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Skipjack Joe
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Quote: | Originally posted by ecomujeres
Another point to consider: from what I've been reading about the Sulphur butterflies, they are migratory. This means that they may actually be
following food sources that are appearing after the rains and so aren't neccesarily leaving their chrysali en mass, but are arriving from elsewhere
and congregating on preferred food sources, along with local hatchlings. |
I gave a bit of thought about this earlier today.
I came across some studies that showed that a butterfly can remain in the diapause state for only a given amount of time before it dies as well. The
study showed one species kept in a lab that survived 5 years, beyond which the cocoons wouldn't recover no matter how perfect conditions were
provided.
I've seen these yellow suphurs in the Los Arcos area which gets much less rain than mulege/santa rosalia and east cape.
What could be happening is that the southern baja climate provides enough moisture for the 'base' populations. Enough moisture that droughts are not
long enough to wipe out these populations entirely.
The central baja populations may die off during some long drought periods but are repopulated by migrations from the more stable populations from the
south.
Also, it doesn't seem to be simply a water issue. The winter rains that come in jan/feb don't seem to excite them very much at all.
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Pescador
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The yellow ones are definately the Statira species. I found a butterfly identification program but they were not listed. Tehags site had a great
listing of butterflies, but alas not much information.
I do not think that these are migratory because there does not seem to be any pattern that would come with a migration, meaning that some show up
followed by a few more each day, whereas these things exploded in a day or two at most.
Guess I will have to build a terrarium and keep a caterpillar to cocoon or Pupa stage and watch for the hatching.
Thanks for all the information and replies, this has been very informative.
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Bugman
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Insects are very adaptable creatures and you really have to be when living on a peninsula with such inconsitent weather like Baja. Most of the
butterflies and moths there go dormant (diapause) in the pupal stage and can remain that way for a number of years (5 or more) until mother nature
presents optimal weather conditions. It is common to have a small but steady population most years but then you can have an explosion when the rains
come and all those that have been in long diapause make an appearance. For some species it is actually the drop in barometric pressure that triggers
them to hatch so it does not always work to just throw water at them.
The Rothschildia moths feed on the Jatropha bushes and their cocoons can wait many years to hatch but shortly after a hurricane or big rainstorm they
can be very common and so will their large caterpillars on the Jatropha. The black witch moths can reach near pest proportions in wet years and they
will move north up into areas where they normally do not call home. Whenever Baja has a good year for them we often start seeing them in Southern
California as well. In fact, I just had one at my porch light a few nights ago in Escondido. They are attracted to any sweet substance from rotting
fruit to regular soda. I remember many years ago camping north of Loreto and it was about a month after a hurricane so the place was nice and green.
My friend spilled his orange soda in the back of my car as we were getting ready to call it a night. I forgot and left a window open that night and
in the morning there must have been more than 50 of those moths in the car. That was quite sight when I opened the truck in the morning to have
dozens of those things flying in my face trying to escape. Now when I go down there anymore I just buy some bananas at the store and let them rot in
the sun in a plastic bag for a couple days. They draw in lots of butterflies during the day and the black witch moths at night. It makes for a good
nature lesson for my kids.
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Skipjack Joe
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Perhaps I used the wrong term - migration. Dispersion is better suited. Anything that flies has the ability to disperse during "rich" years. They will
remain in new territories until severe drought conditions cause die offs. Then their distribution range is reduced back to more stable regions.
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BajaBlanca
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Osprey - I have not seen that gorgeous moth around yet but i will keep an eye out. The ones we have seem to be all brown with no design on the wings.
but they are huge. and at first I wanted to call them a butterfly. But I don't recall ever seeing an all-brown insect being labeled a butterfly.
so...what is the difference between a moth and butterfly ?
also, we have these HUGE caterpillars that are now crawling everywhere and mostly trying to enter the house. I think they have some incredible sense
of temperature and are looking for the coolness of the Mexican tile we have thoughout the house ... they are gross. yuck. this city girl does not
like them !
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Bugman
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The main way to tell the difference between a moth and a butterfly is to look at the antennae. Moth antennae come in a number of shapes (including
feather like) but they always get skinnier at the tip. With one very rare exception that we need not worry about, butterfly antennae always start out
skinny and then get a little thicker at the very tip forming a club at the end. You can also go by some of the other general rules like butterflies
fly during the day and moths look a little furrier and fatter but there are a number of exceptions to those general rules. The big caterpillars you
are seeing may be those of the white lined sphinx (google the name for pictures). If they are mostly black or black and green and have a horn
sticking off one end then that is cetainly what they are. These are harmless and no need to be worried unless of course you like to be
worried.........
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Skipjack Joe
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Quote: | Originally posted by BajaBlanca
also, we have these HUGE caterpillars that are now crawling everywhere and mostly trying to enter the house.
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Yum! Think of the protein.
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