Tinsel, the Christmas spider and other arthropods that decorate your holiday tree

 

Yes Virginia, there is a spider ornament on my Christmas tree.

 

Each year as we put the finishing touches on our holiday tree, a serious debate arises regarding the quantity of tinsel necessary to complete the task. During this year’s deliberation, I pondered the murky origins of tinsel. To some, the silvery strands of unknown composition evoke images of glistening icicles or shimmering crystals of frost on evergreen branches. But how did tinsel become part of a holiday tradition in so many households?

When morning dew glistens on silken strands, it's not hard to imagine why shimmering tinsel conjures thoughts of beautiful spider webs.

To aficionados of arachnids, the tradition of festive tinsel has several different origins. One Christian story tells of Mary’s harrowing escape from Roman soldiers as she and Jesus hid in the hills near Bethlehem. With Herod’s legion in hot pursuit, Mary entered a cave seeking refuge. Spiders quickly sealed the entrance with silk and when soldiers arrived and saw the undisturbed webs, they disregarded the cave as a hideaway and continued their search elsewhere. Often-maligned spiders saved the day! Since that time, tinsel has been strung on Christmas trees to represent a glistening spider web and to commemorate the spiders’ miraculous deed. Other tinsel legends from Germany and the Ukraine tell of spiders escaping the lethal brooms of housekeepers by hiding in dark corners of the home during preparations for holiday celebrations. After exiting their redoubts on Christmas Eve, spiders excitedly explored the evergreen trees that had been brought inside and then left behind glorious cloaks of gossamer webs. When Father Christmas arrived that night and saw the gray spider webs, he miraculously changed them into sparkling silver strands, much to the delight of families who viewed the trees on Christmas morning. Since that time, tinsel has been strung as a symbol of the remarkable event.

Watch as the beautiful spined micrathena carefully places each strand of silk in her gossamer web. 

In the warmth of a home, spiderlings may soon hatch from this egg sac and decorate my tree with silk.

Many spiders survive winter’s chill as eggs protected in silken sacs. If the spider’s last haunt was a spruce or fir, then egg sacs may enter homes as stowaways on Christmas trees. In the warmth of holiday homes, eggs hatch and humans may be recipients of dozens of unexpected visitors in, on, and under the Christmas tree. If you discover a spider egg sac on your Christmas tree or fresh evergreen boughs, simply pluck off a small piece of the infested branch and place it along with the egg sac outside on a shrub. This will allow the spiders to hatch just in time to deliver a deferred holiday gift of pest control in your garden.

Other common visitors that may enter homes with holiday greenery include egg cases of praying mantises such as those of the Carolina mantis, European praying mantis, and Chinese praying mantis. In temperate areas like the DMV, these apex predators spend the winter as eggs in Styrofoam-like masses called ootheca. In spring when temperatures warm and prey are once again abundant, mantis eggs hatch and hungry nymphs get busy ridding your farm, garden, or flower bed of pests. For a bug geek, the notion of hundreds of tiny mantises hatching on a holiday tree might bring an unusual kind of holiday cheer, but for most folks, all those tiny mouths to feed might be somewhat overwhelming. So, before you choose a holiday tree or other greenery to bring into your home, do a quick inspection and remove any mantis egg cases and leave them outdoors where they will provide pest cleanup in spring.

Spider egg sacs like these of the Basilica spider on holly sometimes inadvertently enter homes.

 

Egg cases of praying mantises can also find their way into your home. If you find one, place it outdoors in your garden and reap the benefit of this apex predator next spring.

Several insects and arachnids spend the winter on greenery that you might bring into your home. When you choose your holiday tree, inspect it before you bring it indoors. Look for egg cases of Chinese praying mantises, Carolina mantises, and European praying mantises. Egg cases like this one of the basilica spider may be on a thread of silk or some may be small white fluffy wax tufts on branches. If you live in a region with spotted lanternflies, scrape off egg masses on the bark and destroy them. Some sucking insect pests with white wax, like adelgids on Douglas firs or pines and tiny white scale insects on needles, will not survive in your home and will not cause problems.

