Carpenter Ants (1/29/14)

Carpenter ant season is now, by Dr. Mike Merchant

(Originally published in School Integrated Pest Management News)

Many social insects periodically do something called “swarming.” Swarming occurs when reproductively mature, but unmated, kings and queens leave the nest to mate.  These mating couples are winged and are referred to as alates, or swarmers.  The earliest swarmers to emerge in the winter are carpenter ants.

Male (left) and female carpenter ant swarmers. Note the pinched waist that distinguishes these insects from termites.

Male (left) and female carpenter ant swarmers. Note the pinched waist that distinguishes these insects from termites.

This week my youngest daughter, home for the weekend for a visit, informed her entomologist dad that the upstairs shower was covered with large ants. A quick inspection confirmed that we were being invaded by carpenter ants. A few years ago we remodeled this particular shower, tearing out sheet rock and insulation and encountered carpenter ants living in the surrounding walls. We throughly cleaned out what we could and sprayed the walls down with a residual insecticide before reinstalling insulation and more water-resistant Hardyboard® in the new shower stall. Apparently, they are back.

Carpenter ants are relatively large for ants, 1/4 to 1/2 inch-long.  They may come in different colors, but are usually red or black, or a mixture of the two colors (see pictures).  They may or may not have wings.  In my home I only spotted the wingless worker ants, but I suspect the swarmers will show up soon.  Dozens, even hundreds of swarmers may emerge from an indoor carpenter ant nest.

In some parts of the U.S. carpenter ants are important wood-destroying pests–not something that any homeowner wants to see in their house.  But here in Texas our carpenter ants are a little less threatening.  They certainly can be a nuisance through their presence, and for the little piles of debris they often deposit on windowsills and floor near their nests.  However, they do not do significant damage to 2×4 studs or other structural wood.

Unfortunately, carpenter ants are always difficult to treat and eliminate completely from the home.  For my part I plan to inject an insecticide into the gap in the shower grouting from which they obviously emerged, reseal the grout and not lose much sleep over the incident.

If you discover carpenter ants in your home, business, or school,  look for the hole where they are emerging.  This may or may not mark the exact location of the nest, but it will be close.  For most people, calling a professional is the best option for control. If you choose to try the DIY route, you can either seal up the hole and do nothing, or attempt to treat the hole with an aerosol insecticide labeled for use indoors against ants and then seal the hole. You may be fortunate, and eliminate the colony in this way, or you may eventually have to resort to professional assistance.  In any case, doing nothing to the ants will not likely result in any serious damage to the home…just some nuisance ants emerging from time to time.

For more information about these ants, see publication E-2001 on carpenter ants, or the publication on swarming insects indoors, Ent-2012.

Ironclad beetles (September 13, 2013)

We occasionally get identification requests for ironclad beetles, usually from Texas. These insects are a bit of a mystery because no one is sure of what they eat, or anything else about them for that matter. Texas A&M has a fact sheet, and there is a rather short page at Wikipedia. The adults are thought to feed on lichens, and the food source of the larvae is unknown but may be fungi in rotting trees. These are a real mystery in this age of knowing a pretty good amount about insects, especially the big and showy ones such as these. 

Ironclad beetle, Zopherus nodulosus haldemani. Photographer unknown.  

Ironclad beetle. Photo Credit: Rebecca Mcentee.

Assassin bugs (August 29, 2013)

We get a lot of assassin bug identification requests in the winter when the insects have moved inside houses and occasionally bite people. They do bite, but in the case of people it is because they are trapped near the skin; they don't seek us out as a food source. Assassin bugs are predators of other insects and use their straw-like beaks to puncture the body of their prey and suck out the juices. It is very common to see these insects in the outdoors during summer and occasionally they will be found eating another insect. They are slow-moving and easy to see when they are perched and waiting for their meal to walk by. Assassin bugs don't have venom and do not sting, but their bite is sufficient to get one's attention. 

