The ants, bees and wasps of Canada, Alaska and Greenland – a checklist of 9250 species

Knowing what species live in which parts of the world is critical to many fields of study, such as conservation biology and environmental monitoring. This is also how we can identify present or potential invasive and non-native pest species. Furthermore, summarizing what species are known to inhabit a given area is essential for the discovery of new species that have not yet been known to science.

American Pelecinid Wasp (Pelecinus polyturator) from Driftwood Provincial Park, Ontario, Canada. Photo by Henri Goulet

For less well-studied groups and regions, distributional species checklists are often not  available. Therefore, a series of such checklists is being published in the open-access, peer-reviewed Journal of Hymenoptera Research, in order to address the issue for a group of organisms that, despite its size and diversity, is still poorly known: the insect order Hymenoptera, which includes ants, bees and wasps. The surveyed area spreads across northern North America, which comprises Canada, Alaska (U.S.) and Greenland (Denmark), and occupies about 9.3% of the world’s total land mass.

The last distributional survey of Hymenoptera in North America was published in 1979, where about 6000 described species were recorded from Canada and 600 from Alaska. The current survey lists 8933 species in Canada and 1513 in Alaska, marking an increase of 49% and 152%, respectively. A total of 9250 described species are recorded from northern North America. Considering that there are approximately 154,000 described species of Hymenoptera, northern North America has about 6% of the current world total. 

A cuckoo wasp of the genus Hedychridium from Manitoulin Island, Ontario, Canada. Photo by Henri Goulet

Highlights of the series will include updated distributions of over 900 species of bees, which will provide valuable insight into native pollinators at a time when honey bees are in decline. Nearly 230 species of ants and over 100 species of vespid wasps (hornets and yellow jackets) are recorded, including pest species such as the widespread pharaoh ant and the newly invasive Asian giant hornet in British Columbia.

Pigeon tremex (Tremex columba) from Manitou Lake, Manitoulin Island, Ontario, Canada. Photo by Henri Goulet

By far, the majority of species of Hymenoptera found in northern North America and the world are parasitoids, which develop on or in other invertebrate hosts and are therefore of great interest to the biological control of pests. Of the 9250 species recorded, more than three-quarters (over 7150 species) are parasitoids. These distributional lists provide essential baseline information required prior to undertaking studies to introduce biological control agents of invasive pests that may have escaped their native, natural enemies when they arrived in North America.

Megarhyssa macrura from Ottawa, Ontario, Canada. Photo by Henri Goulet

The topical collection “Checklists of the Hymenoptera of Canada, Alaska and Greenland” is to contain a total of eleven papers, where the introduction and the first two checklists: of sawflies (758 species) and one of the groups of “microhymenoptera” (the chalcidoid parasitic wasps) (1246 species) have just been published.The other checklists are to follow over the next several years. The associated data are also being uploaded to the Global Biodiversity Information Facility (GBIF), allowing for periodic updates over time.

When complete, this will be the largest species checklist for any group of organisms in northern North America. Considering that it is estimated that we currently have documented less than half of the species of Hymenoptera present in northern North America, there is still a great amount of work to do on this fascinating group of insects.

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Original sources:

Bennett AMR (2021a) Checklists of the Hymenoptera of Canada, Alaska and Greenland – Introduction. Journal of Hymenoptera Research 82: 1-19. https://doi.org/10.3897/jhr.82.60054

Bennett AMR (2021b) Checklist of the Hymenoptera of Canada, Alaska and Greenland. Agriculture and Agri-Food Canada. Checklist dataset https://doi.org/10.5886/4piso5 [accessed via GBIF.org: 12 March 2021].

