Tag: Phoridae

Tiny fly from Los Angeles has a taste for crushed invasive snails

Living individual of Draparnaud’s glass snail
Photo by Kat Halsey

As part of their project BioSCAN – devoted to the exploration of the unknown insect diversity in and around the city of Los Angeles – the scientists at the Natural History Museum of Los Angeles County (USA) have already discovered numerous insects that are new to science, but they are still only guessing about the lifestyles of these species.

“Imagine trying to find a given 2 mm long fly in the environment and tracking its behavior: it is the smallest imaginable needle in the largest haystack. So when researchers discover new life histories, it is something worth celebrating,”

explains Dr. Brian Brown, lead author of a recent paper, published in the scholarly open-access Biodiversity Data Journal.

However, Brown and Maria Wong, former BioSCAN technician, while doing field work at the L.A. County Arboretum, were quick to reveal a curious peculiarity about one particular species discovered as part of the project a few years ago. They successfully lured female phorid flies by means of crushing tiny, invasive snails and using them as bait. In comparison, the majority of phorid flies, whose lifestyles have been observed, are parasitoids of social insects like ants.

Within mere seconds after the team crushed tiny invasive snails (Oxychilus draparnaudi), females representing the fly species Megaselia steptoeae arrived at the scene and busied themselves feeding. Brown and Wong then collected some and brought them home alive along with some dead snails. One of the flies even laid eggs. After hatching, the larvae were observed feeding upon the rotting snails and soon they developed to the pupal stage. However, none was reared to adulthood.

Female phorid fly feeding on a crushed Draparnaud’s glass snail
Photo by Kat Halsey

Interestingly, the host species – used by the fly to both feed on and lay eggs inside – commonly known as Draparnaud’s glass snail, is a European species that has been introduced into many parts of the world. Meanwhile, the studied fly is native to L.A. So far, it is unknown when and how the mollusc appeared on the menu of the insect.

To make things even more curious, species of other snail genera failed to attract the flies, which hints at a peculiar interaction worth of further study, point out the scientists behind the study, Brown and Jann Vendetti, curator of the NHM Malacology collection. They also hope to lure in other species of flies by crushing other species of snails.

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In recent years, the BioSCAN project led to other curious discoveries from L.A., also published in Biodiversity Data Journal. In 2016, a whole batch of twelve previously unknown scuttle fly species was described from the heart of the city. A year later, another mysterious phorid fly was caught ovipositing in mushroom caps after Bed & Breakfast owners called in entomologists to report on what they had been observing in their yard.

Original source:

Brown BV, Vendetti JE (2020) Megaselia steptoeae (Diptera: Phoridae): specialists on smashed snails. Biodiversity Data Journal 8: e50943. https://doi.org/10.3897/BDJ.8.e50943

A Bed & Breakfast in L.A. reveals the lifestyle of a secretive fly species

For nearly 30 years, Dr. Brian Brown knew about a mysterious unidentified phorid fly species, whose females would often be spotted flying above mushrooms, while the males were nowhere to be found.

Little did anyone know that this years-long puzzle would be solved once and for all after a surprising call came in earlier this year, in April.

Los Angeles Bed & Breakfast owners Patsy Carter and Lisa Carter-Davis had decided to alert entomologists about the newly emerged numerous mushrooms in their yard.

The study is published in the open access Biodiversity Data Journal by Dr. Brian Brown and his colleague at the Natural History Museum of Los Angeles County, Emily A. Hartop. It is the latest in a series of publications resulting from the extensive BioScan Project, which surveys the biodiversity in the Los Angeles area and was launched in 2012 by the NHMLA.

It turned out that these mushrooms were hosting the mysterious flies. Females were ovipositing in the mushroom caps with the larvae subsequently developing and feeding on the lower surface of the fungi, deep within the gills. Later, the larvae would exit the mushroom to pupate into the soil underneath before emerging as adults.

Most importantly, the team managed to collect specimens of the previously unknown males, which allowed them to successfully identify the mysterious species as Megaselia marquezi. Over the span of the BioScan Project, the species had already been known to be the sixth most commonly collected one around Los Angeles, yet its lifestyle has remained a secret until now.

“About 100 species, mostly of Megaselia, are known from Los Angeles, but many were new to science and had nothing known of their lifestyle,” explain the authors. “Matching a lifestyle with a species previously known only from a name is a significant accomplishment.”

They also noted that, “We can do great things with the help of citizen scientists, who extend our reach into urban areas that are generally off-limits”.

“Possibly, the widespread irrigation of lawns allows fungal growth that supports an abundant fungivore community, but our ignorance of the fauna of the surrounding natural areas makes such statements highly speculative.”

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Original source:

Brown B, Hartop E (2017) Mystery mushroom malingerers: Megaselia marquezi Hartop et al. 2015 (Diptera: Phoridae). Biodiversity Data Journal 5: e15052. https://doi.org/10.3897/BDJ.5.e15052