In areas invaded by spotted lanternfly, we know that adults lay eggs on many types of trees and structures. Scientists at Penn State recommend inspecting the trunks of holiday trees and scraping off any egg masses of lanternflies lest they hatch in the warmth of your living room and bring some holiday mischief to your home. Other lanternfly relatives, sucking insects such as scales on pine needles and adelgids on branches and bark of pine and spruce, may also accompany greenery into your home. They can be recognized by the white wax that covers their tiny bodies. Even if these insects enter your home, the conditions inside your house are not likely to support their establishment or survival.     

Bug of the Week wishes one and all a joyous Holiday season and a wonderful New Year!

 

 

Acknowledgements

We thank Jason and our friends at the Weather Channel for providing the inspiration for this episode. The interesting article “Insects on Real Christmas Trees” by Michael J. Skvarla was used as a reference.

To learn more about spiders and associated legends and stories of Christmas, please visit the following website: http://www.willowmoonmarket.com/legends.html#Tin

To learn a bit more about dealing with insects and spiders that enter your home in winter, please click on this link for a story on the Weather Channel, and visit the following website:  https://extension.psu.edu/insects-on-real-christmas-trees

 

Insects roasting on an open fire: Bess beetles, Passalidae, carpenter ants, Formicidae, darkling beetles, Tenebrionidae, and longhorn beetles, Cerambycidae

 

This handsome longhorn beetle developed in the woody tissues of a hackberry log. It’s easy to see why it is called a longhorn beetle.

 

Buggy adventures arise when splitting firewood for chilly winter nights.

What’s better on a chilly winter night than a roaring fire in the hearth, right? Must be time to head to the woodpile to split a few logs. A year ago, I felled a rather large hackberry tree. Last week, as I split the bucked-up logs, I was astonished by the diversity of insects snuggled beneath the bark. Some were there to escape winter’s chill. Others were there to extract nutrients from woody tissues for growth and development. One and all will soon travel to bug Valhalla in the funeral pyre of a fireplace that helps heat my home. In a rather punky piece of wood, a beautiful bess beetle, champion recycler of lignan and cellulose, slowly escaped the probing eye of the camera lens. Bess beetles and their youngsters consume and digest wood.

Next year’s carpenter ant queens winter in voids beneath the bark of trees.

Another stroke of the maul revealed a hidden chamber where a gaggle of winged carpenter ant queens were disturbed from their overwintering torpor. With the return of warm weather next spring, these callow queens would establish new colonies and lay thousands of eggs during a lifespan of several years.  Carpenter ants use powerful jaws to remove wood from logs or human-made structures to build galleries for their enormous colonies. Unlike bess beetles that consume wood for sustenance, carpenter ants eat living and dead insects, honeydew from sap-sucking insects, fruit and sap from plants.

Splitting firewood provides lots of buggy adventures. An astonishing diversity of recyclers live underneath the bark. Beneath a bark flap of a rather punky piece of firewood, a beautiful bess beetle tried to escape the probing eye of the camera when exposed to view. On another log, the stroke of a maul revealed a hidden chamber where a gaggle of winged carpenter ant queens hunkered down for the winter. The next split revealed a sleepy pair of darkling beetles ensconced in a narrow void in the log. From another log a lovely longhorn beetle, Neoclytus mucronatus, crawled out of its gallery when the log was cleaved. Larvae of longhorn beetles like this one bear a strange resemblance to Jabba the Hutt. Jingle Bells 7 by Kevin MacLeod is licensed under a Creative Commons Attribution 4.0 license.

 Bevies of darkling beetles can often be found overwintering beneath the bark of trees.

A strike at the next log revealed a sleepy pair of darkling beetles ensconced in a narrow void in the log. Adult darkling beetles like these seek hibernal refuge beneath the bark of trees. Adults eat decaying and fresh vegetable matter, while the larvae of darkling beetles eat fungi, mosses, lichens, guano, and other insects. Some, like mealworms, are pests of stored products in our pantries.  One of the most interesting denizens of dead wood was a lovely longhorn beetle, Neoclytus mucronatus. This beauty crawled out of a gallery when a log was cleaved in two.  Longhorn beetles, so named for the remarkable length of their antennae, are well known for colonizing dying and dead trees. It was no surprise to find this handsome adult emerging from my fallen hackberry tree. Adult longhorn beetles eat leaves, flowers, pollen, fruit, and nectar. Larvae use powerful jaws to bore into even the hardest of trees. Aided by a diverse and complex gut microbiome, wood boring larvae of longhorn beetles, known as round headed borers, are able to harvest nutrients from the woody tissues to sustain their growth and development. Many longhorn beetles, like the dreaded Asian longhorn beetle we met in a previous episode, attack living trees with a preference for those under stress. This beetle is responsible for the death of tens of thousands of trees in New York, Chicago, New Jersey, Massachusetts, Ohio, and South Carolina since its introduction to the United States in the 1990’s.