Goulet H, Bennett AMR (2021) Checklist of the sawflies (Hymenoptera) of Canada, Alaska and Greenland. Journal of Hymenoptera Research 82: 21-67. https://doi.org/10.3897/jhr.82.60057

Huber JT, Bennett AMR, Gibson GAP, Zhang YM, Darling DC (2021) Checklist of Chalcidoidea and Mymarommatoidea (Hymenoptera) of Canada, Alaska and Greenland. Journal of Hymenoptera Research 82: 69-138. https://doi.org/10.3897/jhr.82.60058

Bees thrive where it’s hot and dry: a unique biodiversity hotspot located in North America

The United States-Mexico border traverses through large expanses of unspoiled land in North America, including a newly discovered worldwide hotspot of bee diversity. Concentrated in 16 km2 of protected Chihuahuan Desert are more than 470 bee species, a remarkable 14% of the known United States bee fauna.

One of the late-summer desert bees, female Svastra sp. on flower of Verbesina enceliodes. Photo by Bruce D. Taubert

This globally unmatched concentration of bee species is reported by Dr. Robert Minckley of the University of Rochester and William Radke of the United States Fish and Wildlife Service in the open-access, peer-reviewed Journal of Hymenoptera Research.

Scientists studying native U.S. bees have long recognized that the Sonoran and Chihuahuan deserts of North America, home to species with interesting life histories, have high bee biodiversity. Exactly how many species has largely remained speculation. Together with students from Mexico, Guatemala and the United States, the authors made repeated collections over multiple years, identifying more than 70,000 specimens. 

Without such intensive collecting, a full picture of the bee diversity would not have been possible. Most of these bee species are solitary, without a queen or workers, which visit flowers over a 2-4 week lifespan and specialize on pollen and nectar from one to a few plants. Furthermore, these desert species experience periodic drought, which the immature stages survive by going into dormancy for years, much like the seeds of the desert plants they pollinate. 

One of the spring-active desert bees, female Centris caesalpiniae on flower of Krameria. Photo by Bruce D. Taubert

Additionally, bee diversity is notoriously difficult to estimate and compare among studies, because of differences in the collecting techniques and the size of the studied area. An unexpected benefit of the regular and intensive sampling for this study was the opportunity to test if the observed bee diversity approached the true bee diversity in this region, or if many more species were yet to be found. In this case, the larger San Bernardino Valley area is home to 500 bee species, only slightly above the number of species recovered along the border – an unusually robust confirmation of the researchers’ estimate. 

One of the spring-active desert bees, male Centris caesalpiniae on flower of Acacia. Photo by Bruce D. Taubert

What we know about the decline of bees due to human activity, along with that of other pollinators, is based primarily on diversity data from human-modified habitats. Needed is baseline information on native bees from pristine areas to help us assess the magnitude and understand the ways in which humans impact bee faunas. This study from the Chihuahuan Desert is therefore an important contribution towards filling that knowledge gap from one of the bee biodiversity hotspots in the world. 

Original source

Minckley RL, Radke WR (2021) Extreme species density of bees (Apiformes, Hymenoptera) in the warm deserts of North America. Journal of Hymenoptera Research 82: 317-345. https://doi.org/10.3897/jhr.82.60895

Under Extinction Pressure: Rare Australian bee found after 100 years

A widespread field search for a rare Australian native bee (Pharohylaeus lactiferus) that had not been recorded for almost a century found the species has been there all along – but is probably under increasing pressure to survive. Prior to this study, only six individuals had been found, with the last published record of this Australian endemic bee species, from 1923 in Queensland.

Male Pharohylaeus lactiferus bee. Photo by James Dorey.

A widespread field search for a rare Australian native bee (Pharohylaeus lactiferus) that had not been recorded for almost a century found the species has been there all along – but is probably under increasing pressure to survive. Prior to this study, only six individuals had been found, with the last published record of this Australian endemic bee species, from 1923 in Queensland.

“This is concerning because it is the only Australian species in the Pharohylaeus genus and nothing was known of its biology,”

Flinders University researcher and biological sciences PhD candidate James Dorey says in the new scientific paper in the peer-reviewed, open-access Journal of Hymenoptera Research.

