To see a World in a Grain of Sand And a Heaven in a Wild Flower, Hold Infinity in the palm of your hand And Eternity in an hour. William Blake (1757-1827)
viernes, 29 de diciembre de 2017
miércoles, 27 de diciembre de 2017
martes, 26 de diciembre de 2017
sábado, 23 de diciembre de 2017
viernes, 22 de diciembre de 2017
miércoles, 20 de diciembre de 2017
.
Domestication of tomato has reduced the attraction of herbivore natural enemies to pest-damaged plants
Xiaohong Li, Michael Garvey, Ian Kaplan, Baoping Li, Juli Carrillo
- Plant domestication can alter species interactions and influence novel associations among crops and insects. We performed a series of preference and performance experiments to test predator and herbivore attraction to domesticated and wild plants and to evaluate the efficacy of herbivore-induced plant volatiles (HIPVs) across a domestication gradient in tomato, including wild relatives, landraces and domesticated commercial cultivars.
- We employed a tri-trophic system consisting of the specialist lepidopteran herbivore Manduca sexta and two of its natural enemies: an egg predator, the stilt bug Jalysus wickhami, and a larval parasitoid, the wasp Cotesia congregata.
- In olfactometer trials, natural enemies consistently preferred HIPVs of wild tomatoes over domesticated cultivars, with landraces in between. Plant-domestication effects were also apparent in terms of decision speed: predators were slower to orient towards damaged crops than to damaged wild relatives.
- By contrast, M. sexta moths were more likely to oviposit on domesticated than on wild or landrace tomatoes, indicating that insect responses to plant odours vary with trophic level. Field trials confirmed olfactory preference tests: caterpillars recovered from wild tomato relatives were more likely to be parasitized than those recovered from landraces or domesticated tomatoes.
- The results of the present study suggest that tomato domestication has reduced the efficacy of HIPVs in attracting predators compared with wild relatives and also that this decreased attraction leads to lower attack rates by enemies in the field. This outcome has implications for understanding the specificity of tri-trophic plant defences and the compatibility of natural enemies for biocontrol in agro-ecosystems.
.
martes, 19 de diciembre de 2017
In these days it may be good to remember some historical facts about
ideologies and science.
Lysenkoism (1920s -1960s) was an ideology-based approach to
agriculture in the USSR, supported by Stalin (and developed by Trofim Lysenko) that
assumed the heritability of acquired characteristics (explicitly denying Mendelian
genetics). Because of it, many
scientists were sent to prison (e.g., Nikolai Vavilov) or executed. Finally, it
produced declined yields and famine.
Not a good idea to denied fact-base science.
.domingo, 17 de diciembre de 2017
sábado, 16 de diciembre de 2017
jueves, 14 de diciembre de 2017
martes, 12 de diciembre de 2017
sábado, 9 de diciembre de 2017
.
In the very earliest time
When both people and animals lived on earth
A person could become an animal if he wanted to
and an animal could become a human being.
Sometimes they were people
and sometimes animals
and there was no difference.
All spoke the same language
That was the time when words were like magic.
The human mind had mysterious powers.
A word spoken by chance might have strange consequences.
It would suddenly come alive
and what people wanted to happen could happen--
all you had to do was say it.
Nobody could explain this:
That's the way it was.
-- Nalungiaq, Inuit woman interviewed by ethnologist Knud Rasmussen in the early twentieth century.
When both people and animals lived on earth
A person could become an animal if he wanted to
and an animal could become a human being.
Sometimes they were people
and sometimes animals
and there was no difference.
All spoke the same language
That was the time when words were like magic.
The human mind had mysterious powers.
A word spoken by chance might have strange consequences.
It would suddenly come alive
and what people wanted to happen could happen--
all you had to do was say it.
Nobody could explain this:
That's the way it was.
-- Nalungiaq, Inuit woman interviewed by ethnologist Knud Rasmussen in the early twentieth century.
"...A few years ago, I was entering a restaurant very near my home and
noticed a sign in front that said "Native Grass Garden-Do Not Disturb."
My first response, naturally, was to trample over to the sign to see
what the fuss was about. I knelt down and admired the soft, variegated
green foliage, the tiny pointed leaves and small yellow and orange
flowers. Suddenly it occurred to me that these were exactly the same
plants that I had been mowing down on my John Deere sit-down mower the
day before...but I had been thinking of them as "weeds"! This was a
lesson in the power of labels, of the trances induced by the word-worlds
that are enacted every time someone categorizes in speech or thought.
