Orbweaver – Field Station /field-station/tag/orbweaver/ UW-Milwaukee Mon, 06 Jan 2025 17:53:25 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 The Twelve (or so) Bugs of Christmas /field-station/bug-of-the-week/the-twelve-or-so-bugs-of-christmas/ Wed, 25 Dec 2024 17:50:00 +0000 /field-station/?p=15763 Season’s Greetings, BugFans, It’s time to celebrate a dozen (or so) of the beautiful bugs that posed for the BugLady this year (and that have already graced their own episodes).  Click on each photo to read more. Great Spangled Fritillary …

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Season’s Greetings, BugFans,

It’s time to celebrate a dozen (or so) of the beautiful bugs that posed for the BugLady this year (and that have already graced their own episodes). 

Click on each photo to read more.

Great Spangled Fritillary

A butterfly on the aptly-named butterfly weed.

European Mantis

The BugLady intercepted this mantis as it was attempting to cross the road and moved it to a friendlier spot. The tiny bulls-eye in its tiny armpit tells us that it’s a European, not a Chinese mantis. Both are non-native, invited to God’s Country by gardeners who buy them and release them as pest control. (Alas, to a mantis, a honey bee looks as tasty as a cabbage worm).

When fall freezes come, they die, leaving behind ǴDZٳ𳦲(egg cases) that . Eggs in ooethecae can survive a mild winter here but not a Polar Vortex; . Every fall, The BugLady gets asked if it’s possible to keep a pet mantis alive in a terrarium over the winter. Short answer—no. Its biological clock is ticking pretty loud.

Gray Field Slug

It was an unusually hot and muggy day, a day when the cooler air above the Lake did not quite reach inland (15 yards) to the BugLady’s front door. She glanced out and saw a gray field slug extended at least six inches on the storm door. Read here for more info on gray field slugs.

Candy-Striped Leafhopper

When a spectacular insect picks an equally spectacular perch. What a treat!

Brown-Marmorated Stink Bug

This stink bug shared the hawk tower with the BugLady on a cool day in late October. They’re a huge pest in the East because they eat orchard crops in summer and hole up/stink up in your house/closets/attics/coat pockets/boots in winter, and they’re becoming more numerous here.  Remember, not every brown stink bug is a BMS. Look for the pale stripes on the antennae and on the legs.

Orange Sulfurs

They are very common, and they don’t put on airs, they’re just quietly beautiful.

Tachinid Fly

When the BugLady thinks about Tachinid flies, she pictures the bristly, house-fly-on-steroids species that frequent the prairie flowers in late summer, but tachinid flies also come in “tubular.” The larvae of this one, in the genus Cylindromyia, make a living by parasitizing some moths and grasshoppers and a few species of predatory stink bugs (for which efforts they are not appreciated, because the predatory stink bugs are busy preying on plant pests).The adults, which are considered wasp mimics, feed on nectar. 

Ebony Jewelwings

They are frequent flyers on these pages. The spectacular males usually have a metallic, Kelly-green body, but some individuals, in some light, appear royal blue.

Shamrock Orbweaver

The BugLady loves the big ArgiopeԻAraneusǰɱ𲹱., they grow slowly throughout the summer until they reach a startling size. Most go through the winter in egg cases. Some hatch early but stay inside and ride out the winter in the case, eating yolk material and their siblings, while others hatch in spring. They emerge from the egg sac, and after a few days, balloon away in the breezes. and see why, like the Marbled orbweaver, they’re sometimes called Pumpkin orbweavers.  

Skimming Bluet

Note to self: ask insects to pose on the very photogenic leaves of Arrow Arum. 

Red-Velvet Mite

The BugLady is frequently struck by the fact that the weather data we rely on was measured by instruments inside a louvered box that sits five feet above the ground, but the vast majority of animals — vertebrate and invertebrate alike — never get five feet off the ground in their lives. The weather they experience depends on microclimates created by the vegetation and topography in the small area where they live. Red velvet mites search for tiny animals and insect eggs to eat; their young form temporary tick-ish attachments to other invertebrates as they go through a dizzying array of life stages (OK — prelarva, larva, protonymph, deutonymph, tritonymph, adult). Read more about them here.

Bush Katydid

What child is this? A nymph of a bush katydid (Scudderia).

Ants with Aphids

While shepherds watched their flocks at night…… Some kinds of ants “farm” aphids and tree hoppers, guarding them from predators, guiding them to succulent spots to feed, and “milking” them — harvesting the sweet honeydew that the aphids exude from their stern while overindulging in plant sap.

Eastern Pondhawk

And an pondhawk in a pear tree.


Whatever Holidays you celebrate, may they be merry and bright and filled with laughter.

The BugLady

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Lined Orbweaver Spider /field-station/bug-of-the-week/lined-orbweaver-spider/ Fri, 17 Nov 2023 18:08:34 +0000 /field-station/?p=14460 Note: All links below go to external sites. Howdy, BugFans, When the BugLady spotted this small spider on its horizontal web (while she was officially censusing butterflies and dragonflies), she thought it might be one of the sheet-web spiders. Fortunately, she …

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Note: All links below go to external sites.

