Each year in the fall you may notice tent-like webs in hardwood trees with dead or stripped foliage inside. These unsightly webs and foliage damage are caused by a common forest insect in our area, the fall web worm. These are the caterpillar phase of a native moth which tend to cause varying degrees of damage to tree foliage each year. Luckily, the caterpillars’ defoliation is usually late in summer to fall when the leaves are beginning to go dormant in hardwoods. Since the trees have stored most of the energy they need for the winter dormant period the defoliation fall web worms cause is usually not a problem especially on mature trees. Nonetheless the webs are often unsightly and in severe outbreak years they may completely defoliate some trees, particularly smaller and newly established trees. They can be controlled to some degree and luckily bad outbreaks are few and far between. Mostly fall web worms become a problem in home landscapes, orchards, and urban settings. In forests they tend not to cause significant damage but are noticeable due to the tentlike webs. In recent tree plantings for wildlife, they can be problematic by stripping the foliage on the trees.
Here in the Panhandle there can be several generation in a year, and as the growing season goes on the population grows. Earlier in the year the webs are smaller and the caterpillars feeding is less noticeable. By fall when the populations get large, the tentlike nests and stripped foliage is very noticeable. The caterpillars are gregarious and aggregate together close to where they hatch. The female moth lays eggs in the late spring in clutches on the underside of leaves. When the eggs hatch the caterpillars group together and start spinning webs out of silk as the young caterpillars skeletonize leaves. As they grow the web nest becomes larger and more foliage is consumed, forming the large unsightly tent nests we notice in the fall. They tend to form the web tent out toward branch tips and several colonies may form on a tree. The caterpillars only feed on foliage inside the web tent and expand they need more fresh foliage to feed on. The web is a natural defense against predators and by forming the tent nest they can feed in relative safety. As temperature cool and fall comes to a close the caterpillars leave the nest to pupate in leaf litter and bark crevices. They overwinter as pupa to become adult moths next spring. The wind and rain over winter usually removes the web nest and the tree puts on new growth next spring with no lasting damage.
Fall Webworms defoliating a persimmon tree Photo Credit: UF IFAS Entomology Department
Mostly webworms and their feeding activity are unsightly, especially in landscape settings. The main issue with fall web worm is when a large number of colonies form on a young tree, which can completely defoliate a tree. Orchards are another setting where large outbreaks of webworms can be an issue. When only a couple of web nests form on a tree control is usually not necessary except from an appearance and aesthetic point of view. Fall web worms have a broad range of host plants and will readily feed on a majority of deciduous hardwood trees and shrubs. They seem to favor pecans, hickories, walnut, and persimmon particularly along with sweetgum, yellow poplar, maples, and oaks to a lesser extent. Fall web worm is a particularly troublesome pest in pecan orchards and home landscape pecans. It is important to watch the extent of webworm infestation in these settings, particularly on younger trees. By the time late fall rolls around though removal of the webs and dead foliage may be helpful, but most trees have gone dormant for the year. On young trees that have had total defoliation this can weaken them during winter dormancy, so some TLC and extra attention in the spring are usually good follow ups.
Luckily since fall web worm is a native species there are plenty of predators, parasitoids, and disease that keep these pesky caterpillars in check. If you have a few fall web worm nests in your landscape there are some simple and effective control methods that can be used. One of the best is to simply destroy the web nests and expose the caterpillars to predators. The webs protect the caterpillars from birds and other predators and are their main defense. By simply taking a pole, tool handle, or other implement to reach the web you can simply tear it open and shake it, predators will help do the rest. Another option is to simply prune out the webbed branch, especially since they tend to be towards the tip. They can then be disposed of and the caterpillars along with them. Using sprays and pesticides are usually not extremely effective. Since the caterpillars are inside the dense web any spray usually cannot penetrate the protective web. Treatment of the foliage around the webs can be effective if applied earlier in the year since active feeding will ensure contact with control treatments. Several insecticidal soaps, horticultural oils, and effective insecticides are available and labeled for fall web worm control. This is only necessary in a severe outbreak and timing is everything. If you wait until mid to late fall most feeding activity has ceased and caterpillars will be beginning to pupate for winter, making pesticides ineffective.
