A Little Bit of Lace

This guy came to the porch light last night:

Brown Lacewing (Hemerobius stigma), Zion, Lake Co, IL  4/8/2014

This is a Brown Lacewing, and I believe it's Hemerobius stigma. This is a species that is widespread in the northern hemisphere, and it's actually an important species in agriculture. It's active in very cool weather (like early April nights in Chicago), and it eats aphids -- lots of them. Neuenschwander & Hagen investigated the related H. pacificus for use as a biological control agent in artichoke fields, and found that they reduced aphid populations by 30%! This contrasts with the 14% reduction they found associated with the wasps that are often used for this purpose. (1)


Neuenschwander, P., & Hagen, K. S. (1980). Role of the predator Hemerobius pacificus in a non-insecticide treated artichoke field. Environmental Entomology,9(5), 492-495.

A Shocking Exploration.

Here's a neat critter from the Amazon:

Electric Eel (Electrophorus electricus),
Shedd Aquarium, Cook Co, IL  1/20/2013

This is an Electric Eel, (Electrophorus electricus). They live in shallow waters in South America, often in ponds and back channels that nearly disappear in the dry season. Oxygen levels can get very low in these waters, and the Electric Eel is not only capable of breathing air through an organ in its mouth, it actually has to, every 10 minutes or so! (1)

Of course, it's called an Electric Eel because it's got a bunch of specialized cells that can generate up to 500 watts of electric current over a very short time. Known as electrocytes, they are modified muscle cells. Where does the electricity come from?

Well, most animals can produce electric currents -- nerve cells conduct information by opening ion channels in their membranes, allowing charged ions (mostly Sodium and Potassium) to move in and out of the cells. Muscle cells use a similar system to signal the actin and myosin proteins to start working to contract the cell. So all the eel had to do is decouple the motor system from the signaling system, and then stack a whole bunch of these cells on top of each other.

Still, that's a fair bit of work for evolution to do without some intermediate payouts. What good is a little bit of electricity?

Turns out, quite a bit. Other members of the same family, as well as several species of African fish, produce weak electric fields that aren't much use for self-defense, but are very good at detecting living critters in the surrounding water. Since they don't require light, these guys can still hunt at night, or in very murky water.

Electric Eels didn't have to invent the system from scratch -- early, weakly electric fish modified an already working system, and then the eels simply strengthened it. This is typical of evolution -- it uses what's handy. Fins become forelimbs, forelimbs become wings, and suddenly there's a whole range of places for evolution to explore.

Something like this may have happened with the electric fish in yet another sense. In most species, predation pressure is considered to oppose sexual selection, such that a male's features (usually the male, anyways) are a balance between attractiveness and survival. But in the Eel's relatives, the signals they use to hunt and to communicate appear to have evolved in such a way as to make them harder to detect by electro-sensitive fish. (Especially the Electric Eel, interestingly enough.) Males of these species now appear to have coopted the new features of those signals for indications of fitness, in much the same way as frogs do with their calls. (2) So we have a case where a feature has evolved a new set of uses from a very different basis, just like the electric signals the fish put out in the first place.

(1) Johansen, Kjell (1968). "Gas Exchange and Control of Breathing in the Electric Eel, Electrophorus electricus".Z. Vergl. Physiologie (Springer Berlin / Heidelberg) (Volume 61, Number 2 / June, 1968): 137–163.

(2) Stoddard, P. K. (1999). Predation enhances complexity in the evolution of electric fish signals. Nature, 400(6741), 254-256.

A Little Good News

Here's a success story, in four parts:

Eastern Bluebird (Sialia sialis),
Ryerson Forest Preserve, Lake Co, IL 3/16/2012

This is an Eastern Bluebird (Sialia sialis). In the middle of the 20th century, Eastern Bluebirds underwent a serious decline as a result of competition from House Sparrows and European Starlings for nest sites. But biologists figured out that the right nest boxes could encourage the bluebirds and exclude the starlings, and the establishment of trails of nest boxes, often manned by volunteers, have made the Eastern Bluebird a common sight again. As an example of the decline, CBC numbers in Alabama went from an average of 1.87/party hour in the 1950's to an average of 0.62 in the 1960's, before rebounding to an average of 2.33 over the last 10 years. (1)

This next bird is quite widespread, extending from Cuba to the northeastern corner of Siberia:

Sandhill Crane (Grus canadensis),
Volo Bog SNA, Lake Co, IL 3/6/2012

It's a Sandhill Crane (Grus canadensis), a common breeder and very common, if very local, migrant through northeastern Illinois. But it wasn't always such - by 1890, hunting and draining of marshes had eliminated them as a breeding species in the state. It wasn't until 1979 that they started nesting here again. (2) Now, between March and November, it doesn't seem as if I've been birding unless I've heard their stuttering trumpet calls.