If you store firewood inside your home for long periods of time before use, don’t be surprised to see one of these characters wandering about your living room on a winter’s eve. And during this most wonderful time of the year, on a nippy night when you are sitting by the fireplace singing the songs you love to sing without a single stop, the sounds you hear in the hearth may be more than chestnuts going pop, pop, pop.

Acknowledgements

Bug of the Week thanks Professor Larry Hanks for identifying the handsome Neoclytus that crawled out of the firewood. The fascinating article “Essential Amino Acid Supplementation by Gut Microbes of a Wood-Feeding Cerambycid” by Paul A. Ayayee, Thomas Larsen, Cristina Rosa, Gary W. Felton, James G. Ferry, and Kelli Hoover provided valuable insights into the digestive wonders of cerambycid beetles.

Cold weather arrives but don’t let your guard down for a tick attack: Blacklegged tick, Ixodes scapularis

 

On a warm day after Thanksgiving, I was surprised to see this blacklegged tick nymph embedded in my arm. Be vigilant when going outdoors on warm winter days.

 

In a behavior known as questing, ticks will climb high on vegetation and then with outstretched legs try to snare a victim on warm days in late fall, winter, and early spring.

Over the past several weeks we explored different strategies employed by insects to survive winter’s chill.  Some migrate to warmer regions while others actually tolerate freezing or avoid freezing with cryoprotectants. A week or two ago, before the current arctic blast chased away daytime highs in the 60s and 70s, I received an almost fully engorged blacklegged tick from a friend. Fortunately, with confirmation that this ectoparasite was a blacklegged tick, my friend was able to begin a course of treatment to reduce the chances of contracting a tick-borne illness like Lyme disease.  While many arthropods enter a state of arrested development called diapause in late autumn, others like our pathogen–toting nemesis the blacklegged tick are a bit more opportunistic. Some may enter diapause but others may be active on warmish winter days even when snow is on the ground. According to tick experts at the University of Rhode Island, “Blacklegged (deer) tick adults are not killed by freezing temperatures. Even in the coldest regions of North America, these ticks can still be active on days when temperatures are above freezing and they’re not covered over by snow.”  A recent study in four Midwestern states found blacklegged ticks and other disease carrying species actively searching for a blood meal, a behavior called questing, on several days in January and February.

And in a classic case of “do as I say, not as I do”, last week after spending a couple of hours in a deer- laden forest near Antietam Battlefield, I awoke the next morning to find a partially engorged blacklegged tick nymph embedded on the inside of my left arm. Several past episodes of Bug of the Week have opined about ways to avoid being a meal for a tick, and quoting one, here is what I should have done before and after my jaunt in the woods:

“To reduce the risks of becoming a meal for a tick and the unfortunate recipient of alpha-gal, STARI, ehrlichiosis, or other tick-borne illnesses including Lyme disease, remember the word “AIR”. This stands for avoid, inspect, and remove.”

“A” - Avoid ticks and their bites in the following ways: When taking Fido for a walk, stick to the path, trail, or pavement. You are unlikely to encounter ticks on non-grassy surfaces. If you enter habitats where wildlife and ticks are likely to be present, such as grassy meadows, borders of fields and woodlands, and vegetation along the banks of streams, wear long pants and light-colored clothing. This will help you spot ticks on your clothes as they move up your body. Be a geek - tuck your pant legs into your socks. Pants tucked into socks force ticks to move up and over your clothes rather than under them where tasty skin awaits. Tuck that shirt into your pants as well. Apply repellents labeled for use in repelling ticks. Some are applied directly to skin, but others can be applied only to clothing. Don’t forget to treat your footwear, socks, and pant legs. Immature ticks, the rascally and hard to detect nymphs, are a key vector of diseases and these precautions will help prevent nymphs and adults from attaching to your skin. If repellents are used, be sure to read the label, follow directions carefully, and heed precautions, particularly those related to children. If your adventures take you into tick territory, consider placing your cloths directly into a clothes dryer rather than a hamper upon returning home. The heat of the dryer will kill hitchhiking ticks that might otherwise escape clothes in the hamper and cause trouble after your return home.