Assassin bug, probably in the genus Zelus. Photo Credit: Patrick Porter

Assassin bug, probably in the genus Zelus, eating a small fly. Photo Credit: Patrick Porter


Argiope Spider (August 18, 2013)

Guest post by Sydney Glass, Integrated Pest Management Intern. 

The insect of the week is not an insect, but is a spider. The Argiope spider is also known as the black and yellow garden spider, the zipper spider, the corn spider, the writing spider, as well as several other names.


The Argiope is fairly large, about 3 inches. The spider is yellow with black, silver and yellow stripes and silver hairs.


The Argiope builds webs in open fields, tall grass, and other similar climates. It prefers dry places. The web will, for the most, part be invisible except for what looks like a thick white string that can be in an “x” pattern, or will weave back and forth like a zipper. The spider will rest in the center of the web unless tending to prey. The zig-zag in the web is thought to alert large animals to avoid the web, as well as it reflects certain ultraviolet rays, causing insects to be attracted to the color and pattern.


The bite of the Argiope is not toxic, but it can be painful. 

Here is some information from the Texas A&M Extension Service on the Argiope

Here is information from Master Gardeners of Galveston County.

On another note, yes we identify insects that are unknown, but spiders are not insects and this is an insect identification help blog. 


Argiope spider. Photo Credit Jerry Marshall. 

White-lined sphinx moth (August 2, 2013)

The insect of the week is the White-Lined Sphinx Moth.

Guest post by Sydney Glass, Integrated Pest Management Intern


            The caterpillar of the white-lined sphinx moth can vary in coloration, but all sphinx moths have a “horn” on their tail, as do the caterpillars of tomato hornworm and tobacco hornworm. The white lined sphinx usually has a yellow or orange horn tail with a black tip, and has a body that is usually orange, yellow, or green with black stripes on the side and will have pale spots along the side. The feet are usually orange. The body can reach 3 inches long.

            The adult is usually very large and is brown with grey and pink bands. These moths can sometimes be easily mistaken as hummingbirds. They are very common in West Texas and on the High Plains.


            Sphinx moth adults eat nectar from flowering plants. They prefer to feed in the afternoon and evening. Caterpillars prefer to feed on chickweed, mustards, purslane, apple, evening primrose, tomato, willow weed, and will even feed on a few crops like corn, but only occasionally and if no other food source available.


            There is absolutely no bite with white-lined sphinx moths, nor are they poisonous.

For more information here is a link to a page on about white-lined sphinx moths, including more photos.

White-lined sphinx caterpillar. Photo Credit: Jakob Bingham. 

Ensign wasps (July 28, 2013)

We have received several ensign wasp submissions lately. These small wasps are in the Order Hymenoptera (bees and wasps) and Family Evaniidae. Submitters will always note that they are seeing these wasps in the house and want to know if they are dangerous. The good news is that they are not dangerous unless you are a cockroach. Yes, these wasps indicate the presence of cockroaches in the house, usually American, smoky brown or oriental cockroaches. The wasps lay their own eggs in cockroach egg cases and the developing larvae consume the roach eggs. This is biological control in action. The presence of several ensign wasps usually indicates a significant cockroach problem and roach control measures should be undertaken. 

Here is the Wikipedia page for ensign wasps. Here is our publication on Recognition and Control of Cockroaches by Wizzie Brown, Mike Merchant and Roger E. Gold.  

Ensign wasp. Photo Credit: Micah Meyer

Giant redheaded centipede (July 25, 2013)

The insect of the week is the Giant Redheaded Centipede.

Guest post by Sydney Glass, Integrated Pest Management Intern.


The giant redheaded centipede can grow to as long as 8 inches and has a red head, a black body, and yellow legs. The centipede has a pair of legs right below its head which are adapted to be claws, and actually do have venom.


Centipedes like to hide under rocks and in dead/fallen tree limbs. Logs are also a good hiding place for a centipede. The centipede lives in the soil, and passes the winter as an adult then has eggs once the temperature warms up.


