Natural Resources

Brazil is blessed with natural resources, a huge and fertile country exporting vast quantities of food around the world. There is even oil under the rolling South Atlantic, but it doesn´t stop there.

New medicines, new drugs, are often based on chemicals found naturally in nature and few countries have more nature than Brazil. That flower deep in the Amazon may hold the cure for any number of diseases, just as aspirin came from willows, digitalin from foxgloves, and the common anti-cancer drug Vincristine from the Madagascar periwinkle.

Cayenne Ticks, as shown in a Globo News report on amblyomin-X

It´s not a rule of nature that something has to be beautiful to be useful. Few animals are uglier or more unpleasant than the Cayenne Tick, Amblyomma cajennense, which lives to suck blood from any animal it can find, including man. Not only that, but it can transmit disease, including Sao Paulo fever, or Rocky Mountain spotted fever. If you see one biting you, don´t just flick it away, you might leave the head still biting you, or at least cause the tick to regurgitate it's infected saliva into your wound (what you should do is use forceps to grasp it as close to your skin as possible, and gently pull straight back, then disinfect the wound).

So how is this tick a good thing? Well, researchers at the Butantan Institute in Sao Paulo have isolated a compound from that saliva called amblyomin-X. It´s not quite clear how, but amblyomin-X persuades cancer cells to self-destruct, whilst leaving healthy cells alone. Even better, it stops angiogenesis, which is now tumours get their own blood supply - so the tumour cannot grow, cannot spread around the body, and basically "starves".

 Harvesting tick saliva (Globo News)

Amblyomin-X works very well on rats, and next year should enter human trials. If these are successful it would be historic, because it would be the very first medicine developed from discovery to industrial production in Brazil.

Me, Me, ME!!

There is an election coming up in Brazil, the most obvious manifestation of which is the use of vans playing annoying, repetitive, jingles, very very loudly. As with most things, there is a natural equivalent.

The master of "political" advertising is the male Screaming Piha (Lipaugus vociferans), a grey thrush-size bird that lives in the tree canopy in northern Brazil and Amazonia. The call is not unpleasant the first time you hear it, but you tend to hear it a lot, and he is one of the loudest birds on Earth! The Piha's call reaches 111.5 decibels, whilst for comparison, an electric drill is 98 dB, and a power saw 110 dB. The aim of course, like that of the advertising vans, is to draw attention, although in this case he is after mates, and is presumably more positively received.

http://www.freesound.org/people/felix.blume/sounds/140623/

The Screaming Piha works on the "lek" system, which is basically like an election, all the candidates in the same place screaming for attention. Apparently there is little difference in content in each lek, just in volume, but the calls change a little over the years.  Perhaps we have more in common with birds than we think.

Like fire-walking over flaming charcoal with a 3-inch rusty nail grinding into your heel

As probably you know, the sting of a wasp is more painful than the the bite of a mosquito (though not necessarily more dangerous!). If you wanted, you could rank the stings of all insects in order, from the mildest to the most painful, but don´t worry, you don´t have to, for the Hymenoptera (bees, wasps and ants) it has already been done - the Schmidt Pain Index.

So who is the winner?, the most painful possible sting, described as......

"immediate, excruciating pain and numbness to pencil-point pressure, as well as trembling in the form of a totally uncontrollable urge to shake the affected part"
"Pure, intense, brilliant pain. Like fire-walking over flaming charcoal with a 3-inch rusty nail grinding into your heel."

Not a wasp, but an ant, the Bullet ant (Paraponera clavata), and guess where they live? Yes, as well as piranhas, anacondas and parasites that enter your private parts when swimming, Brazil also has Bullet ants! Mainly in the Amazon, but they´ve also been reported in the Cerrado, the hot dry savanna in the north of Brazil.

The Life of Bullet ants

Paraponera clavata (Wikipiedia)

Bullet ants live in colonies several hundred strong, mostly built in the soil at the base of trees, and ruled by a queen. And they are big, about an inch long, and jet black. Although they are omnivorous, and will chop up any insects they come across, their main food seems to be nectar, each day they climb up into the forest canopy and bring back nectar from the flowers there. But don´t imagine gentle giants, colonies can be quite close to each other and a state of war is more or less continuous. Injured ants give off a scent which attracts parasitic wasps, sort of ant Valkyries, who feed off the ants and lay their eggs there.

There aren´t many other things which eat Bullet ants, not surprisingly. But why exactly is the venom so powerful.

Why so painful?