The ‘hunt’ began after bee experts Olivia Davies and Dr Tobias Smith raised the possibility of the species’ extinction based on the lack of any recent sightings. The ‘rediscovery’ followed an extensive sampling of 225 general and 20 targeted sampling sites across New South Wales and Queensland.

Along with extra bee and vegetation recordings from the Atlas of Living Australia, which lists 500 bee species in New South Wales and 657 in Queensland, the Flinders researchers sought to assess the latest levels of true diversity, warning that habitat loss and fragmentation of Australia’s rainforests, along with wildfires and climate change, are likely to put extinction pressure on this and other invertebrate species.  

“Three populations of P. lactiferous were found by sampling bees visiting their favoured plant species along much of the Australian east coast, suggesting population isolation,”

Mr Dorey reports.

Highly fragmented habitat and potential host specialisation might explain the rarity of P. lactiferus.

Additionally, the scientists remind of previous findings that Australia has already cleared more than 40% of its forests and woodlands since European colonisation, leaving much of the remainder fragmented and degraded.

“My geographical analyses used to explore habitat destruction in the Wet Tropics and Central Mackay Coast bioregions indicate susceptibility of Queensland rainforests and P. lactiferus populations to bushfires, particularly in the context of a fragmented landscape,”

Mr Dorey says.

The study also warns the species is even more vulnerable as they appear to favour specific floral specimens and were only found near tropical or sub-tropical rainforest – a single vegetation type.

“Collections indicate possible floral and habitat specialisation with specimens only visiting firewheel trees (Stenocarpus sinuatu), and Illawarra flame trees (Brachychiton acerifolius), to the exclusion of other available floral resources.”

Known populations of P. lactiferus remain rare and susceptible to habitat destruction (e.g. caused by changed land use or events such as fires), the paper concludes.

“Future research should aim to increase our understanding of the biology, ecology and population genetics of P. lactiferus.”

Female Pharohylaeus lactiferus bee. Photo by James Dorey.

“If we are to understand and protect these wonderful Australian species, we really need to increase biomonitoring and conservation efforts, along with funding for the museum curation and digitisation of their collections and other initiatives,”  

Mr Dorey says.

Research paper:

Dorey JB (2021) Missing for almost 100 years: the rare and potentially threatened bee, Pharohylaeus lactiferus (Hymenoptera, Colletidae). Journal of Hymenoptera Research 81: 165-180. https://doi.org/10.3897/jhr.81.59365

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First Australian night bees recorded foraging under the cover of darkness

Original post by Flinders University, Australia

Australian bees are known for pollinating plants on beautiful sunny days, but a new study has identified two species that have adapted their vision for night-time conditions for the first time.

The study by a team of ecology researchers has observed night time foraging behaviour by a nomiine (Reepenia bituberculata) and masked (Meroglossa gemmata) bee species, with both developing enlarged compound and simple eyes which allow more light to be gathered when compared to their daytime kin.

Published in the Journal of Hymenoptera Research, the researchers explain that this improved low-light ability could potentially also exist in other Australian species secretly active at night, with their image processing ability best observed through high-resolution close-up images. 

Lead author PhD Candidate James Dorey, in the College of Science & Engineering at Flinders University, says the two Australian bee species active at night and during twilight hours are mostly found in Australia’s tropical north, but there could potentially more in arid, subtropical and maybe even temperate conditions across the continent.

“We have confirmed the existence of at least two crepuscular bee species in Australia and there are likely to be many more that can forage both during the day and into the early morning or evening under low light conditions. It’s true that bees aren’t generally known to be very capable when it comes to using their eyes at night, but it turns out that low-light foraging is more common than currently thought,”

says Mr Dorey.

“Before this study, the only way to show that a bee had adapted to low-light was by using difficult-to-obtain behavioural observations, but we have found that you should be able to figure this out by using high-quality images of a specific bee.”

Mr Dorey says bees that forage during dim-light conditions aren’t studied enough with no previously reliable published records for any Australian species.  

