Multi-Colored Asian Lady Beetle

For nearly a hundred years the multi-colored Asian lady beetle, Harmonia axyridis has been used as a biological control agent. They are native to Asia from the Altai Mountains in the west to the Pacific coast in the east, and from southern Siberia in the north to southern China in the south. The first reported release of H. axyridis in the United States as a biological control species was in California in 1916. It wasn’t until 1988 that they were considered established within North America. There is speculation as to whether this establishment was from intentional release or from accidental occurrences. Many attempts to release this species as a biological control occurred after 1916 and each attempt seemed to have failed. With the discovery of an established population in 1988 the population of this species has spread exponentially. They now occur throughout most of the United States with exception to parts of the Southwest, Idaho, Montana and Wyoming. 

 (Map taken from Bugguide.net)

The multi-colored Asian lady beetle is listed in the family Coccinellidae with other lady beetles. This species went through many name changes beginning as far back as 1773 when it was originally known as Coccinella axyridis. It wasn’t until 1915 that the name H. axyridis was finally decided on by Jacobson, and is still used today. There are nearly 475 species of Coccinellidae in North America, and we can now add H. axyridis to this number as it is now considered an established species.

 

Documentation of descriptions for H. axyridis has not changed since its first description during the 1960s. They vary greatly in coloration from red, orange-red, yellowish to black. They measure 0.19-0.32 inches with a width of 0.16-0.26 inches and are oval in shape. The wings may contain anywhere from 0 to 19 spots, which on the red, orange and yellow species will be black, and on the black species will be red. Coloration is weather dependent. The spots on their wings can actually be a winter weather gauge. Specimens with more spots would indicate a colder or longer winter. This allows the beetle time to produce more melanin to form more black spots. Black specimens are typically found in the western United States and all other color forms are found throughout the eastern United States east of the Rocky Mountains. 

                                               (Photo taken from Wikicommons)

Likely the polymorphism of this species is inherited, each type passing on its own color to its offspring. Diet, temperature and other environmental influences may also contribute to color variations. No other species of lady beetle exhibits this type of polymorphism. This highly variable appearance can make identification difficult; therefore it may be necessary to use other key identification factors when identifying this species. In this species the characteristic to look for is a distinct “M” shape on the pronotum. Sometimes this mark may look more like two lines, or a series of four black spots. This species of lady beetles has more white on its pronotum than any other lady beetle species. All this variance in appearance has earned this species numerous common names including Halloween beetle, Harlequin ladybird, Japanese ladybug, Asian lady beetle, pumpkin ladybird, and the many-named ladybird. 

The larval stage of this species goes through four distinct stages; egg, larval, pupae and adult. The larvae must go through four to five instars to reach adult size. There may be up to five generations per year depending upon region and temperature. 

 (Photo taken from Wikicommons)

This species occasionally participates in cannibalism during the larval stage. Predominantly it is the eggs that are preyed upon by the larva. In large aggregations of aphid populations where H. axyridis eggs are laid the larvae of non-siblings feed on large amounts of eggs. In areas where aphid populations are reduced feeding on eggs or larvae provides necessary nutrients. However they seem to recognize fellow siblings and are most likely to feed on non-siblings. This practice affects overall population growth in a given area. It may affect populations as much as 16 percent in a given area. 

 

Another factor affecting population growth is a bacterium in the genus Spiroplasma. This bacterium targets the male eggs which reduces the risk of cannibalism of females by siblings. The consumption of nonviable male eggs reduces the risk of starvation of female offspring by infected females. This behavior is so far not reported in North America, but instead is restricted to their native Asian range. 

H. axyridis have a keen ability to track down aphid populations which is the main reason they are favored as biological control. The mating season of H. axyridis corresponds with peak aphid population growth. They must time oviposits with high densities of aphid populations in order to provide enough food sources for their offspring. Low populations of aphids would cause starvation of their offspring. There are indications that sight plays a huge role in larvae locating aphids. Larvae of H. axyridis will climb stems in search of aphids. Studies show that they hunt more frequently during daylight hours rather than nighttime. Females are able to detect aphids by smell from short distances which aid her in finding appropriate food sources for her offspring. Multi-colored Asian lady beetle larvae are voracious eaters and may consume up to 370 aphids during this stage. In their lifetime they may consume up to 4,000 aphids. 

