Monday, July 31, 2006

ENV: Snouts!

John Branch in the San Antonio Express-News nails it!

Our state non-game invertebrate biologist Mike Quinn has produced a page of links to media accounts of the invasion. It's here:

An excellent overview of Snout Ecology by Mike is here:

The big news in these parts has been Snouts of course. But the story is larger than snouts. The past three weeks have been a huge education for me -- mostly about bugs, but about some other things as well. Over the next week i hope to post a lot of pictures and some text about the doings of the past mid-summer weeks -- snout movements and doings, the larger Lepidoptera picture, a huge revelation about Kerr County Odonates -- inluding the documenting and discovery of several species in this already well-known ode county, and a bunch of observations about hummingbirds.

Today though, to start off with a post for the 11th edition of the Circus of the Spineless, i'm going to feature Snouts. Ours are of the taxon known as Southwestern Snout, Libytheana larvata. In this regard i'm following Dr. Chris Durden, a UT entomologist who likes to spend time looking for the kind of fine detail that separates populations. His splits are not always recognized by others, but what i like about his work is that he a) has tons of data and has analyzed it thoroughly, b) he's not at all afraid to buck trends, and c) he's very open with his information. There may be others in the tight-cliqued community of lepidopterists who have other good info, but they're dang stingy about sharing it (and pretty condescending too to anyone new who shows a burgeoning interest).

Using that taxonomy for the moment, Dr. Durden has information to show four species/taxa of Snouts in Texas: L. larvata (the one showing up as the critter involved in the current invasion, L. carinenta, the primarily eastern form (which occurs west to at least Austin, L. bachmanii, and the Mexican form L. motya.

All of the Kerr County critters i've examined, true to Durden's prediction, have been L. larvata.

The education part for me comes because of a quirk of my employment. I am very active in the field every year from late August to mid-May, but i have not had a summer available to work in the field (except at my work location a little) since 1971. Because of that i have been unable to witness much less document many of the summertime dynamics of vertebrate and invertebrate, heck even flowering schedules, in all that time.

This year however i changed jobs in April and for the first time in decades have been able to actually get out and do some real investigative work. Perhaps a drought year was not the best year to begin with, but i think the drought itself has exacerbated a lot of natural phenomenon and perhaps focused emergences such that they became more visible.

Snouts typically are movers to adjust to environmental extremes. That is why they are undertaking what looks like a reverse migration. They are moving north to find foodplants (the genus Celtis) that has not been ravaged by drought.

I grew up in the lower Rio Grande Valley where Snout explosions are fairly frequent. They were always fun but hardly ever a surprise. Huge movements of course might make the news as this one has. And in this age of mobile news crews and citizen newsmaking a big migration was ready made for attention.

In the 20 years i have lived in Kerr County, i have seen a huge movement of Snouts twice. I can't recall the specific years right now, but at least one was related to drought -- i remember going to check out some ponds to see if they were concentrating migrant shorebirds. The ponds were dry, but no matter i could hardly see the cracked bottoms for the Snouts passing through.

This year i was envious, because even though i have my summer available to me, the other aspect of my new job is that i have access to 7700 acres of new territory to explore at will, and am using that to add to my years-long project of documenting the fauna of the county and area. I have already compiled a list of 1500 species of fauna and flora for just the Ingram 250-acre site, and there is much to be done (like working with 4500 photos of unidentified moths!). The envy comes from reading Tom Collins reports of Snouts migrating at his place -- just 15 miles east -- and yet i had no movement going on here at all.

I did have a Catalpa tree outside my office that one day was suddenly covered in Snouts. All without my having detected migration. A little shake of a limb would cause the tree to explode. A few days later i found another catalpa on the grounds with the same horde of Snouts.

By Thursday however, there were Snouts moving here as well -- thousands. Then an overnight rain quelled it somewhat. Now i'm back down to the hordes at the Catalpa, and today a sudden discovery by them of the hummingbird feeders outside my office window. The hummers don't know what to do. They had finally adjusted to the bees, and now along comes these flashy winged things.

The other thing that's happened in the last week is the appearance here of large numbers of other butterflies. Whether because of drought or other reasons, i have been unable to locate more than a handful of species and individuals all spring and summer of anything (except moths)! It's been disappointing because after several years of increasing numbers and rarity of cool Mexican species showing up in the Valley, i was hoping that some things would be moving north.

So, we have some decent gardens here, and i was really hoping for a good summer of butterflies. But alas nothing. Until this week, and whether they're moving along with the Snouts, or the rains spurred some emergence is irrelevant to me -- i just know i suddenly have leps.

Among the things arriving are huge for this county numbers of Cloudless and Large Orange Sulphurs. I'd bet that the largest number of individuals of either i've ever had in the county in one day is around five -- and yet this weekend i estimated 100 of the two combined. Also arriving were large numbers of Queens, Southern Dogfaces, Lyside Sulphurs, and Sleepy Oranges.

Altogether just in the last five days i added 14 species to the property list! Besides Cloudless and Large Oranges, the other more southerly species that showed up included a single Soldier and a single Common Mestra.

The best butterfly of the week for me however was a bright but rather nondescript skipper> it's a species that i've only seen once before, and not in this county. There are previous county records for it from somewhere, but there are precious few species left in the county that i have not encountered. And this one i found eight of concentrated in a small dry swale -- Delaware Skipper, Atrytone logan. Yup, a basically eastern species that barely creeps into the Hill Country.

Alright, enough of all that -- i'll be back with commentary on Odonates and Hummingbirds in the next few days. And will likely add more to this post as well, so check back. Now, here's some snout and recent lep pictures:

Snouts on Eupatorium serotinum

Snouts on Euphorbia marginata

Snouts on Pluchea purpurascens

Snouts swarming around Catalpa bignonioides

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