urbanization

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

New species of spider discovered ‘next door’ at the borders of cereal fields in Spain

The image that comes to mind when we think of new species being discovered is that of scientists sampling in remote tropical forests, where humans have barely set foot in. However, new species waiting to be discovered can in fact be very close to us, even if we live in a strongly humanized continent like Europe.

Scientists Eduardo Morano, University of Castilla-La Mancha, and Dr Raul Bonal, University of Extremadura, have discovered a new species of spider, formally called Cheiracanthium ilicis, in an area which does not match the image of a pristine habitat at all.

The new species was found in a strongly humanized area in central Spain, specifically, in isolated trees at the borders of cereal fields. These trees, mainly Holm oaks (Quercus ilex), are those remaining of the former oak woodlands that once covered the Iberian Peninsula and which have been cleared for centuries.

The systematic sampling revealed the newly discovered spider had a an exclusive preference for Holm Oaks, as all individuals were collected from the trunks and branches of these trees. Therefore, it was named after this tree’s scientific name “ilicis”.

While adults measure about a centimetre in body length, juveniles are smaller and have greenish colouration that mimics new oak shoots.

The mouthparts are proportionally large, as in the case of other species of the genus, like closely related C. mildei. In the case of the latter, the mouthparts are large enough to penetrate human skin, although the effects of the poison appear mild.

From a conservation perspective, the present study puts forward the need to preserve isolated trees in agricultural landscapes. They are not only a refuge to common forest organisms but to novel species yet to be discovered as well.

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Original source:

Morano E, Bonal R (2016) Cheiracanthium ilicis sp. n. (Araneae, Eutichuridae), a novel spider species associated with Holm Oaks (Quercus ilex). ZooKeys 601: 21-39. doi: 10.3897/zookeys.601.8241

Flightless survivors: Incredible invertebrate diversity in Los Angeles metropolitan area

Urban wildlife is surprisingly understudied. We tend to know more about animals in exotic places than about those that live in our cities.

This is why researchers Emile Fiesler, president of Bioveyda Biological Inventories, Surveys, and Biodiversity Assessments, USA, and Tracy Drake, manager of the Madrona Marsh Preserve, looked into the fauna of the Madrona Marsh Preserve, California, a small nature preserve in one of the world’s largest metropolitan areas.

Consequently, they published the astonishing number of 689 species of invertebrates, which have managed to survive decades of farming and oil exploration, followed by development pressures, in the open access Biodiversity Data Journal. The study was minimally invasive as the live animals have been recorded with macro-photography.

Even though it is the insects that first developed the ability to fly, long before the dinosaurs became birds, the latter have always received the most of our attention. This major evolutionary breakthrough, which has occurred more than once in the past, is also a reason why insects are currently the most diverse animals on earth in terms of number of species.

“Insects and other invertebrates have filled all ecological niches and all corners of our planet,” explain the authors. “No surprise that these small creatures conquered our cities and invaded our homes as well.”

Most of the urban dwellers, however, have been introduced – accidentally or deliberately – by humans.

“The remainder – native ‘wild’ species – are able to survive in the city mainly due to their adaptivity,” they point out. “It is therefore surprising to find a number of flightless species in a small area surrounded by urbanization.”

The Madrona Marsh Preserve is located in Torrance, which is part of the Los Angeles metropolitan area. The greater Los Angeles Metropolitan area is one of the world’s largest, with a human population of more than 17 million.

The Madrona Marsh Preserve, boasting seasonal wetlands, is well known as a birdwatchers’ paradise. Besides birds, its other vertebrates (mammals, reptiles, amphibians, and fishes), as well as its flowering plants, are relatively well known. The invertebrate fauna of the Preserve, on the other hand, aside from butterflies and dragonflies, was virtually unknown.

Interestingly, night surveys revealed the presence of a ‘second shift’ diversity, or creatures seemingly complementary to those active during the day.

Among the long-time survivors are wingless camel crickets as well as velvet ants, which are wasps whose flightless females look like furry ants. Another curiosity that intrigued the researchers is an obscure flightless female bradynobaenid wasp.

The researchers were especially surprised by their encounter with a large Solifugid [image 3] – also known as Camel Spider or Wind Scorpion. Solifugids are little-known arachnids that are neither spiders, nor scorpions, and can grow up to 15 cm (6 in). Their order’s name Solifugae translates from Latin as “those that flee from the sun”.

All in all, the biodiversity study resulted in 689 species without a backbone, belonging to 13 classes, 39 orders, and 222 families, found on this island surrounded by urbanization.

“Not unlike the moas and dodos, these ‘island’ inhabitants stayed grounded through the ages,” acknowledge the researchers.

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Original source:

Fiesler E, Drake T (2016) Macro-invertebrate Biodiversity of a Coastal Prairie with Vernal Pool Habitat. Biodiversity Data Journal 4: e6732. doi: 10.3897/BDJ.4.e6732

About the authors:

Emile Fiesler is president of Bioveyda Biodiversity Inventories, Surveys, and Studies, and Tracy Drake is manager of the Madrona Marsh Preserve.