Fishflies and Dobsonflies

No, this is not a prehistoric monster from a horror film (e.g. Them! or The Beginning of the End). It is an insect in the family Corydalidae. The common names of these insects are Fishflies or Dobsonflies. They are very important insects in healthy aquatic ecosystems. 

Immature corydalids (larvae) live underwater in well oxygenated streams and are also called hellgrammites.

Adult corydalids (pictured here) are very large insects with wing lengths ranging from 2.5 cm (1 inch) to over 5 cm (2 inches) and wingspans of up to 14 cm (5.5 inches). 

The individual in these pictures is probably a fishfly. Fishflies are smaller than dobsonflies, with wings that are usually less than 5 cm long. Adult dobsonflies and fishflies don't actually eat very much (if anything) and they are around for only a few weeks before they die. The larvae however are alive for up to five years, living underwater as predators of other insect larvae. The next time someone tells you that dobsonflies only live for a few weeks you can kindly explain to them that while they only spend a few weeks of their lives as adults, they are alive for up to five years before that.

My friend found this fishfly last May in her yard near Long Lake, MI

The Red Headed Menace

Many insects are not what they seem to be.

This (above) is a red-headed ash borer (Coleoptera: Cerambycidae 

Neoclytus acuminatus), but it looks like a paper wasp (below).

The red headed ash borer is not really a menace. Unless you are a recently cut or dead ash tree, they will not harm you. They have evolved to resemble paper wasps and other stinging insects, which protects them from predators. They might be found in homes in late winter or early spring when they are brought in with firewood. My friend found this one last week inside of a local business. 

How to: help the bees!

An article I saw yesterday about how bees might be harmed by neonicotinoid pesticides reminded me to put up my wild bee house in my front yard.

This is an easy thing you can do at your home to help some of the wild bees in your neighborhood. If you live somewhere with four seasons, early spring is the best time of year to put out a bee house, but you can really do it any time of year, anywhere. Then enjoy watching as bees start to fill it up with nests!

This type of nest will only attract certain kinds of bees called stem-nesting or cavity-nesting bees, but its a great start to your home pollinator protection program. Stem-nesting bees are solitary bees, which means that they don't make large nests like the social bees (e.g. honey bees and bumble bees). 

Honey bee Apis mellifera

Honey bee hives in a blueberry field

Bumble bee Bombus sp.

A solitary bee entering her nest

Solitary bees also don't aggressively defend their nests, which means that they are much less likely to sting you or your family. I made my bee house out of an empty steel can, but any container that is impermeable to water and open on one end will work just fine. Size doesn't matter much either, although it should be at least 15 centimeters (6 in.) long or a little bit longer to protect the nest entrances from the rain. One important consideration is the direction that the nest faces. It is best if the open end or the bee house faces toward the east so that the sun warms it in the morning. However, if its not convenient to hang yours facing due east don't worry about it, the bees will probably still use it. I filled mine with a variety of nesting options to increase the diversity of the bees that will nest there. Bees can be pretty picky about their nesting sites, so if you only have one size nest hole you might only get one kind of bee. Easy options for nesting sites are sections of hollow reeds (e.g. bamboo) or blocks of wood with holes drilled in them. The tunnels for the bees should be about 15 cm (6 in.) deep and anywhere from 3 to 7 mm (1/8 to 1/4 in.) in diameter. If you're feeling really ambitious you can create a bee hotel with a variety of different nesting options.

Now if this post has piqued your interest, I recommend that you look at a couple of fact sheets that were produced by the Xerces society and provide more detailed information on Nests For Native Bees and Tunnel Nests For Native Bees. Good luck and have fun!

First insect sighting of the year!

This stonefly (Order: Plecoptera) ran out in front of me on the trail last weekend. It was one of the warmest days of the year so far (7 C, 44 F) so I was hoping to see some insect activity. This one was very active and I could barely keep up with it running across the snow, but it did pause long enough on the tip of my finger to get a good picture of its wings. Stoneflies have the scientific name Plecoptera (pleco-, folded or plaited; -ptera,wing), which refers to the way that the adult's hindwing is folded beneath the forewing. 

