Wednesday, August 19, 2015

Black & Yellow Garden Spider

Black & Yellow Garden Spiders (Argiope aurantia) are found throughout the United States and are one of the most commonly seen spiders in Missouri. They build elaborate webs at the edges of field and meadows or crop ground which earned them another common name of Corn spider. You may also find them in their webs on the eaves of your home, or on your porch railings. Also look for them around outbuildings.

Their webs are unique structures measuring up to 2 feet in diameter with a stabilimentum running up the middle in a zig-zag pattern. There are differing opinions as to the purpose of the stabilimentum. Some researchers feel it may be a form of camouflage that aids in hiding the spider as it rests upside down in the center of the web. Others feel it acts as a lure of sorts to attract insects to the web and still others feel it may be a deterrent for birds to keep them from flying into the web and destroying it. I've even read that it may act as a stabilizer to strengthen the web and keep it from being completely destroyed by the large insects these spiders favor. Bugs like cicadas and grasshoppers struggle quite a bit when tangled in sticky webbing and can easily wipe out a well constructed web. Only spiders that are diurnal have stabilimenta at the center of their webs. So it must have something to do with other things that are also active during the day.

At the end of each day they will consume the center portion of the web, leaving the radial line that the "orb" is attached to. It may be that she consumes the web for the extra protein available from the tiny insects caught in the webbing. Or perhaps its just because webbing is a pricey commodity to create and conserving it only makes sense.

Males are much smaller than females and only measure up to .35" whereas females measure up to 1.10". Males will roam around seeking females to mate with, when he finds a likely candidate he will sit at the periphery of her web and use his front legs to "tap" out a dance of sorts that she will recognize as a possible mate and not food (if he's lucky). Once mating has taken place the male will die, having lived for the sole purpose of mating. She may consume him at this point for extra protein.

She will begin laying eggs on a thin sheet of silk, then cover them with another layer of silk. Then she wraps this all up in another layer of brownish colored silk that she will form into a sac with her legs. She is capable of laying up to 4 egg sacs containing up to 1,000 eggs within each sac. She usually places the sacs at the center of the web where she hangs out. This allows her to guard the egg sac until she dies, which usually happens when the first frost arrives. The egg sacs overwinter and hatch in the spring. The spiderlings will "balloon" to new locations and build their own webs. Many of them will be predated on by other spiders, insects, birds, frogs and other creatures fond of tiny spiders. So even though a single female may produce up to 4,000 eggs, only a small percentage of them will survive to adulthood.

Humans have little to fear from these strikingly beautiful spiders. They are not known to be harmful to humans. Bites are only likely to occur when you grab one or mishandle one. A bite is reported to be no worse than a bee sting. If you have allergies to bee venom or other insect venom, then a bite from one could be medically significant and you should seek help.

Garden spiders are extremely beneficial to gardeners and farmers alike. They feed on harmful insects like crickets, moths and grasshoppers, controlling their populations and protecting your plants and crops from the voracious feeding habits of those insects. Not to mention watching them construct their web each morning is a fascinating thing to see. They should be welcomed to live in your garden and appreciated for the help they are providing, free of charge.

Thursday, August 13, 2015

Orchard OrbWeaver

What these spiders lack in size they more than make up for in absolute beauty. The Orchard Orbweaver (Leucauge venusta) is without a doubt one of the most stunningly gorgeous orb weavers in Missouri. They belong to the spider family, Tetragnathidae , which are the Longjawed Orbweavers. This species has exceptionally long legs, especially the front two pairs, which makes them look an awfully lot like long-jawed orbweavers that they are closely related to, and which it is sometimes called. Like most species of spiders females are larger than males. Spiders are never measured in terms of legspan, but rather body length. Females may reach lengths up to 5/16ths of an inch, and males are smaller at 5/32nds of an inch. The background color of the abdomen is creamy or pearly with a series of yellow, black and orange lines running down the length. There is a sheen to the abdomen, almost a metallic look.

Look for them in low hanging shrubs, bushes and other plants especially in moist woodlands or wetlands. Like most orb weavers they build elaborate webs up to a foot in diameter for capturing insects. Spiders within the family Tetragnathidae build webs with a hole at the center where they will "Hang out" waiting for prey to fall  or fly into the web. You will usually find them hanging upside down and with their back facing the ground, so they will be placed on the underside of the web. This exposes their belly for viewing and sometimes causes them to be mistaken for black widows, which I find amazing. But, I guess if you see a reddish or orangish marking on the belly of a spider your first thought might be widow!