“Our study provides a framework to help identify low-light-adapted bees and the data that is needed to determine the behavioural traits of other species. This is important as we need to increase efforts to collect bee species outside of normal hours and publish new observations to better understand the role that they play in maintaining ecosystems.”

The researchers outline why more needs to be understood about the behaviour of bee species to help protect them from the potential impacts of climate change. 

“Global weather patterns are changing and temperatures in many parts of Australia are rising along with the risk of prolonged droughts and fires. So, we have to improve our understanding about insects pollinating at night or in milder parts of the day to avoid potential extinction risks or to mitigate loss of pollination services.” 

“This also means we have to highlight the species that operate in a narrow window of time and could be sensitive to climatic changes, so conservation becomes an important concern. Because quite frankly, we have ignored these species up until now.”

Publication:

Dorey JB, Fagan-Jeffries EP, Stevens MI, Schwarz MP (2020) Morphometric comparisons and novel observations of diurnal and low-light-foraging bees. Journal of Hymenoptera Research 79: 117–144. https://doi.org/10.3897/jhr.79.57308

How quickly do flower strips in cities help the local bees?

Insects rely on a mix of floral resources for survival. Populations of bees, butterflies, and flies are currently rapidly decreasing due to the loss of flower-rich meadows. In order to deal with the widespread loss of fauna, the European Union supports “greening” measures, for example, the creation of flower strips.

A group of scientists from the University of Munich, led by Prof. Susanne S. Renner, has conducted the first quantitative assessment of the speed and distance over which urban flower strips attract wild bees, and published the results of the study in the open-access Journal of Hymenoptera Research.

Flower strips are human-made patches of flowering plants that provide resources for flower-visiting insects and insect- and seed-feeding birds. Previous experiments have proved their conservation value for enhancing biodiversity in agricultural landscapes.

The success of flower strips in maintaining populations of solitary bees depends on the floristic composition, distance from suitable nesting sites, and distance from other habitats maintaining stable populations of bees. To study the attractiveness of the flower strips in urban landscapes, the scientists used an experimental set-up of nine 1,000 sq. meters flower strips recently established in Munich by a local bird conservation agency.

“We identified and counted the bees visiting flowers on each strip and then related these numbers to the total diversity of Munich’s bee fauna and to the diversity at different distances from the strips. Our expectation was that newly planted flower strips would attract a small subset of mostly generalist, non-threatened species and that oligolectic species (species using pollen from a taxonomically restricted set of plants) would be underrepresented compared to the city’s overall species pool,”

shared Prof. Susanne S. Renner.

Bees need time to discover new habitats, but the analysis showed that the city’s wild bees managed to do that in just one year so that the one-year-old flower strips attracted one-third of the 232 species recorded in Munich between 1997 and 2017.

Surprisingly, the flower strips attracted a random subset of Munich’s bee species in terms of pollen specialization. At the same time, as expected, the first-year flower-strip visitors mostly belonged to common, non-threatened species.

The results of the study support that flower strip plantings in cities provide extra support for pollinators and act as an effective conservation measure. The authors therefore strongly recommend the flower strip networks implemented in the upcoming Common Agricultural Policy (CAP) reform in the European Union.

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Original source:

Hofmann MM, Renner SS (2020) One-year-old flower strips already support a quarter of a city’s bee species. Journal of Hymenoptera Research 75: 87-95. https://doi.org/10.3897/jhr.75.47507

19th-century bee cells in a Panamanian cathedral shed light on human impact on ecosystems

About 120 clusters of 19th-century orchid bee nests were found during restoration work on the altarpiece of Basilica Cathedral in Casco Viejo (Panamá). Having conducted the first pollen analysis for these extremely secretive insects, the researchers identified the presence of 48 plant species, representing 23 families.

Casco Viejo, Panamá in 1875, as seen from the summit of Cerro Ancón.
A white tower of the Cathedral where bees were nesting is visible in the distant background in the centre of the peninsula.
Photo by Eadweard Muybridge, courtesy of the Smithsonian American Art Museum; gift of Mitchell and Nancy Steir.