Stonefly larvae (AKA nymphs) live under the water where they eat algae, plants, or other insects. The adults emerge at different times of year depending on what species they are. I'm pretty sure this adult is a winter stonefly (Family: Taeniopterygidae). They tend to emerge from January to April. Insects have some amazing abilities when it comes to surviving and remaining active when temperatures are very cold. 

Stonefly adults are one of the few insects you will see in a cold winter day, but I think this one is a sign that spring is on its way!

The insect life cycle and metamorphosis

Yes, it's February and in the northern hemisphere that means it's very cold outside (-22 C, -8 F this morning to be exact). Too cold for insects to do much of anything, so I have decided to take this opportunity to create a post about the insect life cycle. 

All insects begin life as an egg. This picture shows a cluster of insect eggs on the underside of a leaf. The tiny wasp on the eggs is a parasitoid looking to lay some eggs of her own inside the other insect's eggs.

 If all goes well the eggs will hatch, and insect larvae will emerge. 
Insect larvae come in many shapes and sizes.

Below are several larvae of the darkling beetle (Coleoptera:Tenebrionidae) species Zophobas morio. The smaller ones to the left are the younger larvae and the one on the far right is very close to becoming an adult insect. 
(The scale on the bottom half of the ruler is in centimeters.)

As the insect larvae grow, they must shed their hard exoskeleton in a process called ecdysis. Following ecdysis the larvae are very pale colored and they must wait for their new exoskeleton to harden. A larva in this state is referred to as a teneral larva (shown below).

Once a larva has reached its full size and the time is right it will shed its last larval exoskeleton and enter the pupal stage.

 In these two photos (below), you can see a pupa emerging from its last larval exoskeleton. 

The insect pupa is not very active as it undergoes the process 

of metamorphosis from larva to adult.

 Following pupation, the insect will undergo one final ecdysis and emerge as an adult. The adult pictured below has recently emerged from the pupal exoskeleton. Much like a recently emerged larva, the adult beetle must wait for its exoskeleton to harden.

As the exoskeleton hardens, it also darkens to black and this darkling beetle is finally ready to begin its adult insect life.

Now, I should mention that not all insects follow this progression from egg-larva-pupa-adult. This is just one example of what entomologists call complete metamorphosis (or a holometabolous life cycle). In a future post, I will try to run the hemimetabolous life cycle, but for now please feel free to peruse the Wikipedia links that I have provided. 

Thanks for reading!

Flying scorpion? No.

I'm sure this has happened to you. You're walking along in the woods and you see something black and wispy go by out of the corner of your eye. You naturally think, "Oh, there goes a damselfly, a mayfly, or a crane fly," but when it lands on a nearby plant you realize that its something much more sinister. That happened to me in late September this year and all I could get was this fuzzy photo before it flew away.

Fortunately, I was gardening a few weeks later, in October, and my friend found another one. This time it was not flying because it was probably too cold outside, so I was able to get in close for a really nice picture.

These are pelecinid wasps (Hymenoptera: Pelecinidae) in the genus Pelecinus and they are actually not that sinister...unless you are a june beetle (Coleoptera: Scarabaeidae Phyllophaga). That long "tail" is really just their abdomen, which all insects have. Their abdomen is longer and skinnier than most because they use it to dig into the soil in search of june beetle larvae (AKA white grubs). Once they find a white grub, they lay an egg on it. Eventually the egg hatches and the wasp larva attacks and kills the grub, feeding off of its corpse until it matures.  Then the wasp larva will pupate right there in the soil and emerge next summer as an adult wasp. 

Because of their long curved abdomen, pelecinids do sort of resemble scorpions which has led some people to call them scorpionflies. However, that name belongs to another group of insects in the order Mecoptera, the true scorpionflies. Of course, neither are flies (order Diptera) or scorpions, and scorpions are not even insects. Scorpions are arachnids (like spiders, harvestmen, and mites). Whew, glad we cleared that up. 

Regardless of how scientists classify them, pelecinid wasps attack and kill white grubs, which can be a nuisance to gardeners and homeowners, so we here at Crunchy Segments classify them as beneficial insects. Keep up the good work pelecinids!

Wolf Beetles

This is a beetle of the family Lycidae (Coleoptera). 