This next one is a work in progress:

Trumpeter Swan (Cygnus buccinator), Independence Grove FP,
Lake County, IL 1/2/2013

This is a Trumpeter Swan (Cygnus buccinator). There are historical records of them nesting in Illinois, although it's hard to say how common they were. But they were eliminated from their Great Lakes nesting range in the 19th century, with the last nesting record for Illinois around 1856. Until May of 2006, that is, when a pair from a release program in Iowa set up shop in Carroll County in NW Illinois. (3) While they still aren't a common sight in Illinois, the populations in Michigan, Wisconsin, and Minnesota are showing dramatic increases.

Finally, one that has a long ways to go -- largely because of how few there were at one point:

Whooping Crane (Grus americana), Milwaukee County Zoo,
Milwaukee County, WI, 1/9/2013

This is a Whooping Crane (Grus americana), the tallest bird in North America. Adults can stand 5 feet tall. This shot came from the Milwaukee County Zoo -- this individual wouldn't be able to survive in the wild. And getting shots of free-living birds is difficult: from a low of 21 wild and 2 captive birds in 1941, they've managed to recover to a count of 385 wild and 151 captive birds in 2008. (4) Some of those wild birds are releases in Necedah NWR in west-central Wisconsin, where a handful of successful nesting attempts have occurred. These birds have probably always had a low reproductive rate, which makes recovering from a population crash a long, slow process. But today, if you're lucky, you can again see wild Trumpeters and Whoopers crying the wilderness out over the skies of Illinois.

(1) National Audubon Society (2010). The Christmas Bird Count Historical Results [Online]. Availablehttp://www.christmasbirdcount.org [4/6/2014]

(2) http://www.npwrc.usgs.gov/resource/birds/cranes/gruscana.htm

(3) Sheryl Devore. http://www.dnr.illinois.gov/oi/documents/may08trumpeterswan.pdf

(4) BirdLife International 2012. Grus americana. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 07 April 2014.

A Couple of Fisher Ladies.

Here's a quick shot from today:

Belted Kingfisher (Ceryle alcyon),
Gander Mountain Forest Preserve, Lake Co, IL  4/5/2014

These are two female Belted Kingfishers (Ceryle alcyon), having a dispute about who owns that stretch of the river. Kingfishers are normally quite camera shy, but when they're preoccupied with fighting, you can get lucky. Here's a closer shot of the winner:

Belted Kingfisher (Ceryle alcyon),
Gander Mountain Forest Preserve, Lake Co, IL  4/5/2014

Of course, youngsters are often brazen, or just stupid, and they'll allow things like this:

Belted Kingfisher (Ceryle alcyon),
Illinois Beach State Park, Lake Co, IL 6/19/2012 

You can tell this one's a youngster by the rufous invading the blue band across the chest.

Kingfishers are neat birds. As their name implies, they mostly eat fish, although they will take frogs, crayfish, and even small mammals, usually catching their prey by diving head-first into the water. While trying to spot prey, they will hover, head down, in one spot for several seconds. Add in their big-headed look and rattling call, and they almost resemble a wind-up toy!

I will often point out to my students that while we try to describe discrete ecosystems, especially when water is involved, those ecosystems actually interact a good deal. Sullivan, et al. found that the quality of streams in a Kingfisher's territory was a major determinant of their reproductive success. (1) (Although I don't know how they handled the non-random distribution of birds between territories -- more experienced birds are likely to select and successfully defend the best territories, and also to nest successfully.) Kelly found that the complexity of a stream's bed affected the choice of prey types by Kingfishers, essentially reducing the effects of the birds' preferences to reflect the availability of different prey. (2) Both of these papers looked at the effects of an aquatic ecosystem to a bird that is to some degree terrestrial. Steinmetz, et al. examined the effects of Kingfishers and egrets on fish communities, finding that they play major roles in determining the structure of those communities by acting as top predators. (3)

As humans, we seem to like drawing boundaries -- they appear to help us in living such social lives, particularly in larger, denser societies. But when we're doing ecology, we have to remember to look at those boundaries as our study species see them, which is often a very different thing.

(1) Sullivan, S. M. P., Watzin, M. C., & Hession, W. C. (2006). Differences in the reproductive ecology of belted kingfishers (Ceryle alcyon) across streams with varying geomorphology and habitat quality. Waterbirds, 29(3), 258-270.

