Recent Travels: Places

by Carl Strang

I have fallen behind on blog posts. The season is heating up, and I have kept busy doing various surveys in various places. Today’s start on catching up will focus on some scenes and miscellaneous photos taken along the way.

The Marquette Trail at Indiana Dunes National Lakeshore passes beautiful marsh and sand savanna habitats.

The Marquette Trail at Indiana Dunes National Lakeshore passes beautiful marsh and sand savanna habitats.

I found northern wood crickets singing along the trail. They bury themselves in leaf litter like this.

I found northern wood crickets singing along the trail. They bury themselves in leaf litter like this.

Another example of a wood cricket song site. I tried to get a look at one, but they choose deeply stacked litter areas with plenty of hidey holes and escape routes.

Another example of a wood cricket song site. I tried to get a look at one, but they choose deeply stacked litter areas with plenty of hidey holes and escape routes.

Painted turtles wandered the savanna seeking good places to lay their eggs.

Painted turtles wandered the savanna seeking good places to lay their eggs.

Another good sand area is Illinois Beach State Park. Here a trail goes through the zone behind the fore dunes.

Another good sand area is Illinois Beach State Park. Here a trail goes through the zone behind the fore dunes.

Farther back from the edge of Lake Michigan, black oak savanna lines the trail.

Farther back from the edge of Lake Michigan, black oak savanna lines the trail.

Though my main interest was singing insects, there were many four-spotted skimmers to enjoy at IBSP.

Though my main interest was singing insects, there were many four-spotted skimmers to enjoy at IBSP.

I also have spent some time in Kendall County. This plains clubtail was at Hoover Forest Preserve.

I also have spent some time in Kendall County. This plains clubtail was at Hoover Forest Preserve.

This year’s Indiana Academy of Sciences bioblitz was at Goose Pond in southern Indiana. I stopped on the way down for a walk at Turkey Run State Park. Ravines there provide many scenes like this.

This year’s Indiana Academy of Sciences bioblitz was at Goose Pond in southern Indiana. I stopped on the way down for a walk at Turkey Run State Park. Ravines there provide many scenes like this.

I didn’t end up taking any scenery shots at Goose Pond. As I was setting up the UV light, I found this mama spider crossing the road, her back covered with babies. All their eyes glittered like jewels in the headlamp.

I didn’t end up taking any scenery shots at Goose Pond. As I was setting up the UV light, I found this mama spider crossing the road, her back covered with babies. All their eyes glittered like jewels in the headlamp.

St. James Farm is Humming

by Carl Strang

As the cold spells have become fewer and weaker, insects and other invertebrates increasingly have decorated the landscape at St. James Farm Forest Preserve. None decorate better than the butterflies.

A few American lady butterflies appeared early in May.

A few American lady butterflies appeared early in May.

The silver-spotted skipper attests to the presence of black locust trees on the preserve.

The silver-spotted skipper attests to the presence of black locust trees on the preserve.

Very early in the season I was seeing abundant grasshopper nymphs in the forest. I had a suspicion about them, which was confirmed as they matured.

The green-legged grasshopper is an early season forest species.

The green-legged grasshopper is an early season forest species.

Dragonflies increasingly appeared in the second half of May.

The most abundant dragonfly in recent days has been the common baskettail. Though they usually are seen on the wing, this one gave me a rare opportunity for a perched shot.

The most abundant dragonfly in recent days has been the common baskettail. Though they usually are seen on the wing, this one gave me a rare opportunity for a perched shot.

No baskettail this. It’s another early season species, a female dot-tailed whiteface.

No baskettail this. It’s another early season species, a female dot-tailed whiteface.

All these insects bring out the parasites and predators.

Epalpus signifer is a tachinid fly, a parasite of caterpillars.

Epalpus signifer is a tachinid fly, a parasite of caterpillars.

Morning dew highlights the abundant webs of bowl and doily spiders.

Morning dew highlights the abundant webs of bowl and doily spiders.