 

Even with their aposematic (warning) coloration and reflex bleeding of alkaloid secretions they still have enemies. Certain species of flies will lay their eggs within H. axyridis as will a parasitic braconid wasp called Dinocampus. These parasitic predators lay their eggs within the lady beetle. The resulting offspring will hatch and feed on the lady beetle from the inside. Once the wasp or fly larvae have reached full size they will pupate. Shortly thereafter the beetle will die. There are also numerous birds that will feed on these beetles as well as certain species of ants. Other lady beetles will also feed on H. axyridis but only if they are smaller. Spiders have also been reported to feed on H. axyridis when they are unfortunate to become ensnared in webs. 

 

The introduction of H. axyridis to the United States was to provide biological control of aphid populations in a wide variety of crops. The first crops designated for release were pecan groves and red pines. Despite the intentional release into the environment during the early to mid-century it wasn’t until the late 1980s and early 1990s that establishment was realized.  They not only controlled aphids in pecans and red pines, they also moved to other areas and exhibited successful control of aphids in a wide variety of crops. These crops include apples, soybeans, citrus, sweet corn, hops, strawberries, peaches, cotton, alfalfa, winter wheat, and tobacco as well as many others.

 (Multi-Colored Asian Lady Beetle consuming Aphid)

For many years insect supply houses provided H. axyridis for purchase, but fewer supply houses are rearing them now because of the invasive implications now associated with this species. In the larval stage they are an effective control of aphids as well as scale insects in pine groves, this effectiveness comes from their inability to fly at this stage. The effectiveness of this species was questioned in the adult stage because of their ability to fly to other regions. In order to improve control in this species a flightless strain was created and released. This flightless specimen proved effective because of its inability to fly.

They are easy to rear in captivity and can be reared on a wide variety of aphids as well as numerous artificial diets making them excellent candidates for mass rearing and release projects.

Pesticides used to control insect pest populations have little adverse affects on H. axyridis except in the larval stage. Synthetic pyrethroids seem to affect H. axyridis less than it does aphids. The adult beetles are less affected by pesticides, fungicides and other chemicals in the environment than are the larvae. With constant changes being made in the pesticide industry and safer chemicals being developed all the time fewer H. axyridis are falling victim to chemical applications. 

While it is true that H. axyridis is excellent at aphid control, as well as the control of other soft-bodied insects like thrips and scale insects, we must ask ourselves, at what cost? They are not particular about their diet and feed on a wide variety of insect prey including other lady beetle larvae. This can cause a serious decline in native species of coccinellids, and may potentially lead to several species being listed as imperiled. Nine-spotted lady beetles, Coccinella novemnotata are becoming increasingly more difficult to find in their native range. It is suspected that the much larger and more aggressive H. axyridis is at the very least partially responsible for this decline. In addition to native species falling prey to H. axyridis, they are also less able to compete for viable food sources against a much larger and voracious hunter. The result is less food to sustain the population of native species. Monarch butterfly eggs and young caterpillars have even fell victim to H. axyridis.

There is no question that H. axyridis is more than capable of providing excellent aphid control, but the cost may be considered too high. They not only feed on nuisance insects, they also feed on beneficial insects as well as insects that hold a worldwide appeal such as butterflies.  In addition, as with most exotic biological control species that become too abundant, they cause problems for humans. In the fall they form large aggregations on human dwellings, and other structures. This leads to many of these insects finding their way inside homes. It is not uncommon for these beetles to form aggregation populations in the hundreds of thousands. Persons sensitive to their presence have on occasion developed an allergic rhinoconjunctivitis as well as other allergies. As they fly around our homes and land on surfaces they leave behind frass which can trigger allergic responses in individuals that are sensitive, especially if they occur in large numbers.  Many people find it annoying to have these lady beetles accumulate inside their homes and fight an ongoing battle each fall to control their numbers. The secretions of these beetles stain furniture, floors and curtains. Many homeowners use toxic chemicals to kill the lady beetles, others are more tolerant and remove the lady beetles by vacuuming them up and moving them back outside. This species is reported to give off a musky odor when disturbed and may inflict a minor bite. Not only is it homes that face invasion, so do beehives. Beekeepers reportedly fight to keep these lady beetles out of hive boxes. They appear to cause no harm to the bees themselves, but are a nuisance to the beekeeper. 