(2) Kelly, J. F. (1996). Effects of substrate on prey use by belted kingfishers (Ceryle alcyon): a test of the prey abundance-availability assumption. Canadian journal of zoology, 74(4), 693-697.

(3) Steinmetz, J., Kohler, S. L., & Soluk, D. A. (2003). Birds are overlooked top predators in aquatic food webs. Ecology, 84(5), 1324-1328.

Freeloading Plants Doing Good?

Our cold winter and late snow seem to have left our local plant life a bit behind schedule. So here's a plant that was still green in March of last year:

Eastern Mistletoe (Phoradendron leucarpum),
Louisville Zoo, Jefferson Co, KY  3/28/2013

This is Eastern Mistletoe (Phoradendron leucarpum) growing on an oak tree at the Louisville Zoo. Mistletoes are parasitic plants, that grow into their host tree's tissues and absorb nutrients from them. Here's the entire tree:

Eastern Mistletoe (Phoradendron leucarpum),
Louisville Zoo, Jefferson Co, KY  3/28/2013

This genus includes over 200 species. There are quite a few other species of mistletoes, but they fall into 5 different families. Apparently parasitism in these guys has evolved independently on several occasions. One of the interesting aspects of parasite evolution is the occurrence of host-race evolution, where a population can split into several, sometimes sympatric races, each specializing on a different host species. Apparently, this happens in Phoradendron, as Glazner, et al. found evidence for it in Desert Mistletoe (P. californicum). (1)

European Mistletoe (Viscum album) has been used as a folk remedy for a number of ailments for centuries, and preparations of it have been marketed as anti-cancer agents. These studies appear to offer a mixed bag of results (2,3,4), although it does appear that it can act through both cytoxic effects (5) and by stimulating the immune system. (6) That cytotoxin, however, should be a concern for anyone rushing down to the corner drugstore -- in at least one case, Mistletoe consumption has been linked to hepatitis. (7)

That's a lot going on for a plant most of us only know as a plastic Christmas ornament!


(1) Glazner, J. T., Devlin, B., & Ellstrand, N. C. (1988). Biochemical and morphological evidence for host race evolution in desert mistletoe, Phoradendron californicum (Viscaceae). Plant systematics and evolution,161(1-2), 13-21.

(2) Joller, P. W., Menrad, J. M., Schwarz, T., Pfüller, U., Parnham, M. J., Weyhenmeyer, R., & Lentzen, H. (1996). Stimulation of cytokine production via a special standardized mistletoe preparation in an in vitro human skin bioassay.Arzneimittel-Forschung, 46(6), 649-653.

(3) Friess, H., Beger, H. G., Kunz, J., Funk, N., Schilling, M., & Büchler, M. W. (1995). Treatment of advanced pancreatic cancer with mistletoe: results of a pilot trial. Anticancer research, 16(2), 915-920.

(4) Stein, G., Henn, W., von Laue, H., & Berg, P. (1998). Modulation of the cellular and humoral immune responses of tumor patients by mistletoe therapy.European journal of medical research, 3(4), 194-202.

(5) Janssen, O., Scheffler, A., & Kabelitz, D. (1993). In vitro effects of mistletoe extracts and mistletoe lectins. Cytotoxicity towards tumor cells due to the induction of programmed cell death (apoptosis). Arzneimittel-Forschung, 43(11), 1221-1227.

(6) Heiny, B. M., & Beuth, J. (1993). Mistletoe extract standardized for the galactoside-specific lectin (ML-1) induces beta-endorphin release and immunopotentiation in breast cancer patients. Anticancer research, 14(3B), 1339-1342.

(7) Harvey, J., & Colin-Jones, D. G. (1981). Mistletoe hepatitis. British medical journal (Clinical research ed.), 282(6259), 186.

NOT Just Another Lizard!

Spent the morning writing a test and the afternoon giving it. Since it was partly on evolution, here's a favorite bit of that topic:

Tuatara (Sphenodon punctatus), St. Louis Zoo, St. Louis, MO 3/2/2012

This little guy lives in a nice enclosure in the corner of the St. Louis Zoo's reptile house, where I heard someone dismiss him as "just another lizard." (Although  I don't quite get why you would go into a reptile house if you don't like lizards.) But he isn't a lizard at all! In fact, the vipers in another part of the house have a better claim to the title lizard, as they actually split off from one of the two branches of lizards at least 50 million years more recently than the last common ancestor of this guy and all of the lizards and snakes.

So what is he? A Tuatara (Sphenodon punctatus). He belongs to one of two species of Rhynchocephalians left, the other being the congener Sphenodon guntheri. During the early Mesozoic era, however, Rhynchocephalians were a diverse, wide ranging (1) and very successful group, filling niches similar to many of our modern lizards, and even including a marine form, Pleurosaurus.

