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LinkedInPosts Tagged: pollinaTION
Flower Visitation Technique
An Australian Curtin University study has revealed a new method of capturing DNA could provide farmers with a valuable tool for boosting crop production — while also benefiting the environment.
Researchers from the School of Molecular and Life Sciences used an emerging scientific method known as ‘eDNA metabarcoding', to track which insects interacted with avocado flowers at two orchards in Western Australia.
Led by Dr Joshua Kestel and Associate Professor Paul Nevill, the team took bunches of flowers from avocado trees, which were then frozen and ground up before being taken through the DNA extraction process.
“We use eDNA metabarcoding to effectively amplify the DNA from whatever interacts with that flower and that lets us work out who was there,” Dr Kestel said.
“We are literally able to detect the footprints of a bee.”
eDNA metabarcoding was found to detect five times the number of unique pest species than filming plants with digital cameras, which is another cutting-edge method currently used.
“Digital video recording is advanced, but eDNA metabarcoding is Star Trek level – we are talking about a different universe,” he said.
Dr Kestel said eDNA metabarcoding could help improve yields and make agricultural operations more efficient.
Many farmers hire honeybee hives at significant expense to encourage pollination and grow more fruit, however Dr Kestel said native pollinators aren't currently part of the bigger picture and their role remains unknown for many types of trees and crops.
“Honeybees aren't big fans of avocado pollen and nectar: an avocado tree has about a million flowers, but less than 200 will be pollenated and mature into fruit,” Dr Kestel said.
“Using eDNA metabarcoding allows us to detect pollinators, pests, and — quite conveniently — predator species which can help protect crops by eating these pests.”
Dr Kestel said there was immense benefit to knowing which pests were occurring in a crop or orchard and where on the trees they were.
He said it would give farmers the option to introduce natural predators or, if they were to use pesticides, to use them more efficiently and in a more targeted way.
“At the moment we manage these pests with very generalised methods, which comes at a huge cost as the pesticides kill the wild pollinators and the natural predators, not just the pests you want to be rid of.
Dr Kestel said while the application of eDNA metabarcoding was still in its infancy, it could have a large impact.
“While it's not yet widely adopted, there's growing interest in this technology because there's a recognition of how powerful it is.”
‘Spatio-temporal variation in arthropod-plant interactions: A direct comparison of eDNA metabarcoding of tree crop flowers and digital video recordings' was published in Ecological Indicators. https://www.sciencedirect.com/science/article/pii/S1470160X24012846?via%3Dihub
flower visits
What Happened to Avocado Fruit Set this Year?
Avocado fruit set is lousy up and down the coast this year. The trees were flowering in many places from January to June. They kept trying to set fruit, but nada. According to Daniel Swain at UCLA Weather West, this was the coldest winter on record without freeze and a long drizzly spring with little sun - cool days and night time temperatures. Cold day time temps mean poor pollinator activity. Honeybees just weren't working much. Then if pollen is transferred to the female stage flower, it takes 48 hours of above 50 deg F for fertilization - the deposition of pollen on the stigma and growth of the pollen tube down the style to the ovule. If the temp at night drops below 50, the process stops and the ovule never gets fertilized. So it doesn't matter if day time is warm and the pollinators are working, if it gets cold at night, the fertilization process stops.
So that's exactly what happened. Cool days for poor pollination and then cold nights for fertilization. It didn't matter how hard the tree flowered, it just wasn't the right weather. It didn't matter if you sprayed gibberellic acid. The weather was just not right for fruit set this tear.
And this should set off alternate bearing for next year if we have the right weather conditions. So you might think seriously about pruning because there could be a branch breaking crop set next spring – if the weather is right.
Interestingly,just as an observation it looks like GEM and Lamb Hass right next to Hass did set fruit just at the end of the flowering period. So there is some difference in varieties to weather conditions.
Image from American Museum of Natural History
The cool/moist weather has also created conditions for anthracnose and alternaria in fruit which causes problems for the consumer, but also caused early fruit drop and color change in the fruit on the tree. The trees just can't hold on to the fruit as one normally expects. It's a tough year for avocado growers. In the Central Valley all the stone fruit is late by almost a month. Apricots and cherries are just coming in season when they should have been available in late May.