Bullet ants sting through a syringe-like spike at the tip of their abdomen. The consequent horrendous pain can last until the next day, and meanwhile you will have nausea, trembling and probably paralysis. It takes a lot of stings to actually kill you, about 30 per Kg of your weight, though after just one, death probably feels like a good alternative

Like most venoms, the Bullet ant sting is a cocktail of bad things, but most of the effect comes from poneratoxin. This blocks nerve transmission and causes long lasting contraction of smooth muscle fibres, which translates as pain and trembling. One sting contains only 1 ug of poneratoxin, a tiny, tiny, quantity, but enough.

What are they good for?

Various Indian tribes of the Amazon have utilised Bullet ants for years. The sting is a treatment for rheumatism, presumably as the pain takes your mind of it. More productively, the mandibles at the other end can be used as a form of suture, they clamp shut on a wound even when the head of the ant is twisted off, and ant saliva causes the patients wound to swell, closing it.

The Satere-Mawe tribe have found another use. Hundreds of ants are sedated and then woven into a leaf to form a sort of glove. Wearing this glove for 10 minutes, and surviving, is an initiation rite for boys of the tribe. The Satere-Mawe were also the first people to domesticate the stimulant producing Guarana plant (Paullinia cupana), the product of which is now found in a hugely popular soft drink in Brazil. All of which suggests that the Satere-Mawe have a rather "innovative" approach to biology.

Reference

A very good guide to poneratoxin by Vivienne Baillie Gerritsen can be found at
ttp://web.expasy.org/spotlight/back_issues/2001/09/princess_balas.shtml

Pity the poor mosquito!

You are probably, dear reader, a little prejudiced against mosquitoes. Take Aedes scapularis. Whilst it´s true that it is a vector for yellow fever, and  human and Venezuelan equine encephalitis, poor A. scapularis has a hard life. In 2002, Casanova and do Prado studied them in the pastureland around a farm near Campinas, in Sao Paulo state, Brazil.

During the hot rainy season (October to March) muddy puddles form all over the land, and the drought resistant eggs of Aedes scapularis hatch, little larvae swimming off hopefully into the water. It seems a good life in a hot bath full of rich organic matter, but little scapularis does not realise the horrors ahead.

For a start, it might rain, it might not, it might rain a LOT. Aedes only needs 9 days from hatching to adulthood, but even that might be too long. Of the 58 populations studied by Casanova and do Prado, 27 were wiped out by their ponds drying up, and 15 were washed away by floods, they never stood a chance.

Life in the 16 remaining pools was better, but not by much. The good news was that starvation was almost unknown, the bad news that all those mosquitoes ensured that starvation was unknown for their predators too. Estimates of total mortality from tiny larvae to emerging adults varied from 68 to a massive 96% per pool!

Predators included........

Giant water bugs "Baratas d' aqua" (Belostomatidae), aggressively predaceous insects who feed on, well, anything, injecting a digestive saliva and sucking out the remains. One of the most painful bites of any insects to us, let alone to a little mosquito.

Giant Water Bug larva (Wikipedia)

Water scorpions (Nepidae) - actually another type of insect

Diving beetles (Dytiscidae) -  you can eat these, if you want to,  in Mexico the adults are roasted and salted and added to tacos

Dragonfly larvae - there are, incredibly, at least 267 species of dragon- and damsel-fly in Sao Paulo state alone, and many of these eat mosquitoes

Last, but not least, larvae of a predatory mosquito, Psorophora ciliata. Don´t start to feel too grateful to this one, they feed on us as well, and infact are the largest blood feeding species found in the USA.

So, the little larva hatching into a warm, muddy, pool will almost certainly desiccate, be swept away, or be eaten. No wonder they are so angry!

Reference
Key-factor analysis of immature stages of Aedes scapularis (Diptera: Culicidae) populations in southeastern Brazil byC. Casanova and A.P. do Prado (Bull. Entomol. Res. 92, 271-7)

Speedy banana

Plants grow fast in Brazil, but few grow faster than the banana. The plant you see here sprouted from bare earth covered with several cm of gravel, reaching 70 cm tall in just 10 days!

The banana you bought in the supermarket probably didn´t grow like this, as most commercial varieties are seedless. You can take suckers from the base of the plant, simply lopping them off with a spade when they´re about 3 ft tall and planting them somewhere else, and this works fine for small holdings. But these days large plantations mostly plant seedlings grown by micropropagation, which can be generated in large numbers and, importantly, certified disease free.