 
H. axyridis is one of just a few species of lady beetles that form large aggregations in the fall. In their native range of Asia they are known to orient themselves to visual landmarks on the horizon. Often these areas are mountains or large rocky hillsides.  They will use these sights to hide within cracks and crevices to wait out winter’s icy blast. In the United States they incorporate this same orientating technique and often “home” in on our houses and other structures. There are reports of these beetles making their way into hospital operating rooms and into institutes with bio-containment facilities. These are areas with zero tolerance policies in place for possible biological invasion of outside pests. They have also been reported to contaminate food processing plants, making their way into food being processed for human consumption. This destroys large lots of food costing significant financial losses to those companies. It is believed they are more widely attracted to buildings at higher elevations. They are also reported to aggregate on mountain ranges such as the Smoky Mountains. They are also attracted to light colored structures, such as white, tan, yellow, etc. However, this does not mean they won’t be found on other buildings as well. 

  These beetles will hibernate, or enter into a type of diapause beginning about November and ending in March. They are not looking for places to stay warm, as most places where they spend the winter months are not heated. They instead are waiting for winter to end and warm weather to return so their food source will once again be plentiful. They seek areas that protect them from exposure to the outside weather. I’ve found them in basement window wells, behind the bark of trees, and under rocks. H.axyridis use pheromone cues to signal to others of their kind that a suitable location has been found. It is these chemical cues that lead to such large numbers of lady beetles accumulating in a given area. They may also smell feces left behind by previous aggregations of Harmonias indicating that the location is suitable. They prefer areas that are cool with little to no light. Basements or attics are perfect overwintering areas for these beetles. Occasionally during the winter we have a warming of weather, on these days H. axyridis will become active and seek out warmth. It is not uncommon to find them flying into light fixtures or towards windows. This warming of temperatures seems to trigger a chemical response in the beetle that signals them to wake up and become active again. As soon as the temperature drops again however they will once again become dormant. The biggest problem comes in the autumn and spring when the beetles are moving in or out of structures. It is at this time that human contact is the highest and most aggravating. 

 Besides using harsh insecticides to keep these lady beetles out of our homes, the use of DEET and camphor have been used successfully as a deterrent and are much safer alternatives. The beetles find these odors offensive and will avoid areas that are sprayed with these chemicals. One drawback to using DEET is its ability to dissolve paint. Therefore it must be applied to surfaces that will not suffer from its application. There are DEET strips that can be purchased and used and would be a less expensive way to repel these beetles. ⁴ While the large aggregation of these beetles is no doubt annoying and bothersome, killing them outright may not be the best solution depending upon your viewpoint. If you are a gardener or farmer you may appreciate the biological control of aphids they provide, even if you temporarily forget their importance when trying to keep them out of your home. On the other hand if you prefer native species of lady beetles and are opposed to the much more aggressive newcomer displacing our own lady beetles you may feel differently and have no love for these beetles.
H. axyridis sets itself apart as one of the few lady beetles that will feed on substances other than aphids and soft bodied insects. They will also form aggregations in fruit orchards and gather on the ripening fruit. It has been reported they will feed on apples, pears and grapes thus ruining the fruit meant for human consumption. Vineyards suffer the highest economic impact of the H. axyridis. The beetles are next to impossible to remove from the grape clusters, so many are crushed along with the grapes. The result of this insect contamination is tainted wine with a foul flavor that cannot be consumed. All of these negative impacts of the beetle can cause significant economical losses to fruit growers, homeowners and consumers. More research needs to be done to quantify the annual financial impacts this species is causing to the environment, orchards, and croplands. 