 

Mayslake Marsh Update: Amphibian Traps

by Carl Strang

I set out some amphibian traps in Mayslake Forest Preserve’s stream corridor marsh to assess how the marsh has recovered from the drought of 2012 and another drying out in 2013.

This leopard frog still is dark from its recent emergence.

This leopard frog still is dark from its recent emergence.

I have caught and released several of the large predaceous diving beetles, Dytiscus hybridus.

I have caught and released several of the large predaceous diving beetles, Dytiscus hybridus.

Similar in size, this water scavenger beetle, Hydrophilus triangularis, was an addition to the preserve species list.

Similar in size, this water scavenger beetle, Hydrophilus triangularis, was an addition to the preserve species list.

The club-like end of the antenna separates the water scavenger beetles from the predaceous diving beetles, whose antennae are thread-like.

The club-like end of the antenna separates the water scavenger beetles from the predaceous diving beetles, whose antennae are thread-like.

The identification of this juvenile crayfish is uncertain, but the slender pincers have me thinking White River crayfish, in the past the most common species in that marsh.

The identification of this juvenile crayfish is uncertain, but the slender pincers have me thinking White River crayfish, in the past the most common species in that marsh.

I caught only one magnificent adult White River crayfish against 10 or so juveniles, sign of a recovering population.

I caught only one magnificent adult White River crayfish against 10 or so juveniles, sign of a recovering population.

Meanwhile, the grassland crayfish have been opening up their tunnels around the peripheries of the wet areas.

Meanwhile, the grassland crayfish have been opening up their tunnels around the peripheries of the wet areas.

Grassland crayfish mainly come out at night to forage on land. Sometimes these foragers become foragees.

Grassland crayfish mainly come out at night to forage on land. Sometimes these foragers become foragees.

The marsh’s muskrats regard the amphibian traps as suitable platforms for their territorial markings.

The marsh’s muskrats regard the amphibian traps as suitable platforms for their territorial markings.

Through all of this, the marsh’s sounds have been dominated by the songs of western chorus frogs. They are so small that they can squeeze their way out of the traps.

Through all of this, the marsh’s sounds have been dominated by the songs of western chorus frogs. They are so small that they can squeeze their way out of the traps.

 

Literature Review: Paleozoic Era

by Carl Strang

The first animals which unambiguously connect to present day forms appear in the fossil record early in the Paleozoic Era, which began 542 million years ago, billions of years after the planet first formed. Here are some notes from studies of this era published in 2014.

American alligator. One of the following studies places the split between the reptilian crocodile-dinosaur-bird group and the lizard-snake group at the very end of the Paleozoic Era.

American alligator. One of the following studies places the split between the reptilian crocodile-dinosaur-bird group and the lizard-snake group at the very end of the Paleozoic Era.

Cong, Peiyun, et al. 2014. Brain structure resolves the segmental affinity of anomalocaridid appendages. Nature, DOI: 10.1038/nature13486 They studied the brain structure of Lyrarapax unguispinus, a fossilized relative of Anomalocaris, and found it was both simpler than those of its contemporary prey, and very similar to those of today’s onychophorans, or velvet worms, terrestrial southern hemisphere forest floor predators with unusual antennae that connect to the brain in the same way that the pair of grasping appendages connected to the brain of Lyrarapax. The similarities suggest a common ancestry.

Jourdan, F., et al. 2014. High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction. Geology 42 (6): 543. DOI: 10.1130/G35434.1 From a ScienceDaily article. The first major extinction event, which took out 50% of species in the Middle Cambrian, was caused by a mass volcanic eruption in Australia according to this study.

Morris, Simon Conway, and Jean-Bernard Caron. 2014. A primitive fish from the Cambrian of North America. Nature, DOI: 10.1038/nature13414 New Burgess shale fossils from the Cambrian of 505mya (million years ago) show detail in one of the earliest fishes, Metaspriggina, in which branchial arches are revealed as paired, with the first pair slightly thicker than the others (a step toward the first jaw). They had large eyes, and probably were good swimmers.

