ecoevo.social is one of the many independent Mastodon servers you can use to participate in the fediverse.
Dedicated to Ecology and Evolution. We welcome academics, students, industry scientists, folks from other fields with links to E&E, scientific societies, and nature enthusiasts in general.

Administered by:

Server stats:

617
active users

Kaz Ohashi

Every year, up to 4 billion (80 tons in biomass!) migrate between Britain and Europe, providing important pest control by consuming 3–10 trillion aphids, as well as long-range pollen transfer.
bit.ly/3Vi6LNJ

@KazOhashi_Lab they are migrating from Europe to Britain in spring, lay eggs and their offspring is migrating back in late summer, lays eggs there and dies?

@lenahallesaale You're right, thanks for pointing that out! I corrected "from Britain to Europe" as "between Britain and Europe".

@KazOhashi_Lab I was also asking if this migration happens in two generations. Or is there a third summer generation? In German Wikipedia they say that the "German" females of Episyrphus balteatus fly over the alps in autumn and come back in spring. The same ones?

@lenahallesaale I am not sure. In Japan, Episyrphus balteatus can be found from March to November. That means they have at least 4-5 generations per year (they go from eggs to adult in one month). If that's the same for European species, I guess they repeat 2 or more generations during the migration. I mean, they could lay eggs anywhere on their route (except the sea). Just a guess.

@KazOhashi_Lab thanks for the long answer! I remember wondering how migratory birds know how to find their way. It is much more inconceivable how these little hoverflies know where and when to migrate.

@lenahallesaale That's a great question! probably differs from bird migration in many aspects, because they would often repeat generations while migrating. Some butterflies are known to do similar things, as far as I know. People studying the migration of might know more about how these animals find their way while repeating generations.

@herrsaalfeld @KazOhashi_Lab It's both ways: the offspring returns and lays eggs in Britain, to start the cycle again. A great argument in support of (the obvious fact that) Britain being an integral part of the European subcontinent, rather than a separate piece of land.

@albertcardona @KazOhashi_Lab I thought so. One way migration would be hard to select for by evolution 🙂. But now to the most important fact, where are most aphids consumed?

@herrsaalfeld @KazOhashi_Lab Great point: given this distribution of aphid observations in the whole European continent (including the UK; left), and in the UK alone (right), there are likely far more aphids in the rest of Europe ... there's also far more land area, and I can't be bothered to normalize it, so I'll vaguely gesture at marginally relevant data.

Plots from here, filtering for "Europa" and "United Kingdom" (notice the location filter near the top right under the search box):
inaturalist.org/taxa/52381-Aph