cuckoo bees

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

Canadian scientist names a new species of cuckoo bee after Sir David Attenborough

A total of fifteen new species of bees, where one honors the English broadcaster and naturalist Sir David Attenborough, are described by Thomas Onuferko, PhD candidate at York University in Toronto, Canada. His paper is published in the open access journal ZooKeys.

The new species, called Attenborough’s epeolus (pronounced ee-pee-oh-lus), is rare and known from only nine specimens observed at two localities, in Colorado and New Mexico.

To name the other new species, the author referred to colleagues or relatives, the species’ physical appearance, their collectors, or the flowers on which the insects have been found.

Currently, not much is known about any of the newly described species, except that they belong to a specialized group of bees called cuckoo bees. Much like cuckoo birds, these bees sneakily lay their eggs in the nests of other species. When they hatch, the younglings seek out and kill the host egg or larva and then feed on the pollen stored by the female who has built the nest.

Female of the newly described cuckoo bee species, Epeolus attenboroughi . This specimen is the holotype for the species, meaning it is the one used to describe the new bee.

All new species belong to the cuckoo bee genus Epeolus, known to invade nests of polyester bees in the genus Colletes. In his publication, Thomas speculates that the name ‘epeolus’ is probably a diminutive of Epeus/Epeius, the soldier in Greek mythology said to have come up with the Trojan Horse. The sinister nature of these cleptoparasitic bees must have been compared to the Greek’s famous war strategy.

Cuckoo bees are difficult to recognize as bees because they lack the characteristic fuzzy look, which comes from the numerous long branched hairs evolved to efficiently pick up pollen. Instead, cuckoo bees rely on other bees to collect pollen for their offspring, leading to the trait being lost.

While, as a result, these species would rather be likened to wasps, their appearance is not plain at all. Cuckoo bees, including Attenborough’s epeolus, possess very short black, white, red, and yellow hairs that form beautiful patterns.

“It only seemed appropriate to name a species with such an unusual life strategy and attractive appearance after someone who has dedicated his life to illustrating the beauty and complexity of the natural world,” explains Thomas.

Including the new species, there are now 43 known Epeolus species in North America.

“It may seem surprising to some that in well-researched places like Canada and the United States there is still the potential for the discovery of new species,” says the scientist.

Male of the newly described cuckoo bee species, Epeolus attenboroughi , with its proboscis (i.e. mouthparts) extended. These are elongated in order to reach and feed on the nectar within flowers.

Since cuckoo bees are rarer than their hosts – as predators are rarer than their prey – and relatively small (5.5–10.0 mm in body length), they are likely to go undetected, which partly explains why it’s taken so long to identify these new ones.

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Original source:

Onuferko TM (2018) A revision of the cleptoparasitic bee genus Epeolus Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae). ZooKeys 755: 1–185. https://doi.org/10.3897/zookeys.755.23939.

A new hope: One of North America’s rarest bees has its known range greatly expanded

The Macropis Cuckoo Bee is one of the rarest bees in North America, partly because of its specialized ecological associations. It is a nest parasite of oil-collecting bees of the genus Macropis which, in turn, are dependent on oil-producing flowers of the genus Lysimachia.

In fact, the cuckoo bee – which much like its feather-bearing counterpart does not build a nest of its own, but lays its eggs in those of other species instead – is so rare that it was thought to have gone extinct until it was collected in Nova Scotia, Canada, in the early 2000s. As a result, the Macropis Cuckoo Bee was brought to the attention of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

Recently, an individual reported from Alberta, Canada, brought new hope for the survival of the species. In addition to previously collected specimens from Ontario, this record greatly expands the known range of the cuckoo.

Scientists Dr Cory S Sheffield, Royal Saskatchewan Museum, Canada, who was the one to rediscover the “extinct” species in Nova Scotia, and Jennifer Heron, British Columbia Ministry of Environment & Climate Change Strategy, present their new data, and discuss the conservation status of this species in their paper, published in the open access journal Biodiversity Data Journal.

“This species has a very interesting biology,” they say, “being a nest parasite – or cuckoo – of another group of bees that in turn have very specialized dietary needs.”

The hosts, bees of the genus Macropis (which themselves are quite rare) are entirely dependent on plants of the primrose genus Lysimachia. Moreover, they only go after those Lysimachia species whose flowers produce oil droplets, which the insects collect and feed to their larvae. Thus, Macropis bees require these oil-producing flowers to exist just like Macropis cuckoo bees need their hosts and their nests. Curiously, this reliance, as suggested by previous studies on related European species, has made the female cuckoos develop the ability to find their host’s nests by the smell of the floral oils.

“This level of co-dependence between flower, bee, and cuckoo bee, makes for a very tenuous existence, especially for the cuckoo,” the authors comment. “The recent specimen from Alberta lets us know that the species is still out there, and is more widespread than we thought.”

In conclusion, the authors suggest that continuing to monitor for populations of rare bees, and documenting historic records, are crucial for conservation status assessments of at-risk species.

“Biodiversity Data Journal provides a great venue to share this type of information with our colleagues for regional, national, and international efforts for species conservation,” they note.

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Original source:

Sheffield C, Heron J (2018) A new western Canadian record of Epeoloides pilosulus (Cresson), with discussion of ecological associations, distribution and conservation status in Canada. Biodiversity Data Journal 6: e22837. https://doi.org/10.3897/BDJ.6.e22837