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The old cat and mouse game November 24th, 2019 by

Did ancient farmers domesticate cats to catch mice? If so, this would have been a classic example of biological pest control, but so far the evidence is largely circumstantial.

Evidence for domestication of a crop or animal is generally based on two lines of study, genetic and archaeological. When both types of research are well and thoroughly done, they tend to support each other. In the case of cats, we still have a ways to go for archaeology to match the genetics.

Oxford zoologist Carlos Driscoll and colleagues explain that there are five living sub-species of wildcats, from Europe to Africa to Asia. Modern domesticated cats are genetically quite close to the Near Eastern wild cat; they even share the same mitochondrial DNA. Based on genetic evidence Driscoll suggests that cats were domesticated some 10,000 years ago in the Fertile Crescent (modern Turkey and Iraq) about the same time that grain farming and livestock tending started there.

Cat domestication at the dawn of agriculture would suggest that early farmers appreciated the wildcats as mousers. With early farming came stores of grain, attracting mice.  

Yet cats are a poor candidate for domestication, because they are obligate carnivores and solitary. Driscoll agrees with archaeologists that ancient farmers did actively domesticate herd animals (sheep, goats and cattle), i.e. penning them, culling undesired individuals, selecting for smaller, tamer, food animals. But Driscoll says that cats were different: cats domesticated themselves—much like dogs, pigs and even swallows, rats and mice. Cats were attracted to the food scraps, the fat mice, and the warm nest sites to be found on small farms. Cats moved in with the farmers, who tolerated them.

This is of course just a hypothesis, consistent with (but not demonstrated by) the genetic evidence and there is little archaeology to back it up.

Some of the earliest cat bones from an archaeological site are much later and far from the Fertile Crescent, in China, from a 6000-year-old site where Yaowu Hu of the Chinese Academy of Sciences and colleagues found cat bones tossed into the refuse pits of Quanhucun village. One cat bone was from an old individual, suggesting that the individual had been cared for by farmers.

Ancient farmers quite possibly gave kittens to their neighbors, spreading cats of Near Eastern extraction from Ireland to China to South Africa. Cats then reached the Americas with the Spanish Conquest.

Cats are not universally appreciated as mice killers. Pest control advice books encourage homeowners to get traps to control mice, writing that cats bring in fleas and disease, kill songbirds, and that their effectiveness as biological control agents of mice is not scientifically documented.

My own experience suggests that if you bring a kitten into a mice-infested household, you will have no rodents left in the house or garden by the time the cat is half grown.

Modern smallholders I have met from Portugal to Honduras to Bolivia do keep cats expressly to control mice, and the cats are often treated with a respectful distance, not petted, not given medical attention and not fed (although they may be allowed to eat scraps). Even today, in the large, informal market of Cochabamba, La Cancha, kittens are sold in little wire cages, along with chickens, guinea pigs and other small farm animals.

To get back to the dawn of agriculture, if ancient farmers perceived cats as mice-killers, that may have been enough to earn cats a space to live on farms, where they could domesticate themselves.

Further reading

Driscoll, Carlos A., Marilyn Menotti-Raymond, Alfred L. Roca, Karsten Hupe, Warren E. Johnson, Eli Geffen, Eric H. Harley, Miguel Delibes, Dominique Pontier, Andrew C. Kitchener, Nobuyuki Yamaguchi, Stephen J. O’Brien, and David W. Macdonald. 2007 “The Near Eastern origin of cat domestication.” Science 317(5837): 519-523.

Driscoll, Carlos A., David W. Macdonald, and Stephen J. O’Brien. 2009 “From wild animals to domestic pets, an evolutionary view of domestication.” Proceedings of the National Academy of Sciences 106. Supplement 1: 9971-9978.

Hu, Yaowu, Songmei Hu, Weilin Wang, Xiaohong Wu, Fiona B. Marshall, Xianglong Chen, Liangliang Hou, and Changsui Wang. 2014 “Earliest evidence for commensal processes of cat domestication.” Proceedings of the National Academy of Sciences 111(1): 116-120.

The problem with water hyacinth November 17th, 2019 by

The Pantanal wetland, shared by Bolivia and Brazil, is the size of a small sea. In the Pantanal it rains for six months, followed by a half year drought. During the rainy season the rivers overflow their banks, creating a seemingly endless sheet of shallow water reaching to the horizon. In the dry season the water retreats to the river courses. There are few trees in the Pantanal, but there are dense stands of a delicate-looking purple flower, the water hyacinth.

