Explaining Science – vermiform mites

You have heard of mites – minute arachnids that have four pairs of legs when adult, are related to the ticks and live in the soil, though some are parasitic on plants or animals. But what are vermiform mites? Maybe you have heard of vermi-compost, a composting technique that uses worms (like your earthworm in the garden) to decompose organic matter. So vermiform mites are mites with a body shape like a worm:

worm-shaped nematalycid Osperalycus

Why are they shaped like a worm, you may ask – To find out more I interviewed Samuel Bolton, former PhD student in the acarology collection at our museum, now Curator of Mites at the Florida State Collection of Arthropods. Sam’s main research interest is in mites that live on plants and in the soil, especially Endeostigmata, a very ancient group of mites that dates back around 400 million years, before there were any trees or forests. Sam’s PhD research with Dr. Hans Klompen here at OSU, was focused on a small family (only five described species) of worm-like mites, called Nematalycidae.

side note: You may have heard of Sam’s research in 2014 when he discovered a new species of mite, not in a far-away country, but across the road from his work place in the museum.

When Sam started his research it was not clear where these worm-like mites in the family Nematalycidae belong in the tree of life. To find out Sam studied several morphological characters of Nematalycidae and other mites. He focused in particular on the mouth-parts of this group. As he learned more about the mouth-parts of this family, he found evidence that they are closely related to another lineage of worm-like mites, the gall mites (Eriophyoidea). Eriophyoidea have a sheath that wraps up a large bundle of stylets. They use these stylets to pierce plant cells, inject saliva into them and suck cell sap.
Although Nematalycidae don’t have stylets, one genus has a very rudimentary type of sheath that extends around part of the pincer-like structures that have been modified into stylets in Eriophyoidea.

So what did Sam and his co-authors discover?

“.. Not only are gall mites the closest related group to Nematalycidae, but the results of our phylogenetic analysis places them within Nematalycidae. This suggests that gall mites are an unusual group of nematalycids that have adapted to feeding and living on plants. Gall mites use their worm-like body in a completely different way from Nematalycidae, which live in deep soil. But both lineages appear to use their worm-like bodies to move around in confined spaces: gall mites can live in the confined spaces in galls, under the epidermis (skin), and in between densely packed trichomes on the surface of leaves;  Nematalycidae live in the tight spaces between the densely packed mineral particles deep in the soil.”

This research potentially increases the size of Sam’s family of expertise, Nematalycidae, from 5 species to 5,000 species. We have yet to confirm this discovery, but it is highly likely that gall mites are closely related to Nematalycidae, even if they are not descended from Nematalycidae. This is interesting because it shows that the worm-like body form evolved less frequently than we thought. This discovery also provides an interesting clue about how gall mites may have originated to become parasites. They may have started out in deep soil as highly elongated mites. When they began feeding on plants, they may have used their worm-shaped bodies to live underneath the epidermis of plants. As they diversified, many of them became shorter and more compact in body shape.

I wish I could tell you now to go out and look for these oddly shaped mites yourself, but you really need a microscope. Eriophyoid mites are minute, averaging 100 to 500 μm in length. For your reference, an average human hair has a diameter of 100 microns.

eriophyoid Aceria anthocoptes

Reference:

Bolton, S. J., Chetverikov, P. E., & Klompen, H. (2017). Morphological support for a clade comprising two vermiform mite lineages: Eriophyoidea (Acariformes) and Nematalycidae (Acariformes). Systematic and Applied Acarology, 22(8), 1096-1131.

 

About the Authors: Angelika Nelson, curator of the Borror Laboratory of Bioacoustics, interviewed Samuel Bolton, former PhD graduate student in the OSU Acarology lab, now Curator of Mites at the Florida State Collection of Arthropods, in the Florida Department of Agriculture and Consumer Services’ Division of Plant Industry.

 

Bat sounds

Bats are social mammals that use a repertoire of vocalizations to communicate with each other and to move around in the environment.

To detect obstacles and prey in their environment, bats emit a series of ultrasounds, very high-pitched sounds above 20,000 Hz, beyond our range of hearing. As a bat flies and calls, it listens to the returning echoes of its calls to build up a sonic image of its surroundings. Bats can tell how far away something is by how long it takes the sounds to return to them, how big the target is based on the strength of the returning signal, and what shape the target has based on the spectral pattern of the returning sound waves. We call this process echolocation.

Individual bat species echolocate within specific frequency ranges that suit their environment and prey types. This means that we can train ourselves to identify many bats by listening to their calls with bat detectors.

