This is Dr. Kurt Johnson, co-author of Nabokov's Blues, retired lepidopterist from the American Museum of Natural History. You all know the details better than me but the question came up a few years ago on VNF about whether population explosions of the Red Admiral Butterfly (Vanessa atalanta) actually occur. In Nabokov-lore, the numeral-like underwing pattern of this species and the reported occurrence of such an outbreak in Russia supposedly had some fateful parallel with the dates of the Russian revolution. I remember at the time of that VNF query, that it was hard to find anything in the lepidopterological literature to check whether this kind of thing happens. Well, in the last two days we have had an outbreak of Red Admirals in NYC the likes of which
I have never seen (not even close) and I've been here 45 years.
I live across from Prospect Park and the Botanical Garden in Brooklyn and, today, even walking down the streets, like 6 blocks, to the business district there were at least a half dozen Red Admirals for every 10 paces one walked. And this remained true for several blocks until I turned around. I then came back to the Botanical Garden and Red Admirals were also flying all over the place in the garden, chasing each other etc. By comparison the only other butterflies around were a Cabbage White (Pieris rapae) or two and a Comma Butterfly (Polygonia comma) or two. It will be interesting to see how long this explosion lasts, AND I will make sure to record it is this year's Lepidopterists Society-published Season's Summary so there is
documentation for the future.
A couple notes: re this: I have seen outbreaks like this with butterflies in the tropics. Perhaps the most notable one was an outbreak of the VERY RARE swallowtail Eurytides zonarius in the desert areas along the Pedernales border area with Haiti and the Domincan Republic in the 1990's. This is a butterfly you seldom see (very rare in collections) and on one day there there were thousands "mud-puddling" after a long desert rain the day before. I mention that because in NYC this year, it has been the warmest March (don't know about April yet) on record and on top of this warmth we then had 3 luscious days of heavy rain but not accompanied by wind. This might have initiated the breakout. Considering that, to my knowledge, spring Red Admiral adults (this would be first-brood adults) would have to come from crysalids that overwintered from last
year. The outbreak cause might well be that the warm spring, and then this latest rain, caused far larger number of crysalids to survive and hatch as opposed to simply die off. One would have to account for why there are so many of them in this year's spring brood if nothing last year seemed unusual.
Well, I thought this note might be useful re: the Nabokov lore about that report of incidents of Red Admiral breakouts in Russia at the time of the revolution. I was surprised today; never seen anything like it.
best!
Dr. Kurt Johnson
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