In the twentieth century, gardeners innocently spread the water hyacinth to Asia, Africa and elsewhere. Water hyacinth has striking blue flowers and was used to adorn ornamental fountains. But it escaped and was soon clogging lakes, ponds and municipal water supplies.

Water hyacinth is such a survivor that you can drain ponds, let the plants dry out and burn them – then watch them grow again when the pond is refilled. It’s not surprising that control options are limited, particularly in open water, such as lakes and rivers.

The plants can be hand removed, by people willing to do heavy labor in the mud, cutting and dragging water hyacinth to the shore. Even this drudgery only works if you repeat it every year.

When the water hyacinth is removed, people tend to leave it in heaps at the edge of the water, where it is unsightly and gets in the way.

I recently saw another solution for water hyacinth in Benin, in West Africa. At Songhai, a training center in Porto Novo, they harvest water hyacinth, chop it, mix it with manure and use it to make methane (biogas) for cooking. Songhai also keeps a large tank of methane to run an electrical generator when the power is out.

Making biogas isn’t for everyone, as we saw in a previous blog. The Moreno family in Peru has trained people for years to make biogas from guinea pig manure, but few if any of the trainees later made biogas at home. For this to happen you need to buy equipment, provide labor, and pay close attention to managing the microorganisms that ferment the organic matter and give off the gas.

I liked the Songhai method because they don’t just remove the water hyacinth. They treat it like raw material and they make something with it.  But I wondered if using it to make biogas was profitable. A more detailed study is needed to gauge its potential to make money. The Songhai solution has one key advantage: the water hyacinth does not need to be dried, a plus because the big heaps of flesh plants hold retain a lot of water.

Water hyacinth is a water thief in some of the thirstier parts of the world. Finding uses for it may help to defray the costs of weeding it out.

Related blog story

The guinea pig solution

The juice mobile

Harsh and healthy

Floating vegetable gardens

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Learn how to use water hyacinth to make a floating garden

Floating vegetable gardens

Learn how to make biogas

Zero-grazing and biogas

Scientific name

Water hyacinth is Eichhornia crassipes.

Poisoning our friends October 20th, 2019 by

Except for entomologists, no one knows more about insects than farmers. Wherever researchers have bothered to talk to smallholders about insects, whether in Honduras, Nepal, or among the Dogon of Mali, or the KayapĂł of the Brazilian rainforest, we see that rural people know the names of hundreds of insects and spiders. This is especially true of critters that are conspicuous (such as the big ones that are active during the day) or those that make themselves important, e.g. by eating crops.  

However, a recent, quantitative global literature review by Kris Wyckhuys and colleagues confirms that farmers know little about beneficial insects, especially in industrialized countries. As we saw in this blog last week, it is fairly easy to notice toads and other relatively large animals eating insect pests. Many farmers know that birds, frogs and cats are natural enemies of pests. Yet Wyckhuys found that worldwide, farmers mention on average only 0.9 insects or spiders that help to control insect pests.

Farmers can have sophisticated knowledge of certain, individual insect species. For example, Paul Van Mele and colleagues have described Vietnamese farmers who used weaver ants to control pests in fruit orchards. Such cases are, however, disappointingly rare. Weaver ants are big, diurnal, and easy to spot in their treehouse nests sewn together from leaves. Farmers were also motivated to watch weaver ants because they prey on insects like fruit flies in high-value orchards.  Most other natural enemies of insect pests, “farmers’ friends” go unnoticed. Hardly any rural people know about other common natural enemies of pests, such as parasitic wasps, insect-eating fungi and nematodes.

Farmers tend to use more pesticides in cash crops, and know fewer natural enemies for these crops, than in food staples. The use of pesticides is growing worldwide, while the pest problems are as bad as ever. Farmers are born experimenters, but to find alternative to pesticides, they need to know more about the natural enemies of insect pests.

Wyckhuys suggests that some of the world’s half trillion-dollar subsidies for agriculture could be devoted to agro-ecological education. Farmers will never find alternatives to pesticides unless they understand that most insects are beneficial. As farmers use insecticides to kill pests, they unwittingly poison their friends, the insects that eat and kill those pests.

Further reading

Van Mele, P 2008 “The importance of ecological and socio-technological literacy in R&D priority setting: the case of a fruit innovation system in Guinea, West Africa.” International Journal of Agricultural Sustainability 6: 183–94.

