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Welcome to austinagrodolce … My family and I garden with more intention and enthusiasm than allocated budget or overall design plan. It shows. Wildlife populations don't seem to notice our lack of cohesive design, they just like the native plants here. It seems by growing local we've thrown out a welcome mat. Occasionally, we're surprised at who (and what) shows up.



Wednesday, June 3, 2015

Wildlife Wednesday - June Drips Dry

After the big wetting down our area experienced last month I'll venture everyone in Central Texas, gardener or not, has begun keeping a closer eye on the weather long range, and the skies, short term.

We've all turned to various sources for updates and information in attempts to understand what happened and why.  All except for the wildlife, that is.  Long lived denizens or one season wonders, the various populations of wild creatures in our area are all coping as best they can with fluctuating local conditions, one day at a time.

Native bee populations have been significantly shifted due to the ongoing presence of standing water where usually there is nothing but dry ground. Carpenter bee numbers seem relatively unaffected, and I've seen many of them out and about whenever the sun shines.

This one, a male judging by the large size of the eyes, is probably Xylocopa virginica.  It seemed to be satisfied to simply hang in mid air, without working nearby flowers.  Perhaps it was eyeballing fence posts for potential new habitat, or was simply stretching its wings after having spent days cooped up in brood galleries while heavy rains fell.  I empathize.
After recent rains I could not wait to get back outside, but once I did I was not always happy with the welcome I received.  Mosquitoes in particular seemed happy - SO happy! - to find me.  I was surprised to read that there are several different species of "flood mosquitoes" (Psorophora, Ochlerotatus, and Aedes genera) who lay eggs well above normal water lines.  The eggs wait in dormancy up to several months until waters rise and trigger immediate hatching.

These mosquitoes emerge swarming and hungry, but are not typically the carriers of any serious illness.  A second wave of flood mosquitoes can be expected 10-14 days after the initial rise of waters, so we have that to look forward to.  I'll warrant there is currently not a single flood mosquito egg left high or dry in all of central Texas.

Though it is significantly annoying to be relentlessly attacked by biting insects with each foray outside, this "bloom" of bugs serves as a boon to all the many insect eating creatures, who are all working with rain scrubbed habitat and the potential depletion of many of their other ground dwelling meal tickets. Mosquitoes as a silver lining to recent clouds?  It all depends on what you like for dinner.  Or who...

Recently my eye was caught by a flash of white in a patch of Virginia creeper (Pathenocissus quinquefolia).
What I believe to be an Achemon sphinx (Eumorpha achemon) caterpillar is carrying the spun silk cocoons of developing larvae of a parasitic wasp, Cotesia congregata.  

While I was vaguely aware that some wasps utilize caterpillars as hosts for their developing larvae, I had the idea the caterpillars were paralyzed as part of the process.  That meant I was especially startled when this caterpillar began to move slightly after I relocated it into a sunnier spot for close-up examination.

Achemon cats are one of several "hornworm" caterpillars, and are known for a defensive whipping back and forth motion, used to startle predators into dropping them to the ground.  This caterpillar was exhibiting a very faint version of that defensive mechanism but if I'd have been holding it up, I'm pretty sure I would have dropped it in a big hurry.  Realizing the caterpillar was not only alive but responsive, and seeing that the creeper stalk it attached to had been chomped on fairly recently, I knew I had some information gaps to fill.

What I found out was equally disturbing and fascinating.  Cotesia congregata wasps inject their future nurseries with genetic material that seems to both slow the host's metabolism, allowing it to eat (and eat) without moving forward in the metamorphic process, and to simultaneously provide interior hosting space for the wasp's eggs without triggering an immune response.

Some caterpillars reportedly reach relatively enormous size before succumbing, never reaching their reproductive moth stage.  Talk about arrested development.