Shubin, Neil H., Edward B. Daeschler, and Farish A. Jenkins, Jr. 2014. Pelvic girdle and fin of Tiktaalik roseae. PNAS, DOI: 10.1073/pnas.1322559111 From a ScienceDaily article. They describe the anatomy of the rear part of this fish, previously known only from anterior portions. This animal was transitional toward terrestrial life, living in a delta environment where the ability to cross over land from stream to stream was advantageous. It was large, as much as 9 feet long, with large teeth making it somewhat reminiscent of a crocodile. It was lobe-finned, had a flexible neck, and rudimentary lungs. Its well-developed shoulder girdle previously was known, but it had been assumed that it crawled with only its front fins. The surprise was that the pelvic girdle also is developed, with a ball and socket joint and strong hind fins, so these fish had rudiments of four, rather than just two legs.

Ezcurra, M.D., T.M. Scheyer, and R.J. Butler. 2014. The origin and early evolution of Sauria: reassessing the Permian saurian fossil record and the timing of the crocodile-lizard divergence. PLoS ONE 9(2): e89165. doi:10.1371/journal.pone.0089165 They took a close look at Permian fossils in an attempt to resolve debate on when the split happened between the reptilian line leading to crocodiles, dinosaurs and birds on the one hand (archosauromorphs) and lizards and snakes on the other (lepidosauromorphs). They concluded that only the former have been found in the Permian, and place the earliest possible time for the split at 254.7 million years ago (very late Permian).

Common Goldeneye Species Dossier

by Carl Strang

This week’s feature species is chosen in celebration of my seeing its close cousin, the Barrow’s goldeneye, as accounted recently.

Goldeneye, Common

Common goldeneyes, black and white males with brown headed females

Common goldeneyes, black and white males with brown headed females

Fairly common migrant and winter resident at Lake Maxinkuckee in northern Indiana, staying as long as open water remained, and appearing as open water appeared in spring. Although they fed in the lake (these ducks dive for food), they also flew to the Tippecanoe River to forage. When only holes remained in the center of the lake ice, the river was their sole food source. Crayfish the principal food taken from the river (gut contents of hunted birds). Usually seen in small groups of 2-7, although larger flocks of >20 occasionally were spotted. Called “whistlers” by hunters because of the distinctive whistling of their wings in flight. Occasional small flock seen at Kokechik Bay, western Alaska, in spring. Courtship display of males includes extreme head throwback, so that bill points up and the back of the extended neck is against the duck’s back.

Observed on the Rock River in early spring 1986.

23JA88. Pair in west branch of the DuPage River at McDowell Forest Preserve.

21FE99. 14, mostly females, and one incompletely molted-in male, actively diving in the Fox River just south of downtown St. Charles, IL.

21MR05. On Lake Maxinkuckee, two male hooded mergansers in separate small flocks of goldeneyes. In one of the flocks, courtship displays began, and the merganser displayed as well, fanning his crest open to the fullest extent. No female mergansers in those groups.

22FE09. A number of goldeneyes of both genders on the Fox River at the park downstream from Batavia’s Island Park. The current is very swift, and carrying a lot of small ice pieces. The ducks are diving repeatedly, and at some point when the current has carried them downstream a distance they fly back up and begin again. Their diving within the fairly dense ice pieces is an impressive sight.

12FE13. A number of goldeneyes at Widewaters on the Des Plaines River at Channahon, and at the rookery at Channahon and at Lake Renwick, evidently wintering there.

Literature Review: Evo-Devo

by Carl Strang

One of the most fascinating biological disciplines to emerge in recent years is evo-devo, the study of the genetic regulation of embryological development, with the goal of understanding the role of evolution. Most of the work to date has been done in animals, and the connections between distantly related species often are amazing, as several studies cited below reveal. Plants are increasingly subjects of this form of study, and the general patterns often prove to be similar to those in animals, as illustrated in the Vlad et al. study. Humans don’t escape this type of scrutiny, and we prove to have very similar vocal controls to those of songbirds. Fossil studies often are brought into these researches, as shown in the studies of breathing in turtles and the evolutionary relationships of daddy longlegs (harvestmen). Even the electric organs of various groups of fishes are subject to this kind of analysis.

