Photo of the Week – October 21, 2011

Garden spiders, aka black and yellow argiopes, are one of the most recognizable spiders in many prairies (not to mention backyards).  In fact, my kids spent several weeks this August doing daily checks on one big spider in our yard, feeding it every kind of insect they could find.  They had a great time catching insects and figuring out the best way to toss them into the web so that the insect would get tangled up and the spider could rush over and finish it off.

A black and yellow argiope (Argiope aurantia) with its egg sac. Lincoln Creek Prairie - Aurora, Nebraska. (For context, the egg sac was about an inch wide.)

A couple weeks ago, I took the above photo of a black and yellow argiope and its egg sac in a local prairie.  Female argiope spiders typically lay several hundred or more eggs in the early fall, encase them in an egg sac, and die soon after.  (Remember Charlotte’s Web?)  In Nebraska, the eggs hatch in the fall, but the spiderlings remain in the egg sac over the winter before emerging the next spring.  The tough egg sac protects them from winter weather and helps protect the eggs and spiderlings from many predators.

I’ve spent this week at a big conference for scientists of The Nature Conservancy.  One of the themes of our conference has been the need to do a better job of involving people – particularly kids – in conservation.  Clearly, one of the keys to getting kids into conservation is helping them to make personal connections with nature.  I’m convinced that intimate experiences like feeding a spider, holding a turtle, or watching a butterfly emerge from its chrysalis create long-lasting impressions that shape future convictions about the importance of nature.  When my kids are older, I hope that memories of watching and feeding that big spider in our yard will be influential and inspirational to them, regardless of where they go or what they do.  Now if we could just get a big spider in the backyard of every kid in the world…

Black and Yellow Argiopes – the new worldwide ambassador for conservation!

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About Chris Helzer

Chris Helzer is an ecologist and Eastern Nebraska Program Director for The Nature Conservancy. He supervises the management and restoration of approximately 4,000 acres of land in central and eastern Nebraska - primarily along the central Platte River. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press.
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28 Responses to Photo of the Week – October 21, 2011

  1. Carol Rice says:

    When I was a kid during 40′s, we called these “banana spiders”. We had a very large “prairie” on our block – it was a large undeveloped tract which we used to explore. Banana spiders were a frequent object of our curiosity.
    On the subject of involving kids in nature, even getting them to do a leaf collection, or raising caterpillars and feeding them the appropriate host plant, are things that can introduce children to natural areas, and potentially lead them to more curiosity. Some of the children’s publications from earlier times may have great outdoor activities that involve nature.

    • Chris Helzer says:

      Carol – you’re right. There are lots of great activities that can all be helpful.

      On the banana spider – there are some very venomous South American spiders called banana spiders, but I think the name also gets applied to harmless North American spiders, including the black and yellow argiope and the golden silk spider (Nephila clavipes).

      Glad to hear I’m not the only one who has positive memories of spiders from childhood. Poor Craig seems to have gotten pushed the other way!

  2. Amazing close up shot of a very cool looking spider!

  3. Jesse Bolli says:

    “If a child is to keep alive his inborn sense of wonder, he needs the companionship of at least one adult who can share it, rediscovering with him the joy, excitement and mystery of the world we live in”.~Rachel Carson~

    So how do we make TNC, NPS, etc… attractive to both kids and their parents? How do we get parents to be that adult that wants to rediscover nature?

    • Chris Helzer says:

      Jesse – it’s a big and important question. I certainly don’t have the answer. If all of us reach out to as many kids as we can, that’ll be a start, but we’ll need some help.

      TNC is certainly trying to ramp up our efforts. Lots of other organizations have been doing a great job for years. Between all of us, maybe we can figure it out.

  4. Craig says:

    I don’t know about being ambassadors of conservation, Chris. Around six years of age while playing in a pasture, it was one of these spiders that I found racing up my arm (undoubtedly going to plunge his chelicerae into my jugular) that, 24 years later has given my a case of arachniphobia. Still gives me the willies.

