There are numerous insects and insect relatives that can produce webbing, and webbing can be a sign that something unwanted is near. Arachnophobes might grow uneasy at the sight of a spiderweb, and gardeners might frown to see the tiny filaments that spider mites spin. Tree lovers might assume that webs on a tree are a sign that caterpillars such as the eastern tent caterpillar have taken up residence. But what about webs on a tree trunk?
Bark louse webbing. Photo courtesy of Evan Anderson.
If you come across a tree trunk coated in silk, chances are you’re looking at the work of a bark louse. Also known as psocids or tree cattle, these little insects eat all the stuff that sticks to a tree’s bark. Lichen, moss, algae, and dead bark can all end up as meals for a hungry bark louse. The good news is that while lichens don’t hurt trees, neither do bark lice!
Bark lice spin their webbing as protection from predators. They often produce large quantities of webbing, because there are often large quantities of bark lice present. The name ‘tree cattle’ comes from the fact that they form these large colonies, and move in a manner similar to cattle in groups. While swirling swarms of creepy-crawlies rarely make people feel at ease, don’t worry about these. Acting as a sort of clean-up crew, they will do their work, grow and mature, and move elsewhere by themselves.
There are often several generations of bark lice each year in Florida, so they may reoccur. No control is needed for these insects, though if leftover webbing is considered aesthetically unpleasing it can be removed by spraying with a sharp jet of water. For more information about bark lice, see our EDIS publication at https://edis.ifas.ufl.edu/publication/IN553.
Bark louse nymph. Photo courtesy of Evan Anderson.
It is late summer and many of us enjoy being outdoors in the landscape and taking early morning walks before the temperature rises for the day. There are precautions to take while being outdoors and the activities as many insects are very active, including the yellow jacket. Late summer and many of us being outdoor brings us increases the change of being stung by this insect. The Yellow Jacket sting can be painful and potential dangerous to certain individuals with strong reactions to stings.
Yellowjackets are pollinators and eat caterpillar pests! Credit: Whitney Crenshaw, Colorado State University, Bugwood.org
In the State of Florida there are two species of this Yellow Jacket Wasp, the Eastern Yellow Jacket and the Southern Yellow Jacket. It is difficult to distinguish between them and for this article I will refer to them as Yellow Jackets. Yellow Jackets most often colonize in the ground and are often found in lawns that tend to stay dry, landscape beds and edge of woodlands. Colonies of this flying insect can grow into hundreds or even larger numbers. Often by observation in morning or evening light the entry and exit point of the nest can be see with some luck. It looks like an extremely busy airport with lots of landings and departures. The unfortunate way to find the nest can occur by mowing the lawn disturbing the nest with many yellow jackets emerging from the nest to protect it. The colony quickly goes into defense mode with vibrations occurring nearby. This has occurred with me on more than one occasion. All modesty can be lost while run away from the nesting area with several yellow jackets stinging you move quickly move away. Clothing has been known to be shed to hopefully remove the yellow jackets busily stinging either under or on the outside of clothing.
Southern yellowjacket, Vespula squamosa (Drury), nest dug from ground.
Credit: Gerald J. Lenhard; http://www.insectimages.org/
During the early part of the spring and summer season yellow jackets are busy foraging for protein sources to feed to queen and young larvae. During the consuming of the insects, with many of those harvested being harmful insects to plants. The yellow jackets derive their sugar sources from the larvae secretions as they consume the proteins provided. This is part of the reason we do not often see Yellow Jackets in late spring and early summer. As the queen begins to reduce the amount of egg laying, hence the less numbers of larvae to feed and harvest the sugar for a wasp population at its peak creates a more aggressive need to find alternate sources of sugar. This is part of the reason why yellow jackets show up in greater numbers at outdoor sporting events and other places to look for additional sugar sources. Sugar water for hummingbirds is another backyard site for yellow jackets to work hard for the sugar. Even the birds are careful about approaching the feeders.
I do not advocate the destruction of yellow jacket nesting sites unless they are in proximity to human activity as this can set the situation of stings and potential health challenges for people. If you identify a nest location do not approach and call a company that specializes in addressing these types of stinging insects. Keep in mind that this insect provides a benefit in harvest of many harmful pests to plants yet do pose a potential threat. Be observant as you garden situations that seemed fine last month may have changed quickly.
Summertime is known for cookouts, barbeque, a stroll through the park or even in your backyard; Be aware of stinging insects. These pests are especially active during the second half of summer and early fall when the colonies forage for food to sustain their queens during the winter. Although many are beneficial pollinators they often pose a danger because of their sting. While some of these stings causes minor reactions, others can pose a serious heath threat, which makes them medically important. These stinging hymenopterans includes wasps, hornets, yellow jackets, velvet ants, Africanized and European honey bee and fire ants.
Unique /Important Traits of this group of insects.
Photograph by Lyle Buss, University of Florida
Yellow jackets, paper wasps, and bald-faced hornets can sting multiple times causing allergic reactions. The female velvet ants have a very potent sting that has earned them the nickname “cow-killer.” Unlike Wasps, hornets, and yellow jackets, honey bees only sting once and lose their barbed stinger killing the bee within minutes talk about a sacrifice. Africanized honey bees are dangerous stinging insects that have been known to chase people for over quarter of a mile once they get excited and aggressive, earning the name “killer bee”. Imported fire ants both bite and sting repeatedly, and envenomation (injecting venom) only occurs through the sting.