The centipede has a very painful bite. And, as previously mentioned, the giant redheaded centipede has venomous claws with which it latches onto prey. The bite is not fatal, but causes extreme pain, irritation, and swelling. The centipede has been known to eat insects, mice, small snakes and small mammals. The legs of the centipede have sharp tips. As the centipede walks along something like human skin, it leaves little cuts that can become severely irritated and swell, along with if the creature becomes alarmed it can excrete poison into the fresh cut with its feet.  To be safe, do not handle the giant redheaded centipede.

Here is an informational link about the giant redheaded centipede by IPM program specialist Molly Keck. Here is a really good comment about centipedes from a chilopoda specialist, Dr. Rowland M. Shelley, who I believe is with the Virginia Museum of Natural History.

Giant redheaded centipede. Photo Credit: Michael McCullar.  

Robber fly (July 19, 2013)

The insect of the week is the Robber Fly, also known as the assassin fly.

Guest post by Sydney Glass, Integrated Pest Management Intern.


The robber fly is in the order of true flies, Diptera, in the family Asilidae, and the name of the robber fly actually is in reference to its aggressive feeding behavior. The flies are rather large, being anywhere from about ½ inch up to a little over 1 inch. The robber fly is grey-black with a large hairy body and a long abdomen similar to a dragonfly or damselfly. The robber fly has very long and powerful legs with which it catches its prey with in mid-flight. The fly also has an interesting eye structure with a hollow spot between the eyes, and the robber fly is called “bearded” because of the several long hairs around the mouth.


Robber flies are found on all continents but Antarctica. However, the preferred habitat is one that is open, sunny, and mostly dry. The robber fly feeds on beetles, moths and butterflies, grasshoppers, wasps and bees, and other flies.


The mouth of the robber fly is a very stout straw for piercing-sucking. The robber fly grabs its prey, stabs the insect with its mouth, “injects” enzymes into the insect causing paralysis and digestion of the insides of the insect, and the robber fly carries the prey off to drink him up. Robber flies are beneficial insects but if handled roughly they will bite you, very painful but not harmful.

There is a good little page from Texas A&M Extension on the Robber Fly.

Robber fly lunching on a southern cabbageworm moth. Photo Credit: Patrick Porter.

Robber fly eating a honeybee. Photo Credit: Patrick Porter. 

Hardwood stump borer (July 11, 2013)

Guest post by Sydney Glass, Integrated Pest Management Intern.

Two people from Texas submitted hardwood stump borer beetles for identification this week.


The hardwood stump borer is around two inches long, having a black to almost dark violet or dark purple tint. Sometimes the beetles have patterns to help camouflage them into their surroundings. The hardwood stump borer male has long antennae,and the females have shorter antennae. Males have a slender body whereas the females are rounder. Both sexes have very visible mandibles (mouth pinchers).


Hardwood stump borer beetles are nocturnal and found in open places like sandbars, rocky areas, and anywhere close to trees and woodlands.  The beetles are fast, fly quickly, and are extremely active. The hardwood stump borer is a predator and is an opportunistic feeder on any insect it can catch. The adult mates in the late summer/fall and lays eggs on the underside of tree bark. When the egg hatches, the larva “bores” into the wood and feeds, later to pupate and emerge as an adult.


The hardwood stump borer is not an aggressive beetle and is not considered dangerous, the hefty mandibles it has will draw blood if handled carelessly and aggressively.


Hardwood stump borer. Photo Credit: Ron Becker

Giant swallowtail, Papilio cresphontes (July 6, 2013)

This has been the week for submissions of caterpillars of the giant swallowtail. The larva is very distinctive in appearance and feeds on leaves of trees in the citrus group. Of course they can grow quite large and consume many leaves in the process of developing. The question posed by people, when they find out these are swallowtail larvae,  is whether they can move the larvae to some other type of tree so as to halt the damage to their citrus (usually lemon or lime trees). In short the answer is no, because this species can only feed on citrus. Other hosts in addition to lime and lemon are common pricklyash and common hoptree. The adult insect is a stunning butterfly and here is a link to more information on Bugguide

Larva of the giant swallowtail butterfly. Photo Credit: Anastasia Pankau. 