Let’s LISTEN to recordings of the little brown bat (Myotis lucifugus) and the big brown bat (Eptesicus fuscus) for comparison. – But how can we listen, if we cannot hear their calls? Let’s use a trick: When we slow down the recordings by a factor of 10, the calls are transposed to 10 times lower pitch and become audible to us.

Note: To make the sounds visible in sonograms we plotted frequency in thousands of cycles per second (kilohertz, kHz) on the vertical axis versus time in seconds on the horizontal axis. The varying intensity of colors ranging from dark blue (low intensity or quiet) to red (high intensity or loud) indicates the amplitude or loudness of each call. Amplitude is also shown in the top part of each figure with larger waves representing louder calls.

Little brown bat: Calls last from less than one millisecond (ms) to about 5 ms and sweep from 80 to 40 kHz, with most of their energy at 45 kHz.

sonogram of little brown bat Myotis lucifugus calls

Call series of a little brown bat Myotis lucifugus

 

Big brown bat: Calls last several milliseconds and sweep from about 65 to 20 kHz, and are thus lower pitched than calls of little brown bats.

bigsonogram of brown bat Eptesicus fuscus echolocating calls

Call series of a big brown bat Eptesicus fuscus

 

 

The above call series were recorded when the bat is generally surveying its environment, but what happens when it actually detects prey? Listen to this feeding buzz of a little brown bat:

sonogram of feeding calls of little brown bat

Feeding calls of a little brown bat Myotis lucifugus

 

When closing in on prey, a bat may emit 200 calls per second.

What might sound to us like the bat is getting excited – don’t you talk faster when you are excited about telling something? – this rapid series of calls actually helps the bat to pin-point the exact location of its prey, then it swoops in, and GULP – dinner is served, or not!

 

We hope you enjoyed listening to these bat sounds; if you have any questions please contact Angelika Nelson.794@osu.edu, curator of the animal sound archive at The Ohio State University.

The Ohio State University - logo

 

All recordings are archived with the Borror Laboratory of Bioacoustics (BLB.OSU.EDU) at The Ohio State University.

Dragonflies and Damselflies of Ohio


Dragonfly at Magee Marsh Wildlife Area.

Dragonfly at Magee Marsh Wildlife Area.

The Triplehorn Insect Collection is beginning a collaborative project to survey the dragonflies and damselflies of Ohio.

These spectacular aerial predators are surprisingly diverse: currently 164 species have been recorded in the state. Brilliant colors and striking markings make them the songbirds of the insect world. The immature stages of all species are aquatic, and these animals are found in lakes, rivers, ponds, and streams from Lake Erie to the Ohio River.  Although many dragonflies and damselflies are common, a number are listed as threatened or endangered.

This new Ohio Odonata Survey is scheduled to last 3 years. The work will be done together with the ODNR Division of Wildlife, the Ohio Odonata Society, and a network of avid volunteers and citizen scientists across the state.

MaLisa Spring, an Entomologist and recent OSU graduate, just joined us as coordinator for all of these efforts.  She will be working out of the Triplehorn Insect Collection in Columbus, and will be actively interacting with participants around the state.

Information on the project can be found in the newly created Ohio Odonata Survey website.  Project activities will also be widely advertised on social media.

Ohio naturalists are invited to contribute to the project. If you have images that can help document the distribution and seasonality of the various species of dragonflies and damselflies in our state, please check out the guidelines.

Finally, the Ohio Odonata Society will be holding its 2017 annual meeting, ODO-CON-17 on 23-25 June at the Grand River Conservation Campus in Rock Creek, OH.

Resources:

Photos by L. Musetti (dragonflies) & Huayan Chen (damselfly).

About the Author: Dr. Norman F. Johnson is an Entomologist, Professor at Ohio State University, and Director of the Triplehorn Insect Collection.

Backyard Bug Explorer


Visitors touring the Triplehorn Insect Collection are invariably drawn to the biggest, longest, most colorful creatures that we have among our four million specimens. Giant walking sticks, Goliath beetles, white witch moths, and birdwing butterflies are a sure hit with visitors of all ages.  One question that usually follows that exhilarating experience is … “Are these from Ohio?” And, unfortunately, we have to say that no, those enormous and colorful insects come from tropical forests in Africa or South America or elsewhere.

That is not to say, though, that there aren’t plenty of interesting and very striking insects in Ohio. In fact, there are plenty of cool insects right in our own backyards, many of them still poorly known or even completely unknown to science.

Here are just a few examples of the insect fauna that I found in my urban backyard in the past few weeks.