Mating takes place in late spring or early summer and the female will create an egg sac and deposit several hundred eggs within. She may place the egg sac at the edge of her web within the bush or shrub where she lives or she may attach it to a branch or twig. She will die by the end of the summer.  The egg sac will overwinter and the spiderlings will emerge from the sac in the spring and the cycle will begin all over again.

This is thought to be the only spider named by Charles Darwin, who we know to be the person behind the theory of evolution. The genus name of Leucauge in Greek translates to *with a bright gleam* and combined with the species name venusta which is Latin for elegant, beautiful or charming makes for a very apt name for these spiders. Although I'm not sure if spiders can be charming or not, but as evidenced here they can certainly be beautiful.

Like many spiders they will retreat when they feel threatened. Some will follow a drag line made of silk to a safe hiding spot somewhere near the edge of the web in some shrubbery, this species often drops completely to the ground to hide among the leaf litter. While this can make them somewhat difficult to find, taking a little time to search for them is well worth it to be awarded a closer look at the spectacular species.

Monday, August 10, 2015

Two-Spotted Longhorn Bee

One of my favorite bees are these tiny little bees that I always refer to as the "napping bees" because every time I find them they are grasping blades of grass, or stems of plants with their manibles and appearing to be snoozing. I find them frequently, but didn't know  what they were. I asked Eric Eaton for help on identifying these adorable little bees and very quickly he replied that they are Two-Spotted Longhorn Bees (Melissodes bimaculata). Then when I began working on this post,  I discovered I had written a post about them many years ago. I had completely forgotten this entry to my blog, and what I had learned at that time about the ID of these bees. The ironic thing is....I had asked Eric at that time to ID them! My only excuse is that it was 6 years ago....or maybe I am just getting old and forgetful.

If you'd like to learn more about Eric and his passion for all things buggy please visit his wonderful blog Bug Eric

There are 119 known species within the genus Melissodes, and most species are solitary ground nesters and will dig a burrow within the soil and line it with a wax-like substance that they secrete. This habit of digging their burrows earned them the common name of Digger Bees. A few species within the genus are communal and will nest in small community nests.  Cuckoo wasps with the subspecies of Triepeolus use the offspring of these bees as the host for their own offspring. Being a solitary nester means you have no family to protect and therefore not prone to being defensive.....there is nothing to defend. This is unlike Honey bees or bumbles bees which guard honey stores, offspring and a queen.

Honey bee hives may contain upwards of 40,000 individuals, nearly all of them females that provide food for the adult hive members, as well as the offspring of the queen. They also care for the queen since her only job is to lay eggs. These little workers also guard the hive from invaders, clean the hive, air condition the hive, and communicate with the colony where food is available and how to find it. They have a very complex lifestyle and much to lose should the hive become threatened, so it stands to reason that they would be somewhat defensive near the hive. However, when they are out foraging for food they rarely sting unless provoked or accidentally stepped on or grabbed. 

The little digger bees got the name longhorn from the long antennae the males possess which are much longer than most bees. For those who are familiar with these bees this is apparently a great way to identify them. This particular species also has two yellowish-white spots near the tip of the black abdomen. These two spots earned them the specie name of bimaculata, which means translates into *bi* (Two) *Macula* (Spot). 
They also have long yellowish colored hairs on their hindlegs. Females are approximately a 1/2 inch in length, males are a bit smaller at 3/8 of an inch. 

The adults of these bees seem to prefer plant nectar from daisy's, asters and coneflowers. They are a very common sight in the mid to late summer months. I have a tremendous amount of coneflowers in my gardens which must be why I see so many of them in my yard.

When evening nears and the sun is riding low on the horizon slowly walk along the plants and flowers in your yard, or a nearby field or meadow and you might spot these little bees tucking in for the night.

Friday, August 7, 2015

Common Water Strider

Water Striders are unique, and interesting insects that are often found skimming across the surface of the water in lakes, ponds, rivers and streams. The one pictured here is the Common Water Strider (Aquarius remigis), and is possibly the most common water strider found throughout North America, especially in the Midwest. Many people refer to them as water spiders, however they are not arachnids at all, but rather true bugs in the order Hemiptera and family Gerridae.