Banana plants are greedy, they need lots of food, water and heat, but with this they grow very vigorously indeed. In plantations, bananas are usually picked when green and unripe, as they transport better that way, and can be ripened later. You can wait and pick then from the tree of course but be warned, it isn´t a myth about monkeys and bananas - given the chance they´ll eat the fruit before you have the chance to!

Grass for cows

Cows eat grass. So all you need to do is stick a cow in a field and let her get on with it, right? Well, more or less. It you are doing this commercially, you cannot just use any grass, you plant it like a crop, and the choice of grass is very important. It´s nutritional value, how well it grows in this soil, in this climate etc etc. The most important grass for cattle production in Brazil, and in the tropics generally, is Brachiaria, or rather various strains of the Brachiaria genus.

Brachiaria evolved on the savannas of Africa. Some probably came over with the Portuguese, but it was first introduced on a commercial scale in the 1950s. First B. decumbens  in 1952 and later  B. ruziziensis in the 1960’s. It´s hard to be sure, but there might now be up to 80 milion hectares of Brachiaria grassland in Brazil. Brazil is the largest producer of Brachiaraia seeds in the Americas, although production and sales in Mexico and other countries are increasing rapidly.

Brachiaria grows incredibly quickly, up to a metre high. It can also tolerate drier conditions, more acidity and more light than most plants, giving nutritious grass on soils normally described as infertile. Most Brazilian pastures aren't fetilised so this can be important.

The problem with a crop that grows everywhere is that it DOES grow everywhere, from flooded Amazon pastures to savanna to the cerrado, and given half a chance will swamp native species. It can also swamp legumes in the pasture that might fertilise the soil. Conversely, it is very good for the local froghopper insects, who can eat so much it doesn't leave enough for the cows.

Also, rather unfortunately for a forage crop, it can poisonous. For some reason, certain individual animals can get sick and even die if they eat too much. Some individuals are more susceptible than others, and sheep are more susceptible than cows, but it is rare. The varieties that cause problems also tend to be the ones that survive best on poor soil. On the other hand, these varieties function well for the other use of Brachiaria, for erosion control by roads, railways and electricity lines.

Apples

You can grow virtually anything in Brazil (apart apparently from grapefruit, to my chagrin). This includes apples ("maçãs")  though until the 1970s hardly anyone bothered, there was only about 100 hectares of commercial orchards in the 1960s. This is surprising given a) the number of German and Pomeranian immigrants, many of whom were farmers, and b) imports of apples at the time accounted for about 100 million US dollars. Following considerable government and state investment in the 70s there are now 37,000 ha under cultivation, with 3,450 growers, and 1,253 thousand tons of apples were picked in 2009/2010. This investment included the importation of guaranteed virus free material from the famous research station at East Malling, England, which alone increased productivity by 25-50%.

 Granny Smith apple

The commonest variety at the start was Golden Delicious and some Granny Smith, but these have been mainly replaced by Gala and Fuji, which make up 90% of production between them. In fact, it is often the redder types of these varieties, such as Royal Gala, Imperial Gala, Maxi Gala, Brookfield, Fuji Suprema, Fuji Seleta and Mishima, as these export better. Another development was increased use of "drawfing rootstocks". When you see an apple tree you are not seeing one tree but two, the bottom half from one variety, the top from another, joined together as seedlings. This allows you to get strong healthy trees (from the bottom part, the root stock and delicious apples, from the top). Another advantage of this is that if you choose the right rootstock, you can get dwarf trees, an idea developed at East Malling in the 1930s. Admittedly these have fewer apples per tree, but you can have a lot more trees per hectare, from roughly 600 to 2,500. This means more apples per hectare, and they are a lot easier to pick!

Fuji apples

Now, one peculiarity of apples is that they need a winter, or rather they need a period of cold, to induce the production of buds and flowers for next years crop. Gala and Fuji, for example, need more than 600 chilling hours (hours less than 7 C) to give a good crop. Even in the south of Brazil where there can be frosty nights, and even snow some days, this isn´t guaranteed, so sprays are used to mimic this as in parts of Europe. Commercially you also need to add bee hives to the orchard, as otherwise there simply won't be enough bees to pollinate the flowers! Of course, that does give you honey as a particularly delicious byproduct.

One emerging trend in Brazil is cider. This tends to be based on French rather than English techniques, but made much faster, without much maturing. Brazilian cider, like Brazilian wine, is made with extra sugar and can seem sweet to north European tastes.