After a period of time the wasp eggs hatch and the larvae exit the caterpillar, attach, and spin themselves a silk cocoon for pupation. Eventually the adult wasps emerge from the end of their silk cylinders and fly off to begin the cycle anew.
As hornworms can cause major damage to vulnerable cultivated crops, these wasp hitchhikers are considered beneficial insects, one of nature's many checks and balance systems.  I'm not growing tomatoes this year and though we have wild grapes they all fruit high in surrounding treetops, so these hornworms have been welcome to feast undisturbed, except for this one.  After taking a closer look I carefully relocated the caterpillar back into the creeper undergrowth, where the wasp cycle will complete without further interruption by curious humans.
Nearby a backlit small garden spider, (Argiope aurantia) had established its web for the day.  Notable for the stabilimentum, or stabilizing denser zig-zag silk center, these spiders reweave that portion of their web each day, after having consumed the silk, potentially to recycle the chemical components.
If she has chosen well, this spider will continue to use this location for the entire season.  I'm looking forward to having this lovely spider as company in the garden, weaving her daily web centers in amongst the inland sea oats (Chasmanthium latifolium).  
Not so beneficial, Aztec spur-throated grasshopper babies (Aidemona azteca) are numerous and causing damage to leaves and blossoms all around the gardens again this year.  While I've managed to capture and dispatch a couple of the dowdier brown adults, these brightly colored early instars often perch like tiny insouciant jewels, glittering in amongst the holey damage created by their incessant eating.
Also appearing in larger numbers than ever before, snails of every size and shape have been taking full advantage of a temporarily wet and therefore more easily traveled world.
It has been impossible to walk around the paths without accidentally crushing some with every other step, the telltale crunch giving them away even when their size is too small to easily detect.

Well hidden by placement and coloration rather than size, this fritillary chrysalis continues to develop, whatever the weather.  Watching this one develop during the course of some of our rainiest hours, I am encouraged that native populations have developed good coping mechanisms for all the worst the Texas weather has to offer.
And here is a mystery yet to be revealed, or perhaps unraveled...  This tiny ball of what appears to be an insect silk of some sort, might harbor spider eggs, or it might be silk cast off and set aside for some other purpose.  After admiring it I resisted the impulse to open it for inspection, choosing rather to try and check it daily to see what develops.  Anybody seen one of these before?
We've had the usual assortment of avian visitors, many of them overheard more than seen.  Wrens, mockingbirds, blue jays, cardinals, woodpeckers, tufted titmice, golden finches and chickadees, all are out and about, enjoying a return to more normal circumstances.  Including this non-feathery familiar...
 who joins me in wishing you a most pleasant June!

Thanks to Tina, of My Gardener Says for hosting Wildlife Wednesday, the first Wednesday of each month.  Please visit her site to read her post and other contributors as linked to in the comments section. In fact, we'd love for you to join in all the fun.  Please consider sharing a post of your own, as we observe and salute the myriad wild creatures who so generously share their spaces with us.  Rain, or shine.

24 comments:

Debra said...

As always, thank you for the amazing images. You always have the most charming anoles visiting! I have to say that the caterpillar parasites are kind of horrifying. I imagine that just has to be a world of pain for the host. Or is it? Maybe the paralytic numbs them? Who knows. Fascinating in a gruesome way.

TexasDeb said...

Debra: I was aghast when the caterpillar moved - I'd assumed it was paralyzed. Since it was otherwise still I've decided it was not in pain despite all the extracurricular activity. I'm not even sure how pain would be experienced in a creature with this sort of rudimentary nervous system. And though I found the concept ghastly on the individual level, the way the parasitic wasps have developed a use for injectable genetic materials that works to their advantage was absolutely fascinating in the abstract.

Thanks about the images. I really do try! : )

Travis Heights Garden Mama said...

Nature! Fascinating pictures of the parasitic wasps. And yes- good carpenter bees are everywhere (and mosquitos, too). Beautiful pictures!

Tina said...

Great information on the mosquito species--I knew there were several, but didn't know the specifics of their remarkable survival mechanisms. I hate them.

I like the fact that the wasps parasitize the caterpillars, especially of species that are not wanted or desired in the garden, but it reads (and looks like a horror show). Though I must say that your photos are fab.