Weird and Maybe we are going to have to get used to it.
Read more about the Basics of flowering
pollination - movement of male pollen to female stigma
fertilization - growth of pollen tube down to stimulate ovule
Bee Probiotics?
Microbes multiply in heat,
Changing nectar,
Upsetting bees
Bumblebees pollinate many of our favorite foods, but their own diet is being upset by climate change, according to a new UC Riverside study.
served as taste tester for this experiment.
Bombus impatiens, aka the common eastern bumblebee, served as taste tester for this experiment.
There's a sweet spot where floral nectar that bees eat has just the right balance of microbes like bacteria and yeast in it. Hotter weather can upset the balance, endangering the bees' health and potentially, our own.
A new study in the journal Microbial Ecology examines the effects of these nectar composition changes on an American bumblebee. Without bumblebees, who perform a type of pollination that honeybees do not, it would be difficult to mass produce food crops like tomatoes, blueberries, peppers, or potatoes.
“Micro changes in floral nectar may alter the way bees forage and look for food, affecting their health and in turn, potentially affecting human health, by reducing the availability of fresh foods,” said UCR entomologist and study lead Kaleigh Russell.
Bumblebees do enjoy nectar with some microbes in it, but too much of a good thing can deter them, Russell said.
With even a small increase in temperature, microbes' metabolism speeds up, causing them to reproduce more and eat up a higher percentage of the sugars in the nectar. “Less sugar means the nectar could be less palatable for our pollinators,” Russell said.
To test the bumblebees' taste preferences, Russell made nectar in a laboratory. Some was sterile and some contained microbes, and she grew both at a lower and a higher temperature.
The lower temperature, 80.6 degrees Fahrenheit, represents the average springtime high for Riverside in 2017. The higher temperature, 89.6 F, corresponds with what the predicted average temperature will be at the end of the century due to climate change.
Southern California, was collected for this
experimental taste test.
Nectar from wild mustard, abundant in Southern California, was collected for this experimental taste test.
A clear preference for some level of microbes was evident even when the nectar contained less sugar. However, the bees only went for this less sugary nectar containing a moderate amount of microbes at the cooler temperature. They did not prefer the nectar with too many microbes, as well as the nectar with no microbes at all.
It isn't yet clear why the bees have such specific preferences. Russell speculates that bacteria or yeast may help bees digest sugars in the nectar. Another theory is that the microbes produce secondary metabolites that aid in bee health.
What is clear is that it isn't likely that an increase in average temperatures will have a positive effect on bumblebees.
“We could see shifts in the locations of bee communities, since they leave when they can't find the food they like or need,” Russell said. “We might also see a decline in overall pollinator populations.”
For concerned readers with gardens, Russell recommends growing native plants that have not been treated with insecticide. “That's the best thing someone could do right now to help bumblebees,” she said.
bee avocado flower
Avocado Growers, Dont Overlook Flies
Rae Olsson rachel.olsson@wsu.edu 509-335-4846
PULLMAN, Wash. - A tiny bee imposter, the syrphid fly, may be a big help to some gardens and farms, new research from Washington State University shows.
An observational study in Western Washington found that out of more than 2,400 pollinator visits to flowers at urban and rural farms about 35% of were made by flies--most of which were the black-and-yellow-striped syrphid flies, also called hover flies. For a few plants, including peas, kale and lilies, flies were the only pollinators observed. Overall, bees were still the most common, accounting for about 61% of floral visits, but the rest were made by other insects and spiders.
"We found that there really were a dramatic number of pollinators visiting flowers that were not bees," said Rae Olsson, a WSU post-doctoral fellow and lead author of the study published in Food Webs. "The majority of the non-bee pollinators were flies, and most of those were syrphid flies which is a group that commonly mimics bees."
Syrphid flies' bee-like colors probably help them avoid predators who are afraid of getting stung, but they are true flies with two wings as opposed to bees which have four. The flies might have additional benefits for plants, Olsson added, since as juveniles they eat pests like aphids. As adults, they consume nectar and visit flowers so have the potential to move pollen the same way that bees do, though it is less intentional than bees who collect pollen to feed their young.