Fall web worm caterpillar in the early stages of development. Photo Credit: UF-IFAS Entomology Department
If you are seeing a bit of fall web worm in your area it likely catches your attention. If you have just a few branch tips affected the issue will likely go away on its own. Unless a tree is being almost completely defoliated this pest is more annoyance than anything, despite the unsightly and noticeable webs. If you are just now noticing an issue it is probably best to just wait and let the annual cycle play out. Fall webworm is an unsightly and annoying annual occurrence in trees but luckily it causes minimal damage and can be easily controlled. It is part of our natural landscapes and forests although it can be unsightly and concerning in years with significant outbreaks. For young or recently planted trees it only becomes an issue if complete defoliation occurs and usually the tree will shake this off and leaf out full next spring. Fall web worm can be noticeable and unsightly, but there is really no cause for concern in most cases. As with most things letting nature take its course and the annual cycle play out is usually the best option.
One thing about nature that you can be sure of is, nobody can say that they have “seen it all.” Just around the next corner is something that you have never seen before in your life. It doesn’t matter if you are the most seasoned, highly educated naturalist on the planet. There are oodles of delightful discoveries that you have yet to make. Sometimes you happen upon them in your roaming about. Other times they just come to you. That was the case with the two damselflies pictured with this article. Now, I have seen plenty of damselflies before and even observed them flying in tandem with the male’s tail tip attached near the female’s head. However, I had never before observed a mating pair completely “hooked-up” like this. Literally out of the blue, they landed on my knee while I was sitting outside one day. Without even thinking about the fact that it might be considered a rude invasion of their privacy, I whipped out my cell phone and got a decent pic (darn paparazzi are everywhere).
This mated pair of damselflies landed on my knee one day – Erik Lovestrand
With the world of information available at our fingertips, it didn’t take long for me to find an explanation for the heart-shaped mating configuration of these winged beauties. Once the male has attached to the female’s head or prothorax, she bends here abdomen down and connects the tip of her tail under the base of his abdomen. This is where she is able to collect his gametes that will fertilize her eggs. Shortly after mating, she will deposit her eggs somewhere near or in the water so her hatching larvae have access to the aquatic environment where they will live until they emerge as adults. This particular species of damselfly has several different color morphs. It seems that there is a genetic component to this feature but there is also a time factor. As they go through life, they exhibit color changes related to their age also. I have observed orange, copper, blue, and green colored individuals during a massive emergence event. Hundreds of individuals had landed on the walls of a building where I worked. The biology and life history of damselflies are much more complex than what I have shared here, of course. Some scientists have made entire careers of collecting data and learning about this fascinating group of insects. I wonder, however, if it was not a detailed bit of information that sparked their curiosity to learn more, but instead an encounter with a heart-shaped pair of beautiful, winged jewels that came to them out of the blue one day.
The Chinese wu-ful symbol is a ring of bats used to symbolize luck and blessings in life.
When I start talking about bats, it often elicits a strong response in people. Folks either gush about how great they are, how interesting and helpful, or they shudder and talk about how bats give them the creeps. I understand why they make people nervous. They hide out and swoop around in the dark, may show up in unwanted places (like attics or sheds), and are omnipresent in every creepy horror movie or Halloween theme. Interestingly, the have absolutely the opposite cultural reputation in China. There, bats have been considered a symbol of good luck for millennia. Buildings, jewelry, artwork, etc. are adorned with bats or the “wu-fu” symbol, a circle of five bats. I certainly come down on the side of “bats are the best ever.” Collectively, the bats in our communities eat millions of mosquitoes and agricultural pests every night. Without them, we’d be overrun with insects, disease, and damaged crops.
