[Fwd: Fw: Re: [SoWestLep] 2005 prospects for S. Calif. and NW Arizona.]
Stanley A. Gorodenski
stan_gorodenski at asualumni.org
Fri Jan 21 16:42:31 EST 2005
I'm forwarding this in case anyone might be interested. This was
originally posted in SoWestLep and then subsequently cross posted to
leps-talk. Since leps-talk does not appear to have geographic boundaries
it seems appropriate to cross post in Leps-L also as the subject matter
might be of interest to some on this list.
-------- Original Message --------
Subject: Fw: Re: [SoWestLep] 2005 prospects for S. Calif. and NW Arizona.
Date: Fri, 21 Jan 2005 08:49:49 -0800
From: Kenneth E Davenport <flutterflies at juno.com>
To: SoWestLep at yahoogroups.com, TILS-leps-talk at yahoogroups.com
The below issue came up on Southwest Leps. and it is a very
little understood matter with the majority of lepidopterists. I
recommended people get their nets, cameras and binoculars ready because
the coming spring season is likely to be a very good one in SE California
and NW Arizona. My further comments after Stan's:
Kenneth E Davenport wrote:
> this looks like a good year to plan trips to the desert ranges to see
our California desert
Stanley A. G. commented:
The rains will undoubtedly produce a lot of vegetative growth and
flowering, but coming after a lengthy draught, at least in Arizona, I
wonder if this year will be an exceptionally good year for butterflies.
I'm assuming it will take a year to two to rebound and so maybe next
year or the year after will reflect the rains we got this winter - ???
The comments Stan makes are reasonable and logical and would
apply to many butterflies in the more montane portions or non-desert
lowlands of California and Arizona.
If should be noted that desert butterflies (and many species
inhabiting more montane habitats like Papilio indra) have survival
mechanisms to aid them to survive years of drought and take advantage of
those relatively few years in which good rainfall and plant growth occur.
Many of our western butterflies develop as larvae in those wet
years when larval hosts do well. In many cases, adults emerge from pupae
only in favorable years of rainfall. Rarely if ever will any of these
species have complete emergences on any given year. In an extreme
drought, pupae may take up to 5 or 7 years to emerge as they await
favorable conditions. John F. Emmel has explained to me that even in his
extensive rearing of western butterflies, only a certain percentage will
emerge on a year by year basis even under favorable lab conditions and
this appears to be true in the wild as well.
What this means is that desert butterflies are not dependent on
how conditions were last year. If no one saw any Martin's Swallowtails
(Papilio indra martini) in the Providence Mountains in SE California
last year it does not mean they are facing extinction or that too few
adults flew last year to sustain the species. It means the pupae did not
emerge into adult butterflies because of unfavorable conditions.
Governmental agencies and even professional entomologists were not aware
of this survival mechanism and wrongly concluded this butterfly was
endangered when few martini were seen in very dry years. The butterfly
suddenly appeared in numbers following a wet winter. They thought it was
their management plan working but actually it was the normal way desert
butterflies operate from year to year. In a wet year, a high percentage
of P. indra martini will emerge to take advantage of these relatively
brief conditions. But even in a wet year, many pupae will not emerge.
Another survival mechanism that an unexpected freeze or cold spell will
not wipe out the species.
These principles apply even with many montane species. Leanira
Checkerspots (Thessalia or Chlosyne leanira wrighti) and Clemence's Blue
(Plebejus lupini monticola) had very poor flights in the southern Sierra
in 2004. Look for much better flights last year. Those pupae decided to
forego emergence as well.
For those who live in the Eastern U. S., I understand that such
survival mechanisms are much less seen in areas of stable year to year
In southeastern Arizona, there are more tropical species which
alternately expand and contract ranges based on many other factors.
Rainfall from year to year can be and is a factor with these. But
freezes in the winter can also kill such transient invasions of such warm
weather species. It may take several favorable years with good rainfall
and mild winters for some of these to reach and maintain transient
populations there. See the Bailowitz and Brock Southeast Arizona book
which discusses many such situations.
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