Aren't the carpenter bees just the most charming things EVER? Unlike the mosquitoes, I love them! Thanks for your WW post--so great, as usual.

Shirley said...

It's always fun to view such an array of wildlife accompanied by your interesting and informative narrative. The parasitic wasps are especially fun when they select tomato hornworms as their host.

TexasDeb said...

Travis HG Mama: Thank you! I think there must be a new batch of carpenters out looking for homes - they are everywhere lately. I love watching them even if it usually means sustaining mosquito attacks. I'm not in a hurry for things to dry all the way out but I am so tired of itchy bites!

TexasDeb said...

Tina: Haha. I too hate mosquitoes with a passion. Every year The Hub and I get into a tussle over whether or not to spray. He (being a nearly retired physician) is all about their potential as a health threat and I just can't see spraying when that method of toxin delivery is so non-specific and of dubious value. This year I bought him all sorts of sprays he can use on his-own-self and we'll see if that solves our impasse.

I used not to notice carpenter bees - I thought they were all bumblebees. It was your enthusiasm for pollinators in general and bees in particular that helped me realize I was seeing different bees - all sorts. And yup - the carpenters are so much fun to watch. Such graceful flyers right up until they carom into me or our house, but then they just bounce off unharmed and get back to whatever it was they were doing. I realize this isn't the case but they just seem so durned cheerful! Bee jesters!

TexasDeb said...

Shirley: Thank you! I almost didn't include the parasitized caterpillar, I wondered if it would be too grisly. And it nearly is, except that it is a natural mechanism in play as part of a series of checks and balances between predators and prey (and crops and pests). If I am going to even pretend to garden here, I figure I can't select out for only the sweethearts but have to realistically assess all the action, beneficial or not.

Kris Peterson said...

Fascinating post, although the wasp-caterpillar story may creep into my nightmares. I'm sorry to hear you're already being plagued by mosquitoes. They sure respond quickly to environmental changes - it's too bad humans don't.

Rock rose said...

One can only hope that the caterpillar is not in agony throughout this process. Of course we all know how agonizing invasions can be for humans so I doubt that nature has taken that into consideration. I can just see you stalking around in the garden looking for natures little treasures. Fascinating post.

TexasDeb said...

Kris: Drought or not we've always had a bit of a mosquito problem in our area. There are folks all around us who are not much for actually spending time in their yards. I wouldn't really say many of them have anything you would consider a garden. They run their automated sprinklers overnight, leaving water standing just long enough for a consistent swarm to regenerate. The Hub and I are out working on some part of our property daily, so we are easy targets. I can almost hear tiny trumpets blowing each time I exit our house "Ta-TAH! Calling all available mosquitoes! Movable feast sighted!".

TexasDeb said...

Jenny/RR: I opened a bit of a Pandora's box in my readings about this. It was reportedly precisely this situation in nature, parasitized hosts, that prompted Darwin to question that if there is a God, how could that being be considered benevolent or good while allowing for the pain/suffering apparent in nature.

A generalized consensus amongst the layperson level readings I could decipher is that the relatively rudimentary nervous system in caterpillars can register sensations triggering a response geared towards survival. Their nervous system will react to stimulus but there is no emotional response attached, nothing a human would consider "suffering". In this case, the caterpillar has been genetically modified by the wasp in ways that allow it to support the wasp's developing offspring. The immune response has been altered and whatever signals trigger the caterpillar to form a chrysalis, etc. have been disabled. The caterpillar continues to eat and eliminate waste (at least to some extent) and is potentially unaware of the tiny travelers within.

Since what I do in the garden directly impacts the wild creatures living there, I feel I have to be unflinching in my observations of what is happening around me. I feel the need to be accountable.

My daughter wouldn't look at the photos or tolerate any discussion of the situation in her presence. In retrospect, perhaps I should have put a bit of a warning at the top of the post to warn away more sensitive readers.


Linda/patchwork said...

A few years ago, I found some of those wasps on a tomato worm. Kind of creepy and interesting at the same time.
You always get such good shots.
And, of course...the anole. :)

Anna said...