Cicada Killer Wasps (June 26, 2013)

The insect of the week is the Cicada Killer wasp, also known as a sand hornet. The scientific name is Sphecius speciosus

Guest post by Sydney Glass, Integrated Pest Management Intern.


            Adults are usually between 1/2 an inch to 2 inches long. These wasps are large, and can be hairy on the thorax (middle) and the color is usually a red-black. The wings are transparent brown-orange color. The abdomen is black with yellow stripes, very similar to yellow jacket and hornet markings.  Females are larger than males.


            The adults usually emerge in summer around late June and die in October. The female cicada killer burrows in lawns and next to driveways creating a nest for her offspring. Her preferred location is well-drained sand or grass covered banks and hills. A full sun location with little vegetation is also preferred. There is only one generation per year and the adults do not overwinter. Cicada killers target cicadas, which they will capture and sting. Once stung, the wasp will drag the paralyzed cicada to its den where it will bury it with one egg. The wasp larvae can grow very large, so usually two cicadas are buried with one egg.


Only female cicada killers sting. Males will travel in groups, and are very curious and will go check out anything that moves or flies near them. Males are also very territorial and will chase humans and pets, but will not land on their target. Normally, the wasps are non-aggressive towards humans and will fly away when swatted at instead of attacking. Females will sting if aggressively handled, stepped of with a bare foot, or if caught in clothing. Both male and female can bite, but do not appear to grab human skin and bite.

If you would like to read more, here is a web page on the cicada killer courtesy of Texas A&M AgriLife Extension.  

Cicada killer wasp. Photo Credit: Bart Drees, Texas A&M AgriLife Extension

Dobsonflies (June 19, 2013)

Guest post by Sydney Glass, Integrated Pest Management Intern. 

The insect of the week is the Dobsonfly. Names for the larval stage include are hellgrammites, go-devils, and crawlerbottoms. The larva of the dobsonfly is used for fish bait, and many lures and artificial flies are now fashioned to look like this creature.


            The dobsonfly can usually be around 5 inches long (12.5cm) and the male has very large and sharp pinchers. The dobsonfly has wings that are usually twice as long as the body and the coloring is usually dull and mottled.


            The dobsonfly only lives about seven days once in adult form. The larval stage lives in lakes, streams, and rivers where they hide under rocks. Dobsonfly larvae live in water for a couple years, then crawl to land to pupate. Adults usually appear in late spring to mid-summer and try to stay near bodies of water so that, after mating, eggs can be laid close to the water’s edge. Dobsonflies fly at night and are attracted to bright lights, and this explains why we get so many sent for identification.


The male can grow pinchers as large as about an inch, but lacks the leverage to be able to actually break skin. These pinchers are used mostly for mating. The females, however, have short pinchers and can cause very painful bites that can draw blood. The dobsonfly is not poisonous, but will just pinch the heck out of you. When either of the sexes feels threatened, they will raise their head and spread their jaws as a warning.  In the last line of defense, the dobsonfly will emit a foul smelling spray, also not poisonous. The larva, which is predaceous, has a powerful and painful bite as well. More on dobsonflies at the Texas A&M Department of Entomology.

Dobsonfly larva. Photo Credit: Bart Drees, Texas A&M AgriLife Extension. 

Dobsonfly adult female. Photo Credit: C. L. Cole, Texas A&M AgriLife Extension.  

Dobsonfly adult female. Photo Credit: Bart Drees, Texas A&M AgriLife Extension. 

Brown recluse spiders (June 6, 2013)

Guest Post by Sydney Glass, Integrated Pest Management Intern.

The insect of the week is the Brown Recluse. The brown recluse has many other names such as the violin spider, the brown fiddler, and fiddleback spider. The brown recluse is very dangerous, and if bitten seek medical attention immediately.