The first study goes into the development of leaves, which in some species results in their division into separate leaflets as in this buckeye leaf.

The first study goes into the development of leaves, which in some species results in their division into separate leaflets as in this buckeye leaf.

Vlad, Daniela, et al. 2014. Leaf shape evolution through duplication, regulatory diversification, and loss of a homeobox gene. Science 343:780-783. They looked at developmental regulation of leaflet formation. A particular protein produced through homeobox activity represses growth in areas that end up being between leaflets. The associated gene evolved within a duplicated section of DNA. They found a species in which the duplicate was lost, resulting in simple leaves.

Pfenning, Andreas R., et al. 2014. Convergent transcriptional specializations in the brains of humans and song-learning birds. Science 346:1333. They studied genomes of a variety of birds and primates, and found that song-learning birds and humans share genes that produce connections between their brains and vocal apparatus, genes that are inactive in bird and primate groups that do not sing or speak. Thus brain structure and circuitry features associated with song learning in birds and vocal learning in humans are analogous and similar, and homologous at the level of brain regions. Genetic underpinnings for these structures likewise are similar. “The finding that convergent neural circuits for vocal learning are accompanied by convergent molecular changes of multiple genes in species separated my millions of years from a common ancestor indicates that brain circuits for complex traits may have limited ways in which they could have evolved from that ancestor.”

Lyson, Tyler R., et al. 2014. Origin of the unique ventilatory apparatus of turtles. Nature Communications 5: 5211. DOI: 10.1038/ncomms6211  Described in ScienceDaily. They did a detailed study of modern and fossil turtles, focusing on breathing, because turtles are the only air-breathing vertebrates that cannot employ the ribs. Turtles breathe with a ring of muscles surrounding the lungs. This system was in place in the early (260mya, Permian Period) African turtle Eunotosaurus africanus. They found that the system evolved gradually, the body wall stiffening as ribs broadened (for reasons still to be determined), and the musculature gradually developing to take more and more of the load.

Gallant, J. R., et al. 2014. Genomic basis for the convergent evolution of electric organs. Science 344:1522-1525. They studied the genetic and developmental aspects of electric fishes, 6 separate groups of which independently evolved the ability to produce electricity. They found that the same genetic basis and developmental pathway evolved to the same endpoint in all these different lines. Certain muscle cells lost their contraction ability and increased their membrane’s ability to manipulate ions and build up charge. They are set up in series down the length of the fish, increasing the voltage. The most powerful is the Amazon’s electric “eel” (more like a catfish), which one of the researchers characterized as “in essence a frog with a built-in five-and-a-half-foot cattle prod.” These fishes all live in murky waters, and use their electric capability to sense their surroundings, communicate, stun prey, and defend themselves.

Nuño de la Rosa, Laura, Gerd B. Müller, and Brian D. Metscher. 2014. The lateral mesodermal divide: an epigenetic model of the origin of paired fins. Evolution & Development 16 (1): 38. DOI: 10.1111/ede.12061  From a ScienceDaily article. They looked at the fossil record and the genetics of development, and found that the body cavity prohibits development of limbs in the region of body axis where it occurs. The result is a single pair of limbs in front, and a single pair behind that region.

Garwood, Russell J., Prashant P. Sharma, Jason A. Dunlop, and Gonzalo Giribet. 2014. A Paleozoic stem group to mite harvestmen revealed through integration of phylogenetics and development. Current Biology, DOI: 10.1016/j.cub.2014.03.039  From a ScienceDaily article. They studied a rare early harvestman fossil with x-ray scanning which provided unusual 3D detail. The fossil was 305 million years old (Pennsylvanian Period), from France. It showed an extra pair of eyes, set laterally, which subsequent study revealed appear in vestigial form at a point in embryo development (mature present-day harvestmen have only a single pair of eyes). The authors mentioned that harvestmen are more closely related to scorpions than to spiders.