Solitary vs. Eusocial Most wasps and bees are solitary – being alone or in solitude, and do not defend their nests, but will sting in defense if caught. On the contrary, the eusocial group, especially ants, bees, and wasps, will display territorial behavior and it is mostly these groups that cause medically significant stings.
Photograph by James L. Castner, University of Florida
What makes Hymenopterans important medically? Unlike the male, the female Hymenoptera possess specialized stinging apparatus used to inject their venom into prey’s or intruder’s body. Entomologist Justin O. Schmidt’s knows about this all too well, he records his own experience of venomous stings and rate it on a pain scale index ranging from 1- 4, with four being the most painful. It could be life-threatening for people sensitive to the venom. While most stings cause only minor problems, stings cause a significant number of deaths.
What are some possible reactions after the stings? Local reactions (pain, small edema, redness at the site of the sting); regional reactions, (extensive local swelling, exceeding 10 cm, persisting longer than 24 hours). Systemic anaphylactic responses – most dangerous of the reactions. Symptoms may include itching, rashes or hives, tightness or swelling in the throat, stomach pain, nausea and vomiting and dizziness. More severe cases the individual may experience severe shortness of breath, a drop-in blood pressure, loss of consciousness. Even though some of these reactions are mild about 3% of people ends up the emergency room each year from symptoms related to stings. Some may result in death of the individual.
Treatment/ Preventative Measures What to do? Capture the organism, if possible, for identification; allergy desensitization shots; sting removal; hive removal (certified handler); antihistamine (oral or parenteral) and epinephrine by inhalation or epinephrine by injection.
For more information, please contact your local county extension office. Supporting information for this article can be found in the UF/IFAS EDIS publications/websites below: Differences Between European and African Honey Bees: IN784-9221465.pdf (ufl.edu); Stinging or Venomous Insects and Related Pests: IG099-D1czi7xu65.pdf (ufl.edu) ; https://www.ncbi.nlm.nih.gov/pubmed/17265905 https://extension.entm.purdue.edu/publichealth/insects/stinging.htm
Sometimes the tiniest creatures can freak you out! One creature that may give you the chills is the pseudoscorpion. Pseudoscorpions are arachnids like other traditional scorpions, but they lack the stinging tail. They can range from 2 to 8 millimeters in length, so they often go unnoticed. Pseudoscorpions have four pairs of legs and two body regions. In addition to their legs, they possess a pair of pincer-like claws called pedipalps. Pseudoscorpions are light brown in color and are teardrop shaped similar to a tick. Their pedipalps are about twice as long as their body regions.
An adult pseudoscorpion. Photo Credit: Steve Jacobs, Sr. – Penn State Extension
Pseudoscorpions are often found in bathroom sinks and tubs and are not dangerous. They eat small arthropods such as caterpillars, flies, ants, beetle larvae, and booklice. Most species are tropical, but they can be found throughout the continental United States.
Female pseudoscorpions produce 20 to 40 eggs, at one time, that they carry beneath their abdomens. After the eggs hatch, the young stay with their mother for several days. Sometimes they ride on her back during this time. Adult pseudoscorpions can live up to four years.
If anything, pseudoscorpions are beneficial, as they are predators of nuisance insects. It is not recommended to use pesticides to control these arachnids.
While we think of most flies as pests, garden flies, such as Allograpta obliqua species found in Florida, are excellent pollinators and predators of insects. Photo by Jessica Louque, Smithers Viscient, Bugwood.org.
While our sentiments toward flies usually involve fly swatters, believe it or not, not all flies are nuisance pests! Some types of flies can actually be quite helpful in the garden.
These garden flies are nothing like your typical pesky house fly. While house flies and garden flies are both insects in the order Diptera, they are not in the same insect family, which is the next classification down in Linnaean taxonomy.
The nectar-loving garden flies that specifically visit flowers are in the family Syrphidae and are known as Syrphid flies, hoverflies, or flower flies. Although not as well-known in the pollinating world, there are almost 900 species of flower flies in North America, and they can be very colorful and eye-catching in the garden.
Allograpta obliqua flower fly adults are small and have bright yellow and black crossbands on their abdomens. Photo by Susan Ellis, Bugwood.org.
One of the most common flower flies in Florida is the species Allograpta obliqua. Members of this species, also called hoverflies, are often mistaken as fruit flies, and can therefore be perceived as harmful. But to the contrary, adults cross pollinate many flowers, and hoverfly larvae feed on predators, such as aphids that attack vegetables, fruit trees, cotton, ornamentals, and many wild plants. In fact, when there are numerous hoverfly larvae present, they can reduce aphid infestations by 70 to 100 percent!
Allograpta obliqua adults can be hard to spot, as they are a mere six-to-seven millimeters in length. Although small, they have distinct bright-yellow and black crossbands on their abdomen and become particularly abundant in the spring and summer here in the Florida Panhandle.
So, before you go swatting at any ole fly you see, remember that flower flies are our allies in the garden. Adults will aid in the pollination of our crops and landscape plants, and larvae will help defend our spring and summer veggies from the devastation of harmful insect attacks.
