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

Springtime flowers for springtime bees!

As insects begin to become active in the spring, one of the first things they need to do is find a food source. Spring wildflowers are one of the earliest food sources for many insects, but they are especially important for the bees that gather the nectar and pollen from these flowers to feed their offspring. 
Willow flowers are one of the first places you'll see a lot of bees on a sunny day in the spring. The larger bee in the picture below is a honey bee (Hymenoptera: Apidae, Apis mellifera) and the smaller bee is a halictid bee (Hymenoptera: Halictidae).  Springtime is a very important time of year for social bees like honey bees and bumble bees because this is the time of year when they start to build up their colonies of hundreds and thousands of worker bees that will collect resources for the hive all summer. 

This bee (below) might be a species of Ceratina (Hymenoptera: Apidae, Ceratina sp.), commonly called the small carpenter bee because they excavate holes in the stems of pithy plants in order to build their nests. 

Many plants, like willow, provide nectar and pollen that is easily accessible by a variety of insects. Other plants, however, make it a little bit harder for insects to get at that sweet sweet nectar. The flower pictured below, called a fringed polygala (Polygala sp.) requires a bee to land on a specific part of the flower in order to access its nectar. 

The polygala flowers are mainly pollinated by bumble bees because they are the only bees heavy enough to trip the mechanism that opens the flower and that have a long enough tongue to reach the nectar at the bottom of the long nectar tube. 

In order to access the nectar and pollinate the polygala flower, a bee has to land on the purple fringed structure at the tip of the lower petals. This will open up the flower to expose the pistil and stamens, which the bee will contact as it reaches its tongue down into the corolla to drink nectar from the base of the flower. 

Another of my favorite spring flowers, Spring Beauty (Claytonia spp.,below), is not so picky when it comes to choosing its pollinators. 

As you can see the pistil and stamens of this flower are right out there for any insect to access, and the corolla is not long and narrow, so they don't need a long tongue to get at the nectar. 

Interestingly, however, there is a bee that only gathers nectar and pollen from spring beauty and almost no other flowers. It is called the spring beauty bee (Hymenoptera: Andrenidae, Andrena erigeniae) and it is a solitary bee that nests in the soil under the leaf litter in forests where spring beauty grows. I didn't get a photo of one so I won't spend too much time on it today, but you can count on a future post on this charming little bee. 
Thanks for reading!

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!

Flying in the winter

I caught this insect out of the corner of my eye the other day while I was on a hike.

This is a Winter Crane Fly (Diptera: Trichoceridae). It was sitting on the snow when I took the picture, but it had been flying moments before even though the air temperature was about 35℉  (1.5℃).

Winter crane flies are active in the fall and early spring, when temperatures are too cool for most other insects to fly. They are able to fly on cold winter days because they have a special enzyme system that allows their wing muscles to function at low temperatures. 
Insects have a number of different adaptations that allow them to survive at very cold temperatures. This is especially important in parts of the world where the temperature drops below freezing for several months of the year. Most insects are able to keep their blood from freezing with the help of special compounds called cryoprotectants. Cryoprotectants work like the antifreeze in a car by lowering the freezing point of the blood. Thanks to the cryoprotectants in its blood, the winter crane fly in this picture survived temperatures as low as 18℉ (-8℃) the night before. 
Insects can also allow their bodies to freeze completely by controlling where and when ice crystals form with the help of ice nucleating proteins. Ice nucleating proteins cause ice crystals to form outside of the insects' cells rather than inside of them. Ice crystals forming inside of the cells would destroy them and kill the insect. 
As amazing as these adaptations are, they do not happen instantly. The insects need  time to adjust their bodies and prepare for the cold weather, so if you catch an insect in the summertime and put it in your freezer overnight it will probably die.
If you're interested in reading more about this topic, check out the Wikipedia article on insect winter ecology or this book chapter on freeze tolerant animals.

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. 

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.

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!

Familiar Jumpers!

I found this spider on our basement stairs last week.

She is a jumping spider (Salticidae), and a pretty large one. Here is a picture with my thumb to give you a sense of her size. My thumbnail is about a half of an inch (1.3 cm) long.

Jumping spiders don't build webs to trap prey like other spiders. They actively hunt prey and are capable of moving very quickly when necessary. Even though they don't spin webs, they still possess silk glands and they will trail a tiny thread of silk behind them as they hunt. This thread serves as a safety line should they lose their footing when pouncing on their prey.
Two of their eyes are very large and are oriented forward, which gives them better vision for hunting.

The two appendages under her eyes that look like a mustache are called palps. In females, they are mainly used for sensing the environment and manipulating food. Male spiders also use their palps for mating and courtship, so their palps are often larger and more noticeable. One of the clues that this spider is a female was that her palps are not enlarged at the tip. Also, the males of this species have an orange band of hairs underneath their eyes. Jumping spiders are one of the few spider families that possess color vision and the males will often have colorful markings on their faces that serve a purpose in courtship. This species is known as the Familiar Jumper (Platycryptus undatus).
Here is a link to a really great video of some other Familiar Jumpers.

Pollinator Pit Stop

I took a break from my bike ride the other day to see what insects were visiting this patch of wildflowers.

Flowers that bloom late in the summer are often teeming with insects. This is an important time of year for them to stock up on pollen and nectar to help them or their offspring survive the long winter.
Many of the insects on flowers have black and yellow stripes, which make them easily mistaken for bees or wasps. This syrphid fly (Diptera: Syrphidae) for example, is a fly, not a wasp, and it couldn't sting you if it tried!

Syrphids are actually very beneficial insects in the garden. They lay their eggs near aphid colonies and when the syrphid larvae hatch out, they devour the aphids one after another.

Here is another fly that could be mistaken for a bee. This is a bombyliid fly or "bee fly" (Diptera: Bombyliidae).

Some members of this fly family are parasites of bees and wasps. They attack their hosts insects by flicking the eggs into their nests. The bombyliid eggs then hatch and the larva eats the host larva as well as the food that the host's mother provided for it in the nest. Its a pretty nasty strategy, but bombyliids are pollinators too, so they're not all bad.

Speaking of pollinators, there were honey bees visiting this flower patch as well.

Honey bees (Hymenoptera: Apidae) are the #1 insect pollinator of our food crops and they are also important for honey production.
Honey bees are not the only bees that pollinate our food crops though. There are hundreds of other bee species that help with the pollination.
This is a sweat bee or halictid bee (Hymenoptera: Halictidae).

They are called sweat bees because of their habit of landing on our skin to drink droplets of sweat. Many people find this irritating so they have a bit of a reputation as a nuisance, but they are important pollinators. They can sting people too, but will only do so in defense and their sting is fairly mild. Next time you have a sweat bee on your arm try just shooing it away rather than swatting it. Sweat bees come in a variety of shapes, sizes, and colors. The green metallic one above, is one of the largest ones in our area (Northeastern United States).
Here is a much smaller one on a goldenrod flower.

As you can see halictids tend to carry pollen on their hind legs. The pollen is held in place by tiny hairs on their legs. They are gathering pollen to take back to a nest where they form it into a ball for their offspring to feed off of while they grow. Halictids usually nest in burrows in the ground, sometimes in large groups. If you ever come across a cluster of tiny holes in the ground with sweat bees bees going in and out you may have found a colony of halictids.
Halictids are just one of the many important bee pollinators of our wild and cultivated plants. I will hopefully get to cover other groups in future posts. You can also follow this link to all of my previous posts about bees. Thanks for reading!