Wyckhuys, K.A.G., K.L. Heong, F. Sanchez-Bayo, F.J.J.A. Bianchi, J.G. Lundgren and J.W. Bentley 2019 “Ecological Illiteracy Can Deepen Farmers’ Pesticide Dependency.” Environmental Research Letters 14: 093004

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See also the many other farmer learning videos about Integrated Pest Management on www.accessagriculture.org.

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Toads for watermelon October 13th, 2019 by

The south coast of Jamaica is just right for growing watermelon, where I recently saw the fruit stacked under the shade trees in front of comfortable farm houses. Farmers can earn a tidy living from selling melons on the local market and to the hotels and resorts.

But the trick is to get enough water. In the dry season, a tanker truck will deliver 1000 gallons (almost 4,000 liters) for $50. Most of the farmers economize on water by using drip irrigation. For many years, farmers have saved on water by using mulch, made from the light-weight Guinea grass.

Professional crews cut and dry the grass, which is grown in small fields scattered among the patches of watermelon.  The grass crews lay out a neat carpet of mulch, which not only keeps the soil moist, but also suppresses weeds, and creates a soft, clean bed for the fruit to grow, so it develops an attractive, green rind all the way around the fruit. After harvest, the grass decomposes, enriching the soil with organic matter.

I learned about this while visiting Jamaican farmer Junior Dyer, with a group of colleagues. We asked when Junior watered his plants. He said at 9 or 10 AM. “I never water at night,” Junior explained, because if he does that frogs and toads come into the field to eat the insect pests, but then the amphibians stay for the night, digging holes into the moist soil and disturbing the roots. The frogs and toads still come and eat the insect pests when watering is done in the morning, but then they bed down on the edge of the field.

Junior also showed me some of his 13 beehives, which he moves around to pollinate his melons, cantaloupe and cucumbers. I asked Junior if he used insecticides to control major insect pests such as whiteflies, thrips and especially aphids, which transmit disease (like watermelon mosaic virus). He admitted, a bit reluctantly, that he did use insecticides. I asked how he managed that without killing his bees. Junior replied that he looks for insecticide labelled as bee-friendly. In truth, insecticides are never good for bees, but some are less toxic than others.

Junior’s extension agent, Jermaine Wilson, said that Junior belongs to a farmers’ group, but that the farmers had already observed on their own that toads and frogs are beneficial creatures. Farmers see them eating insects. Beneficial amphibians are an example of how valuable local knowledge often develops around a topic that is culturally important (like watermelon pests) and easy to observe (like toads eating bugs). I found it encouraging that Junior appreciated the frogs and toads, even though they tend to eat larger insects rather than the really small ones that are the main pests in Jamaican watermelon.

I admired the efficient system the Jamaicans have for producing watermelon, even though they still largely rely on insecticides, with little organic production. But the Jamaican farmers are moving in the right direction by encouraging frogs and toads, and beekeeping will certainly motivate them to further reduce insecticides. Watermelons are a fairly sustainable, commercial crop from family farms. The bees pollinate the melon flowers, and the fruit grows nestled in a bed of mulch, precision-watered with drip irrigation. It’s a nice blend of appropriate technology and local knowledge, with frogs and toads contributing along the way.

Acknowledgements

RADA (Rural Agricultural Development Authority) graciously hosted my visit to Saint Elizabeth Parish, Jamaica, as part of the 10th Annual Meeting of GFRAS (Global Forum for Rural Advisory Services).

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Two heads film better than one September 15th, 2019 by

Vea la versión en español a continuación.

I used to think that committees and group work killed creativity, but teamwork can help individuals produce things – like a cool video – that they couldn’t do by themselves.

Late last year, I was part of a team making a video in the southern Altiplano of Bolivia, along with Paul (the director), Marcella (the cameraperson) and Milton Villca. Milton is an agronomist who grew up in a village on the windswept plains where we were filming. He still lives in the area, helping local farmers to cope with challenges, especially the immense loss of soil caused by wind erosion.

After watching Marcella film for two days, Milton confided that he had tried making his own video, about a wasp that attacks and helps to control some of the caterpillar pests of the quinoa crop. But like the farmers, Milton had also struggled with the wind, losing two cameras because of damage by the fine sand. He’d continued filming the wasps with his cell phone, but he told Marcella he wasn’t sure about the quality of the images. Would she mind taking a look at them?

