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?

 

Buttonbush:  A Pollinator’s Favorite

Buttonbush: A Pollinator’s Favorite

Beginning in 2007 the US Senate, in support of the North American Pollinator Protection Campaign, declared the last week of June as “National Pollinator Week.”  As humans, we depend on pollen-moving animals for one out of every three bites of food.  Without birds, bees, bats, beetles, butterflies, and various other animals, many flowers would fail to reproduce.  In Florida there are numerous native plants that serve as hosts for these pollinators.

One of the favorites, due to its heavy flowering over the summer, is Buttonbush (Cephalanthus occidentalis).  It is a semi-aquatic woody shrub to small tree that develops white golf-ball-sized clusters of fragrant flowers, attracting various pollinating animals.  Bees of various species, several different wasps, assorted moths and butterflies, flies and even hummingbirds scramble for the flowers’ sweet treat within each of the trumpet shaped flowers. The pincushion-like flower balls stand on two inch stalks in clusters arising from stem tips and leaf axils.  They are produced over a long period in late spring and summer. The flowers give way to little reddish-brown nutlets which persist on the through the winter.  Buttonbush seeds are important wildlife food, especially for ducks; and the dense, impenetrable tickets provide nesting and escape cover for many wetland birds and herptiles.  Buttonbush is a fast-growing wetland plant that can be grown in a naturalized landscape if given supplemental water during dry spells.  It is at its best, through, in an area where the soil is frequently wet and can tolerate soggy soils.  Buttonbush is not drought or salt tolerant.  The deciduous shrub grows well in full sun to partial shade on soils that are acidic to slightly alkaline.  The leaves of Buttonbush turn yellow in the fall before dropping off.  While short-lived, requiring rejuvenation pruning to improve its longevity, Buttonbush (Cephalanthus occidentalis) serves a critical role to wildlife in the wetland habitat.  Deer browse the foliage and twigs.  Ducks, especially the mallard, eat the seeds.  And, the summer flowers attract bees, butterflies and moths; our wonderful pollinators.

Air Potato Leaf Beetles are Here to Help

Air Potato Leaf Beetles are Here to Help

Air Potato Leaf Beetle

I’m sure many of you could easily recognize air potato with its winding vines and heart-shaped leaves climbing high along roadsides, fencerows and natural vegetation, but could you recognize its key predator, the air potato leaf beetle? Believe it or not, a small, red leaf-feeding beetle was introduced and is here to help control the invasive air potato vine!

The Issue with Air Potato Vine

Air potato (Dioscorea bulbifera) is a plant species that is native to Asia and was first introduced to the United States as a landscape plant but has now become one of Florida’s most problematic invasive plants. Air potato has spread to 60 of the 67 counties in Florida, including many in the Panhandle. Air potato vines can grow up to 8 inches per day! The dense vines smother vegetation and displace native plants, trees and animals. The air potato vine is on the Florida Noxious Weed List. This means that is illegal to plant, propagate or move the air potato unless you have a permit.

The air potato vine spreads by vegetative reproduction. This is through the formation of aerial tubers, or bulbils that are formed in the leaf axils. The aerial tubers are roundish and vary in size. In addition to aerial tubers, air potato also produces underground tubers, making control that much more difficult. During the winter, the aerial tubers will drop to the ground and give rise to new vines in the spring.

Park managers and homeowners throughout Florida have battled with the air potato as its covered our landscape. For years, the primary means of control were by manually pulling, digging and destroying the tubers or by herbicide applications, until recently.

Classical Biological Control of the Air Potato Vine

Another method for controlling invasive plants is with classical biological control. This method involves searching for insects that feed exclusively on a plant in its native range and releasing them in an area that has been invaded by the plant. Scientists with the United States Department of Agriculture discovered the air potato leaf beetle (Lilioceris cheni) that feeds on air potato in its native range of Asia. After extensive testing, scientist found that the beetle is species-specific and poses no risk to other plant species.

In 2012, air potato leaf beetles were first released in Florida to help battle the air potato.  Now, according to the Florida Department of Agriculture and Consumer Services (FDACS), they are officially established in the state!  This means, they are here to stay and research has shown they are helping!

 

While you likely won’t see the beetles now, because they are overwintering (a period of suspended development), look for them in the spring! Adults are bright red with a black head and legs and about the size of your pinky fingernail. The females lay white, pale eggs on the underside of leaves. The egg-laying process causes the leaves to curl and cup. In addition to that, larvae feed on the leaves skeletonizing them. This feeding by the beetle negatively affects the growth and reproduction of the plant.

Skeletonized leaf damage to Air Potato from the Air Potato Leaf Beetle. Photo: Danielle Sprague

For more information on air potato leaf beetles, please visit: