Affects of late Spring on hatch timing

[jjensen35]

Just wondering what the group experience and thoughts are on the effect of this very late and cool Spring on some of the earlier hatches. I would expect to a great extent emergence timing would depend upon water temps, but I would also think length of day and stage of plant growth along the stream or river would potentially be a factor as we'll. Not really sure what the key is. I'd say our Spring is running as much as three weeks behind "normal". Does this mean that some of the earlier insect emergence might be significantly pushed back as we'll? As always your thoughts and experience are appreciated.

 

[pcray1231]

It's based on the development of nymphs. When they get to a point, they hatch. Length of day does matter, but water temp and time plays a large role.

But consider, even though cold water does slow down development, these things have been developing since their eggs were laid last year. A warm summer or fall can cancel out a cold winter. If the hatch was 2 weeks early last year, these nymphs got a 2 week head start. There's just so many variables.

I haven't been on top of hatches this year, but from what I gathered, yes, the early hatches were late, likely due to a cold winter and early spring. But judging by reports of late April/early May bugs, we're catching up to "average" pretty quickly here.

 

[PennKev]

pcray1231 wrote:
But judging by reports of April/early May bugs, we're catching up to "average" pretty quickly here.

This is the key thing to remember IMO. The farther you get from the point where the winter weather finally breaks, the less affect the winter has on timing and recent weather (as in past week) is the dominant controlling factor. It seems that every year we see posts on this forum about concern for early or late hatches but by early may we are right where we should be give or take a few days. As spring temperature and weather changes become less drastic, hatch timing becomes more predictable and consistent.

I'm not so sure the actually severity of winter weather has much affect on the earlier hatches in April either but in most years the weather in early April is all over the place so it could be just a matter of getting enough days of decent weather in a row to trigger a hatch. Grannoms, for instance, this year started in good numbers just a few days ago but the reality is that this is only a few days later than I've normally seen them in my area. I don't even know if I'd call them late.

Kev

 

[jjensen35]

Thanks guys. That's what I was thinking and hoping would be the case. Nice to have confirmation of what my experience and gut have been telling me.

 

[Chaz]

It's temperature related in that the temperature when they initially hatch from the egg to the time of the year the emerge from the nymph or pupae, it's a year plus or minus 2 weeks depending on the temperatures. There are many stages the nymphs go through to get to the point of hatching and they will eventually hatch in that time frame.
What we consider late or early is tempered by the fact that springs are generally earlier now then even 20 years ago as determined by stream flows of the run-off period according to USGS. Also hatches are comparatively earlier now then say 50 years ago, in part because of this early run-off and temps. So the hatches may be right on time according to when they used to hatch based on records.