Bees & bee nests

During Spring, carpenter bees and bumble bees are very busy building their nests and collecting pollen. Well, that’s true of the female bees, anyway. The male carpenter bees are far too worried about patrolling their territory and checking out everything that comes along, all in the hope of finding a female that might be susceptible to their charms. Not to worry: the males are harmless, and you’d practically have to grab hold of a female before she would think of stinging.

 

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Under a clay pot that was left leaning against a wall, a queen bumble bee has dug a hole into the soil where she’s starting her own colony. The same sort of gardening accessories are also great places for spiders to build their webs and for insects to hide away their eggs from predators.


Wasp nests

A mud-nesting solitary wasp found the perfect place to build her nest among the wrinkles of a deteriorating plastic cover on an old outdoor fireplace in our yard.  This might be a mud dauber or perhaps a potter wasp nest. Either way, the mother wasp builds the nest using soft mud, then goes hunting for caterpillars or other insects.  The prey – stung into a state of suspended animation – is stuffed into the nest accompanied by a single wasp egg.  The larva that later hatches will feed on the living prey and develop into a new flying adult wasp.


Insect eggs (my all time favorite)

The most exciting finds for me are insect eggs. Sometimes the eggs are parasitized and produce the little wasps that are my object of study. Here on our screen door I found the eggs of an assassin bug. Each egg is like a small piece of art in itself each with a beautiful ornate crown. I’ve been watching carefully to see if assassin bug nymphs will emerge or if the eggs will produce any of my parasitic wasps.

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Ants

When I rolled over a log, I found a number of Lasius interjectus.  These bright yellow ants are commonly called “citronella ants.” If you disturb them, they respond by releasing a bouquet of repellent chemicals that smell like lemon or the citronella candles used to repel mosquitoes. These ants are farmers: they maintain underground “herds” of aphids or mealybugs. These “cows” feed on the fluids in plant roots and excrete a sweet honeydew that the ants love.

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Here’s a quick video of the citronella ants. They are very cute!


Beetle larvae

I love looking for insects on, in, and under dead trees. Recently I found quite a number of very slick and shiny beetle larvae beneath the bark of a large dead tree near our house. I actually don’t know what kind of beetles they are, but I am hoping my buddies who study beetles will be able to identify them. And who knows, maybe I found something entirely new?!

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When disturbed the larvae move deeper into the soft wood.


I have more photos and videos of local insects, but I’ll stop here for now.  Yes, I know, the local bugs are not massive and showy like the amazing things that come from tropical rain forests, but pay close attention and you will find that they are just as fascinating. And best of all, they are right here in our backyard!

 Insects are everywhere. The more we learn about them the more we see how absolutely fascinating, beautiful, and important they are.

 

So take your family outside the house and go explore. Look around your backyard, watch for signs of insects, check out the flowers, the underside of tree leaves, listen to the buzz of the bees and see what they are doing.  Notice the differences between a bumble bee and a carpenter bee and other bees (get more info here.)



A final note: Monday, May 22, is the International Day for Biological Diversity. People all over the world and here in Ohio will be celebrating the day with the goal of increasing understanding and awareness about biodiversity, and to have a good time observing nature.

What a great opportunity to connect with fellow bug explorers and to promote the insect biodiversity that is right around us! Post your discoveries, photos, and musings about Ohio insects on social media. Use the hash tag #OhioBugs so we can keep in touch.

Hope to see you out there!


About the Author: Dr. Luciana Musetti is an Entomologist and the current Curator of the Triplehorn Insect Collection at The Ohio State University.

facebook.com/TriplehornInsectCollection

Follow on Tweeter or Instagram: @osuc_curator

Songsters on the move

I have been teaching a class on Ohio Birds since January during which we visit various field sites around Columbus to look for birds. One main goal is for students to be able to identify birds visually and acoustically by the end of the semester. As you may imagine the birds we have been seeing over this time period have  changed quite a bit.

Not only the species have changed but also overall diversity. Venture out in January and you can call it a good day when you see 15-20 bird species. You want to choose your birding location carefully, a variety of habitats (lake, woodlot, open field, and bird feeder) will increase your numbers. These days however 30 species are the norm, it is migration season! While most of our winter guests such as Dark-eyed Junco and American Tree Sparrow have left us and gone north to their breeding grounds in Canada, many other species that spent the winter south, some as far as Argentina, are on their way to our temperate region.

Blue-gray Gnatcatcher. Photo by Christopher Collins, 2017

Blue-gray Gnatcatcher. Photo by Christopher Collins, 2017, via www.fb.com/roguebirders

Have you seen a Blue-gray Gnatcatcher yet? Guess what this bird feeds on! Listen for their begging-like calls high in the tree tops. Their long tail and light-gray appearance are a good give-away.

