Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Picky Pollinators - Native Bees are Selective about Where They Live and Feed

22.06.2011
Native bees – often small, stingless, solitary and unnoticed in the flashier world of stinging honeybees – are quite discriminating about where they live, according to U.S. Geological Survey research.

The study found that, overall, composition of a plant community is a weak predictor of the composition of a bee community, which may seem counterintuitive at first, said USGS scientist and study lead Ralph Grundel. This may be because specialized plant-bee interactions, in which a given bee species only pollinates one plant species and that plant species is only pollinated by that bee species are not common. More common is for a plant species to be pollinated by many pollinator species and each pollinator species pollinating many species of plants.

Given this complex network of interaction between plants and their pollinators, it is not surprising that knowing which plants occur in an area does not necessarily allow us to predict which bees will occur in that area, Grundel said.

Unraveling such mysteries surrounding how native bees inhabit and use different habitats is especially essential now -- the National Academy of Sciences has reported that not only is there direct evidence for decline of some pollinator species in North America, but also very little is known about the status and health of most of the world's wild pollinators. Yet without them, the ability of agricultural crops and wild plants to produce food products and seeds is jeopardized.

"The issues facing honeybees introduced pollinators whose populations are spiraling downward, means that it is even more vital to understand the role of native bees as pollinators and how they divide up and use a landscape," said Grundel.

Many studies have been conducted to determine how a variety of animals – birds, mammals, and reptiles, for example – use their native landscapes, but few such studies have been undertaken for native bees. “That’s why this type of study is fundamental for enhancing our understanding of native bee distribution,” Grundel said. “Our research findings clearly reveal that maintenance of a diverse and abundant bee community requires that managers consider a suite of local and landscape characteristics and management actions.”

Grundel and his colleagues wanted to find out if the kinds of plants that live in different habitats can predict what kinds of bees will be there or if other factors – such as soil type, tree density or even fire -- are more important. To do this, the team surveyed landscapes and collected and identified nearly 5,000 native bees representing at least 175 species in five kinds of habitats at Indiana Dunes National Lakeshore and nearby natural areas around northwestern Indiana. These habitats ranged from dense forests to open fields.

"We had suspected that the closer our collecting sites were to each other the more similar the bees communities we found would be – but we were wrong," Grundel said. "In fact, mere physical proximity wasn't a very good predictor of how similar bee communities at different sites would be to each other. Instead, local factors – and even the micro-habitats that we often ignore – are really important in determining what kinds of bees use an area."

Because many native bees are ground- and cavity-nesters, the scientists weren’t surprised to find that an abundant supply of dead wood, such as woody debris and dead tree limbs, was essential in determining what kinds of bees lived where. They were surprised, however, at how important other factors were, including bee preferences for specific soil characteristics and for areas that had burned in the previous two years.

Bee abundance – how many bees were captured at a site – was lower in areas with a dense tree canopy and higher if a fire had occurred recently in the area. Bee diversity – the number of different kinds of bees – was higher in areas with less tree canopy, but with a higher diversity of flowering plants and an abundance of nesting resources, such as woody debris.

The presence of suitable nesting material was at least as important in determining how many types of bees might use a site as was diversity of plants, which provide nectar and pollen to the bees. The composition of an entire bee community was linked to higher plant variety, less canopy cover and soil characteristics that may be best-suited for nesting.

The study found that specialist bees – those picky native bees that gather pollen from only a few kinds of plants – were more likely to live in open areas than areas with a higher density of trees.

"Specialist bees, not surprisingly, were also more associated with the presence of native plants in the areas, but a lot of these native plants were more likely to occur in disturbed areas, including areas that had recently been burned and, somewhat to our surprise, residential areas where soil disturbance is commonplace," Grundel said.

However, specialist bees were often rarer and mainly used open habitats, such as grasslands and savannas. According to a 2005 study, said Grundel, such open Midwest habitats are today perhaps the most poorly conserved habitats on the planet, causing concern about long-term conservation of such bee species.

"At several locations around the world, specialist bumblebees living in plant rich areas, such as these open habitats, have declined significantly," Grundel said. "Similar bumblebee declines have been documented in the Midwest U.S. Documenting how diet breadth, rarity and habitat use are related is important for understanding such patterns of decline and was one of the main objectives of our study. We collected six bumblebee species in our study while a 1930s study in this area collected twelve species. Four of the species we did not find in our study have been identified as bumblebees of special concern due to their disappearance from sites across the Midwest."

USGS researchers in Indiana and Maryland are following up on this research with a recently initiated study examining how native bee populations across the national park system might be affected by climatic variation.

The paper, Floral and nesting resources, habitat structure, and fire influence bee distribution across an open-forest gradient, was published in Ecological Applications and may be read online. Primary authors are Ralph Grundel, USGS; Robert Jean, Indiana State University; and Krystalynn Frohnapple and Noel Pavlovic, USGS.

Ralph Grundel | EurekAlert!
Further information:
http://www.usgs.gov

More articles from Ecology, The Environment and Conservation:

nachricht 5000 tons of plastic released into the environment every year
12.07.2019 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Climate impact of clouds made from airplane contrails may triple by 2050
27.06.2019 | European Geosciences Union

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-ever visualizations of electrical gating effects on electronic structure

Scientists have visualised the electronic structure in a microelectronic device for the first time, opening up opportunities for finely-tuned high performance electronic devices.

Physicists from the University of Warwick and the University of Washington have developed a technique to measure the energy and momentum of electrons in...

Im Focus: Megakaryocytes act as „bouncers“ restraining cell migration in the bone marrow

Scientists at the University Würzburg and University Hospital of Würzburg found that megakaryocytes act as “bouncers” and thus modulate bone marrow niche properties and cell migration dynamics. The study was published in July in the Journal “Haematologica”.

Hematopoiesis is the process of forming blood cells, which occurs predominantly in the bone marrow. The bone marrow produces all types of blood cells: red...

Im Focus: Artificial neural network resolves puzzles from condensed matter physics: Which is the perfect quantum theory?

For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.

Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...

Im Focus: Extremely hard yet metallically conductive: Bayreuth researchers develop novel material with high-tech prospects

An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".

The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...

Im Focus: Modelling leads to the optimum size for platinum fuel cell catalysts: Activity of fuel cell catalysts doubled

An interdisciplinary research team at the Technical University of Munich (TUM) has built platinum nanoparticles for catalysis in fuel cells: The new size-optimized catalysts are twice as good as the best process commercially available today.

Fuel cells may well replace batteries as the power source for electric cars. They consume hydrogen, a gas which could be produced for example using surplus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

Genetic differences between strains of Epstein-Barr virus can alter its activity

18.07.2019 | Health and Medicine

Algae-killing viruses spur nutrient recycling in oceans

18.07.2019 | Life Sciences

Machine learning platform guides pancreatic cyst management in patients

18.07.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>