Many of the recent investigations into bees has focused on honeybees and bumblebees, with relatively little research on the problems facing solitary or communal bees.  A  female solitary bee must find a nest, collect pollen, then lay eggs and provide food for her offspring.  In contrast, communal bees share a common entrance to a nest where there are a number of females, but each female maintains her own area and offspring. There is no hierarchy within the communal nest, for example, no queen. It is known that the diet of bees has changed over the years.   In the past, the bees were able to forage and collect pollen and nectar from a wide variety of native plants.  However, the loss of ‘natural wild’ areas means that their diet is often dominated by a small number of plants, such brambles, clover and dandelions. Studies have indicated that some pollens have low levels or lack certain amino acids.  Bees need the same essential amino acids as us.  Without a supply of these particular amino acids  the development and growth of bees is impaired,  disease resistance is reduced the ability to raise the brood is compromised.   So, it is important to find ways to offer our pollinators a range of plants / pollen to provide all their essential nutrients.  An abundance but limited range of flowers (and hence pollen / nectar) will not necessarily meet the needs of the pollinators.  The changing floral landscape may be more challenging for the solitary and communal bees.  Much depends on how far they can forage and how flexible they are in terms of their food sources.  A species that can forage over a wide area and that can collect pollen from a number of different flowers might well survive in a nutritionally deficient area.  Solitary bees that only forage over short distances (when compared to honeybees) are likely to be challenged by the nutritional status of nearby flowers, and the changing agricultural / urban environment.  Poor nutrition could lead to rapid population declines in solitary species.  Bees that live in colonies and have a social organisation can share resources and possibly change their foraging efforts.  It is important that measures are found to support the diverssity of native plants both in rural and urban locations if populations of the various pollinators are to be maintained. Further information on solitary bees and the changing climate can be found here.

Mason bees and agrochemicals The blog has reported many times on the threats to bees - money bees, bumblebees and ‘wild bees, such as mason bees / solitary bees.  The threat to bees from neonicotinoids has been well documented, now there is a report that suggests that certain other agrochemicals may be harmful to bees. Researchers at the Julius Maximilians University at Würburg have been investigation the effect of a fungicide (Fenbuconazole) on the reproductive behaviour of horned mason bees (Osmia cornuta).  A number of Osmia species are used to improve pollination in fruit and nut crops.    They are efficient pollinators having a special pollen collecting / carrying structure called a scopa.  Mason bees are solitary bees.  Each female is fertile and makes her own nest and no worker bees for these species exist. In the Spring, male and female bees emerge from a nest.  The males generally exit first and remain near the nest, ready to mate with the females.  A female bee selects a mate on their ‘smell’ / odour and the ‘quality’ of their thoracic vibrations (achieved through muscle contractions).  After mating the males soon die.  The females search for and select a nest site, visiting flowers to collect pollen and nectar for their nests.  Once a certain amount of food has been collected within the nest, the females lay their eggs on top of this material (in a series of cells) and then seal off the nest.  The eggs hatch to form larvae which feed upon the food and within weeks forms a cocoon, in which it continues to develop to an adult. Though the fungicide (Fenbuconazole) is considered to be of low toxicity and the bees were exposed to a sub-lethal dose, nevertheless the Fenbuconazole had significant effects on the bees.  Pesticide exposed males were more likely to rejected by the females, compared to ‘control’ bees that were not exposed to the fungicide.  The thoracic vibrations of the exposed males were less powerful / noticeable and the composition of their odour or smell was different. The smell of the bees is dependent on particular hydrocarbon compounds in their cuticle  - their exoskeleton.  It is possible, therefore, that the mating behaviour and reproductive success of these bees is being affected by agrochemicals. Carpenter bees. The microbiome refers to the collection of micro-organisms that lives on or in us, particularly within within the gut. Whilst these micro-organisms are small, they contribute to our health and ‘well being’. They offer protection against pathogens, help our immune system develop, and enable us to digest.  Just as we have a microbiome so do bees.  Scientists as York University (Canada) have been investigating the microbiome of three species of carpenter bees (from North America, Asia and Australia). The term "carpenter bee" comes from their nesting behaviour,  most species burrow into plant material such as dead wood or stems, though a few create tunnels in soil.   Social bees (like honeybees and bumblebees) acquire their microbiome by interacting with their hive or nest ‘mates’. Solitary bees, like the carpenter bees, get their microbiome from the environment as they forage for food.   The researchers found that: The bees’ microbiome contained Lactobacilli, which are important for good gut health, helping protect against fungal pathogens and facilitating nutrient uptake. They also discovered crop pathogens in the microbiomes of the carpenter bees which were previously only found in honeybees. Whilst these pathogens are not necessarily harmful, it is possible that the wild bees could be vectors for spreading disease.  With thanks to Pixabay  (Umsiedlungen and Sabinem34) for the above images of bees Finding flowers. Research at the University of Exeter has shown that bees can distinguish between various flowers through a combination of colour and pattern.  This selectivity is achieved despite the ‘acuity’ of a bee’s vision being quite low (about a 100 times lower than ours) - this means they can only see the pattern of a flower when they are quite close (a matter of centimetres).  The researchers analysed a significant amount of data on plants and visiting bee behaviour, and they used experiments involving artificial shapes and colours.  One particular finding was the importance of the contrast between the outside of the flower and the plant’s foliage.  This seemed to help beesfind their way to the flowers quickly .    

This week saw the start of the 2018 Great British Bee Count.  The aim of the count is to estimate the number of bumblebees and solitary bees that are buzzing around this year.  As the woodlands blog has reported on many occasions, bees and bumblebees are threatened by viruses, mites, pesticides*, inclement weather, habitat loss etc - so a count across the country (from John O'Groats to Land's End) is a 'good thing' informing, for example, the Pollinator Monitoring Scheme how bees and bumblebees are faring across the country.  The information also contributes to the  National Biodiversity Network Atlas  (NBN), which records the current status of all species in the U.K. To help with this, there is a smart phone App - available for either iPhones or Android Phones.  The App enables you to submit sightings of bumblebees and bees (with photos where possible) Read more...

At this time of year, it is unusual to see bees flying around, but one that you might see is the ivy bee; the ivy bee is a ‘new bee’.  It was first described as a distinct species in 1993.  It was present in the Channel Isles,  back in the 1970's (where it is abundant) but was not recognised as a separate species.  In the U.K., it was first reported from Dorset (at Worth Matravers) in 2001.  It has since been found in a number of places along the South Coast – from Kent to Cornwall, and in Wiltshire, Somerset, Surrey and Essex.  It is spreading northwards, and reached the north Norfolk coast (in 2014) and Shropshire;  it has been suggested that the presence of the ivy bee here is another aspect of  climate change.    A map of the areas where this bee is likely to be seen can be found here. Read more...