Thursday, October 30, 2014
Meet the domesticated silkmoth (Bombyx mori) better known in its caterpillar state in which it is called silkworm though it’s not a worm at all. This species is an economically important insect, having been domesticated in China from its wild ancestor Bombyx mandarina about 5000 years ago. The adults have actually lost the ability to fly and also lack fear of potential predators. These changes have made the species entirely dependent upon humans for survival and it no longer occurs naturally in the wild.
What makes them so valuable is silk. After they have molted four times the larvae will enter the pupa phase of their life cycle and enclose themselves in a cocoon made up of raw silk produced by the salivary glands or to be more precise - a 900m long single strand of silk. The cocoon provides a protection during the vulnerable, almost motionless pupal state.
About 3,000 cocoons are required to make half a kilogram of silk. At least 40 million kilograms of raw silk are produced each year, requiring nearly 5 billion kilograms of cocoons.
Wednesday, October 29, 2014
|Image from ohio-nature.com|
The great spangled fritillary (Speyeria cybele ) is a well known butterfly mainly because of its large size, abundance, and widespread range. It is found in northern and central United States and southern Canada. I t is only missing from northern Canada and some of the southern states.
One part of its scientific name (cybele) means “mountain mother” or “earth mother”. The common name comes from a Latin word, fritillus, which means chessboard or dice box. Another name for these handsome butterflies is silverspots because of the metallic markings on their wing’s undersides. It is possible that this pattern, similar to a leopard’s spots, serves as camouflage when they are resting in places of dappled sun and shade spots.
Like many other butterflies, the great spangled fritillary caterpillars are very picky about what they eat. They do not go for milkweeds as do monarchs; they prefer violets instead. Without violets, there would be no fritillaries. The adults, on the other hand are thirsty for nectar of many different flowers.
Tuesday, October 28, 2014
Cockroaches are infamous in part because their presence suggests rather sloppy housekeeping. However, it is not true that cockroaches are only found in dirty and poorly-kept buildings. They can be found in any building.
Cockroaches, such as today’s species (Periplaneta americana) are also suspected disease carriers. They can carry microbes on their body including those that are potentially dangerous to humans and they are linked to allergic reactions in humans.
Their diet includes almost anything organic and that’s one factor that helped them to thrive for over 280 Million years as some fossils suggest. In their natural habitats they are valuable decomposers, which means they break down dead or decaying organisms.
The American cockroach is often seen outdoors unlike its relatives that are considered households pests, e.g. the German cockroach (Blattella germanica) that is actually from northern Africa. By the way, the American cockroach probably also originated in northern Africa.
Monday, October 27, 2014
This massive beetle never fails to draw attention. The eastern Hercules beetle (Dynastes tityus) is among the largest beetles in North America, second only to the western Hercules beetle (Dynastes granti) which has longer horns but is otherwise about the same size.
Only the males have horns which they use in combat against each other against over access to females. The adult beetles feed on tree sap and fruit while the larvae feed on decayed wood inside dead or dying trees.
It may take several years for a Hercules beetle grub before they pupate and change into adult beetles.
These insects are called Hercules Beetles because, pound for pound, they are probably the strongest animal in the world, capable of lifting over 850 times their own weight. That’s like you trying to carry six African Elephants at once.
Friday, October 24, 2014
The Horse Guard Wasp (Stictia carolina) is a type of so called sand wasps widespread in eastern North America. The species is named for the behavior of its females, which hover around horses to catch horse flies. These rather large wasps may treat us humans in a similar manner – as fly lures.
The wasps nest in the sand, sometimes in dense colonies with sometimes thousands of other wasps. A female may take anywhere from 30 to 60 flies as food to provision each one of her nests. Nests are simple burrows up to 15 cm deep, with a single enlarged chamber at the bottom. An egg is laid in the empty chamber, and the female wasp brings back paralyzed flies until the chamber is full, at which point she closes the nest and begins another.
Here a little video about horse guard wasps:
Thursday, October 23, 2014
Found across eastern North America, the Luna Moth (Actias luna) belongs to the family that includes Giant Silkworm Moths. These large moths with wingspans of up to 12 cm appear even larger because of long tails on their hind wings.
