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SCIENCE&RESEARCH DISCOVERIES


Pesticide effects on bumblebee brood


The brains of baby bumblebees develop abnormally when exposed to pesticides during the larval stage, say researchers at Imperial College London.


Previous studies have focused on adult bees, but this new study has shown that pesticides on food brought into the colony can have effects throughout the superorganism and affect its performance weeks aſter the exposure to pesticides.


The researchers scanned the brains of 100 bumblebees using micro-CT scanning techniques and showed that parts of the young bees’ brains grew less – an effect that was permanent and irreversible – resulting in poorer performance in simple learning tasks. The scans showed that the mushroom body in the brain, known to be involved in learning ability in insects, was smaller in bumblebees that were exposed to pesticides.


Ref: doi.org/10.1098/rspb.2019.2442 Prairie bee dances


Reconstructed or restored North American prairies can offer honey bees useful forage late in the season if particular prairie flowers are planted – and there are ways to avoid competition with native pollinators.


Keen to restore or reconstruct American prairie lands, which now occupy 2% of their original area, landowners and organisations in the Upper Midwest region of the USA have wondered if restored prairies could significantly improve honey bee nutrition.


By decoding 1528 waggle dances of bees near reconstructed prairies and identifying the pollen coming into the hives using microscopy and DNA barcoding, researchers at the University of Minnesota have discovered that most dances advertised flower patches outside the reconstructed prairies. However, there was most interest in prairie forage in late summer and autumn at one site.


Seven native prairie plant groups seemed popular. The researchers think that including certain native prairie flowers in reconstructed prairies may help honey bee colonies use those prairies as major food sources at important times in colony development. If competition with native pollinators is a concern, honey bee- friendly plants can be limited and colony numbers restricted.


Ref: doi.org/10.1371/journal.pone.0228169 How Amitraz affects honey bees


Although studies have shown that amitraz, an insecticide and miticide used in some anti-varroa treatments, affects learning, memory, behaviour, immunity and various other physiological processes, few studies have explored the molecular mechanisms underlying the action of amitraz on honey bees.


Using genes and genomes pathway analyses of the midgut, Chinese researchers have shown that that amitraz treatment affects the relaxin signalling pathway, platelet activation, and protein digestion and absorption.


Ref: doi.org/10.1371/journal.pone.0228933 Bee Craſt April 2020 Never-ending insect spoting


Despite more than 250 years of taxonomic research, no one knows the size and composition of the flora and fauna of Earth. Using three different methods, Swedish researchers estimate that in Sweden, home of Linnaeus and one of the most-studied countries, there are approximately 33,000 species of fauna. Of those, 8,600 were unknown at the start of the inventory and 5,000 (15%) still await discovery. Most of the new species belong to Hymenoptera and Diptera groups that are decomposers or parasitoids.


Ref: doi.org/10.1371/journal.pone.0228561 35 Some species don’t like it hot


The number of unusually hot days – a result of climate change – is decreasing species richness in many regions of Europe and North America, say researchers at University College London and the University of Otawa, Canada. Using long-term data for 66 bumblebee species, they found that more hoter days predicts species’ local extinction risk, the chances of colonising a new area, and changes in species richness – all irrespective of changes in land use.


Ref: doi.org/10.1126/science.aax8591 Bee-brained is quite a compliment


New Zealand scientists have found oscillations in bee brains that are similar to those found in humans. Discovered in humans in 1929, alpha oscillations are among the most widely studied brain signals and are related to atention, memory and consciousness. But how they work has yet to be demonstrated.


Since honey bees are much easier to study, the researchers have been focusing on honey bee foragers. In the laboratory, the bees were stimulated with odours as microscopic electrodes recording their brain activity. They found 18Hz oscillations, similar to those in humans (around 10Hz) and alpha/beta oscillations in non-human primates (10–20Hz). The oscillations occurred spontaneously but decreased in power during sensory stimulation. The researchers think that in bees the oscillations regulate information transmission between brain regions.


Ref: doi.org/10.1098/rspb.2020.0115 Modern bee evidence from 100


million years ago The oldest evidence of modern bees has been found in Argentina. The 100-million-year-old nests found in Patagonia have tunnels and alcoves where larvae can grow. The only living insects that build nests like these come from the highly diverse bee family, Halictidae, also known as sweat bees.


The fossil find is especially important because it helps confirm that bees and some of the first flowering plants diversified in tandem around 110 to 120 million years ago, during the Early Cretaceous period.


Ref: doi.org/10.1371/journal.pone.0227789


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