A wildlife biologist feeds an overwhelmed mother bat and her young after they were found on the ground. Photo credit: Carrie Stevenson, UF IFAS Extension
As a mom, I also have the utmost respect for bat mothers. When a member of this acrobatic species gives birth, it’s done while hanging upside down by her feet. When the baby is born, mom catches it in her wings and the newborn crawls up to her abdomen. Bat babies are not tiny, either—at birth, they are typically up to a third of an adult bat’s weight. Can you imagine giving birth to a 50+ pound baby, while hanging from your feet? Thankfully, most births are single pups, but occasionally multiples are born. Through our local wildlife sanctuary, I once met an exhausted bat mother of triplets. She and her new brood were found together on the ground—mom was unable to carry all three with her as she flew.
Close-up photo of a Seminole bat and her two pups recovering at the Wildlife Sanctuary of Northwest Florida. Photo credit: Carrie Stevenson, UF IFAS Extension
Summer is maternity season for female bats, typically giving birth in May or June. Being fellow mammals, bats must stay near their newborns to nurse. It takes about three weeks for juvenile bats to learn to fly. During that time, they either cling to their mother, nursing on the road, or stay behind in a maternity colony as she feeds at night. For that reason, during the period from April 16-August 14, it is illegal to “exclude” or prevent bats from returning to their roost—even if it’s your attic. Blocking a bat’s re-entry during this time frame could result in helpless newborn bats getting trapped in a building.
So, if you have seen evidence of bats flying in and out of your attic—or another building that should not house them—you will need to wait until August 15 or later. Excluding bats from a building entails waiting for the bats to fly out at night and putting up some sort of barrier to prevent their return. This can be done using several different methods explained in this video or by using a reputable wildlife professional. The Florida Fish & Wildlife Conservation Commission has regulatory oversight for bat-related issues, and they will work with homeowners to arrange a positive outcome for both the homeowner and the animals involved.
On just about any spring or summer night at dusk, you can look up and see bats darting around, chasing and catching insects. If you are a total bat nerd like me, there are also several places around the southeast with large bat houses for public viewing. In Gainesville, the University of Florida bat houses are home to over 450,000 bats that leave the houses every night. An even larger colony in Austin, Texas (750,000-1.5 million bats) flies out at sunset every night to forage from their dwelling under a downtown bridge. Both are fascinating experiences, and worth a visit!
The University of Florida bat houses on the Gainesville campus are home to hundreds of thousands of bats that emerge every evening. Florida Museum photo by Kristen Grace
If you’re interested in building a bat house for your own backyard, reach out (ctsteven@ufl.edu); I have examples at the office and several sets of plans for building bat houses and installing them correctly. The publication, “Effective Bat Houses for Florida” goes through the best way to figure out where to place a house and includes a set of plans.
In the fall of the year, North American monarch butterflies travel from their summer breeding grounds to overwintering location. Those from east of the Rocky Mountains, travel up to an astonishing 3,000 miles to central Mexico. Unlike summer generations that only live for two to six weeks as adults, Eastern monarch adults emerging after about mid-August can live up to nine months. They enter reproductive diapause and begin migrating south in response to decreasing day length and temperatures. This generation has never seen the overwintering grounds before.
As the Monarch butterflies migrate through the Panhandle, saltbush (Baccharis halimifolia), is a must visit. Their tiny, white to greenish blooms and “fuzzy-looking” fruit come into flower and are attractive at a time when few other small trees and shrubs are flowering, bring this rarely-noticed native plant into view in the fall landscape.
Saltbush is an oval to rounded, freely branched, multi-stemmed, hardy, semi-evergreen to deciduous, cold-tolerant shrub usually not exceeding about 12 feet in height. Its leaves are 1-3 inches long and about 1 1/2 inches wide, often deeply toothed, and shiny to grayish green. No serious pests are normally seen on the plant. Also referred to as Groundsel, it is native to coastal and interior wetlands throughout Florida, often seen in its native habitat with Wax Myrtle, Buttonbush and Marsh Elder.
The monarch butterfly.