Despite being “neotropical-forest-loving creatures,” some orchid bees are known to tolerate habitats disturbed by human activity. However, little did the research team of Paola Galgani-Barraza (Smithsonian Tropical Research Institute) expect to find as many as 120 clusters of nearly two-centuries-old orchid bee nests built on the altarpiece of the Basilica Cathedral in Casco Viejo (Panamá). Their findings are published in the open-access Journal of Hymenoptera Research.

Locations of nest cell aggregations of Eufriesea surinamensis within the Cathedral in Casco Viejo, Panamá
Photo by Paola Galgani-Barraza

This happened after restoration work, completed in 2018 in preparation for the consecration of a new altar by Pope Francis, revealed the nests. Interestingly, many cells were covered with gold leaf and other golden material applied during an earlier restoration following an 1870 fire, thus aiding the reliable determination of the age of the clusters. The cells were dated to the years prior to 1871-1876.

The bee species, that had once constructed the nests, was identified as the extremely secretive Eufriesea surinamensis. Females are known to build their nests distant from each other, making them very difficult to locate in the field. As a result, there is not much known about them: neither about the floral resources they collect for food, nor about the materials they use to build their nests, nor about the plants they pollinate.

However, by analysing the preserved pollen for the first time for this species, the researchers successfully detected the presence of 48 plant species, representing 43 genera and 23 families. Hence, they concluded that late-nineteenth century Panama City was surrounded by a patchwork of tropical forests, sufficient to sustain nesting populations of what today is a forest-dwelling species of bee.

Not only did the scientists unveil important knowledge about the biology of orchid bees and the local floral diversity in the 19th century, but they also began to uncover key information about the functions of natural ecosystems and their component species, where bees play a crucial role as primary pollinators. Thus, the researchers hope to reveal how these environments are being modified by collective human behaviour, which is especially crucial with the rapidly changing environment that we witness today.

The orchid bee Eufriesea surinamensis
Photo by Paola Galgani-Barraza

Original source:

Galgani-Barraza P, Moreno JE, Lobo S, Tribaldos W, Roubik DW, Wcislo WT (2019) Flower use by late nineteenth-century orchid bees (Eufriesea surinamensis, Hymenoptera, Apidae) nesting in the Catedral Basílica Santa María la Antigua de Panamá. Journal of Hymenoptera Research 74: 65-81. https://doi.org/10.3897/jhr.74.39191

Bee diversity and richness decline as anthropogenic activity increases, confirm scientists

The researchers compared wild bee communities in the tropical dry forest of Mexico living in three habitat conditions: preserved vegetation, agricultural sites and urbanised areas

Changes in land use negatively affect bee species richness and diversity, and cause major shifts in species composition, reports a recent study of native wild bees, conducted at the Sierra de Quila Flora and Fauna Protection Area and its influence zone in Mexico.

Having registered a total of 14,054 individual bees representing 160 species, 52 genera, and five families over the span of a year, the scientists conclude that the studied preserved areas demonstrated “significantly greater” richness and diversity.

In their paper, published in the open-access Journal of Hymenoptera Research, a research team from the University of Guadalajara, Mexico, led by Alejandro Muñoz-Urias, compare three conditions within the tropical dry forest study site: preserved vegetation, an agricultural area with crops and livestock, and an urbanised area.

This bee species (Aztecanthidium xochipillium) is known exclusively from Mexico.

The researchers confirm earlier information that an increase in anthropogenic disturbances leads to a decrease in bee richness and diversity. While availability of food and nesting sites are the key factors for bee communities, changes in land use negatively impact flower richness and floral diversity. Thereby, turning habitats into urbanised or agricultural sites significantly diminishes the populations of the bees which rely on specific plants for nectar and pollen. These are the species whose populations are threatened with severe declines up to the point of local extinction.

According to their data, about half of the bees recorded were Western honey bees (49.9%), whereas polyester bees turned out to be the least abundant (1.2 %).