 Ongoing research is being done to further understand the potential impact H. axyridis will have on all native species of coccinellids. Cornell University is a driving force in the research being done on this species. They currently have a citizen science project underway that involves persons from North America. They request that people head outside and photograph lady beetles. Submit your photos, along with data to their website and all information is processed to better understand the impact that H. axyridis is having on the environment. Their website www.lostladybug.org is instrumental in raising awareness of the plight of native lady beetles, and in providing information on H. axyridis.

Exactly why they were imported into the United States for release, beyond the obvious aphid control, is unclear. Apparently persons in the agricultural industry felt the need for a more aggressive aphid predator than our native species. Many attempts to introduce this species into nut groves, pine groves, orchards, croplands and other areas of commerce failed. This continuation of failures did not stop efforts to try and establish this species. One has to wonder if at any time was it seriously questioned the appropriateness of continuing with further releases. It wasn’t until the late 1980’s that an established population was discovered. From this original colony the spread of this species ran rampant. Currently it is found throughout most of North America in large numbers. In Missouri where I live it is the most commonly seen lady beetle. The only other species I find on a regular basis are the convergent lady beetle (Hippodamia convergens) and the pink-spotted lady beetle (Coleomegilla maculate), and their numbers are much lower than in years past. Over the course of a personal 6 year study I’ve found a significant decrease in native species and a large increase in H. axyridis.

In conclusion this species should be considered neither beneficial nor harmful. They provide excellent control of harmful insects such as aphids and scale insects. Their large numbers gives them an advantage in the consumption of large numbers of these harmful insects. On the flip side their prolific breeding and large populations are potentially causing the demise of our own native species of lady beetles. The formation of large aggregations can be an annoyance to humans and potentially cause health problems. Their association with orchards and other fruit crops can lead to destruction of food. To say the good outweighs the bad, or vice versa, would be difficult without further research. I believe it will take time to discover the final verdict on this species.

 

References:

1   1.)  Role of Visual Contrast in the Alighting Behavior of Harmonia axyridis

(Coleoptera: Coccinellidae) at Overwintering Sites

C. A. NALEPA,1 G. G. KENNEDY,2 AND C. BROWNIE3 
2.) The multicolored Asian lady beetle, Harmonia axyridis: A review of its biology, uses in biological control, and non-target impacts R L Koch

3.) The multicolored Asian lady beetle, Harmonia axyridis: A review of its biology, uses in biological control, and non-target impacts R L Koch 

4.) www.bugguide.net (http://www.europe-aliens.org/speciesFactsheet.do?speciesId=50711)

5.) http://www.europe-aliens.org/speciesFactsheet.do?speciesId=50711 
6.) http://en.wikipedia.org/wiki/Harmonia_axyridis 
7.) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC524671/ 
8.) http://edis.ifas.ufl.edu/in361 
9.) www.entomology.ksu.edu/DesktopModules/ViewDocument.aspx?...4521 
10.)linkinghub.elsevier.com/retrieve/pii/S0022201106002199 
11.) www.lostladybug.org

Fishing Spider

This beautifully patterned spider is a Fishing Spider in the family Dolomedes. They earn their name fishing spider from their preferred habitat near water. They are often seen along the shore of lakes and ponds where they rest their front legs on the surface of the water waiting for vibrations that will alert them to possible prey nearby. They are able to dart out across the water and grab unsuspecting aquatic insects. Some reports indicate that they may also capture small fish when the opportunity arises.

It is not uncommon to find these spiders quite a distance from water, in fact, the species pictured here is more commonly associated with moist woodland areas where they climb trees. Their color provides perfect camouflage against the bark of various trees. They are also found in homes upon occasion. I have one that currently lives in our basement. I've given her the name Sadie and actually find myself looking for her when I do laundry. I prefer to co-exist with this gorgeous beast and appreciate the hard work she is doing in the form of insect control than to kill her needlessly.