Have you ever visited a clear stream and noticed shadows passing across the pebbles and debris on the stream bed? Those moving shadows are often the first thing you see of these insects. Upon closer inspection you will see the insect causing those shadows as it moves across the water. Striders have specialized hairs on their legs that help them repel water, which allows them to glide (or stride) across the surface of the water. Their bodies have velvet-like hairs covering them which also repels water keeping them dry despite the fact that they live an entirely aquatic life. 

This is a fairly large species with body lengths up to 3/4 of an inch, but with their elongated legs they look much larger, nearly the size of a quarter in diameter. Their bodies are dark brown, or black and the margins are white. All the literature I read claims the adults generally lack wings, so I assume this means there are a few individuals that may be able to fly.

To find mates they will send ripples across the surface of the water that other striders will recognize as a potential partner. After mating, females will lay eggs on the rocks, logs, water plants or other items in the water. After a few weeks the eggs will hatch and the nymphs look almost identical to the adults only much smaller. After several molts they will reach adult size and sexual maturity. Once mating season is over they will often congregate in large groups all randomly moving in circles. If disturbed they will scatter and hide in cracks, crevices or other secluded areas away from danger. Birds are fond of eating water striders and will often prey on them. Given their aquatic life, you might assume fish would eat them. This however does not seem to be the case as fish rarely consume them. Maybe they give off a defensive substance that fish find distasteful.

Water striders, like many true bugs are predators and feed on other insects and spiders. They have sucking mouthparts and specialized enzymes in their saliva that aid in paralyzing and partially digesting their prey. Bugs and spiders that happen to fall into the water are quickly targeted and consumed by striders. If it is a particularly large prey item, several striders may share, like a communal meal. In the case of smaller prey items they will often fight to keep their meal or run away quickly when another strider approaches. Which is what the one pictured here did. Several other striders attempted to take her insect from her and she wasn't having it! She spent 10 minutes running from place to place to avoid other striders, before finally being able to enjoy her meal in peace. They are also known to feed on mosquito wigglers, which makes them hugely beneficial to humans. After all none of us likes mosquitoes!

Even though they are harmless to humans, a bite from one of these would be a somewhat painful experience. Like most true bugs that piercing mouthpart they use to capture and kill insects can also pierce human skin and the enzyme in their mouth can cause irritation at the bite site which might result in itching or redness. 

I can't think of much I enjoy more than sitting on the shore of a crystal clear stream, and listening to the birds singing, and feel the cool breezes blowing off the water and watching the water striders skate across the surface of the water with no particular place to go.

Tuesday, August 4, 2015

North American Millipede

The North American Millipede, or as it is sometimes called American Giant Millipede, and Iron Worm(Narceus americanus) is found throughout the Eastern United States and can reach lengths up to 3 inches or more. They are much larger than any other species of millipede found in the United States.

Millipedes show up in our basement once in awhile that are about 1 inch in length and light tan in color. I recall one year after record amounts of rainfall we had literally hundreds of them creeping across the basement floor. Millipedes are attracted to moisture and it is common to find them in cellars, basements and along foundations of houses and other manmade structures. Narceus americanus however is a forest dweller and will be found in moist, deciduous woodlands among decaying logs and other organic matter on the forest floor.

The one pictured here was photographed in Tremont, TN on the Spruce Flats Falls trail at the Smoky Mountain Institute. My husband and I had hiked 1400 feet uphill for 1 1/4 miles to view the waterfall and on our way back down I spotted this millipede on the primitive trail after nearly stepping on it. I picked it up and placed it in the mosses and lichens along the side of the trail.

 These millipedes are black or dark brown with visible reddish coloration between the segments. Millipedes also have two pairs of legs per body segment, rather than one pair per segment like centipedes. Millipedes feed on organic matter like fungi and other decaying plants, but may also feed on decaying animal matter as well. They are important decomposers in the environment where they live. There are some species of millipedes that are capable of producing a cyanide-like substance that can be harmful to humans and cause bad reactions. This species however does not produce any such substance. They do have a milder secretion they produce that may cause skin discoloration in sensitive individuals who handle them.