Modern Tuatara are limited to New Zealand, where they were widespread before human settlement. By the time Europeans arrived, they were limited to a few offshore islands. There is some evidence that the Maori used them for food, but they also brought rats to the islands, and recent evidence from islands with Tuatara suggests that while rats don't eat adult Tuatara, they do eat eggs and juveniles. (2,3) Over a long enough time, this could easily cause the extinction of a species. Fortunately for modern conservation efforts, Tuatara live a long time and can reproduce for decades. So we have time to deal with rats on those islands they've colonized.

On the other hand, S. guntheri was only described as a separate species in 2008, and it's only known from one island (North Brother Island). Since 4 islands have lost their Tuatara completely in recent years, we could easily have lost this species before we knew we had it. (4)

In 2005, an attempt was made to introduce them back onto the North Island. In 2009 the first mainland hatchling in over 200 years was found - a bit of very good news for one of our last reminders of the age of the dinosaurs!

(1) Reynoso, V. H. (1996). A Middle Jurassic Sphenodon-like sphenodontian (Diapsida: Lepidosauria) from Huizachal Canyon, Tamaulipas, Mexico. Journal of Vertebrate Paleontology, 16(2), 210-221.

(2) Cree, A., Daugherty, C. H., & Hay, J. M. (1995). Reproduction of a rare New Zealand reptile, the tuatara Sphenodon punctatus, on rat‐free and rat‐inhabited islands. Conservation Biology, 9(2), 373-383.

(3) Newman, D. G. (1988). Evidence of predation on a young tuatara, Sphenodon punctatus, by kiore, Rattus exulans, on Lady Alice Island. New Zealand journal of zoology, 15(3), 443-446.

(4) Daugherty, C. H., Cree, A., Hay, J. M., & Thompson, M. B. (1990). Neglected taxonomy and continuing extinctions of tuatara (Sphenodon).

A Chorus Line?

These guys finally warmed up enough to make some noise last weekend:

Western Chorus Frog, (Pseudacris triseriata),
Van Patten Woods FP, Lake Co, IL 3/29/04

This is a Western Chorus Frog, (Pseudacris triseriata). It's a member of the family Hylidae, often called Tree Frogs for their habit of climbing trees.

Striped Chorus Frogs are our first frogs to call in the spring, and if you've ever been close to a pond full of them, you know where they got their name. A single frog sounds like someone running a fingernail along a comb, from the broad side to the narrow one. A whole pond of them sounds like a fairly high-pitched white noise generator, and they can be heard for a surprising distance. Seeing them, though, is really difficult -- I got this shot by spending 15 minutes knee deep in cold water, and if there was emergent vegetation to deal with I probably wouldn't have.

Any critter that's that hard to spot is probably dealing with a lot of predators, and these guys are no exception. Small frogs are eaten by everything from larger fish to really big diving beetles or dragonfly larvae to Red-shouldered Hawks. Their tadpoles are even more vulnerable.

Another way that these guys avoid predators is to breed in temporary ponds, where aquatic predators can't survive the summer. But that requires quick development -- if the pond dries up, the tadpoles die. On Isle Royale, Smith found that this dynamic limited the frogs to certain ponds, ones that stayed wet long enough for tadpoles to develop but not long enough for predators to colonize. (1) In SE Michigan, Skelly found that Chorus Frogs colonized temporary ponds while these guys used permanent ponds:

Spring Peeper (Pseudacris crucifer),
Ridges Sanctuary, Door Co, WI  8/12/2013 

This is a Spring Peeper, (P. crucifer). It's another early tree frog, as it's name suggests. Doing some manipulations enabled Skelly to determine what was driving the difference in pond usage, with Peepers developing more slowly and therefore being more susceptible to the ponds drying, while Chorus Frogs were able to develop quickly and avoid the ponds drying out, but were more susceptible to predators if they were present. He noticed that Chorus Frog tadpoles spent more time moving while feeding, which would help explain both their faster development and their greater risk of predation, and therefore the difference in how they use the environment. (2)

We often summarize natural selection as Survival of the Fittest, and ask which species is the best adapted to the environment. But as these frogs point out, there are many ways to use your environment, and the fittest frog is the one that fits its strategy to it's own little bit of the world around it.


(1) Smith, D. C. (1983). Factors controlling tadpole populations of the chorus frog (Pseudacris triseriata) on Isle Royale, Michigan. Ecology, 64(3), 501-510.

(2) Skelly, D. K. (1995). A behavioral trade-off and its consequences for the distribution of Pseudacris treefrog larvae. Ecology, 150-164.