For the study, the researchers surveyed plants and pollinating insects and spiders on 19 rural farms and 17 urban farms and gardens along the Interstate 5 corridor in Western Washington. They conducted surveys six separate times over two years. In addition to the visits by bees and syrphid flies, they also catalogued more rare visits by other arthropods including wasps, lacewings, spiders, butterflies, dragonflies, beetles and ants--all with visits of less than 4%.
Olsson first noticed the many different non-bee pollinators while working on a bee-survey project led by Elias Bloom, a recent WSU doctoral graduate. The results of this study underscore the need for researchers as well as gardeners and farmers to pay more attention to alternative pollinators, Olsson said, and hoped that similar studies would be conducted in other regions of the country.
"Bee populations are declining, and we are trying to help them, but there's room at the table for all the pollinators," Olsson said. "There are a lot of conservation and monitoring efforts for bees, but that doesn't extend to some of the other pollinators. I think people will be surprised to find that there are a lot more different types of pollinating insects - all we really need to do is to start paying a little more attention to them."
The study also noted pollinator differences between rural and urban spaces. Observations sites in urban areas showed a greater diversity of pollinators corresponding with the wider range of plants grown in city gardens and smaller-sized farms. Rural farms with their larger fields of plants had a greater abundance.
For every grower, urban or rural, who is interested in increasing the number and diversity of pollinators visiting their fields or gardens, Olsson recommended increasing the variety of flowering plants.
Making sure that something is flowering all throughout the season, even if on the edge of a field, will support the biodiversity of pollinators because their different life stages happen at different times of the year.
"Some pollinators like certain butterflies and moths are only present in a pollinating form for a small period of time," Olsson said. "They may only live for a few days as adults, so when they emerge and are ready to pollinate, it's good to make sure that you have something for them to eat."
Read On: https://news.wsu.edu/2021/06/22/bee-impersonating-flies-show-pollinator-potential/
Photo: Not a bee, a hover fly or syrphid fly
syrphid adult
Avocado Pollinators Are Not Just Honeybees
A recent publication points out the need for identifying and improving habitat for avocado pollinators.
The role of insect pollinators in avocado production: A global review
Keira Dymond, Juan L. Celis-Diez, Simon G. Potts, Brad G. Howlett, Bryony K. Willcox, Michael P. D. Garratt
Insect pollination increases the yield and quality of many crops and therefore, understanding the role of insect pollinators in crop production is necessary to sustainably increase yields. Avocado Persea americana benefits from insect pollination, however, a better understanding of the role of pollinators and their contribution to the production of this globally important crop is needed. In this study, we carried out a systematic literature review and meta-analysis of studies investigating the pollination ecology of avocado to answer the following questions: (a) Are there any research gaps in terms of geographic location or scientific focus? (b) What is the effect of insect pollinators on avocado pollination and production? (c) Which pollinators are the most abundant and effective and how does this vary across location? (d) How can insect pollination be improved for higher yields? (e) What are the current evidence gaps and what should be the focus of future research? Research from many regions of the globe has been published, however, results showed that there is limited information from key avocado producing countries such as Mexico and the Dominican Republic. In most studies, insects were shown to contribute greatly to pollination, fruit set and yield. Honeybees Apis mellifera were important pollinators in many regions due to their efficiency and high abundance, however, many wild pollinators also visited avocado flowers and were the most frequent visitors in over 50% of studies. This study also highlighted the effectiveness of stingless bees (Meliponini) and blow flies (Calliphoridae) as avocado pollinators although, for the majority of flower visitors, there is a lack of data on pollinator efficiency. For optimal yields, growers should ensure a sufficient abundance of pollinators in their orchards either through increasing honeybee hive density or, for a more sustainable approach, by managing wild pollinators through practices that protect or promote natural habitat.
Read the full article: https://onlinelibrary.wiley.com/doi/full/10.1111/jen.12869
Hover fly visiting an avocado flower in the South-West of Western Australia (©2021 DPIRD)