Is this a question of "mere semantics" as some might argue? The
plants remained "the same" regardless of any label I might apply in this
view. But the effect in the real world was as tangible as in
Nalungiaq's story where what people said came to be. Having labeled the
plants in my yard "weeds," I mowed them down. The "native grasses" at
the neighboring restaurant remained untouched because a
conservation-minded gardener had, by contrast, elevated them to a place
of respect with his label.
Among indigenous peoples, the concept of "weed" does not exist. Every
plant has a purpose or it would not be here. The entire field of
ethnobotany consists of attempts to articulate in western terms the web
of life as it is perceived through native eyes and the categories of
native languages. Comparative ethnobotany reminds us that the Linnaean
system of categorization is but one of an infinite number of possible
taxonomies available to humankind. The categories we use in our everyday
speech and thinking, like the formal categories of Linnaeaus for
plants, are inherited as part of socialization and constitute in large
measure a collective sense of "reality." In the view being advanced
here, language always mediates experience in some measure. Yet the path
of least resistance is to accept the habitual categories in lieu of the
complexities of experience. Language creates reality rather than
merely describes it as the First Peoples still remember..."
https://www.globalonenessproject.org/library/articles/lessons-old-language
.
miércoles, 6 de diciembre de 2017
DNA metabarcoding data unveils invisible pollination networks
André Pornon, Christophe Andalo, Monique Burrus & Nathalie Escaravage
Animal pollination, essential for both ecological services and ecosystem functioning, is threatened by ongoing global changes. New methodologies to decipher their effects on pollinator composition to ecosystem health are urgently required. We compare the main structural parameters of pollination networks based on DNA metabarcoding data with networks based on direct observations of insect visits to plants at three resolution levels. By detecting numerous additional hidden interactions, metabarcoding data largely alters the properties of the pollination networks compared to visit surveys. Molecular data shows that pollinators are much more generalist than expected from visit surveys. However, pollinator species were composed of relatively specialized individuals and formed functional groups highly specialized upon floral morphs. We discuss pros and cons of metabarcoding data relative to data obtained from traditional methods and their potential contribution to both current and future research. This molecular method seems a very promising avenue to address many outstanding scientific issues at a resolution level which remains unattained to date; especially for those studies requiring pollinator and plant community investigations over macro-ecological scales.
Bipartite pollination networks built from visit surveys (Nobs, right panels) and metabarcoding (Nseq, left panels) data. (a,b) Plant-pollinator groups; (c,d) plant-pollinator species; (e,f) individual pollinator-plant species (Empis leptempis pandellei as an example of pollinator species). Line thickness highlights the proportion of interactions. Apis: Apis mellifera; Bomb.: Bombus sp.;
W.bee: wild bees; O.Hym.: other Hymenoptera; O.Dipt.: Other Diptera;
Emp.: Empididae; Syrph.: Syrphidae; Col.: Coleoptera; Lep.: Lepidoptera;
Musc.: Muscidae.
.
martes, 5 de diciembre de 2017
sábado, 2 de diciembre de 2017
Spatial diversification of agroecosystems to enhance biological control and other regulating services: An agroecological perspective.
Hatt S, Boeraeve F, Artru S, Dufrêne M, Francis F.
Hatt S, Boeraeve F, Artru S, Dufrêne M, Francis F.
Spatial
diversification of crop and non-crop habitats in farming systems is
promising for enhancing natural regulation of insect pests.
Nevertheless, results from recent syntheses show variable effects. One
explanation is that the abundance and diversity of pests and natural
enemies are affected by the composition, design and management of crop
and non-crop habitats. Moreover, interactions between both local and
landscape elements and practices carried out at different spatial scales
may affect the regulation of insect pests. Hence, research is being
conducted to understand these interdependencies. However, insects are
not the only pests and pests are not the only elements to regulate in
agroecosystems. Broadening the scope could allow addressing multiple
issues simultaneously, but also solving them together by enhancing
synergies. Indeed, spatial diversification of crop and non-crop habitats
can allow addressing the issues of weeds and pathogens, along with
being beneficial to several other regulating services like pollination,
soil conservation and nutrient cycling. Although calls rise to develop
multifunctional landscapes that optimize the delivery of multiple
ecosystem services, it still represents a scientific challenge today.
Enhancing interdisciplinarity in research institutions and building
interrelations between scientists and stakeholders may help reach this
goal. Despite obstacles, positive results from research based on such
innovative approaches are encouraging for engaging science in this path.
Hence, the aim of the present paper is to offer an update on these
issues by exploring the most recent findings and discussing these
results to highlight needs for future research.