Spectrogram of calls of Blue-gray Gnatcatcher

Spectrogram of calls of Blue-gray Gnatcatcher, BLB28872

 

Similarly flitting around in the tree tops are kinglets (family Regulidae). These tiny birds (even smaller than chickadees! they weigh only 10g or 2 nickels) seem to be constantly on the move. One of the two species that can be added to your Ohio list, the Golden-crowned Kinglet, even spends the winter with us. Truly an amazing feat in temperatures that can drop to zero Fahrenheit and below on occasions. A good photo of this species shows off their flashy bright yellow crest bordered by a black eyebrow stripe on each side.

My favorite though is the Ruby-crowned Kinglet, in particular because of its song. It starts out like its close-relative the Golden-crowned with some very high-pitched tsee notes, but then truly distinguishes itself through a jumble of notes, a musical twitter, that seems incredibly loud given the small size of this songster.

Spectrogram of song of Golden-crowned Kinglet

Spectrogram of song of Golden-crowned Kinglet, BLB17541

Spectrogram of song of Ruby-crowned Kinglet

Spectrogram of song of Ruby-crowned Kinglet, BLB11487

 

But do not underestimate the small! My all-time favorite, the Winter Wren, delivers the loudest song (per unit body weight) of all birds, a beautiful cascade of bubbly notes.

Winter Wren. Photo by Christopher Collins, 2016

Winter Wren. Photo by Christopher Collins, 2016, via www.fb.com/roguebirders

While you may get lucky to hear this song in Ohio on occasion from one of the male Winter Wrens passing through, their song is commonly heard in the deciduous and evergreen forests of the north. By the way, did you know that the male hormone testosterone greatly influences bird song? As these males migrate and get ready for the breeding season, their testosterone levels increase and they start practicing their song – even though they are not setting up territories here or trying to attract females.

Spectrogram of song of Winter Wren

Spectrogram of song of Winter Wren, BLB44620

 

There are many ways to appreciate our songbirds. Since I am fascinated by their song I like to record their vocalizations and take these recordings back to our sound lab and look at them. We humans are just so visually oriented that even the song of a Winter Wren may look more beautiful to us than listening to its sound (This is of course not true if you have a musical ear or train yourself to listen carefully and pick out intricate details).

If you are interested in learning how to record bird songs, look at them at home and compare them to each other join me for a Sound Analysis workshop at the nature center at Battelle Darby Creek metro park on Saturday April 29 from 10:30-11:30 am. If you are an early riser, join us on a Bird Walk at 8 am that same day and listen to the bounty of birds singing at this time of the year.

Credits:
Sound descriptions based on the ones given by the Cornell Lab of Ornithology, All about Birds.

Thank you Christopher Collins and Jim McCormac for the bird photos.

All recordings are archived in the Borror Laboratory of Bioacoustics. More detailed information for each can be accessed online; just click on each species’ name:
Blue-gray GnatcatcherGolden-crowned KingletRuby-crowned KingletWinter Wren

About the Author: Angelika Nelson is curator of the Borror Laboratory of Bioacoustics and instructor of Ohio Birds each spring.

*** Which birds are your favorites? ***

 

More than just a pretty (fish) face – Do you recognize some of these small fish from your aquarium?

As I mentioned in Monday’s post, species in the genus Anableps post the largest size (at just about a foot long) in an order of rather small fishes, the Cyprinodontiformes. Don’t let their small size fool you, it does not reflect their importance in several areas. Many are quite easy to raise, and some are cultivated for beautiful colors, particularly in their fins. Unfortunately, being popular fishes in aquaria frequently results in introductions to non-native areas from aquarium owners. In several instances exotic populations have become established. Here are some of the more enigmatic species that the OSUM Fish Division has vouchers for, arranged by family:

CYPRINODONTIDAE

Sheepshead Minnow, Cyprinodon variegatus, occur along the Atlantic coast from Massachusetts south to northern South America.  Abundant and easily cultured for the aquarium trade, also used as bait.  One introduced specimen was actually caught (back in the 1950’s) next to the Olentangy Indian Caverns in a small stream tributary to the Olentangy River.

Flagfish, Jordanella floridae, are common in the St. John’s and Ocklocknee Rivers to southern Florida. This species is listed in The Guinness Book of World Records as the fish with the fewest eggs, laying only 20 over several days.

FUNDULIDAE

Members of this family are distributed across North and Central America including some of the Caribbean islands, in coastal and interior low gradient, slow moving rivers, streams, and swamps.