These are a large spider that somewhat resemble Wolf spiders. In fact many people who encounter these spiders mistake them for wolf spiders. They may reach legspans up to 4 inches, which is quite large for a spider. Average body length varies from 15 to 26 millimeters....males are smaller at 7 to 13 millimeters. They are brownish-gray with lighter brown and black markings. Some specimens have a pinkish tint on their abdomen. The legs are banded black and brown.

Mating takes place in spring soon after hibernation. The female will form an egg sac sometime in June that she will carry with her. This maternal care helps guarantee that the spiderlings will hatch and get the best start possible free from predation. Egg sacs may contain up to 1000 individual spiderlings and hatch sometime between July and September. The young spiders will overwinter under the bark of trees, under logs, or rocks or in leaf litter. When spring arrives the cycle starts over.

While these spiders are large they are not aggressive. They are more likely to flee than stand their ground. Bites typically occur when they are mishandled. The bite is no more severe than a bee sting, however if you are allergic to bee venom or spider venom possible serious reactions can occur.

Imperial Moth

Imperial Moths (Eacles imperialis) in the family Saturniidae are large silk moths commonly found in forested areas throughout Missouri. They are also often found in suburban areas, especially near lights at night. The biggest one I ever found was at a gas station/convenient mart on the outskirts of St. Joseph.
Their range includes most of the Eastern United States from Nebraska to Maine. There are some reports that they are declining at an alarming rate in the northeastern part of their range. The population decline in these locations could and probably is due to habitat loss. Throughout the rest of their range their numbers are secure to abundant. The adults are large with wingspans up to 5.5 inches and are yellow with variable lavender spots. Males are smaller than females.

These large moths do not feed as adults, instead they get all the nutrition they need as caterpillars. If you've never seen one of these in their larval form, it is truly impressive. When hatched they are barely visible and possess an incredible appetite. They feed voraciously and reach lengths up to 3 or 4 inches when ready to pupate. They manage this in the span of several weeks.  It has been said that if a human baby gained weight like a caterpillar, they would weigh as much as a hippo in a single weekend. They feed on a wide variety of tree species like oak, hickory, walnut, pine, maple (including box elder), Norway spruce, sassafras, sweet gum and many others.

Moths are covered in furry scales that protect them from cooler nighttime temperatures. These large moths take it to a whole new level with what appears to be a winter-weight coat, complete with scarf and leg warmers. After midnight the females will begin signalling for males by emitting a pheromone. The males are capable of "smelling" the females from distances of more than a mile. He uses his large, feathery antennae to home in on her scent. Females will lay eggs one at a time, or up to 2 to 5 on the leaves of host plants. Eggs hatch in a couple of weeks. When ready to pupate they will move to the base of the host tree and burrow into the ground to pupate for the winter.

Naturalist Gene Stratton Porter wrote about the Imperial Moth in her novel "A Girl of the Limberlost" It was a prominent character in the plot development of the novel. She had a life long love of silk moths and shared her passion for their beauty in the book Moths of the Limberlost.

Bearded Carpenter Ant

This beautiful little ant is Camponotus subbarbatus, and since I could not find a common name for her.....I took the liberty of giving her one. According to Bugguide their species name of subbarbatus breaks down as follows ----
Latin sub-"under, below, to a lesser degree"+barbatus- "bearded"

 I of course realize that many scientists abhor common names and speak strictly in latin vernacular that the average person cannot understand, nor do they wish to in most cases. I do not have a scientific background, but rather spent my life learning and relying on common names. I recognize the problem with common names, as they can change and vary from region-to-region, whereas scientific names will always remain the same....well almost always. Sooner or later a well meaning taxonomic specialist will discover that such-and-such species, is no longer that species, but rather another. Then that species will undergo another name change equally as difficult to pronounce but supposedly places it in a better category with a more accurate name. That is until some other scientist decides different and changes it again. It boggles the mind and confuses the the heck out of me. As I am not concerned with writing scientific papers, or presenting the world with scientific research I give myself permission to use common names as they apply to the region where I live. If the critter in question does not have a common name, then I shall give it one.