  5. Wonderful blog and photos Chris. This is my first visit to your site, but certainly not my last. I’m looking forward to meeting you and learning more about your photography next month at Fontenelle Forest Photo Club.

  6. Tom Prunier says:

    Feeding garden spiders and the garden toad are almost my first memories of interacting with a wild animal. Since retirement my wife and I were lucky to fall in with folks who ran an after school nature program in VT. It’s so great to see the world again thru young eyes.

  7. David says:

    Chris,

    Do you have any specific knowledge on the egg sacs and fire? From field experience, these guys are common in areas that see frequent fire so it would seem some egg sacs get through or the spiders repopulate?

    Thanks,

    David

    • Chris Helzer says:

      No specific knowledge, but my guess is that their ability to make lots of spiders and disperse widely (through the air) lets them repopulate quickly. In addition, they’re not that picky about habitat, so they are likely to be using habitat all around the edges of frequently burned sites (road ditches, etc.) – which helps them return. It is interesting, though, that they remain common. I can’t imagine the egg sac resisting fire – though I don’t really know one way or the other.

  8. Rex Peterson says:

    Several autumns ago, we drilled a quarter mile of fence post holes and went back a week later to put the posts in the ground. I was amazed to find at least one black widow spider in almost every hole. The site was sandhill prairie half a mile from the Niobrara River.

    • Chris Helzer says:

      Wow. That’s a lot of black widows!! I’ve seen them be fairly abundant in prairie dog tunnels, so it doesn’t surprise me that they’d move into fence post holes, but that kind of abundance is pretty staggering, isn’t it? Makes you wonder where they were before you put in the holes!! Great story.

  9. James C. Trager says:

    Black widows are very shy, nocturnally active spiders that go virtually unnoticed, though they may be locally quite abundant. One evening a number of years ago, strolling down State Street in the ritzy Santa Barbara CA, I discovered that a black widow inhabited nearly every crack and nook near the base of all the trendy shops and cafes, unnoticed by the flocks of tourists, jet-setters, surfer and hippie kids, etc. (If only they knew!)

    Any above-ground living matter is vulnerable to fire, and along with innumerable critters that overwinter in or among the dry winter stems, many Argiope egg sacs get cooked. But they have numerous refuges — grassy fence rows, thickets, weed patches, etc. — and egg cocoons that don’t get burned produce hundreds of spiderlings each. The little spiders disperse on the wind on “parachutes” of long silk strands, and colonize burned sites anew each growing season. Insects that thrive on the prairie have a strong tendency to be underground, as eggs, larvae, pupae or adults, when the fires pass, or are very good disperser/colonizers.

  10. David says:

    Thanks for the fire info. Due to concerns for at-risk amphibians, we do nearly all of our burning on our property in late winter or very early spring. Ice is still on, most ground is still partially frozen, snow patches are scattered about, and many areas the top layer of ground is saturated with water (ground still frozen below). As might be expected, the higher moisture levels results in an incomplete burn. Many thicker stem plant stalks don’t burn and the fire does not penetrate into the litter layer lying directly on the ground. However, enough litter does burns that sunlight is sufficient for plant seedling development and weed control efforts are not inhibited by thick thatch. More importantly, amphibian and reptile populations are increasing. I suspect insects fare better too, but I have no data to prove it.

    David

  11. James C. Trager says:

    David – We have a burn philosophy / strategy similar to yours where I work in eastern Missouri. This shortens our season quite a bit, since the winter is not very cold here, but as you say, results in somewhat incomplete, less destructive burns that seem to leave fire refuges for creatures in soil and in the lower parts of stems.