Male Northern Studfish; note the twisted maxilla (posterior portion of the upper jaw bone) that is characteristic of the Fundulidae, photo by Uland Thomas

Northern StudfishFundulus catenatus. Although reputed to be difficult to keep it is popular in the aquarium trade because of the male’s vibrant breeding coloration. This species is native in disjunct populations in several states along the Ohio and Mississippi Rivers, but has recently been introduced and established in small to medium streams in Ohio and West Virginia.

OSUM 104822 Fundulus catenatus

OSUM 104822 is the voucher for the first specimen found on the eastern side of Ohio, in little Pipe Creek, across the Ohio River from Graves Creek in West Virginia, where there is a well established and thriving population that is believed to have been intentionally introduced.

Golden Topminnow, Fundulus chrysotus.  Common in Florida, but can be found in low lying swamps and backwaters from North Carolina along the Atlantic seaboard and around the Gulf of Mexico to eastern Texas.

 

Female Mummichog, photo by Dave Neely

The MummichogFundulus heteroclitus, frequently spawns inside mussel shells, a life history attribute that is hypothesized to be facilitated by a very long urogenital sheath.

The Diamond Killifish, Fundulus xenicus, inhabits marine, freshwater and brackish waters of the Gulf of Mexico shoreline from Florida to Mexico.

Bluefin Killifish, photo by Julie Zimmerman

Bluefin Killifish, Lucania goodei

Male Rainwater Killifish, photo by Brian Zimmerman

Rainwater Killifish, Lucania parva

GOODEIDAE

This family contains many species that are critically endangered in Mexico and Central America, due to their endemism to restricted bodies of water that are denigrated by anthropological modifications.

Tuxpan SplitfinAlldontichthys tamazulae, is endemic to the Rio Tuxpan in the State of Jalisco, Mexico.

Butterfly SplitfinAmeca splendens, is endemic to the State of Jalisco, Mexico, raised and sold commercially to the aquarium trade.

Redtail Splitfin, Xenotoca eiseni, are listed as endangered and declining.  The species was split as recently as 2016 to add two new species from the original distributions, where the critically endangered X. lyonsi is found in the Tuxpan and Tamazula Rivers and the critically endangered X. doadrioi in the “endorheic region of Metzatlan in the state of Jalisco, Mexico”.

POECILIIDAE

Possibly due to the ease of breeding, this family contains many popular aquarium species like guppies and swordtails.  One species, Poeciliopsis latidens, lives in marine waters, although several others are secondary freshwater species.

Sailfin MollyPoecilia latipinna, is native to coastal lowlands from North Carolina to Vera Cruz, Mexico, but has been introduced to many countries with “adverse ecological impacts” reported.

Variable Platy, Xiphophorus varietus, is endemic to Mexico but is another popular aquarium fish that has been carelessly introduced with resultant harmful ecological impacts (for this species the impacts are primarily competition with native fishes for resources).  These and several other species in the genus Xiphophorus are listed as exotic pests by governmental agencies.

The fact that many cyprinodontiforms (and cichlids) are tolerant to higher salinities as opposed to the primarily freshwater orders of fishes has made them the subject of biogeographical studies particularly for dispersal from one stream to another along coastal areas.  It is hypothesized that their adaptability to variable habitat conditions facilitated their invasion and predominance of the Central American fish fauna as they made their way across the narrow, open waters from South America to Central America before the rise of the Panamanian isthmus.  This hypothesis, formulated by ichthyologist George S. Meyers in the mid ’60s, has been strengthened by genetic work in the current decade.

Photo Credits:
All photos of museum specimens were taken by Marc Kibbey; other photos with permission of members of the North American Native Fishes Association (NANFA.org).

Detailed information for each specimen is available through the OSU Fish Division Database.

About the Author: Marc Kibbey is Associate Curator of the Fish Division at the Museum of Biological Diversity.

 

*** Which of these fish species do you have in your aquarium at home? ***

Ticks in pictures

Some more about ticks.  No, not The Tick comic or the movie Ticks … both may be entertaining, but they feature completely inaccurate depictions of ticks.

Let’s talk about real ticks:  Ticks are rather large mites. To demonstrate this, here is a family portrait:

family portrait of Ixodes pacificus, California Dept. of Public Health

Family portrait of Ixodes pacificus, California Dept. of Public Health [public domain]

From left to right, larva (6 legs), nymph (8 legs), male and female of Ixodes pacificus, the Western black-legged tick, from the west coast (you can see them with the naked eye, therefore they are big).

All members of the family feed on host blood using highly modified mouthparts, but only larvae, nymphs, and females engorge (feed to the point where their body truly swells up).

close-up of mouth parts of Amblyomma extraoculatum, U.S. National Tick Collection (USNMENT00956315)

Close-up of mouth parts of Amblyomma extraoculatum, U.S. National Tick Collection (USNMENT00956315)

Here are some nice examples of engorged females.  Keep in mind that while engorged ticks are easy to find, they are often difficult to identify.