Now back to our pretty little bearded carpenter ant. The one pictured here is a queen and I think the striped gaster (abdomen) is quite attractive and apparently a signature feature of this species in the southeast. They are a small species for ants in the genus Camponotus , which are the carpenter ants. Many species of carpenter ants are quite large and easily recognized by their sheer size and association with wood. 

 Like most carpenter ants they live in woodland understories making their homes in rotting logs, stumps and other organic structures. They may even be found in tunnels underground. They are found throughout most of the eastern United States from Kansas and Iowa eastward.

This species, unlike many carpenter ants are not known to cause significant damage to homes or other human structures. They require much smaller areas to inhabit as their colonies are smaller by comparison to other carpenter ant species. Typical colony sizes are 3,000 individuals or less.

If you want to see one of these beauties, head out to the timber this spring and open up some rotting logs or stumps and you might be rewarded by the sight of a striped abdomen as it rushes to hide from your peering eyes. 

Jack Dempsey---A New Invasive Threat

Tropical Fish in South Dakota Highlights Threat Posed by Exotic Species

 

                                                 (Photo Source: http://fish.netscype.com)

                        This tropical fish, the Jack Dempsey, now is established in South Dakota.

What resource managers long have feared would happen because of irresponsible fish hobbyists has become reality: An exotic species has established itself in a waterway far north of where it should be able to survive.

Earlier this summer, biologists confirmed that the Jack Dempsey, a South American cichlid related to the peacock bass, is reproducing in South Dakota’s Fall River.

How it that possible?

“The hot springs in the river makes it perfect for cichlids,” said Mike Smith, aquatic nuisance species coordinator for South Dakota Game, Fish and Parks. “We first found a Jack Dempsey there in 2009. Then, two weeks ago, we found multiple-year classes.

“And there’s no way that the fish could have gotten there except aquarium release.”

Water nearest the springs stays at about 70 degrees year around, which allows the exotic fish to survive brutal South Dakota winters.

In this case, the Jack Dempsey’s impact on native species likely will be minimal. Few other predators live in the shallow water, and forage species gobbled up by the aggressive cichlid can be replenished from populations outside the range of the hot spring’s influence.

But the discovery is significant because it confirms that exotics can use thermal refuges provided by springs or warm-water releases from power plants to survive in cold climates.

Jack Dempsey and another popular aquarium species, the red-rimmed melania snail, now live in the hot springs of South Dakota's Fall River because of irresponsible aquarium owners. Photo courtesy of South Dakota Game, Fish & Parks.

Could the piranha be the next exotic fish to become established? Or its much larger cousin, the pacu? Every summer, media across the country report catches of both fish in ponds, lakes, and reservoirs. For example, a pacu was caught in Illinois’ Lake Lou Yaeger in June. And at Missouri’s Lake of the Ozarks, piranha captures have been reported several times since 2007.

Fish hobbyists also have contributed to troublesome infestations of plants such as Brazilian elodea, parrot feather, yellow floating heart, and even hydrilla.

“At a lot of our lakes, people just dump their aquariums to get rid of whatever they don’t want anymore,” said Tim Banek, invasive species coordinator for the Missouri Department of Conservation.

Bill Frazier, conservation director for the North Carolina B.A.S.S. Federation Nation, also has seen evidence of aquarium dumping while serving as monitor of water quality for the city of High Point. He thinks the time is long past for directing blame primarily at anglers, especially bass fishermen.

Much of the problem, he insists, lies squarely with aquarium hobbyists and the pet industry that supplies them, as well as with nurseries that sell exotic aquatic plants.

“I haven’t seen a single trace of any invasive (plant) at the ramps, transferred by boat in 28 years,” he said.

“I know the overall perception is that weeds can be spread by anyone with a watercraft. I am not denying this pathway,” Frazier continued. “I just do not believe it as significant as everyone would have you believe.”