The official common name for this family is net-winged beetles but I prefer to call them wolf beetles. The family name Lycidae comes from the Greek lykos, which means wolf. They were given this name because some species have an elongated face that resembles a snout and gives them a somewhat wolf-like appearance. However, the name net-winged beetles is probably more appropriate since the majority of species do not possess a snout, and the distinctive raised ridges on their elytra help distinguish them from other beetle families that occur in the same habitats and have similar coloration.

For example, soldier beetles (Coleoptera: Cantharidae, right)
and fireflies (Coleoptera: Lampyridae, below) are often found on foliage or flowers during the daytime. Many of these beetles also are brightly colored with alternating patterns of black and yellow or orange. This type of coloration is thought to warn predators that they are distasteful or poisonous. 

Aphids, what the heck are aphids?

I have written about aphids before, but never dedicated a post to them. Aphids are in the insect order Hemiptera. Aphids feed almost exclusively on plants so they fall solidly under the category of pests in the garden. 

Annoying as they may be to gardeners and farmers, aphids are very interesting creatures. 

Aphids often live in colonies where the mother or fundatrix gives live birth to many genetically identical offspring. Most of the time they are just feeding on the phloem (AKA sap) of plants, which is where they get most of their nutrients. 

Individual aphids are fairly sedentary creatures, but every once in a while, the colony produces winged aphids that go off in search of new food plants. Ants will also sometimes carry aphids to new plants (e.g. see this article about the corn root aphid). Ants and aphids sometimes form a symbiotic relationship where the ants protect the aphids from predators and the aphids provide the ants with honeydew. The aphids secrete honeydew as a byproduct of their feeding on the carbohydrate rich but nutrient poor plant sap. For the ants, the honeydew is an important source of carbohydrates (sugars). 

If you have ants tending aphid on a plant in your garden, one solution is to create a sticky barrier around the stem of the plant. This will prevent the ants from protecting the aphids, and the aphids' natural enemies will be able to attack them. Aphids have many natural enemies, including lacewing larvae, lady beetles, and parasitoid wasps.

Flying Tigers

This seems to be the summer of predatory flies. I have written about long-legged flies, robber flies, and now tiger flies (AKA hunter flies). Tiger flies are in the family Muscidae, which is the same family as the common house fly and at first glance they are very similar in appearance to a house fly.

If you look closer at this photo though you will see a very important difference.

This tiger fly is eating an insect that it has just caught. Tiger flies sit and wait on vegetation for a potential prey item to fly by. Then they will take off, catch the prey,  and return to the perch to eat it. This is very similar to the predatory behavior of the robber flies that I wrote about a few weeks ago. 

Tiger flies are interesting also because of their apparent tameness. I was able to get very close to this fly with my camera without disturbing it. One researcher has even developed a technique for using these flies to gather insects much like a falconer uses birds of prey to catch game.

Tiger flies can be very helpful to us in the garden, vineyard, and orchard. They are known to eat economic pests such as leafhoppers, whiteflies, and aphids.

Tree crickets are awesome!

This is a tree cricket (Orthoptera: Gryllidae Oecanthus sp.). 

Tree crickets, like all crickets, are closely related to grasshoppers and katydids (see this previous post for some info on how to tell them apart). You may not see tree crickets as often as some other kinds of crickets because they usually blend in with the vegetation that they hang out on. I was lucky enough to find this one on a pink flower. Tree crickets are very interesting but poorly understood insects. Here is a link to a great website created by an amateur entomologist that is very enthusiastic about them. Tree crickets feed on a variety of things from plants to other insects and even fungi. Some species are more predaceous than others, but they are rarely considered pests in the garden.
Tree crickets hear through special membranes on their forelegs.

Hearing is very important for crickets, because they use sound to find their mates. In tree crickets, the male calls females by chirping with his wings. Once, the female locates a male, they engage in some very interesting mating behavior.

Not so cute bug.

I'm pretty sure this is the same species of caterpillar (Lepidoptera: Sphingidae Eumorpha pandorus) that I wrote about in another post last year. The title of that post was, "cute bug?", but I don't think this caterpillar is nearly as cute as the ones that I took photos of last year. This photo is from just a few days ago.

This caterpillar is also much larger and more mature than the bright red one that I saw last year.