Photo: Steven Katovich
The average pace of the migration is around 20-30 miles per day. But tag recoveries have shown that monarchs can fly 150 miles or more in a single day if conditions are favorable. Monarchs migrate during the day, coming down at night to gather together in clusters in a protected area. In the south, they might choose oak or pecan trees, especially if the trees are overhanging a stream channel.
Monarchs migrate alone—they do not travel in flocks like birds do. So they often descend from the sky in the afternoon to feed, and then search for an appropriate roosting site. Most roosts last only 1 or 2 nights, but some may last a few weeks.
By early November, the monarchs gather in oyamel fir (Abies religiosa) trees on south-southwest facing mountains in central Mexico. Orientation of insects is not well understood by entomologists. It can’t be learned from their parents since it’s the fourth or fifth generation that migrates south. Celestial cues (the sun, moon, or stars) and the earth’s magnetic field are the most accepted driving forces influencing the monarch butterflies’ instincts. Unique genetics in North American monarchs have been discovered by researchers. Low metabolic rates and changes in muscle function make migrating butterflies endurance athletes.
The earliest records of overwintering clusters of monarchs are from the 1860s. The chosen grounds provide all the elements needed for overwintering. Because monarchs need water for moisture, the fog and clouds in the two-mile-high mountainous region provide a perfect resting area. Clustered together, covering the trunks and branches of the sacred fir trees, the monarchs are protected form the occasional frost, snow, rain, or hail by the thick canopy of the tall trees, surrounding shrubs, and nectar providing flowers. Milkweed is not the essential plant for the overwintering generation. Come spring, the monarch will begin their search for the milkweed.
Just about everyone has heard this old expression “dynamite comes in small packages.” It is usually invoked in reference to someone of small stature who punches up in weight class. Well buddy, if you have ever unwittingly disturbed a yellow jacket nest, you know the true meaning behind that saying. I have personally gathered a significant amount of data on this topic over the years, to the point that I have developed a new “LAW OF NATURE” which should be included in every outdoor enthusiast’s training manual. More about this later.
Yellow jackets and baldfaced hornets belong to the insect family Vespidae. While larger than other species of yellow jackets, baldfaced hornets are more closely related to yellow jackets than to other hornets. Most people associate hornets with spherical paper nests usually built in the open and hanging from a tree branch. Baldfaced hornets do this, however, the two other yellow jacket species in Florida typically make their nests below ground, with one to many openings. On occasion though, they will make a nest above ground, as seen in this article’s accompanying photos. Another example of this that I once witnessed was a massive nest in the crown of a cabbage palm. It completely encircled the trunk like a large doughnut about two feet below the fronds and extended upward into the frond bases. Overall, it was about 4 feet high and 3 feet wide.
The interior of the abandoned car is almost completely filled with a giant yellow jacket nest. Photo: public domain
Being social insects, yellow jackets have a fascinating life history. Multiple queens are produced each fall and fertilized by drones (males) before dispersing on solitary missions to create a new colony next spring. After overwintering in a protected place, she emerges and gets to work. Chewing wood fibers into a pulpy mass, she builds a small paper nest that contains a small comb of cells where she lays eggs for the first generation of workers (all infertile females). Upon hatching, the workers take over the tasks of building, gathering food resources, rearing brood and defending the colony. The queen’s sole duty now is to lay more eggs. In the fall of that first year, new queens typically leave the nest and the old queen dies. Upon her death, the colony’s social structure begins to breakdown and all remaining occupants eventually die out. On rare occasions, some of the young fertile queens may take up housekeeping in the existing nest structure and continue to enlarge it. Usually though, the old nest is totally abandoned to the elements. Now, back to what I have learned from my unfortunate penchant to collect data on yellow jackets.
LOVESTRAND’S LAW OF NATURE: The number of stings you will be dealt upon disturbing a yellow jacket colony, is inversely proportional to the rate at which you put distance between yourself and said colony. 1st COROLLARY TO LOVESTRAND’S LAW OF NATURE: The time between pain of the first sting and the brain’s capacity to activate your flight reflex, plus the wasted time bouncing off trees and climbing over any other persons in your flight path, diminishes in an additive fashion, the rate at which distance between yourself and the colony can be achieved. 2nd COROLLARY TO LOVESTRAND’S LAW OF NATURE: The rate at which you put distance between yourself and a disturbed yellow jacket colony, is also directly proportional to the number of stings you have been dealt during previous interactions with pissed off yellow jackets.