The North Carolina water expert has found parrot feather upstream of a submerged roadbed, where boats can’t go. He has discovered water hyacinth just downstream from a farmer’s market that featured the exotic in a water fountain. And he has seen a discarded aquarium underneath a parrot feather infestation, where the shoreline borders a large apartment complex.

“Some time later, a bank fisherman caught a skillet-sized pacu there,” he added.

And while anglers and the fishing industry pay license fees and excise taxes to finance management of aquatic resources degraded by aquatic invaders, these special interests are allowed to escape responsibility for the damage they do.

“This is what we need to be attacking and taxing,” he said.

The North Carolina conservation director added that waterfowl, wading birds, and even mammals can spread plants as well.

“I have seen beavers moving this stuff from decorative ponds to natural lakes,” Frazier said. “I watched a momma beaver taking parrot feather by the truckload from a decorative pond to a stream below --- and her den.”

Water quality expert Bill Frazier found invasive water hyacinth at this farmers market, just a short distance from a river.

Yes, anglers do contribute, transporting plant fragments and --- more likely --- mussels on boats, trailers, and tow vehicles, as do owners of jet skis, cabin cruisers, and pontoon pleasure boats. Resource managers are combating this threat with both mandatory and voluntary boat inspections at put-in and take-out sites, as well as check points at state borders.

“This year alone, nearly 80 infested boats have been stopped on the borders of Idaho, Montana, Oregon, and Washington, most coming from Lake Mead,” reported the San Francisco Chronicle.

In those western states, mussels are considered the primary danger, because they can impede water flow by blocking intakes at major reservoirs.

For much of the country, though, Asian carp are the major concern. They are spreading up the Missouri and Mississippi and east and south in the Ohio, Cumberland, and Tennessee River systems, well as threatening to enter the Great Lakes.

“Asian carp are the No. 1 threat for us,” said Missouri’s Banek. “The floods of 2011 made it worse, and they have the potential to be more detrimental than zebra mussels.”

South Dakota’s Smith echoes that sentiment. “We’re seeing exponential growth in their numbers,” he said.

And while floods have helped bighead and silver carp move into new areas, anglers also might have contributed.

“Most people don’t know how to identify fish,” Banek explained. “In collecting bait below dams, they could be getting juvenile Asian carp as well as shad.”

Uneducated anglers might even unknowingly move adult Asian carp from one fishery to another, as a South Dakota creel survey clerk learned on Lewis and Clark Reservoir.

He approached two young anglers who said that they had fished all day and caught “only one walleye and one salmon.”

That “salmon” turned out to be a bighead carp that the two had caught in the river below the dam, before they moved their boat up into the lake in the afternoon.

The clerk reported that the anglers never had heard of Asian carp.

“This is what we are up against in trying to stop the spread of these fish,” said South Dakota biologist Sam Stukel. “It’s going to take a miracle.”

Bait fishermen also are unknowingly spreading invasive crawfish species. About half of U.S. states and Canadian provinces have restricted use, sale, and transport of crawfish, or are considering doing so because the threat that these invaders pose to native crawfish and the fisheries that they inhabit.

In considering regulations to prohibit the import and sale of crawfish, the Missouri Department of Conservation discovered 25 invasions in its streams. It also learned that 40 percent of anglers surveyed release live bait that they don’t use, more than 50 percent of bait shops sell species not native to regions where they are sold, and 97 percent of bait shop owners admitted or showed that they didn’t know what species they were selling.

“It is important for anglers to understand that any crawfish species moved from its natural range to new water bodies has the potential to become invasive in those new waters and to adversely affect fisheries,” said Missouri biologist Bob DiStefano.

Not surprisingly, the aquaculture industry and Farm Bureau oppose Missouri’s proposed regulations, citing economic hardship for those who import, grow, and/or sell crawfish. In the Mid-South years ago, fish farmers made the same argument in convincing resource managers to allow them to import and sell bighead and silver carp.