The Long Flight South

The Long Flight South

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 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.

Dynamite Comes in Small Packages

Dynamite Comes in Small Packages

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.

a large yellow jacket nest in an abandoned car
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.

Our Native Saturniid Moths

Our Native Saturniid Moths

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!

Buggin’ Out! When the Outdoors Comes Indoors

Buggin’ Out! When the Outdoors Comes Indoors

AUTHOR: ETHAN CARTER – Regional Agriculture Specialist; Northwest District

While many people enjoying hiking and exploring the outdoors, coming home to find unexpected bugs in the house is much less enjoyable.

There are several key factors that generally lead insects to a home: stored products, lights (windows, doorways), people and pets.

Stored Products

One of the most common reasons that many types of insects get into a home and complete their life cycles is directly related to food sources and human action. Once the population is large enough, individuals are found throughout the house, but their source is usually uncertain. Beetles and weevils are generally attracted to grains and the pantry is generally the first-place people start to look, through the oatmeal, rice, and other foods. However, the pantry tends to be a dead end in lots of instances and then people will just call pest control to come treat. In this scenario, drugstore beetles are a common nuisance.

Figure 1. Adult drugstore beetle. Photo by B.J. Cabrera, University of Florida.

What they don’t think about is other suitable food sources for household pests that tend to be stored in closets, spare rooms, attics, and garages. Dried flower arrangements, decorative Indian corn, bean or macaroni art, bird seed, fish food, flower bulbs, tobacco products, and old books or papers. A common example of a household pest that favors paper goods is the silverfish

Figure 2. Adult Silverfish. Photo by Larry Reeves, University of Florida.

Another very common household pest is the drain fly. Commonly confused as fruit flies, the drain fly is commonly found around poorly maintained drains (kitchen, shower, etc.). They feed on organic matter such as hair, soap, and other decaying materials.

If rodents are or have been present in the home, their food stores behind shelving, refrigerators, or in the walls can also act as ground zero for ballooning insect populations. Animal fiber products (hair, rugs, etc.) and cotton can also be a food source for different species of beetles and moths.

Lights

Evening hours and lights tend to bring a number of insects to the home.

Figure 3. Moth attracted to a light. Photo by Fir0002 at en.wikipedia.

These range from small flies, roaches, beetles, and moths. Some may crawl up the side of the house or door, while others will fly around the lights. Open windows or people entering and exiting the home after exterior lights have been on for a while increase the risk of insects getting inside. What’s more, frogs and lizards are attracted to areas where insects congregate, and they can also get inside through poorly sealed doors and windows.

People and Pets

A random assortment of creatures (insects, scorpions, spiders, mites, frogs, etc.) can enter the home with the help of unsuspecting people. The most common source materials include firewood, potted plants, and wooden materials (shelves, tables, fireplace mantels, etc.). Larger creatures can generally be connected to firewood or potted plants after the fact, while small beetles can be more difficult to place. Powder post beetles are common wood destructive pests that can occur in households and can generally be traced back to recently constructed or purchased materials brought inside the home. The early part of their life cycle is spent within the wood, but at the end of their life they exit creating a series of holes and leaving their trademark ‘powder’ or dust on the floor.

People and pets are common vectors for several parasitic bugs, including bed bugs, lice, ticks, and fleas. Bed bugs and lice can come from traveling and staying at already infected areas, they travel in luggage or on clothing. Lice are also easily vectored by sharing clothing, especially among children with hats and brushes. Pets can bring fleas and ticks into the house. Fleas may establish a population depending on the cleanliness of the residence, including carpeted areas, pet bedding, and even blankets. Ticks are relatively uncommon, they tend to stay on their food source once attached but can occasionally be dislodged while petting or brushing a pet and found later.

Figure 4. Adult male (left) and female (right) Lone Star Ticks. Photo by Lyle Buss, University of Florida.

When curious to learn more about insects found in the home, free diagnostic samples can be sent to the FDACS Division of Plant Industry or for a nominal $8 fee, the UF Insect ID Lab. For more information contact your local extension agent.

Dirty Jobs Abound in the Natural World

Dirty Jobs Abound in the Natural World

Most of us have had the displeasure of hurrying to our car, late for some appointment, climbing in, only to be assaulted by…sniff-sniff…the overpowering stench of doggy poo on a shoe. I can handle many of nature’s nasty smells pretty well but this one nearly gags me. Imagine if this stuff never went away and kept accumulating on the ground. For any of us that have even one big dog, this would be a problem. Heaven help the dog lovers out there with two or more large canines. Well, this article will be paying homage to the unsung heroes of the manure-removal squad, who could give Mike Rowe a run for his money any day. You guessed it, dung beetles.

Dung beetles are most assuredly not the only critters who make their living by what we would consider disgusting means. Carrion beetles, fly maggots, vultures and many other creatures would qualify for an episode of “Dirty Jobs in the Animal Kingdom.” However, the incredible beauty of many species of scarab beetles (the group to which dung beetles belong), resulted in high reverence in the ancient Egyptian culture. In more recent times, humans have realized the benefits provided by dung beetles and have intentionally introduced them in some places to manage dung accumulation in pasture systems. Their tunneling not only takes the dung below for a nutrient recycling function but also brings soil castings to the surface, which reduces soil compaction and improves aeration.