Marcella was happy to watch Milton’s video clips. All was fine. There were fabulous close ups of a wasp that digs a tunnel in the earth, hides it with grains of sand, finds a big, fat caterpillar, paralyzes it, and drags it back to the burrow, which the wasp is miraculously able to find, with the precision of a GPS. The video clips showed how the wasp uncovers the nest, inserts the unfortunate caterpillar, and lays an egg on it. A wasp grub hatches from the egg, eats the caterpillar and eventually emerges in the summer as an adult wasp.

Paul was immediately taken by the story of the wasp, which locals call nina nina. In our interviews with farmers for a video on windbreaks he decided to also ask them what they knew about the wasp. Unlike many parasitic wasps, which are too small to see clearly with the naked eye, the nina nina is pretty big, and local people know about it and can describe its ecology.

Asking a professional cameraperson to critique your videos can be daunting, but Milton no doubt sensed that Marcella would give him sympathetic and positive criticism. His risk paid off. We collaborated with Milton to write a script for his video. Marcella edited his clips and combined them into a short video, which we are proud to release this week.

Watch the video

The wasp that protects our crops

Related video

Living windbreaks to protect the soil

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Acknowledgements

Milton Villca works for the Proinpa Foundation. Our work was generously supported by the CCRP (Collaborative Crop Research Program) of the McKnight Foundation.

DOS CABEZAS FILMAN MEJOR QUE UNA

Por Jeff Bentley, 15 de septiembre del 2019

Yo solĂ­a pensar que los comitĂ©s y el trabajo en grupo mataban la creatividad, pero el trabajo en equipo puede ayudar a los individuos a producir cosas – como un video genial – que no podrĂ­an hacerse por sĂ­ mismos.

A finales del año pasado, formé parte de un equipo que hacía un video en el Altiplano sur de Bolivia, junto con Paul (el director), Marcella (la camarógrafa) y Milton Villca. Milton es un técnico agrónomo de un pueblo del altiplánico ventoso donde filmábamos. Él todavía vive en la zona, ayudando a los agricultores locales a manejar sus desafíos, especialmente a la inmensa pérdida de suelo causada por la erosión del viento.

Después de ver a Marcella filmar durante dos días, Milton confió que él había intentado hacer su propio video, sobre una avispa que ataca y ayuda a controlar algunos de los gusanos plagas del cultivo de la quinua. Pero al igual que los agricultores, Milton también había luchado contra el viento, perdiendo dos cámaras debido a los daños causados por la arena fina. Había seguido filmando las avispas con su celular, pero le dijo a Marcella que no estaba seguro de la calidad de las imágenes. ¿Ella estaría dispuesta a verlas?

A Marcella le encantaron los videos de Milton. Hubo excelentes primeros planos de una avispa que excava un tĂşnel en la tierra, lo esconde con granos de arena, encuentra una oruga grande y gorda, la paraliza y la arrastra hasta el tĂşnel del nido, que la avispa milagrosamente logra encontrar, como si tuviera un GPS. Los videos muestran cĂłmo la avispa descubre el nido, inserta al desafortunado gusano y pone un huevo en Ă©l. Luego, la crĂ­a de la avispa sale del huevo, se come al gusano y eventualmente emerge como una avispa adulta en el verano.

A Paul le cautivó inmediatamente la historia de la avispa, a la que la gente local llama nina nina. En nuestras entrevistas con los agricultores para un video sobre las barreras vivas, decidió también preguntarles lo que sabían sobre las avispas. A diferencia de muchas avispas parásitas, que son demasiado pequeñas para ver claramente a simple vista, la nina nina es bastante grande, y la gente local sabe de ella y puede describir su ecología.

Pedirle a un camarĂłgrafo profesional que critique sus videos puede ser desalentador, pero Milton sin duda sintiĂł que Marcella le darĂ­a una crĂ­tica positiva, con empatĂ­a. Su riesgo valiĂł la pena. Colaboramos con Milton para escribir un guion para su vĂ­deo. Marcella editĂł sus clips y los combinĂł en un video corto, que estamos orgullosos de lanzar esta semana.

Ver el video

La avispa que protege nuestros cultivos

VĂ­deo relacionado

Barreras vivas para proteger el suelo

Historias de blogs relacionadas

RecuperaciĂłn lenta

Despertando las semillas

Organic agriculture and mice

Agradecimientos

Milton Villca trabaja para la FundaciĂłn Proinpa. Nuestro trabajo fue generosamente apoyado por el CCRP (Programa Colaborativo de InvestigaciĂłn sobre Cultivos) de la FundaciĂłn McKnight.

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