The wings of the Luna Moth are marked by eyespots - an adaptation to scare off potential predators. The eyespots are especially noticeable against the uniform pale green of a Luna Moth's wings. Another obvious characteristic are the large, feathery antennae. In the male Luna Moth, these receptors are especially large and used to pick up minute traces of pheromones--chemicals released by the female that allow males to track her down in complete darkness.
The caterpillars, which reach lengths of 8 cm, are voracious eaters that dine on leaves of hickories, walnuts, birches, Common Persimmon, and Sweet Gum. Like other caterpillars, their multiple mouthparts are well adapted for chewing, and they easily make short work of a tasty leaf.
Wednesday, October 22, 2014
Stink bugs like the Green Stink bug (Chinavia hilaris) are large, oval or shield-shaped insects. They are members of the insect order Hemiptera. They get their common name from the odor of the chemical that they produce in glands on their abdomen. This odor is a defense against predators.
Many species of stink bugs feed on plants. Green Stink bugs eat a wide variety of plants. In fact, they eat just about anything. Some of their favorite food sources are Black Cherry, Flowering Dogwood, Evergreen Blackberry, and pine trees. They will suck juices from leaves, flowers, fruits, and stems. They have sharp mouthparts which they use to pierce the plant. Some stink bugs become serious pests of crops. When they attack fruits, like peaches, they make the fruit unfit for sale.
Stink bugs overwinter as adults and become active in spring when temperatures rise above 21C.
Tuesday, October 21, 2014
Sawflies like today’s Willow sawfly (Nematus ventralis) aren't actually flies. They belong to the insect group Hymenoptera, which means that they are related to wasps and bees. Adult sawflies are inconspicuous wasp-like insects that do not sting. Some of them mimic stinging wasps.
Their larvae are plant feeders and look like hairless caterpillars. The most distinguishing character between sawfly larvae and caterpillars is the number of prolegs (fleshy, leg-like stubs) on the abdomen. Caterpillars have 2-5 prolegs on the abdomen, while sawflies have 6 or more. When alarmed, the larvae thrash their back ends in the air (see photo).
Sawflies often feed in groups and can quickly defoliate portions of their host plant. There are many different species of sawflies and each prefers specific plants or groups of related plants. I guess it is obvious what the Willow sawfly prefers to feed on.
The females use a sawlike organ to deposit their eggs in leaves or twigs, hence the name sawfly.
Monday, October 20, 2014
The large milkweed bug (Oncopeltus fasciatus) is colored orange-red and black. It has a long a long, thin tube that forms part of the mouth which is named proboscis. With that it pierces into plants and sucks their sap. As the name says, it feeds on the seeds, leaves and stems of milkweed. Milkeweed bugs are found in small groups. This behavior is likely meant to enhance their warning coloration.
Because this species feeds on milkweed it is fairly safe from predators. This is similar to the Monarch butterfly, whose larvae also feed on milkweed. Certain chemicals in the milkweed sap, called cardiac glycosides, are toxic which makes the adult safe from most predators. Interestingly the chemicals are not toxic to the milkweed bugs but they have the ability to store them. In order to warn potential predators the bugs wear this warning orange color.
Friday, October 17, 2014
|Taken from bugguide.net|
Mantisflies (Mantispa sayi) are pretty weird looking creatures. Imagine somebody shrinking a praying mantis and attaching its front end to the hind end of a lacewing. Don’t know what a lacewing is? No problem, just check out this Wikipedia page.
The adult mantisfly is a predator, using its big front legs to catch small insects in the same manner as a praying mantis. As larva they are predators of spider egg sacs.
A larva hatches from its egg and may seek a spider upon which it rides until its host spins an egg sac. If the spider happens to be a male, the larva will wait until it mates, in which case it moves over to the female. Once inside an egg sac, the larva changes into a grub that feeds on the eggs and hatched spiders until nothing is left. Then it pupates and later an adult emerges from the empty egg sac. The adults can have very different sizes depending on the amount of food they had as larva. This is very unusual in the insect world as most other species have more or less similar sized adults.
Thursday, October 16, 2014
Potter wasps such are all solitary which means they live alone and not in large colonies. The species I picked for today’s post doesn't have a common name, only a scientific one (Eumenes fraternus). So let’s stick to potter wasp for now.
