Impact of severe storms on butterfly populations
Posted: Thu Jul 07, 2022 11:56 am
Forever I thought that when storms are coming the butterflies do what the other animals do- seek shelter. And, I presumed after the storm passes, they all come out, minus an unfortunate few, and resume life.
However, in the past few years of focus specifically on Tiger Swallowtails I've become more attuned to the environment and the Tiger population. My observations following severe storm fronts:
1. Population of Tigers drops 90% in the days immediately following severe storms, inferring a far higher loss rate than I'd previously thought.
2. Two or three days following the passing of a severe front, Tiger individuals fall into two categories: (a) fresh and recently emerged, and (b) extremely damaged, far more than flight wear or bird damage.
The above two observations I take to indicate that Tigers (specifically) are not adept at protecting themselves as might other Leps (e.g., Catocala and grass-hidden Speyeria)and thus suffer a high mortality rate as a result of severe storms.
Last year the southern shore of Lake Ontario (New York) was swept by a series of severe storm fronts every week or so. Each time the Tiger population plummeted, then slowly rose, only to be knocked down again. In both 2020 and 2021 severe storms in mid-August spelled the end of Tiger observations, whereas in past years with "good" weather they'd be on the wing until the first week of September.
Your thoughts/ observations?
However, in the past few years of focus specifically on Tiger Swallowtails I've become more attuned to the environment and the Tiger population. My observations following severe storm fronts:
1. Population of Tigers drops 90% in the days immediately following severe storms, inferring a far higher loss rate than I'd previously thought.
2. Two or three days following the passing of a severe front, Tiger individuals fall into two categories: (a) fresh and recently emerged, and (b) extremely damaged, far more than flight wear or bird damage.
The above two observations I take to indicate that Tigers (specifically) are not adept at protecting themselves as might other Leps (e.g., Catocala and grass-hidden Speyeria)and thus suffer a high mortality rate as a result of severe storms.
Last year the southern shore of Lake Ontario (New York) was swept by a series of severe storm fronts every week or so. Each time the Tiger population plummeted, then slowly rose, only to be knocked down again. In both 2020 and 2021 severe storms in mid-August spelled the end of Tiger observations, whereas in past years with "good" weather they'd be on the wing until the first week of September.
Your thoughts/ observations?