Despite the fact that they have so many legs, they are not known to be quick. But I must say this one moved much faster then I expected which made photographing it somewhat difficult. I kept having to catch it and place it back in position only to have it scurry off again before grabbing it, placing it back and lining up the shot again. After some patience and persistence I finally managed a few pictures and a couple of videos on my phone.

Millipedes are often long-lived creatures and may have a lifespan of more than 10 years. This species can live several years and will overwinter in leaf litter or old logs. They emerge in the spring to mate. Most millipedes will lay more than a hundred eggs after mating. From all the literature I read and after numerous internet searches it appears that this species only lays one egg. The female will eat some soil and defecate to form a nest of sorts and will lay a single egg within that nest that she will guard until it hatches. The newly hatched nymph will be a smaller, incomplete version of its mother with only 7 segments and 6 pairs of legs. It will gain a new segment each time it molts before reaching adult age. They reach reproductive age at about 2 years.

There are a few predators such as birds, frogs, some lizards and especially shrews that will feed on millipedes. Most animals however will not eat them because of the foul smelling defensive secretion they emit when threatened. This substance tastes bad and most animals will avoid it. The one pictured to the left had somehow died and this opportunistic daddy longlegs found it and made a meal of it. They may also coil themselves into a tight ball to protect their delicate belly from harm.

Look for them in woodlands all across the Eastern United States. These are unique, interesting and beneficial arthropods that are completely harmless to humans. They turn organic matter into nutrient rich materials that greatly benefit the soil and should be left alone and admired.

Sunday, August 2, 2015

Spotted Orb Weaver

We've spent the past week vacationing in the Great Smoky Mountains near Townsend, TN. We rented a cabin in the woods and I expected to see plenty of wildlife. I must say I was somewhat disappointed in the amount of bug life and other wildlife we spotted near the cabin. However, I did spot this gorgeous spider in a web on the spindles of the deck. I'd never seen one quite like her and was anxious to photograph her....much more anxious than her I assure you. She was on the opposite side of the porch so I could not photograph her, instead I captured her and took her to a location to make snapping some photos much easier before placing her back in her web.

I posted her image to bugguide and had an answer within hours as to what she is. Spotted Orb Weaver's or Red-Femured Orb Weaver's (Neoscona domiciliorum) are found throughout the Southeastern United States from the New England States, to Florida and across to Texas. There are no known populations in Missouri where I live and typically post insects and spiders from. However that could just be because no one has reported seeing them. Tennessee is our neighbor so it would not be too much of a stretch to expect them to be here, especially in the bootheel. It is always fun for me to find species I've never seen before.

Like all orb weavers they build elaborate webs to capture insect prey. Each morning they will consume the web; silk is a precious commodity and takes a lot of energy to produce. Then at dusk each day they will build a new web which it takes a surprisingly short amount of time to do. I've seen orb weavers of other species build entire webs in less than 15 minutes. Late in the season they may leave their webs in place for longer periods of time and not concern themselves with dismantling it and rebuilding when other things are on her mating and producing an egg sac. Any energy conserves that she has will go towards forming an egg sac and laying eggs and not so much towards web building.

As you can see by the above picture they are quite speedy too when confronted with a ME. She scrambled away several times and I nearly couldn't catch her. I finally took pity on her and took her back to her web where she had a nice, juicy bug waiting for her to eat that she had captured sometime that morning or the evening before.

 Spiders are measured by their body length without the legs factored in. This species is between 9/23 of inch to 5/8 of an inch. If we count her legspan she was about the size of a half dollar, so pretty large for an orb weaver. Their abdomen is grayish in color with two broad black strips down each side and a white band down the middle in somewhat of a cruciform shape. Legs are red at the first segment, then further down they are gray and black banded. The underside of the abdomen is dark with 4 white spots and a red tip near the spinnerets. Males are smaller and less bulbous in appearance than females.

Look for them in woodlands where hard wood trees are prevalent. They often build
their webs across man made walking trails, and if you've ever walked into a web you know how quickly you can invent some ingenious dance moves in the fear the spider is now crawling somewhere on your person. They will also build their webs on man made structures like cabins in the woods. In fact their species name of domiciliorum literally translates into "of dwellings" and probably refers to their habit of building on human dwellings.