On the other hand, some generalist bees, which feed on a wide range of plants, seem to thrive in urbanised areas, as they take advantage of people watering wild and ornamental plants at times where draughts might be eradicating native vegetation.

“That is the reason why bees that can use a wide variety of resources are often able to compensate when circumstances change, although some species disappear due to land use changes,” explain the scientists.

This is a tropical dry forest in the dry (left) and rainy season (right).

In conclusion, the authors recommend that the tropical dry forests of both the study area and Mexico in general need to be protected in order for these essential pollinators to be conserved.

“Pollinators are a key component for global biodiversity, because they assist in the sexual reproduction of many plant species and play a crucial role in maintaining terrestrial ecosystems and food security for human beings,” they remind.

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Original source:

Razo-León AE, Vásquez-Bolaños M, Muñoz-Urias A, Huerta-Martínez FM (2018) Changes in bee community structure (Hymenoptera, Apoidea) under three different land-use conditions. Journal of Hymenoptera Research 66: 23-38. https://doi.org/10.3897/jhr.66.27367

Towards untangling the ‘antennal grabbing’ phenomenon in mating cuckoo bees

Scientists report this behavior for the first time in the genus Nomada, following both lab and field observations in Germany

One can seldom spot a cuckoo bee, whose peculiar kleptoparasitic behaviour includes laying eggs in the nests of a certain host bee species, let alone a couple mating.

Nevertheless, German scientists – Dr. Matthias Schindler, University of Bonn, Michaela Hofmann and Dr. Susanne S. Renner of the University of Munich, and Dr. Dieter Wittmann, recently managed to record copulation in three different cuckoo bee species in the genus Nomada.

Intriguingly, in field and lab settings alike, the observed couples demonstrated the phenomenon the researchers called “antennal grabbing” where the male cuckoo bee winds his antennae around

Insertion phase of copulation in a couple of the species Nomada flavoguttata. Note the male’s antennae spirally entangling the female’s.

the female’s during copulation, thus transferring pheromones. Even though such behaviour is relatively common in Hymenoptera, this is the first known record for the genus Nomada.

While the particular biological reason for the “antennal grabbing” in different species remains unsettled, the scientists discuss the phenomenon in view of both previous hypotheses and their own observations in a new paper published in the open access Journal of Hymenoptera Research.

The courtship in Nomada cuckoo bee starts with the ‘swarming’ of males at willow shrubs and gooseberry or their patrolling in groups with males of the Andrena or Melitta species that will “foster” their offspring.

Two males of the species Nomada flavoguttata patrolling at a blossom of a common dandelion.

There is no aggression among the males. They were observed to rub their bellies and heads against the grass, in order to leave sexual pheromones, thus marking the “dating spot” for potential mates.

Earlier chemical studies of Nomada bees noted that the mandibular glands of males produce chemical compounds identical with those of their Andrena or Melitta hosts, leading to the suggestion that the males transfer pheromones that help the females mimic the odor of the host bee, and later enter its nest unnoticed to lay its eggs. An alternative explanation for the “antennal grabbing” is that males are spraying a substance onto the females to make them unattractive to other potential mates.

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Original source:

Schindler M, Hofmann MM, Wittmann D, Renner SS (2018) Courtship behaviour in the genus Nomada – antennal grabbing and possible transfer of male secretions. Journal of Hymenoptera Research 65: 47-59. https://doi.org/10.3897/jhr.65.24947

Bee species with little known nesting-behavior observed to use plastic instead of leaves

Little is known about the nesting activities of some lineages of megachiline bees. Dr. Sarah Gess, affiliated with both Albany Museum and Rhodes University, South Africa, and Peter Roosenschoon, Conservation Officer at the Dubai Desert Conservation Reserve, United Arab Emirates, made use of their earlier observations gathered during a survey on flower visitation in the spring of 2015, to fill some gaps in the knowledge of of three species from such lineages.

