Journal of Hymenoptera Research

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.

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

Trapped in a nuclear weapon bunker wood ants survive for years in Poland

Having built their nest over the vertical ventilation pipe of an old nuclear weapon bunker in Poland, every year a large number of wood ants fall down the pipe to never return back to their colony.

Curiously, although trapped in extremely severe conditions underground, the ants have already upped their numbers to these of big, mature natural colonies, while also carrying on with their basic activities of nest maintenance, constructing and moulding. This unique population is described in the open access Journal of Hymenoptera Research by the team of Polish scientist Wojciech Czechowski, Polish Academy of Science.

The studied colony is still unique, despite the fact that there are previously known similar cases, such as a black garden ant colony that found a home in a chassis of an immobilised car, where the insects had built their nest from mud and dry plant remnants stuck to the underbody. Another wood ant colony is known to have lived in almost complete darkness within a cubic wooden box with no openings apart from a narrow slit at the bottom of one side. Yet, unlike the ants from the bunker, they have all had access to the outside world, having deliberately made their own choice to settle in such extraordinary locations.

Thanks to an yearly campaign set to count the hibernating in the same bunker bats, the ant population was discovered in 2013. Interestingly, when the ants were checked on in 2015, the researchers not only found the population still surviving, but even increasing its numbers.

According to the estimates, they counted at least several hundred thousand workers, arguably close to a million. Moreover, when the researchers went back to the bunker in 2016, they found the mound’s damage, caused on their previous visit, repaired, which showed the population still managed to maintain their nest almost as if they were leading a normal life.

The ant ‘colony’ was found to have built an earthen mound in a small 2.3 m high room with a base area of 3 m x 1.2 m. Normally, such wood ants settle exclusively on large forested islands, where they can forage enough food to answer the high energy demand of the colony.

However, the confined space within the bunker has not been the only obstacle the ants have been facing in their underground trap. Beside the lacking food and light, the ‘colony’ had to also deal with the low temperatures between the one-metre thick ferroconcrete walls. All year long it was no more than 10 °C.

Understandably, the severe conditions within the bunker made reproduction effectively impossible. Although the scientists did undertake a special search for larvae, pupae, empty cocoons or queens, they found nothing. Nor did they find signs of male offspring.

Looking for an answer why the population was still seemingly thriving, the scientists deducted that there was a constant influx of newly fallen ants. The metal plate that once covered the pipe outlet had obviously rusted so much that it has been collapsing under a big wood ant colony’s mound built right over the pipe. In fact, the mortality in the bunker is quite high, but the regular ‘newcomers’ turn out to be overcompensating for the dead ants.

“To conclude, the wood ant ‘colony’ described here – although superficially looking like a functioning colony with workers teeming on the surface of the mound – is rather an example of survival of a large amount of workers trapped within a hostile environment in total darkness, with constantly low temperatures and no ample supply of food,” say the authors.

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Original source:

Czechowski W, Rutkowski T, Stephan W, Vepsäläinen K (2016) Living beyond the limits of survival: wood ants trapped in a gigantic pitfall. Journal of Hymenoptera Research 51: 227-239. doi: 10.3897/jhr.51.9096

Bee populations expanded during global warming after the last Ice Age

The Australian small carpenter bee populations appear to have dramatically flourished in the period of global warming following the last Ice Age some 18,000 years ago.

The bee species is found in sub-tropical, coastal and desert areas from the north-east to the south of Australia. Researchers Rebecca Dew and Michael Schwarz from the Flinders University of South Australia teamed up with Sandra Rehan, the University of New Hampshire, USA, to model its past responses to climate change with the help of DNA sequences. Their findings are published in the open access Journal of Hymenoptera Research.

“You see a rapid increase in population size from about 18,000 years ago, just as the climate began warming up after the last Ice Age,” says lead author Rebecca Dew. “This matches the findings from two previous studies on bees from North America and Fiji.”

“It is really interesting that you see very similar patterns in bees around the world,” adds Rebecca. “Different climate, different environment, but the bees have responded in the same way at around the same time.”

In the face of future global warming these finding could be a good sign for some of our bees.

However, the news may not all be positive. There are other studies showing that some rare and ancient tropical bees require cool climate and, as a result, are already restricted to the highest mountain peaks of Fiji. For these species, climate warming could spell their eventual extinction.

“We now know that climate change impacts bees in major ways,” says Rebecca, “but the challenge will be to predict how those impacts play out. They are likely to be both positive and negative, and we need to know how this mix will unfold.”

Bees are major pollinators and are critical for many plants, ecosystems, and agricultural crops.

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Original source:

Dew RM, Rehan SM, Schwarz MP (2016) Biogeography and demography of an Australian native bee Ceratina australensis (Hymenoptera, Apidae) since the last glacial maximum. Journal of Hymenoptera Research 49: 25-41. doi: 10.3897/JHR.49.8066