You had a really fantastic assortment of critters this month! And some great information to go along with your photos. I appreciate the info about the mosquitoes. Aren't they terrible right now? I'm really impressed with the caterpillar story -- seems like something out of a sci-fi movie! The snail is quite lovely! Thanks for a great post.

TexasDeb said...

Linda: When I was still figuring out what was what with our friend the infested caterpillar, it was usually tomato hornworms that were showing up online. I've had tomato hornworms every time I've tried to grow tomatoes and never even knew about the brown ones before. Live and learn!

The anoles around here are such camera hogs. It is hard not to take a good photo the way they pose. : )

TexasDeb said...

Anna: Thank you! The mosquitoes are just awful, I agree. They are the only thing that dampen my enthusiasm for being (and working) outside. The heat I can stand, even the humidity, but the mosquitoes! They just piss me off (pardon my language) which is really quite helpful, yeah? : )

The caterpillar situation is both repelling and fascinating. I vacillated for quite a while about even posting those photos but decided gardeners are made of tough stuff. I'm glad you enjoyed the post.

Donna@LivingFromHappiness said...

Wow Deb There is so much going on there despite the floods....I know most gardeners enjoy seeing parasitic wasps in their garden....and we also have a bumper crop of mosquitoes here...we are constantly swarmed...well they are keeping many critters well fed.

TexasDeb said...

Donna: I can't say I enjoyed seeing those wasps on that caterpillar, but I did (and do) find it fascinating stuff. I am as much a nature geek as a gardener.

The floods here were especially bad this year, but flash flooding is a way of life in our area. We veer from drought to torrential downpours with very little in the way of what might be considered "regular" rain in between times. Because so many people have lawns they overwater in yards they spend no time in, neglected sources of standing water provide a constant source for mosquito populations even without flooding. Honestly the mosquitoes here are much worse than the heat I think. And the heat can be pretty bad... : ) (Texans - we are always complaining!)

Cat said...

Fascinating about the wasps. I've never seen evidence of them though. Excellent coverage! I bet it scared the beejeebees out of you when the cat moved!

TexasDeb said...

Cat: It did in fact scare me quite a bit - I nearly dropped it - injury to insult in this case I suppose. I "may have" shrieked. Just a little. Twice.

Rebecca Newcomb said...

Wow - the wasps hosting on that cat is quite a site to see. I can't say that I've seen anything like it in person before - thanks for the science lesson! I normally think of wasps as pests in the garden (other than as pollinators) since I primarily think of them as eager to sting me if I so much as glance at them, and having parasite larvae continues their pest-like theme. But, I guess if they are hosting off another critter in the garden that can be even more destructive, then really they are doing some good. It is all about perspective.

TexasDeb said...

Rebecca: These parasitic wasps are tiny, work as pollinators when they aren't turning caterpillars into nurseries, and so I think of them as quite garden - and gardener - friendly. I do have a healthy respect for other larger wasps that can be aggressive, but these teeny tiny wasps aren't any sort of threat. To humans, anyway. Thanks for dropping in!

dryheatblog said...

I'm amazed at the detail you're showing, especially the wasp eggs. I've got to see how much growth your plants have, including the larger woody trees and shrubs.

Even here, more insects than usual, but nothing like what I bet you have. I was bitten alive last evening spping a beer on the porch, and the air is bone dry and hot.

TexasDeb said...

DHB/David: The bug populations are waning a bit but that is to be expected in June. Mosquitoes are another story, but we are surrounded by folks who spend zero time outside yet water lawns to excess and judging by their eternal presence are supporting thriving mosquito populations in various places where water is left standing. We've been rigorous about putting dunks in rain barrels and keeping bird bath water fresh - we even keep plant trays emptied but since we have so much growing I think mosquitoes gravitate to our gardens from surrounding wet spots. They most certainly do find humans here to bite - we are out all times of the day and evening. Everyone in my family is sporting a ring of bites around our ankles.