Most of the ticks we encounter in Ohio have females that feed only once.  They engorge, convert all that host blood into a single mass of hundreds to thousands of eggs, and die.

tick with eggs (c) Univ. Nebraska, Dept. Entomology

Tick with eggs, Univ. Nebraska, Dept. Entomology

Ticks in general get really bad press.  Kind of sad, because ticks are very good at quite a few things, like surviving (some can survive hours under water or years without food), or manipulating your immune system (using a dizzying array of chemicals often found only in ticks). On second thought, that may not strike most people as positive, so let me end with a few pictures of beautiful creatures. I already introduced Amblyomma americanum, which occurs in Ohio, the others are African, A. chabaudi on tortoises in Madagascar, A. variegatum usually on cattle. Amblyomma variegatum is the main vector of heartwater, a disease making cattle herding impossible in parts of Africa, but still, very pretty.

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See some more of these specimens close-up, but at a safe distance through microscopes at our Annual Open House, April 22, 2017.

 

Dr. Hans Klompen, Professor EEOBiology at OSUAbout the Author: Dr. Hans Klompen is professor in the department of Evolution, Ecology and Organismal Biology and director of the Ohio State University Acarology Collection.

*** Which of these ticks is your “favorite”? Let us know on Facebook ***

 

Know your ticks: Ohio

Daffodils are in bloom, students walk around in shorts and T-shirts, so it must be the beginning of tick season.  And indeed, the first ticks are out and questing (= searching for a host). This might be a good time to talk about ticks in Ohio.  Ohio is not a major center for tick diversity, but it has some diversity.  Most people only know the three main people biters, Dermacentor variabilis (American dog tick), Amblyomma americanum (lone star tick), and Ixodes scapularis (deer tick), so let’s start with these:

Dermacentor variabilis is perhaps the most widespread and common tick in Ohio.  Immatures feed on rodents and other small animals, but adults feed on medium (opossums, raccoons, dogs) to large (humans) mammals.  Of the “big three” this species is the most tolerant of drying out, and the most likely to be encountered in open areas.  The main activity period for adults is mid-April – mid-July.  D. variabilis is the vector of, among others, Rocky Mountain Spotted Fever (RMSF) and tularemia.  Columbus used to be a focal area for RMSF, but the disease is less common now.  D. variabilis may also cause tick paralysis, although less frequently than the related D. andersoni from the Rocky Mountains region.

American dog tick

Dermacentor variabilis American dog tick

Amblyomma americanum used to be uncommon in southern Ohio, but has increased in numbers and range over the last decades.  This is part of a general trend.  In the eastern U.S., this species is rapidly expanding its range northwards.  All instars, larva, nymph, and adult feed on mid-size to large animals, incl. humans.  Like D. variabilis, females can deposit very large clutches of eggs, but in this case the resulting larvae often stay together.  If you are unlucky and step close to a mass of these “seed ticks”, you may be attacked by hundreds of ticks simultaneously.  These ticks are active in all warm months of the year.  Unlike D. variabilis, “Lone stars” are not common in open areas, preferring more shady and humid sites.  For a long time A. americanum was listed as vectoring few human diseases, but it has now been identified as vector of human monocytic ehrlichiosis and STARI, and possibly tularemia and Q-fever.

lone star tick

Amblyoma americanum lone star tick

Ixodes scapularis appears to be an even more recent resident.  This species was rare or absent in Ohio before 2010, but has now been found in a majority of Ohio counties.  The reason for this sudden expansion is unclear.  This is a relatively small species.  Larvae can be found in summer, nymphs late summer, and adults in fall and early spring.  Immatures tend to feed on smaller sized hosts, e.g. rodents, small birds, while adults prefer larger hosts, such as deer.  However, all instars may attach to humans.  Nymphs are considered the most problematic: they are small (thus often undetected), and can be infected with e.g. Lyme disease (unlike the even smaller larvae).  Like A. americanum, this species prefers shady, humid environments.  New subdivisions build in forests, resulting in large amounts of forest edges with lots of deer, have been a very good habitat for this tick in New England.  Ixodes scapularis has become famous as the vector for, among others, Lyme disease, human granulocytic anaplasmosis, and babesiosis.  Co-infection is common in New England and appears to result in increased pathology.

deer tick

Ixodes scapularis deer tick

So much for the common people biters.  It is important to note that most species of tick rarely if ever bite people.  They prefer different, usually smaller, hosts.  For example, Rhipicephalus sanguineus, the brown dog tick prefers feeding on dogs.  It is one of the few species that may occur indoors in dog kennels etc.  Haemaphylis leporispalustris appears to be specialized on hares and rabbits.  Several Ixodes species, I. cookei, I. dentatus, I. kingi, I. marxi, can be found on small to medium sized mammals, often associated with nests or burrows.  Finally, the so-called soft ticks, family Argasidae, are represented by only a single species in Ohio, Carios kelleyi, primarily found in bat colonies.