Howdy, BugFans,

When the BugLady spotted this small spider on its horizontal web (while she was officially censusing butterflies and dragonflies), she thought it might be one of the sheet-web spiders. Fortunately, she has a Spider Guy, and he set her straight (thanks as always, BugFan Mike). 

Turns out that it’s a small orbweaver called the Lined orbweaver (much has been written in BOTW about some of the larger species in the orbweaver family Araneidae). 

Orbweavers, famously, spin circular/orb-shaped trap webs (the silk that makes up the radii isn’t sticky but the silk in the spiral is). The spiders often hang from the web’s center during the day, or they hide in a nearby retreat. They monitor the vibrations of the web, and when an insect sticks and struggles, they’re all over it. Harmless prey is bitten, stunned, and , but prey that bites back or stings is wrapped and immobilized before the coup de grace is delivered. One source said that the orbweavers are the only spiders that chew their food. 

Many orbweavers (but not this one) spin their webs at night and eat the day-old web, thereby recycling the proteins.  They have eight eyes and poor vision, and they communicate via vibration and chemicals (pheromones). According to an article entitled “Orb-weaver spider uses web to capture sounds” on a Cornell University College of Arts and Sciences Animal Behavior website, “Orb weaver spiders are known to make large webs, creating a kind of acoustic antennae with a sound-sensitive surface area that is up to 10,000 times greater than the spider itself” (another article said that they “outsource” their hearing). They both can and will bite (not dangerously) if mishandled, so — don’t.   

There are more than 3,100 species of orbweavers throughout the world.   

THE STABILIMENTUM RABBIT HOLE

Some orbweavers, especially those that are active in the daytime, that spin webs in the open, and that leave the webs up for a few days (like spiders in the genus Argiope), take the time and energy to produce a heavy silk and to weave it into a non-sticky, thickened area in the web called a “.”&Բ;Why? Short answer – no one knows for sure, but stabilimenta might serve different purposes for the various species that deploy them. Nocturnal spiders and those with unobtrusive webs don’t make them.

Originally, scientists believed that these structures strengthened the web (hence the name), but the silk is only loosely attached, and the web fares just fine if the stabilimentum is removed. 

In other hypotheses, the stabilimentum:

  • provides ; 
  • fools potential predators into ;
  • reflects UV light, like flowers do, and therefore attracts insect prey (but – the silk isn’t sticky, and an insect that flies into it won’t get stuck);
  • makes the surrounding web less noticeable by comparison;
  • attracts the male of the species when the female is receptive;
  • is part of the spider’s thermoregulatory strategy;
  • and/or, protects the web by making it more visible to birds that might blunder through it (though some spider predators have learned to search for stabilimenta).

Addenda: In experiments, some researchers have noted that webs with stabilimenta catch 30% fewer insects, presumably because they are more visible, but other equally reputable scientists say that webs with stabilimenta catch up to 41.6% more prey.  Sated spiders seem more likely to make stabilimenta. Some species change the shape of the stabilimentum as they age.  

The BugLady thinks it’s just grand that these things haven’t been figured out yet.

THE LINED ORBWEAVER (Mangora gibberosa) is the most common of the seven members of its genus that occur north of the Rio Grande (gibberosa is from a Latin word “gibber” meaning “hump-backed” and “osa” meaning “full of” or “extremely”).  Another 180 or so genus members live in Central and South America.  Lined orbweavers are found in open areas – gardens, grasslands, roadsides and woodland edges – in the US east of the Rockies and into Canada. 

These are , with females measuring ¼” and less, and males much smaller.  Like other orbweavers, they come in a range of colors, with some with more lines, and some with more spots:

  •  and here’s a

The webs they build in sheltered areas in grass or brush may be horizontal or slightly angled and are sizable webs (about 12” across) for such a small spider. They have a “bull’s-eye” stabilimentum that is sometimes open and  and that is often occupied by its resident during the day.  

The “Arachnids of North Carolina” website tells us that in October, it “builds web at dawn orienting its web perpendicular to the rising sun, to warm up in its web quicker.”&Բ;And, adds the  website, “Such orientations to sunrise would maximize the surface area of the body exposed to insolation and allow the spiders to warm quickly during the coolest part of the day. A quick warmup in the morning may be advantageous to prey capture, particularly during the cooler months of the year.”&Բ;

Female Lined orbweavers conceal their egg sacs by folding a leaf around them and webbing it shut. Although the eggs within the sac hatch in fall, the tiny spiderlings stay inside the sac through winter (absorbing yolk material in their abdomen) and emerge in summer. 

The tiny Lined orbweaver, of course, is up against competition from other spiders as it tries to make a living. In a study published about 15 years ago, Richardson and Hanks looked at the division of potential prey among four species of orb-weaving spiders living in close proximity in a grassland.

As suspected, it was not a zero-sum game – the spiders survived by occupying different niches within their habitat.  The researchers noted the spiders’ sizes, the web size and height, the density of the webs’ “mesh,” and the kind of plant that the web was attached to. They found that spider size (and therefore the size of prey they were able to subdue) allowed a variety of species to coexist.

The BugLady

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