    Re: Argiope reproduction
    These spiders, like most, only mate once, typically soon after their moult to adulthood. One or more little males lurk at the edges of the web, as the female approaches the last moult, then one successfully courts her and mates. Females store viable sperm in their reproductive tracts for the remainder of their adult lives. It’s interesting to watch the female produce the egg sac. The mother spider loses her appetitie for a few days before egg-laying, and does not build a web. When the time comes, she first produces an uncompleted upper half of the papery outer layer, then produces an inverted basket of soft yellow silk, loosely tangled to form a padded receptacle for the eggs. The eggs are laid in a single mass, extruded like salmon roe, that is pushed up into the inverted basket by upward movements of the abdomen. The eggs are held together in a spherical mass by a a slightly viscous fluid, which keeps the mass from falling out. The spider finishes the layer of yellow padding around the egg mass, then goes on to finish the outer, water-resistent but porous (for gas-exchange) outer sac, including putting reinforcing finishing touches on the upper half. The whole process takes an hour or so, and is a vulnerable period. Parasitioid wasps in the family Braconidae and Ichneumonidae may sneak in and lay eggs that hatch into larvae which can destroy the entire brood. If you should happen to collect one of these parasitized egg saccs to introduce these charming creatures into your garden, several dozen little wasps will emerge, rather than the little white, tan-legged Argiope spiderlings.

    • Chris Helzer says:

      James and David, I like the idea of burning to get patchiness and low intensity fire in terms of herps and insects. My fear would be that ONLY burning in that way would limit the kinds of objectives you can meet. You both know my thoughts on varying the season and intensity of fire and other disturbances to avoid repetition and ensure that all species get to “win” now and then. Do you worry about only burning at a single time of year and with a relatively narrow range of fire behavior? I understand the vulnerability of herps and inverts (and others) to growing season fires, but I also see a lot of larger community benefits that can come from those kinds of fires. Would you be comfortable with growing season fires on portions of your prairie(s) if you left considerable refuges?

    • Chris Helzer says:

      Fantastic spider info, James. Thanks!!

  12. We mix this burn regimen with selective mowing for sweet clover and woody plant control, and some judicious herbicide use, for perennial Eurasian legume problems and occasionally for woodies. We don’t have good fencing for grazing management in our prairie tracts, yet, but may be able to do this in the future in some areas that have been fenced to create multiple paddocks for frequent rotation of the herd grazing another part of the property.

    I would add that we have sometimes burned with a bit greater intensity when we actually hear the peepers and chorus frogs singing in the ponds, the idea being that if they’re concentrated in the ponds, having moved there during rains several days prior, they won’t be harmed. And indeed, after the fires pass, they resume singing loudly.

  13. David says:

    James,

    Incredible detailed knowledge on the garden spider. How do you know this stuff?

    Chris,

    I suspect I could vary fire more than I do. Our lowlands have been managed primarily for the pickerel frog (special concern in WI). We have an isolated population (only breeding ponds and grasslands in the area) and they do not leave the grass to breed in the ponds until summer. I have not figured out a better way to avoid mortality than burning in late winter/early spring. I do not like fall burns in this area because the heavy thatch is needed for overwintering for species like the western chorus frog. However, I suspect I could get away with fall burns as long as I avoided burning over several of the ground water seep areas (primary hibernation areas).

    We do mix it up more in the uplands. In fact, we have a fall burn schedule this year. Objective here is to interseed after the burn. I have only done limited mid/late spring burns (early May for sweet clover control) and have yet to do a summer burn.

    So, yeah, I guess I am partial to dormant season burns. So far, things seem to be moving in the right direction with increasing species diversity. With the exception of sweet clover control, I have not found a reason/opportunity for growing season burns. I know some folks like growing season burns for brush and invasive cool-season grass control, but I just can’t bring myself to hammering the spring ephemerals. I do not find fire very effective against most species of woodies, and prefer chemical treatment. We do have a CRP field that is heavy with warm-season grass that would benefit from a summer burn, but the CRP rules prohibit it (along with grazing). What is working now may not be the answer in the future. As I continue (hopefully) to learn more I suspect I’ll find reason to vary. I certainly understand the value of mixing it up, but it is difficult to knowingly do harm to a certain species by conducting a “negative producing” management practice. We suffer the same fate as many other site managers. Small, isolated natural areas surrounded by a sea of “nothing “ (ecologically speaking).