The brown recluse is normally 6-20mm in length (or about ¼ in – ¾ in) but it can grow larger. The color of the Brown recluse varies from a light shade of brown to a dark brown or black-grey. Often, the bottom section of the spider is not the same color as the top section. Brown recluse usually looks smooth and hairless. Usually, an indicator of identifying a brown recluse is by looking at the top of the body where there should be a violin looking shape on the cephalothorax (head + thorax - the front part of the body where the legs are linked to the body). The violin shape will have the neck pointing the rear of the spider. Be cautious of this as an the only identifying characteristic. Cellar spiders (daddy long legs) and pirate spiders also have very similar markings to the naked eye.


The Brown Recluse usually chooses to live in woodpiles, sheds, closets, garages, and cellars. The choice habitat for a brown recluse is somewhere dry and undisturbed. When indoors, the brown recluse’s choice home is cardboard, because it is the closest thing to rotting tree bark, which is their natural home.  They can also be found in clothes piled on the floor and left unattended for a few days, behind pictures, and inside shoes not often worn. The brown recluse usually tries to avoid conflict, but if brushed it will usually move very quickly horizontally and will rotate to protect itself. The spider does not jump, but it does lunge when trying to quickly flee.


Brown recluse spiders are rarely aggressive.  However, the spider usually bites if against skin, like trapped in the shirt or pants. The bite is not usually felt and is most often not painful. The brown recluse has hemotoxic venom (toxins that destroy red blood cells and other living tissue) and this is why the bite can painful and itchy in 2-8 hours. The pain and the bite location can become irritated and the wound can become gangrenous within 12-36 hours and grow as large as 25cm (10 inches)

If bitten, capture the spider in a jar or bag and take with you to the emergency room for a proper identification. Medical attention is mandatory for brown recluse bites. 

Dr. Mike Merchant, Texas A&M AgriLife Extension Entomologist, has a fact sheet on control of brown recluse spiders. Here is information from the National Institute of Health if you think you have been bitten by a brown recluse.


Brown recluse spider, female. Photo Credit: Bart Drees, Texas AgriLife Extension Service.

Pipevine swallowtail (May 31, 2013)

The larva is easy to recognize, or some might say hard to forget. Two pipevine swallowtail caterpillars were submitted this week from Texas. The scientific name of this insect is Battus philenor, which has a nice ring to it and sounds like it could be a character on Downton Abbey.  The larvae look a bit dangerous and actually are, at least if one intends to eat them. Larvae feed on members of the plant genus Aristolochia, more commonly known as pipevines or birthworts which contain aristolochic acid, a toxic compound known to be a carcinogen and toxic to kidneys. There are actually several species of swallowtail butterflies that feed on Aristolochia and they accumulate aristolochic acid in their bodies. While it might seem that this would be harmful to the swallowtails it is actually good because, while the insects are not affected, things that eat the insects can be made sick. A predator of a larva that contains aristolochic acid is far less likely to make that mistake again and thus forego dining on further swallowtail larvae that use this form of chemical defense. The other thing about this species is that, while the larvae may be on the ugly side (a subjective statement to be sure), the adults are strikingly beautiful. I don't have a photo of the adults, but here is a link to the butterfly photos on Bugguide

Pipevine swallowtail larva. Photo credit: Rebecca Saxon.

Blister beetles (May 24, 2013)

These pretty beetles are mostly bad news. To begin with, they can produce a fluid called cantharadin that, when it comes in contact with skin, justifies the blister part of their common name. Secondly, cantharadin can be very toxic to some vertebrate species, especially horses. There are approximately 100 species of blister beetles in Texas. The adults feed on many types of plants but especially prefer legumes (like alfalfa  which is sold for horse and livestock feed). The larvae are considered to be beneficial because they destroy grasshopper eggs or are parasitoids of other insect species. However, larvae of many blister beetle species are pests of solitary bee nests. So the take home lesson on blister beetles is look but don't touch. Or if you must touch them to remove them from your garden plants, then at least wear gloves and throw them away when you are finished.  The University of Kentucky has published some information on the number of blister beetles that pose a mortality threat to horses - and this is mortality, not sublethal effects, which can be very bad in themselves. The fact sheet also contains tips for alfalfa growers who want to minimize blister beetles in their hay and it also has tips for horse owners. 