The female potter wasp builds a miniature pot out of mud in which it lays an egg, hence the name for this group. The animal does that by collecting a drop of water and then a dry particle of soil, mixing both and putting it in place. Several hundred such fragments will be needed and the pot may take one or two hours to build.
Once the egg is laid the females hunt and paralyze caterpillars, which are then stockpiled in the pot for their offspring to feed on. When she has placed enough provisions in the pot, the wasp seals the top and flies off to build another nest.
By the way, as adults the potter wasps are strictly vegan, they feed only on nectar and pollen.
Wednesday, October 15, 2014
|Image from miracleofnature.org|
Mole crickets such as the Northern mole cricket (Neocurtilla hexadactyla) are nocturnal subterranean insects, in other words they are active at night and life underground. They are well built for their underground existence, complete with spade-like front legs. This adaptation is very similar to that of moles, hence the name.
Today’s species can fly powerfully but only when they need to change their territory, or when females are searching for singing males. Some crickets may fly as far as 8 km during the mating season. Mole crickets are active most of the year, but spend the winter in hibernation.
Mole crickets amplify their song by chirping in a burrow that they've carefully sculpted into the shape of a ‘U’ with two speakers at each end, which acts as a megaphone. Singing usually starts at dusk, often after rain, and ceases within a few hours. The songs of mole crickets are deeper than those of typical crickets and many people have attributed them to frogs.
Tuesday, October 14, 2014
crane flies, but they have two pairs of wings, not one pair like crane flies. Actually many species such as the black-tipped hanging fly (Hylobittacus apicalis) are hunting crane flies in particular.
Hanging flies are often found in open woodlands and forest edges, flying slowly and hanging from twigs, grasses, or leaf edges by their front feet, or by the front and middle pairs of feet. The hind legs are used to capture insect prey, either while hanging or while flying upward along plant stems.
Today’s species has the habit of resting with its wings outstretched to the sides, while all other hangingfly species hold their wings folded down rooflike over their abdomen.
Hangingflies are not flies. They belong to the same group as the scorpionflies, the insect order Mecoptera which is Greek for long wings.
Friday, October 10, 2014
Oecanthus fultoni, also known as the snowy tree cricket or thermometer cricket, is a species of tree cricket from North America. This cricket is probably one the most famous insects as it made an appearance on the T.V. show The Big Bang Theory when the main character Sheldon wrongly believes that a common field cricket, Gryllus assimilis, found in his apartment is a snowy tree cricket. In case you want to check it out it was in Season 3, Episode 2.
So where did this little cricket get its name? This insect is called thermometer cricket because the rate at which it chirps correlates well with the temperature found around the cricket! This means the surrounding temperature can be estimated by using the formula: The air temperature in Fahrenheit equals the number of chirps in one minute, minus 40, divided by 4, and plus 50.
Thursday, October 9, 2014
Scorpionflies (Panorpa nuptialis) are named for the appearance of the male insect. The back of his body is enlarged and modified into a wicked-looking tail resembling that of a scorpion. Despite their look, scorpionflies neither sting nor bite and are completely harmless.
These insects are usually not very common but at times they can be found in fair numbers, sitting on leaves in the undergrowth of open woods or in overgrown old fields.
Larvae resemble the caterpillars of moths or butterflies. The only difference is that scorpionflies already have compound eyes.
Both larva and adults scavenge for dead insects. Sometimes you can see adults feeding on prey trapped in spider webs.
Males often attract female scorpionflies with a morsel of food as nuptial gift which explains the species name.
Wednesday, October 8, 2014
Today's species is the Boll Weevil (Anthonomus grandis) which originally comes from Mexico, where it feeds on wild cotton. Unfortunately, around 1892 it crossed the Rio Grande and entered the United States. What it found were huge and rich cotton plantations which mean rich food resources for them. Nowadays, it does hundreds of millions of dollars’ worth of damage to cotton crops every year.
The Boll Weevil belongs to one of the most diverse insect groups, the weevils. Over 3,000 species live in North America alone, 60,000 are currently known to science. They can be recognized by elbowed antennae and many of them have a prolonged snout. At the tip of this snout is their mouth. Depending on the species, weevils range in size from about 3 mm to over 10 mm in length. They are usually dark-colored—brownish to black. Some have scales or shiny hairs covering part of their bodies.