    David

  14. James McGee says:

    In Cook County, they burn only after herps have gone into hibernation and before they re-emerge. Restricting burning to this time of year still allows for considerable variation in results. Some burns completely combust all thatch. Other burns leave the lowest layers, where more moisture is present, unburned. Even though the county only does dormant season burns, they must occasionally shut down burning due to high temperatures and highly favorable fire conditions. Therefore, the entire range of permissible fire conditions is achieve even though the burns are limited to the dormant season.

    In my experience, even the least favorable fire conditions will set back woody sprouts in prairies. Sometimes cooler fires are better for the control of woody species. A low cool fire can girdle small hawthorn without killing the buds. This causes the leaves to suck all the nutrients out of the roots while giving nothing back. This proves fatal to certain small woody species. In contrast, the same species will resprout if the bud have been killed.

    The really hot fires help knock back clonal species and expand the prairie edge. A hotter fire with more wind to blow heat into the brush is even better. Unfortunately, we can’t burn during extremely favorable conditions. We have to be able to put the fire out. Therefore, in my area the expansion of prairies is mainly achieve through the use of chainsaws and Zeppi mowers.

    In contrast to prairies, I think burning during highly favorable fire conditions is really important to woodlands and savannahs. Hotter fires kill buds further up the trees. This increases light levels, which has a major impact on vegetation.

  15. David says:

    Re: Fire and woodies. I do agree fire can set back woodies, but it is only temporary in my experience. Single stems resprout to multiple stems and some species, like aspen and black locust, spread like crazy after stimulated by fire. Unless the site manager is willing to annually burn or mow sites for control, the woodies will very quickly reclaim ground. What works for us, in terms of limiting the total control effort, is to treat the root crowns with triclopyr in oil after a rain has washed the ash away from a recent burn. Very effective, and our prairies are clean of woodies other than the oak grubs and native shrubs we purposefully keep.

    Oak woodlands do require better burn conditions. We generally burn when the RH is 35% or lower and ideally the sun is shining. It also helps to have wind and slope working together. And yes, head fires are effective for reaching up higher and opening canopy. However, we rarely use them now as most areas (due to a history of burning) can be burned with flanking and backing fires. We also have reptile concern issues so backing fires and dormant season burns tend to be the rule.

    Our big nemesis is buckthorn. Fire will top kill it, but in wet years following a burn it will recover within the same growing season with multiple stems reaching up to 6 feet or greater in height. This species is incredibly difficult to control. I believe, as do others, that segments of the root mass go dormant after cutting and chemically treating only to resprout years later. I suspect that triclopyr in oil on the root crown/basal bark is the best method, as opposed to cutting and treating stems, but I need several more seasons of control to know for sure.

    David

    • James McGee says:

      David, I completely agree with applying herbicide to the woody species that you want to eliminate. I have suggested spraying the foliage when it first emerges in Spring after a burn. This allows you to get the herbicide on the freshly sprouting leaves. At this time the leaf cover is very sparse so it is easy to avoid non-target species.

      The problem with woodland burns is I have never seen a fire that is able to thin larger trees. Only the buds on the lower branches of the larger trees are killed. In areas that have not been burned in many years, use of a chainsaw is the only solution. Once the ecosystem has moved into a new ecological bowl then significant effort is required to return it to a former (more diverse) condition.

      Buckthorn is the devil. About half survive woodland fire. Our best treatment is to cut it and apply triclopyr at about 25% to 4 inches of stem for an average diameter specimen. This works best. If you use Glyphospate on a cut stump you will be reapplying herbicide at least once to restrouts. In disturbed areas where collateral damage is not a concern spray the seedlings. If you control the weeds before you start you will already be half way there.

