Rarely-seen event of ant brood parasitism by scuttle flies video-documented

While many species of scuttle flies are associated with ants, their specific interactions with their hosts are largely unknown. Brood parasitism (attacking the immature stages, rather than the adult ants), for example, is an extremely rarely observed and little-studied phenomenon. However, a research team from the USA and Brazil, led by Dr. Brian Brown, Natural History Museum of Los Angeles County, have recently video-documented two such occasions. The observations are published in the open access Biodiversity Data Journal.

One of the videos, taken in Brazil, shows female scuttle flies attacking ants evacuating their nest. Having had their colony exposed, worker ants try to carry the brood to the nearest shelter. The flies follow these workers on foot, and bump into them in attempt to make them drop the larvae. The scientists have provided a video of an ant which, when harassed, left a larva in a partially exposed position and fled. Immediately, the fly attacked the larva, laying an egg inside its body. The fact that the flies attack the relatively soft-bodied larvae explains the puzzling structure of the ovipositor (egg-layer) of this species (Ceratoconus setipennis), which appears much less hardened than the ovipositor of species attacking adult ants. As a result of the present observation, however, their association with ants is no longer a mystery.

The second footage, filmed in Costa Rica, shows an undescribed species of scuttle fly (genus Apocephalus) that fly above the ants. When they spot a worker carrying brood, it would plunge down to it, approach the ant from behind and land on the (in this case) pupa. Then, it flips over onto its back, keeping the pupa between itself and the ant, while it lays an egg into the pupa from an upside-down position.

“The video documentation of two very different types of brood parasitism of ant species by scuttle flies was recorded in two countries within just a few months of one another,” conclude the authors. “This hints at the many remarkable behaviors of phorid flies that may still await discovery by the patient observer. It appears brood parasitism may not be as rare as was once assumed, and that there may be a tremendous amount of information to uncover about these behaviors.”

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Original source:

Brown B, Hash J, Hartop E, Porras W, Amorim D (2017) Baby Killers: Documentation and Evolution of Scuttle Fly (Diptera: Phoridae) Parasitism of Ant (Hymenoptera: Formicidae) Brood. Biodiversity Data Journal 5: e11277. https://doi.org/10.3897/BDJ.5.e11277

The city of angels and flies: 12 unknown scuttle fly species have been flying around L.A.

Although the second-largest and rather concrete metropolis in the United States might not be anywhere near one’s immediate association for a biodiversity hotspot, the fly fauna of Los Angeles is quite impressive. As part of BioSCAN, a project devoted to exploring the insect diversity in and around the city, a team of three entomologists report on their latest discovery – twelve new scuttle fly species. Their study is published in the open access Biodiversity Data Journal.

Launched in 2013, the Natural History Museum of Los Angeles County‘s project BioSCAN seems to never cease to amaze with large numbers of newly discovered species. The first phase of the study finished with 30 species of flies new to science from sites in 27 backyards, 1 community garden, the Los Angeles Ecovillage, and the Nature Gardens at the Museum. In recognition to the residents, who had literally let the scientists in their homes, each of those flies was named after the relevant site’s host.

When they decided to revisit the specimens they had collected during the first year of the project as well as older museum collections, the authors of the present paper were in fact quite certain they were about to find a new batch of unknown flies.

Img2 M. stoakesi

Having already described so many new scuttle fly species, the latest twelve had initially gone undercover, all being rare and often represented by only one specimen among the total of 43,651 collected individuals.

“The remarkable diversity of biologies of these flies makes them a varied and essential group to document in any ecosystem,” the entomologists explain.

The extensive BioSCAN project is still ongoing thanks to its passionate staff, international collaborators and advisors, as well as the large number of students and volunteers. Being especially grateful for their help, the scientists have named one of the fly species M. studentorum and another one – M. voluntariorum. The project is currently in its second phase of collecting.

“These volunteers are critical to our operation, and have contributed to everything from public outreach in the NHM Nature Lab to specialized work on phorid flies,” point out the authors.

In the end, the researchers hope that they will get their message across to other taxonomists, funding agencies, institutions and the public alike. Urban environments with their fast-changing conditions and biodiversity profile, need constant attention and scientific curiosity.

“There is an enormous taxonomic deficiency, including, or, perhaps, especially, in rapidly changing urban environments,” they say. “Taxonomists and their funding agencies must give time, attention and money to the environments surrounding their towns and cities.”Img3 M. wongae

“Baseline collections of urban fauna must be established in the present if there is hope for understanding the introductions and extinctions that will occur in the future,” they stress.

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Original source:

Hartop E, Brown B, Disney R (2016) Flies from L.A., The Sequel: A further twelve new species ofMegaselia (Diptera: Phoridae) from the BioSCAN Project in Los Angeles (California, USA).Biodiversity Data Journal 4: e7756. doi: 10.3897/BDJ.4.e7756