Find out more about the ticks’ life cycles and their diseases.

Dr. Hans Klompen, Professor EEOBiology at OSUAbout the Author: Dr. Hans Klompen is professor in the department of Evolution, Ecology and Organismal Biology and director of the Ohio State University Acarology Collection.

 

*** Have you found a tick yet this spring? send us a photo of your specimen on Facebook! ***

 

A newcomer to the OSUM Fish Division

We have several voucher specimens belonging to the order Salmoniformes, ray-finned fish like salmon, trout, chars, in our holdings, including the Lake Whitefish Coregonus clupeaformis. While common across most of their range, some are considered of special concern or vulnerable in the State of Ohio, for example, the Lake Trout Salvelinus namaycush. Another Coregonus species, the Cisco, is critically imperiled in Ohio, and Bloaters Coregonus hoyi (the hero of Monday’s post) were never found in Lake Erie due to the lake’s shallowness. Bloaters were extirpated from deeper Lake Ontario where the U.S. Fish & Wildlife Service is now reintroducing them. The specimens from the Tom Simon collection are the first Bloater vouchers (e.g. OSUM 117265) that we have for the OSUM fish collection.

By the way, a voucher specimen is a preserved specimen of an identified taxon permanently stored in our collection and retained as a reference. It has a unique identifier (e.g. OSUM 117265) and can be retrieved and used in scientific studies.

When moving the specimens, we needed many helping hands. Here Kai Raab, husband of OSUM Director Meg Daly, assisted with accession of some of the Tom Simon collection.

All Bloater specimens from the Tom Simon collection were trawled by the United States Geological Survey (USGS) during their surveys and have inflated gas bladders due to being brought from depths quickly.

The Bloater’s specific epithet, C. hoyi, is derived from the name of the man who originally discovered it while dredging in Lake Michigan, Dr. P. R Hoy. Dr. Hoy engaged ichthyologist Dr. James P. Milner to describe the species.

Coregonus is a diverse genus of fish with at least 68 described species. Some are easier to tell apart by morphology than others. Lake Whitefish, Coregonus clupeaformis, are separable from the Cisco and Bloater in the field by observing the mouth position: subterminal versus terminal, respectively. Note the terminal mouth, pointing forward, in the Cisco on the right.

Other species are quite similar in appearance and hard to separate in the field. For example, the Cisco and the Nipigon Cisco C. nipigon, as well as the Bloater and the Kiyi C. kiyi look very similar and occur sympatrically in some water bodies. For these and other species in the genus one must count the gill rakers to separate them. Gill rakers are the bony comb-like structure that serve to sieve food as the fish expels water through its gills while it is eating. The gill rakers are shown under the gill cover in the images below, to the left of the gill filaments that function to transfer oxygen from the water to capillaries. Once the food particles are caught on the rakers the fish can swallow them.

Cisco were found to have gill raker counts from 36 to 50, with a mean of 43 in Lake Saganaga and adjacent Minnesota border lakes. While gill raker counts for the Nipigon Cisco range between 45 to 70 with a higher mean than for the Cisco at 56.

Here are some additional species in the genus Coregonus; some are easy to tell apart by their location of occurrence.

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Reference:

Etnier, David A., and Christopher E. Skelton (2003). Analysis of Three Cisco Forms (Coregonus, Samonidae) from Lake Saganaga and Adjacent Lakes near the Minnesota/Ontario Border. Copeia, Vol. 4, 739-749.

 

About the Author: Marc Kibbey is Associate Curator of the Fish Division at the Museum of Biological Diversity.

 

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The Bloater: A Complicated Story

You may recall from my last post that I mentioned a fish species from the recent Tom Simon Fish Collection acquisition, the “Bloater” Coregonus hoyi.  This is a species that in the recent past has been considered endangered, indeed it was known to be extirpated from some of the Great Lakes and thought to perhaps be on its way to extinction across the rest of its distribution.  Herein I’ll detail some of the reasons for which the bloater came to be in such peril.  But for now, allow me to follow a rabbitfish trail (ahem):

Perhaps you have wondered why this fish is named so cruelly?  Perhaps, one might think, the name was given in less politically correct days when short shrift was given to a fish’s feelings, but that is simply not the case.  No, the name actually describes the propensity of the species’ swim bladder to expand and make it look fat when it is trawled from the deep, colder waters that it prefers.  So you see it actually does have to do with the poor fish having a tendency to be gassy.