Return to Midewin

by Carl Strang

Recently I spent an enjoyable afternoon at the Midewin National Tallgrass Prairie, in Will County, Illinois. My main target was a swale in the northwestern portion of the property.

In one place the swale expands into a ponded area that in this wet year was around 50m wide and a few hundred long.

In one place the swale expands into a ponded area that in this wet year was around 50m wide and a few hundred long.

I added 3 county species records in and around the swale, but all are common in the region and so not the exciting rarities I’d hoped for.

This Forbes’s tree cricket was one of the three. It was perhaps the darkest individual I have seen in Illinois, and more typical of the Indiana coloration in my experience.

This Forbes’s tree cricket was one of the three. It was perhaps the darkest individual I have seen in Illinois, and more typical of the Indiana coloration in my experience.

As I returned to my car, wading through a nicely developing restored prairie, I spotted an unfamiliar grasshopper.

It held still while I took side and dorsal photographs. The color pattern and sculpturing pointed to the band-winged grasshopper subfamily.

It held still while I took side and dorsal photographs. The color pattern and sculpturing pointed to the band-winged grasshopper subfamily.

Note the white X marking on the pronotum (dorsal thorax). That rang a bell, and ultimately helped with the identification.

Note the white X marking on the pronotum (dorsal thorax). That rang a bell, and ultimately helped with the identification.

Unfortunately the hopper evaded me when I tried to catch it so as to check out the hind wing color. As I continued to walk out I saw a couple displaying grasshoppers with bright yellow hind wings, which I was unable to see up close. I made the assumption that they were the same as the photographed hopper, but this proved not to be the case. It turned out to have been a dusky grasshopper, Encoptolophus sordidus, which has an essentially colorless hind wing. It was the first of that species I have found, which always is exciting, but now I know there’s also a yellow-winged species I will have to go back and hunt down on a future visit.

While I was photographing the dusky grasshopper, a nearby movement caught my eye, and led me to a new experience. It was a ballooning spider, half an inch long. I had heard of this but never seen it, and did not expect that such a large individual could travel in that way. The spider sends out a strand of silk which grabs the wind and carries the spider through the air.

The spider had landed on a stalk, and paused long enough for me to get some photos. I haven’t had time yet to try for an ID.

The spider had landed on a stalk, and paused long enough for me to get some photos. I haven’t had time yet to try for an ID.

The spider didn’t wait long before it turned to face into the wind.

The spider didn’t wait long before it turned to face into the wind.

It began shooting out new strands of silk, obviously not satisfied that it had traveled far enough.

It began shooting out new strands of silk, obviously not satisfied that it had traveled far enough.

As I continued my walk to the car I noticed several strands of silk streaming from plant tops, and felt that I had learned something new about them.

I’ll close with a couple photos from other parts of Midewin.

This female short-winged green grasshopper was a county record.

This female short-winged green grasshopper was a county record.

A female fall field cricket posed nicely on a trail.

A female fall field cricket posed nicely on a trail.

Recent Mayslake Arthropods

by Carl Strang

Recent walks at Mayslake Forest Preserve have resulted in some photos to share, all involving Lepidoptera. The wild bergamot have been on the decline, but still were producing enough flowers to attract the attention of pollinators.

A hummingbird clearwing bellies up to the bar.

A hummingbird clearwing bellies up to the bar.

Another flower proved to be a fatal attraction to a cabbage white butterfly, which I saw curiously dangling beneath it.

The yellow flower head of the sow thistle had been a good hiding place for a crab spider. It and its prey dangled from the spider’s safety line until the butterfly was subdued.

The yellow flower head of the sow thistle had been a good hiding place for a crab spider. It and its prey dangled from the spider’s safety line until the butterfly was subdued.