Nearly all known weevils are vegetarians both as larva and adults. Hardly any plant is not affected by at least one species of weevil.
Tuesday, October 7, 2014
The European Mantis (Mantis religiosa) is native to the Mediterranean region and Asia. It has been introduced to North America in 1899 is now very common in Canada and the northern parts of the United States.
Mantises are generalist predators which means that they eat a large variety of insects, e.g. butterflies, grasshoppers, and bees. Larger species can actually prey on small vertebrates including hummingbirds. Their front legs are modified into perfect tools for grasping and holding prey, which is eaten alive. At rest, the folded front legs give the impression of a posture of prayer, hence the common name praying mantis.
Mantises have incredible good eyesight. Some species have a visual range of 20 m which is a lot for a rather small animal. Their compound eyes may comprise up to 10 000 individual eyes.
These animals are also famous for cannibalism of males by females but it seems that this is not the rule among all mantis species.
The photo for this post was made by one of my colleagues here at the institute. Valerie is one of our collections technicians and a fantastic insect photographer as you can see in our school program blog.
Monday, October 6, 2014
Antlions (Myrmeleon sp.) are named for their larval stage. They are known to excavate funnel-shaped pits to trap ants and other insects.
Look for groups of pits, each about 2 cm across, in very fine, dry soil under overhanging rock ledges, beneath bridges, at the base of trees, or in the dirt floor of abandoned barns and sheds. When an ant or another small insect strays over the edge of one of these pits and begins to slide downward on the fine loose grains of sand, the larval antlion kicks up little fountains of earth to shower its victim and thereby accelerating its decent into the hole at the bottom of the pit where the hungry predator is waiting.
The antlion larva is also called doodlebug because of the odd winding, spiralling trails it leaves in the sand while looking for a good location to build its trap, as these trails look as if someone has doodled in the sand. There is a simple reason for the rather odd shape – the larva can only walk backwards when it is on the surface.
Here a short National Geographic video of today’s bug and how it hunts.
Friday, October 3, 2014
Backswimmers (Notonecta sp.) are common predators about 1 cm long with large compound eyes. They swim upside-down, propelling themselves by rowing with their long hind legs that are trimmed with hair. They are also good fliers and have well-developed wings. They are widespread in North America and can be found in slow-moving streams or ponds.
They are very similar to another bug you might know, the water boatman. However, backswimmers are usually larger and as said before, swim upside down.
Backswimmers attack prey as large as tadpoles and small fish. If not handled carefully, a backswimmer can inflict a bite as painful as a bee’s sting which earned it the alternative names water wasp and water bee.
There are various species and genera of backswimmers and when they are not swimming they cling to vegetation and wait for prey to swim or walk by. Backswimmers are attracted at night to artificial lights. People sometimes find these insects in swimming pools, where they end up after the night’s flying excursion.
Thursday, October 2, 2014
Today we are looking at some very common insects that most of the times go unnoticed because they are very tiny (1mm long or less). Thrips such as the Onion thrips (Thrips tabaci) are tiny, slender insects with fringed wings which feed on many different plants and animals by puncturing them and sucking up the contents.
Although they have wings thrips are not very good flyers, although they can be carried long distances by the wind.
The word thrips is used for both the singular and plural forms, so there may be many thrips or a single thrips. You might know this already from the words sheep, deer and moose.
Many thrips are pests of crops due to the damage they cause by feeding on developing flowers or vegetables. Today’s bug for example has an insatiable appetite for onion leaves but also eats pollen and even the eggs of mites.
Wednesday, October 1, 2014
Hover flies such as today’s Syrphus ribesii are dead ringers for bees and wasps. Despite their appearance, not only are they harmless, they are valuable pollinators of flowers. Their larvae prey on aphids, while adults feed on the nectar of flowers. Our species of the day is a very common hoverfly found along hedgerows, in gardens and woods.
There are more than 870 species in North America. Many hoverflies mimic the colouration and hairiness of social bees and wasps. This enables them to avoid attack by predators who believe they might be able to sting. This form of mimicry is termed Batesian mimicry. Batesian mimicry is when a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator they both have in common. This form of mimicry is named for its discoverer, the 19th-century English naturalist Henry Walter Bates.