“I” - Inspect yourself, your family, and your pets thoroughly if you have been in tick habitats. Remember to do this when you return from the outdoors and when taking a shower. A thorough inspection may involve enlisting a helper to view those "hard to see" areas around back.  

“R” - Remove ticks promptly if you find them. Removal within the first 24 hours can greatly decrease your risk of contracting a disease. If you find a tick attached, firmly grasp the tick as close to your skin as possible using a pair of fine forceps and slowly, steadily pull the tick out. Cleanse the area with antiseptic. The CDC and the Bug Guy do not recommend methods of tick removal such as smearing the tick with petroleum jelly or scorching its rear end with a match. Cases of some tick-borne diseases such as Lyme disease are the most common in children and seniors, so take special care to keep kids of all ages safe when they play outdoors.”

This great chart from the CDC demonstrates that tick borne illnesses like Lyme disease can be contracted during winter months as well as those in warmer seasons. Credit: Centers for Disease Control and Prevention

Think ticks are done for the year? Think again. Warmer days in late autumn and winter mean ticks will be active during these seasons. Recently after a day in the field, I was surprised to find a blacklegged tick nymph embedded in my arm. Following unseasonably warm temperatures a short time ago, a friend sent me this almost fully engorged blacklegged tick. Blood in her grotesquely bloated abdomen will allow her to survive a feast-less winter and generate thousands of eggs to be laid next spring. Take precautions for avoiding tick borne illnesses by using tick repellents, putting cloths into the dryer when you get home, doing a tick inspection of people and pets, and removing ticks promptly if you have been in tick territory outdoors. If you have a tick, remove it, get it identified, and share this information with your physician to help avoid a serious illness.  

This fully engorged tick is likely to survive winter’s chill here in the DMV and turn her blood-filled abdomen into thousands of eggs which will be laid next spring.

As winter temperatures rise during this period of climate change, we can expect ticks to be active on more days in late autumn, winter, and early spring. Be vigilant when you venture outdoors. Despite a morning low of 28 degrees Fahrenheit, today’s high is predicted to reach a balmy 40-some degrees, maybe warm enough for ticks to quest for a blood meal. Later today, when I work in the same deer-infested forest, I will follow the mantra of “AIR” and try to prevent another bodily incursion by the dreadful blacklegged tick.

Acknowledgements

Bug of the Week thanks Anne Marie for sharing her engorged tick and Dr. Shrewsbury for removing a tick embedded in my arm. The following interesting references were consulted to prepare this episode: “Winter Tick Activity” by The University of Rhode Island (anonymous), and “Unexpected winter questing activity of ticks in the Central Midwestern United States” by Ram K. Raghavan, Zoe L. Koestel, Gunavanthi Boorgula, Ali Hroobi, Roman Ganta, John Harrington Jr., Doug Goodin, Roger W. Stich, and Gary Anderson.

What do insects do in winter, Part 3? Avoiding the big chill: emerald ash borers, Agrilus plannipenis, ground beetles, Carabidae, fall webworms, Hyphantria cunea

 

Overwintering larvae of the dastardly emerald ash borer use cryoprotectants to survive wintry temperatures as low as – 60 degrees Fahrenheit in parts of Canada.

 

Fall webworms are freeze avoiders. In autumn webworms move from branches to refuges under leaves or in soil to pupate. They produce cryoprotectant compounds in their hemolymph and tissues to avoid a chilly death.