I have seen dung beetles many times, as they work in the yard to reduce my chances of “stepping in it.” Until recently, I have not paid close attention to the incredible beauty of our local species. I had a great opportunity the other day to observe several beetles as they reduced a pile of dog mess to smaller messes and pulled them into their tunnels for long-term storage. The showy, metallic colors of red and green made it apparent why some refer to these creatures as “rainbow” scarabs. They were happy to ignore my presence as I took pictures only inches away from their frenzied activity to salvage their prized doggy treats.

The dung serves as food for both young and adults during periods when they remain underground. Females lay a single egg on what is referred to as a “brood ball” of dung and there may be several of these pre-packaged meals with an egg in the tunnel system made by the beetles. I was able to get some good photos of a beetle as it worked above ground moving dung balls away from the mother lode. It appears to be a species known as Phanaeus igneus, which occurs in our area along with a similar species named Phanaeus vindex. In Florida, Phanaeus igneus tends to occur in sandy soils, while P. vindex prefers clay-type soils. The finely sculptured elytra (hard wing covers) of P. igneus also distinguish it from P. vindex. Eggs hatch into a grub that matures below ground before emerging as a mature adult to continue the cycle.

Dung beetle near burrow entrance

Females of this species are distinguished from males by the lack of a horn.

The dung beetle’s sense of smell is truly a wonder of nature. I have seen them flying in for a sniff test literally within minutes of deposition. Within the next day or two, the only evidence of your pooch’s crime will be small mounds of soil where the excavations took place. I was so taken with these little jewels of the manure pile that you might understand why I think you should be just as amazed. So, the next time you find a fresh pile in the yard, drop down to your knees for a closer look and be prepared to be amazed. If the manure-removal squad has not appeared on the scene yet, give them a few minutes. It won’t take very long. In the meantime, you can be thinking about how you will explain your behavior to your neighbors when they inquire.

Copy Cats Abound in the Insect World

Copy Cats Abound in the Insect World

image showing a wasp mimic that is actually a praying mantis

This praying mantis species mimics a wasp to avoid predation. Photo credit: Erik Lovestrand

When it landed on my hand, the first reaction was to brush it off as quickly as possible. However, something seemed to be slightly odd about this particular “wasp” that made me take another look. First, it was not prone to fly away as I moved my hand up for a better look. It even seemed okay with the interaction as I moved it around for a photo opportunity. There was also something odd about the shape of its body that wasn’t exactly wasp-like. As I looked closer, I realized that its head was very mantis-like and when it began grooming its antennae, I could make out the telltale folded arms that give the praying mantis its name. The yellow and black stripes encircling its abdomen, along with its wing shape and positioning veritably shouted “WASP!” I had never heard of a praying mantis that expertly mimicked a wasp so I did a quick internet search and found that this was a wasp mantidfly (neither a wasp nor a mantis). Mantidflies are grouped by scientists into a separate order called Neuroptera, which includes lacewings, antlions, owlflies, and others. Here are a few other mantidflies that mimic other wasp species.

A simple definition of mimicry would be: similarities between different species of animals.  It is different from camouflage, which refers to an animal resembling an inanimate object, but both are effective forms of deception that generally benefit an animal in some way. Another common insect that would fool most people is the soldier fly. It definitely looks like something that could sting but closer examination will reveal only one pair of wings (a fly trait) rather than two, as bees and wasps have.

Now, not to take you too far into the weeds on this subject, but we should also mention the different types of mimicry that scientists have identified in nature and note an example of each. Henry Walter Bates studied butterflies in the Amazon and described a type of mimicry where one species mimicked the look of another that had some particularly nasty defense to predation. The mimic was lacking the defense mechanism but benefited by predators avoiding it based on its basic appearance. This type of mimicry is now known as Batesian mimicry and a good example are the butterflies that mimic the monarch. Monarchs are toxic because of the milkweed they eat during their larval stage. After a predator eats a few it learns to avoid anything that looks similar, such as a viceroy or queen butterfly. Fritz Mueller was a German zoologist who described a form of mimicry, now called Muellerian mimicry, where multiple species mimic each other and they all have a similar defense mechanism. This spreads the benefit to all that look similar by reducing predation pressure on all.  The third type of mimicry is known as self mimicry, where an animal has one body part that mimics another (i.e. large eye spots to frighten or disorient an attacker), or a body part that may mimic some innocuous thing to fool prey into coming closer. We have a great example of this locally in the alligator snapping turtle. The tip of their tongue has a lure that resembles a worm and is capable of wiggling to enhance its effectiveness in tempting a fish to its doom in the vice-like jaws of the turtle.

Nature never ceases to amaze with the diversity and complexity of adaptations that various animals exhibit to gain an edge on the competition. When it comes to mimicry in the natural world, first impressions are generally wrong. I mean, that’s the point, right?