Blister beetle species common in Texas. Photo Credit: Pat Porter

Windscorpions, Oh My! (May 17, 2013)

Windscorpions are not insects and are more closely related to spiders than insects. They are not scorpions, either, but have been stuck with that unpopular term as part of their common name. Their striking and dangerous-looking appearance gets the attention of those who encounter them and there have been several requests for identification this week. 

Windscorpions do not have venom glands and are not venomous! However, they can bite and are actually rapidly moving predators of insects. They are so fast that some people have claimed they, "run like the wind". Considering that windscorpions eat insects and other arthropods for a living, it is a good idea to think of them as beneficial, except perhaps when they are in a home or building. In this case it would be a good idea to forego the can of insecticide and simply move them outside.  Here is a link to more information at the Texas A&M Department of Entomology.

Windscorpion. Photo Credit: Lynda Myles.

Windscorpion. Photo Credit: Duane, last name unknown.

How to take effective photos for insect identification

It is often very difficult to identify insects from photographs. People who want an identification can make the process easier (or possible) by following a few simple rules.  

1. Get as close as possible to the insect (fill the frame). Many cameras have a "macro" mode, often indicated by a "tulip icon" on the scene selection dial. The macro mode tells the camera to let you focus much closer to the subject than, say, a landscape image or a portrait. 

2. Hold still and focus carefully. Blurry photos most often result from movement of the camera and/or poor focus. To avoid camera shake, rest your elbows or hands on a solid surface rather than trying to hold the camera unsupported. 

3. Shoot some of the photos with the flash turned on. In low light situations the camera will use a very slow shutter speed unless the flash is turned on. Slow shutter speeds usually result camera shake and blurry images.

4. Use a flash when the color of the insect is not much different than the color of the background of the photo.  

5. Do not shoot the photo through glass or plastic. These usually make it impossible to see the fine details of an insect. 

6. Take photos from the top, side and bottom if possible. Often times the features needed for identification are not visible on the top of the insect.  

The following are real images submitted for identification and I am posting them as examples of things that should be corrected if a successful insect identification is to be made from a photo. 

Fill the frame with the insect.

Fill the frame with the insect.

Do not shoot through glass.

Do not shoot through glass.

FOCUS, and use a flash when the insect is close in color to the background.

FOCUS, and use a flash when the insect is close in color to the background.

Honey bee swarms (May 3, 2013)

Here is a timely guest post from Texas A&M AgriLife Extension entomologists Dr. Mike Merchant, Janet Hurley and Wizzie Brown who have teamed up to educate people about the honey bee swarms that have been prevalent this spring. A very nice article is posted here.

Bee swarms consist of a group of bees clustered together.  The cluster often rests on items such as tree limbs, fences, mailboxes, or bushes.  A swarm may stay in the same location for a few hours to several weeks. Swarms are produced as a part of the colony’s reproductive process.  An established colony produces a new queen, causing the old queen and about half the worker bees to leave the colony and search for a new nest location.  Scout bees are sent out from the swarm to search the area for a nesting site.  Swarming honey bees are usually gentle and unlikely to sting. While bee swarms are generally harmless, bee colonies that get into the home can become an expensive problem. Now is an excellent time to check your home for holes and gaps that need filling, BEFORE the bees move in. In most cases, a bee swarm will move on within a day or two and you’ll never see it again. On the other hand, if one of the colony’s scout bees discovers a good nest site nearby, the swarm could become a long-term neighbor or take up more or less permanent residence in your home. For this reason, many people choose to call a pest control company or beekeeper to kill or collect bee swarms that settle near their house.

Honey bee swarm. Photo Credit: Jacques Murphy.

Beekeeper removing the swarm. Photo Credit: Jacques Murphy.