Previously, we learned that some butterflies and true bugs (Hemiptera) simply migrate from frosty regions to warmer, more benign regions in the south to avoid potentially lethal subfreezing temperatures in temperate regions including the DMV. Last week, we discovered how insects known as “freeze tolerant” defy death when the weather turns chilly by producing ice-nucleating compounds that allow water molecules to freeze in extracellular spaces in their body, thereby minimizing destruction and death of cells. These insects also manufacture cryoprotectants that act like antifreeze to prevent tissues from freezing. A third way to survive chilly temperatures in cold places involves a strategy known as freeze avoidance. From a physiological standpoint, freeze avoiders don’t produce ice-nucleating compounds to facilitate the formation of extracellular ice. In fact, they eliminate ice-nucleators like food and microbes to prevent formation of ice in their body. However, like their freeze tolerant relatives, freeze avoiders produce cryoprotectants, including sugar alcohols like glycerol, sorbitol, trehalose. These compounds significantly lower the super cooling point, the temperature at which insects freeze. Additional compounds including antifreeze proteins may also help prevent the formation of ice in the insect’s hemolymph and help prevent internal ice from forming due to exposure to ice outside of the insect’s body.  Insects employing freeze avoidance often cheat death until temperatures drop between -4 to – 40 degrees Fahrenheit. However, some juvenile stages of the emerald ash borer survive temperatures as low as – 60 degrees Fahrenheit in parts of Canada. As with freeze-tolerant insects, cues such as changing food availability and quality, changing day length, and cooling temperatures initiate physiological processes to prepare the insect to enter a stage of suspended development called diapause during winter.

Insects living in cold places have evolved clever ways to avoid a chilly death. Dastardly emerald ash borers, killers of ash trees, survive winter temperatures as low as –60 degrees Fahrenheit in parts of Canada. Larval survival is aided by cryoprotectants in their hemolymph. Many ground beetles, like Scarites, move beneath rocks and into the soil to take advantage of the ‘warmer-than-air’ refuge provided by Mother Earth. Some juvenile Lepidoptera like fall webworm caterpillars move from treetops to the ground to pupate. They find thermal refuges under leaves or in soil. Cryoprotectant compounds in their blood and tissues help to avoid a chilly death in winter. Not all insects can tolerate historically “normal” winter lows here in the DMV. Invaders from the south, including harlequin bugs and kudzu bugs, are banished from our region periodically when temperatures dip to the low teens and single digits.

Some invasive species from the south like kudzu bugs have little ability to tolerate winter temperatures in the low teens or single digits. Their presence in colder regions results from periodic recolonizations following cold winters which they cannot survive.

In addition to physiological adaptations enabling insects to tolerate cold wintry temperatures, many have evolved clever behaviors to help avoid cold stress. For example, several species of ground beetles, kin to Scarites beetles we met previously, burrow into the soil to take advantage of the ‘warmer-than-air’ refuge provided by the relatively stable and benign temperatures of the Mother Earth.  Other species like fall webworm caterpillars move from the tree tops and wiggle below leaf litter or burrow into cracks in the soil to pupate in autumn, and to gain a thermal refuge from freezing air temperatures. Fall webworms are freeze avoiders and appear to use both trehalose and antifreeze proteins to help them survive winter’s chill. Ah, but not all insects in wintry regions like the DMV are as clever or as lucky as migrants, freeze tolerators, and freeze avoiders we have met in the past month. Some southern visitors to Maryland like harlequin bugs and kudzu bugs have little ability to tolerate our zone 7 and 8 temperatures that dip into the low teens or single digits. In this game of climate change and thermal roulette, a few warm winters of bliss followed by one of single digits, spells local extirpation for species lacking cold tolerance.

Acknowledgements

 The following articles provided fascinating insights into the overwintering and anti-freezing strategies of insects: “Insect antifreezes and ice-nucleating agents” by John G. Duman, “Cold Hardiness of Insects and the Impact of Fluctuating Temperatures” by Ashley Dean and Erin Hodgson, “Insect overwintering in a changing climate” by J. S. Bale and S. A. L. Hayward, “Insects and low temperatures: from molecular biology to distributions and abundance” by J. S. Bale, “ Plasticity drives extreme cold tolerance of emerald ash borer (Agrilus planipennis) during a polar vortex” by Meghan E. Duell, Meghan T. Gray, Amanda D. Roe, Chris J.K. MacQuarrie, and Brent J. Sinclair, “Landscape effects on the thermotolerance of carabid beetles and the role of behavioral thermoregulation” by Lucy Alford, Sacha Roudine, Jean‐Sébastien Pierre, Françoise Burel, and Joan van Baaren, and “Cold hardiness characteristic of the overwintering pupae of fall webworm Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) in the northeast of China” by Xiao-Rui Xu, Ming-Ming Zhu, Liang-Liang, Guang-Cai Zhang, Ye Zheng, Ting Li, and Shou-Hui Sun.