Among their findings, published in the open access Journal of Hymenoptera Research, is a curious instance of a bee attempting to build brood cells using green pieces of plastic. Having examined two nests of the leafcutter bee species Megachile (Eurymella) patellimana, they report that one of the females nested in burrows in compacted sandy ground beneath a plant, and the other – in the banks of an irrigation furrow.

11290_Nest of P. grandiceps after emergence of imagines, visible trapped between their natal nest and a nest of Megachile maxillosa

However, while the former was seen carrying a freshly cut leaf, the latter seemed to have discovered a curious substitute in the form of green plastic. Later on, upon checking the nest, the researchers found that the phenomenon they had observed was no isolated incident – at least six identical pieces of narrow, tough, green plastic were grouped together in an apparent attempt to construct a cell. It turns out that the bee had been deliberately cutting off approximately 10-milimetre-long pieces with its large and strong toothed mandibles, before bringing them back to the nest.

“Although perhaps incidentally collected, the novel use of plastics in the nests of bees could reflect ecologically adaptive traits necessary for survival in an increasingly human-dominated environment,” the authors quote an earlier study.

The two studied mason bee species (Megachile (Maximegachile) maxillosa and Pseudoheriades grandiceps) were seen to construct their nests using a mixture of resin and sand in pre-existing cavities, such as trap-nests, above the ground. The researchers note that resin is a common nest-building material among numerous species of mason bees, also known as resin bees. Previously, it has been suggested that apart from making the nest waterproof, the plant secretions may contain substances that fend off parasites.

The authors’ earlier paper exploring the flower visitation by bees and wasps in the Dubai Desert Conservation Reserve is also published in the open-access Journal of Hymenoptera Research.

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Original source:

Gess SK, Roosenschoon PA (2017) Notes on the nesting of three species of Megachilinae in the Dubai Desert Conservation Reserve, UAE. Journal of Hymenoptera Research 54: 43-56. https://doi.org/10.3897/jhr.54.11290

Claims that declines of pollinator species richness are slowing down in Europe revisited

Having conducted a thorough interpretation of the results of a recent study that inferred decrease in the biodiversity loss among pollinators across Europe, Dr Tom J. M. Van Dooren reveals that this conclusion cannot in fact be drawn. It is only supported for the bee fauna in the Netherlands. His study is published in the open access journal Nature Conservation.

Changes in pollinator abundances and diversity are of major concern. Pollinator diversity is quantified by their species richness: the number of species from a specific taxonomic group of pollinating animals present at a given time in a given area. A recent study, adopted in the recent UN IPBES Pollination Report draft summary, inferred that pollinator species richnesses are decreasing more slowly in recent decades in several taxonomic groups and European countries.

However, Dr Tom J. M. Van Dooren, affiliated with both Naturalis Biodiversity Center, the Netherlands, and the Institute of Ecology and Environmental Sciences of Paris, France, has now published his own study to show in detail the inaccuracies that the earlier conclusion has been based on.

Among other points, the scientist notes that the earlier study contained no explicit statistical comparisons between species richness changes in different periods. The earlier study also treated richness changes at country level and small spatial resolution as equivalent, while they probably represent different processes.

“Plants in Great Britain at the smallest spatial scales suggest a reduced rate of changes, but the results for larger spatial scales are not significant,” he illustrates. “The same holds for butterflies in the Netherlands.”

Dr Tom J. M. Van Dooren only finds support in the results of the earlier publication for a decelerating decline in bumblebees and other wild bees in the Netherlands. “This is in fact one taxon, the bees Anthophila, in a single country, the Netherlands”, he notes.

“The lack of robustness points again to the possibility that results found in the data can be due to changes in the shapes of species accumulation curves,” Dr Tom J. M. Van Dooren summarises. “Therefore the status of the statement on decelerating declines in the Pollination Report should be adjusted accordingly.”

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Original source:

Van Dooren TJM (2016) Pollinator species richness: Are the declines slowing down? Nature Conservation 15: 11-22. doi: 10.3897/natureconservation.15.9616

 

Photo credit: 

Aiwok, Wikimedia Commons, CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)