Based on the size and shape of this one, I'd say its just about ready to form a chrysalis and pupate. It was munching away on a wild grape vine and frankly could have used a napkin. 

Robber Fly

I caught this robber fly (Diptera: Asilidae) with my camera a few days ago. 

Robber flies are predators of a lot of other insects. They aren't particular about what they eat, if they can catch it they'll eat it. They sit and wait for prey to fly by and then attack them on the wing. 

They kill their prey by injecting them with a toxic saliva. The robber fly's mouthparts fit together to form the proboscis that they use to inject the saliva. Robber flies can be distinguished from other similar flies by the distinctive notch on the top of their heads between the compound eyes. There is a great deal of variation in body shape, size, and color among the species of Asilidae. For example, some robber fly species are excellent mimics of wasps or bees, which helps protect them from predators. Robber fly larvae can be found in the soil or in decaying wood where they feed on the larvae of other insects.
In the garden, robber flies are generally considered beneficial predators of pests. However, they are not picky about diet choices and will sometimes be seen eating other beneficial insects such as honey bees, wasps, spiders, and even other robber flies.

Dance Fly! Dance!

This is a long-legged fly (Diptera:Dolichopodidae), so named because their legs are rather long in proportion to their bodies compared to other flies. 

My friend sent me this picture of one the other day. 

Unfortunately, that one was deceased. 

Long-legged flies are beneficial insects that you have probably seen around your yard or garden this summer. They are predators of insects and other small invertebrates. They are pretty easy to identify since they are shiny green and metallic with very prominent compound eyes and a thinner body than other green metallic flies. You can tell them from green metallic bees by the fact that they only have one pair of wings. I sometimes confuse them with closely related fly family called dance flies (Diptera: Empididae or Hybotidae), because I see them "dancing" on leaves more often than I see "dance flies". Long-legged flies are very fast runners and you may see them scooting quickly around on leaves in search of their tiny prey. Dance flies on the other hand, got their name from the aerial maneuvers that the males perform in mating swarms.

Some members of these fly families have very interesting courtship behavior. For example in some species the male will kill another insect, bundle it up and bring it to a female as a gift. Biologists call this a nuptial gift and if the female accepts it she will often allow the male to mate with her and use the nutrients in the gift to nourish her offspring. Like many insects, they also perform elaborate behaviors that resemble dances during courtship. Here is a video of the courtship behavior of one species that I downloaded from the Dolichopodidae Wikipedia page.

Long-legged flies are one of my favorite insects to see during the summer and I hope that you will enjoy seeing them too! 

Finding a place to spend the winter

Well, its that time of year again. The leaves are falling from the trees in the Northern hemisphere. Some of us are heading South for the winter and some of us are seeking shelter and preparing to hibernate.

Insects are getting ready for winter as well. Some insects overwinter in self-constructed shelters called cocoons.

This cocoon (above), contains a Green Lacewing pupa (Neuroptera: Chrysopidae). Pupa is the life stage between larva and adult during which some insects undergo complete metamorphosis. The Green Lacewing larva looks something like this:

They use those sickle shaped mouthparts to pierce the exoskeletons of their insect prey and suck their insides out. Once they are fully grown and ready to become adults they curl up into a tight ball and spin this cocoon.

The cocoon is made of silk, a material that is produced by most insects and serves a variety of purposes throughout their lives. Once the cocoon is complete, the larva transitions into the pupa stage. Since it is so late in the year, this lacewing will not emerge as an adult until next spring.
This is what a Green Lacewing adult looks like:

As you can see, they get their name from the lacy appearance of their wings.



These Brown Lacewings (Neuroptera: Hemerobiidae) are also getting ready for the winter.

They don't spin their cocoons nearly as densely as the Green Lacewings do so you can clearly see the pupa inside.

Brown lacewing larvae sometimes cover themselves in debris to camouflage themselves from predators. you can read more about this in my previous post, but here is what they look like:

Brown lacewing adults look pretty much like Green Lacewing adults except that they are brown and quite a bit smaller. 

Next spring as the temperatures start to warm, we'll start seeing both kinds of lacewing adults flying around as they search for places to lay their eggs. Hopefully enough of them will survive the winter to help us control those nasty aphids and scales in our gardens next year!