OSUM 117265 Coregonus hoyi "bloater"

Yes, that bladder does make you look fat! OSUM 117265 Coregonus hoyi 195mm SL 1 of 18 specimens from jar 1 of 3

The rapid ascent from the fairly extreme depths, down to almost 700 feet where the fish resides, and consequent distension of the bladder does cause more than just discomfort for the fish. The complexity of the connection to the gas bladder in the bloaters renders them unable to quickly discharge the air and liable to bursting upon fast ascent from depths.  In many species of fish the swim bladder is directly connected to the gut and the fish can use this connection to directly control the amount of gas in the bladder. This physostomous swim bladder occurs mainly in fish living in shallow waters and swallow air that is passed into the gut and forced into the swim bladder. Not so in the Bloater. Fish in the order Salmoniformes, such as the Bloater, share a character with other advanced fishes: the physoclistous swim bladder. This gas bladder has no direct connection to the alimentary canal but some areas of the membrane separating gut and bladder are very thin and well supplied with capillaries that allow rapid gas exchange. This gas gland secretes oxygen into the swim bladder through the rete mirabile, literally “a wonderful net” of capillaries.

Diagram of the arterial/venous transfer to the gas bladder via the rete mirabile

The Bloater is one of several  “whitefish” species that have become rare and imperiled, some to the point of extinction. Bloaters are invertivores – you guessed right, feed on invertebrates – at all stages of their lives and formerly fed in open water (Many other fish species are invertivores at immature stages and shift their diets to larger prey including vertebrates as adults).  It has been documented that bloaters (and some other fish species) have changed their feeding habits in response to competition from the invasive Alewife Alosa pseudoharengus to feed on benthic invertebrates.  Happily for the bloaters they seem to have benefited, in the long run, from the Alewife invasion.

But there are several other reasons for the drastic declines seen among the bloater populations during the mid-1900’s:  Whitefish provide table fare for many piscivorous people, the fish-eaters among you.  The major upswing of humans in the Midwest region caused concordant increases in demand for food sources, and people began to realize that the Great Lakes could provide fish aplenty to help meet that need.  The lakes and rivers of the Midwest states at one time “teemed with fish”, according to several historians that wrote during that era of expansion and discovery. It seemed that the bounty was inexhaustible, and fishermen quickly capitalized on the surging market, filling their trawl nets to capacity for several decades.

Until, at varying points depending on the species being taken, the catches began to dwindle.  Before long the fishermen began to realize that conservationists were correct in their assessment that the boom wasn’t going to last, and regulations were put in place to husband the resources. However, other influences began to make themselves known, some with alarming results. Compounding the effects of overfishing was the connection of Lake Ontario to Lake Erie via the Welland Canal ca. 1830 that enabled incursion of several invasive fish species:  First to make an impact was the Alewife, a relatively small fish species in the herring family Clupeidae. Alewives compete with coregonids and other fish species for planktonic prey, to the point where diets for some forms shifted from zooplankton to benthic foods, feeding at the lowest level of the water body. Those species that couldn’t adapt their diets disappeared, became smaller or declined in numbers.  The next invader to have a significant impact on bloaters was the Sea Lamprey Petromyzon marinus. Sea Lampreys are piscivorous parasites (or is that parasitic piscivores?) for approximately a year of their several years’ long life cycle.  The invasive lamprey arrived in the Great Lakes in the early 1900’s and by the mid 1900’s had decimated populations of several salmoniform species. It is thought that one reason fish species like Lake Trout, and Lake Whitefish and other coregonids, fared so poorly with the Sea Lampreys is that they tend to inhabit deeper, colder areas of the Great Lakes where the lampreys prefer to feed.  For example, bloaters are most commonly found at a depth of 90 – 680 feet in water temperatures between 34-55 degrees Fahrenheit. Thanks to the monumental efforts of our conservation agencies the Sea Lamprey populations are under reasonably good control to the point where Great Lakes fishes are much safer!

 

Reference:

McDonald, M. E., Crowder, L. B., & Brandt, S. B. (1990). Changes in Mysis and Pontoporeia populations in southeastern Lake Michigan: a response to shifts in the fish community. Limnology and Oceanography, 35(1), 220-227.

 

About the Author: Marc Kibbey is Associate Curator of the Fish Division at the Museum of Biological Diversity.

 

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