of sperm design Proceedings of the National Academy of Sciences, 108 (4), 1490-1495 DOI: 10.1073/pnas.1013892108
Schärer, L., Janicke, T., & Ramm, S. (2015). Sexual Conflict in Hermaphrodites Cold Spring Harbor Perspectives in Biology, 7 (1) DOI: 10.1101/cshperspect.a017673
Wethington, A., & Dillon, JR, R. (1996). Gender choice and gender conflict in a non-reciprocally mating simultaneous hermaphrodite, the freshwater snail,Physa Animal Behaviour, 51 (5), 1107-1118 DOI: 10.1006/anbe.1996.0112
by Piter Kehoma Boll
![A pair of flatworms, Macrostomum sp., mating. See how the white one, at the end, bends over itself and sucks the other guy's sperm in order to get rid of them. Image extracted from Schärer et al. (2004) [see references].](https://earthlingnature.files.wordpress.com/2016/08/macrostomum_mating.png?w=500)
![Two strategies used by species of Macrostomum to force the partner to have your sperm. (A) A species in which two individuals share sperm but later may try to get rid of the partners sperm have evoled sperm cells with bristles that hold the sperm in the female cavity. (B) Other species have evolved a more aggressive behavior, in which they inject sperm in the partner using a sytlet (penis) with a sharp end able to pierce the body. In this case there is no need to have bristled sperm cells. Image extracted from Shärer et al. (2011) [see references].](https://earthlingnature.files.wordpress.com/2016/08/macrostomum_male_anatomy.jpg?w=500)
Earthling Nature 