Fortunately, the most stings I have ever received during a single incident was thirteen. It’s funny how numbers like that stick in your head but it really was quite a memorable experience. Did I mention, unlike honeybees, yellow jackets have no barb on their stinger and will cling to you, stinging until they exhaust their venom supply? Perhaps, tucking this tidbit into the recesses of your brain will somehow add an extra shot of adrenaline to your rate of escape and save you a few stings. It works for me.
It certainly appears that I am on an insect kick of late based on the content of my last three newsletter articles. Honestly though, when I think about it, bugs definitely rank near the top of my list for mystery and intrigue in the natural world. When we begin to dig into the details of their life histories, the revelations are mind-boggling, to say the least. Take the process of metamorphosis for instance. Scientists have described this process in detail and even identified the many hormones that trigger the changes that take place. But when I look at a caterpillar, then a pupa, and finally an adult Luna moth, all of the scientific knowledge in the world could never quell the flood of pure awe that wells up inside. Okay, I get emotional just thinking about it so let’s move on.
Luna moth caterpillars molt four times with the final instar turning a reddish brown just before it pupates.
Photo: Flickr Creative Commons, by Judy Gallagher
Luna moth caterpillars go through four molts, producing five instars, all exhibiting distinctly different characteristics. The fifth instar can be almost three inches long and has more bristly hairs on its skin than earlier instars. It also undergoes a dramatic color change and begins to wander as it gets very close to pupation. I saw one crossing a road once and took a picture to ID later. I was shocked to learn that it was the same species as the bright green ones I had seen pictures of. Another incredible fact about luna moth caterpillars is that when exposed to long photoperiods they tend to complete their pupal phase within 2-3 weeks but short photoperiods (i.e. as winter approaches) result in pupae that enter a dormancy period that can last up to 9 months. I remember finding a silk cocoon when I lived in Indiana during graduate school and brought it inside one Fall. I left it somewhere in the apartment and totally forgot about it. The following Summer we came home one day to find a large, beautiful cecropia moth hanging on the curtains (at least 8 months from when I found it).
All giant silk moths spin a silken cocoon some wrapped in leaves which provides effective camoflauge.
Photo: Erik Lovestrand
Over my years of living in North Florida, I have had the fortune to come across several native moths belonging to the family Saturniidae. These have included the cecropia moth, luna moth, polyphemus moth, promethea moth, royal walnut moth (a.k.a. regal moth), imperial moth, orange-tipped oakworm moth, rosy maple moth, pine devil moth and io moth (beware the stinging spines of the io moth caterpillar). Some of the most visually stunning species in this group belong to the sub-family Saturniinae and are referred to as giant silk moths. This group spins a silken cocoon in which it resides during the pupal phase. When the transformation is complete, it uses horny spurs on its thorax near the base of the forewings to cut its way out of the silk cocoon. Once free of the cocoon it will find a suitable resting place to pump fluid from its swollen body into the wings until they are fully unfolded and hardened for flight. Males typically hatch a few days ahead of females and locate potential mates by homing in on pheromones produced by females.
The adult phase of a luna moth’s life is usually only about 10 days, during which time its sole mission is to mate and produce offspring. Adult moths do not even feed but live off resources stored during the larval phase. A good place to get a look at one of these magnificent creatures would be your local Recreation park during the summer months when the lights are on at the ball fields. Many of our giant silk moths are strongly attracted to lights at night and it is not unusual to find one flying around the lights or resting on a nearby structure. If you ever cease to be blown away by thinking about what it takes to make a moth into a moth, I would suggest you spend a few minutes searching your computer for images of praying mantis species (specifically, the orchid mantis). So many amazing insects out there!