  16. James C. Trager says:

    Good discussion here, and all started by a spider.

    B.t.w., how do I know about them? I have been making detailed observations of spiders and insects since I was a small child, and went on to do degrees in entomology.

  17. David says:

    James M,

    Spraying woody resprouts with a broadleaf herbicide is a good technique. It works best to wait until you are confident that all dormant buds have sprouted with sufficient “green matter” to take up enough chemical.

    In the driftless region of WI where I work, it is not uncommon to kill (top-kill that is) large deciduous trees with fire. Very steep slopes with a heavy, dry and continuous fuel load (usually oak leaves) will take out many trees if a head fire is used. Combine this with dry 10 and 100 hour fuels and you are in for some exciting times. As you can imagine, the flame front charges up the hill preheating all fuel. Once it encounters a tree, the flame front splits and then recombines on the uphill side. This recombining of flame fronts supercharges the heat intensity and the tree is literally scorched (bark boiled) many vertical feet up the tree. In more moderate conditions the tree is only scorched on the uphill side, but in dry conditions it will completely wrap around the diameter of the tree girdling it. I have seen trees up to 1.5 feet dbh top-killed this way. It will top-kill many oaks as well, especially black, Hills, white and red. Bur seems to be the only survivor given an ~ eight inch diameter or larger. This is not responsible burning and we usually don’t do it professionally, but it does happen (smaller scale) occasionally as the ignitor will sometimes misread fuel conditions or firebrands find its way to an opposing adjacent hill. However, others seem to only burn this way. I find it sad to see trees such as white oak top-killed by fire. And forget about finding any native shrubs in areas managed this way. Maybe I am too fussy, but with my own property I like to keep my oaks, greatly enjoy the juneberry, dogwood, plum, nannyberry, etc. blossoms in the spring, and the crazy looking hazelnut nuts that come in early fall.

    Another common way to top-kill large trees is when you have a sequence of fuel types right next to a live tree. Oak leaves ignite small branches which ignite larger branches which ignite logs lying against a live tree. Punky wood lying next to a live tree is yet another way.

    You are right. The best way to remove mature trees is with a chainsaw. Hard work, yes, but it is selective!

    David

    • Chris Helzer says:

      A fun discussion to read. I feel like I’ve lost control of this blog!! (In a good way)

      Here’s what’s running around in my head as I read this. Surely there would have been historic fires that had the intensity to kill large deciduous trees. Probably an infrequent and local event, but undoubtedly something that happened. This is probably a great example of why we shouldn’t look too hard at history as we think about managing in today’s world. Yes, it’s smart to understand the historical context our ecological systems evolved under. But we’re not in a position where we can just try to replicate the kind of historic conditions (including the full continuum of intensity) oak savannas or other systems once endured. When you’ve only got tiny fragments of the system left, you’re forced to manage each of them more carefully. So, do we manage one a particular way (for some species) and another one a different way (for other species)? Or do we try to manage each of them with a modified range of conditions? I don’t have good answers, but the questions are important to think about…

      I feel a blog post coming on…

    • James McGee says:

      In woodlands that have been over taken by sugar maples, the maples over 4 inches in diameter do not seem to be effected by fire. Other more fire tolerant trees do not seem to be harmed at all. I have observed the shrubs you mention surviving up hill head fires. Some are not even top killed by burning up slope. As removal of invasive shrubs and repeated fire increases light levels, more woodland grasses increase the amount of fuel and improve the packing. It is possible that repeated burns will improve fuel conditions to the point that larger trees will be killed. However, I have not observed this yet. The more likely mechanism is that repeated burns prevent the establishment of seedlings. As older trees die, tree slowly begin to disappear. In the instance where you have rare species that need light and are being crowded out by a great number of young maples, waiting for the trees to die of old age is not an option.

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