Enough of the spider was hidden that I could not narrow its identity beyond being in one of two genera.

Wings may be in the future for today’s final subject.

This black swallowtail is maturing on a diet of water hemlock, a plant that is quite poisonous to humans.

This black swallowtail is maturing on a diet of water hemlock, a plant that is quite poisonous to humans.

 

Playing Catch-up 1

by Carl Strang

Photographs have been accumulating in the blog file, but the inspiration to tie them together sensibly hasn’t come, so this week I will simply empty the file out. These all are from Mayslake Forest Preserve, and today’s collection is a miscellaneous one.

We’ve had more rain than usual this far into the summer. Here some fresh mud captured a set of chipmunk tracks.

We’ve had more rain than usual this far into the summer. Here some fresh mud captured a set of chipmunk tracks.

The parking lot marsh surprised me last week with an array of a plant new to the preserve. This is an aquatic buttercup, the yellow water crowfoot.

The parking lot marsh surprised me last week with an array of a plant new to the preserve. This is an aquatic buttercup, the yellow water crowfoot.

This has been a good year at Mayslake for a bumblebee species that varies in numbers considerably between years: Bombus auricomus. The yellow cap on the head, large size, and bold black and yellow pattern are distinctive.

This has been a good year at Mayslake for a bumblebee species that varies in numbers considerably between years: Bombus auricomus. The yellow cap on the head, large size, and bold black and yellow pattern are distinctive.

Queen Anne’s lace is blooming, and on Friday it pointed me to two arthropods new to the Mayslake list. This one has a name I like: Strangalia luteicornis. It is a woods-edge long-horned beetle whose larvae bore into woody plants including grape vines.

Queen Anne’s lace is blooming, and on Friday it pointed me to two arthropods new to the Mayslake list. This one has a name I like: Strangalia luteicornis. It is a woods-edge long-horned beetle whose larvae bore into woody plants including grape vines.

Here a northern crab spider, Mecaphesa asperata, feasts on a flower-visitor fooled by the spider’s camo.

Here a northern crab spider, Mecaphesa asperata, feasts on a flower-visitor fooled by the spider’s camo.

Literature Review: Arthropod Evolution

by Carl Strang

If you’re a bug nerd you’ll enjoy the following notes on research from 2013. Especially significant were studies of butterflies and moths, and an eye-opening paper on periodical cicadas. This concludes my literature review until next winter.

Butterflies and moths had their origin in the Triassic Period according to recent studies, though the first ones were more like caddis flies than like this red-spotted purple.

Butterflies and moths had their origin in the Triassic Period according to recent studies, though the first ones were more like caddis flies than like this red-spotted purple.

Zhang, W, et al. 2013. New fossil Lepidoptera (Insecta: Amphiesmenoptera) from the Middle Jurassic Jiulongshan Formation of northeastern China. PLoS ONE 8(11): e79500. doi:10.1371/journal.pone.0079500  They found 15 species of early moths representing at least 3 families in Chinese deposits, and details of wing venation led to the conclusion that the Lepidoptera (moths and butterflies) diverged from the Trichoptera (caddis flies) by the early Jurassic Period.

Wahlberg, N, CW Wheat, C Peña 2013. Timing and patterns in the taxonomic diversification of Lepidoptera (butterflies and moths). PLoS ONE 8(11): e80875. doi:10.1371/journal.pone.0080875  They estimated timings of major episodes of speciation in the major groups of butterflies and moths. Their results point to a Triassic origin of Lepidoptera, around 215 million years ago. The timing of diversification episodes at least in some cases corresponds to times when plants were diversifying, and also after the end-Cretaceous mass extinction. Coevolution of lepidoptera with their larval food plants appears to be an important theme. They give origin ages for major Lepidoptera groups (in millions of years ago): Gracillarioidea 120, Yponomeutoidea 117, Glechioidea 106 (these first three are small moths, many of them leaf miners), Papilionoidea 104 (butterflies), Pyraloidea (including many local pyralid moths) 93, Bombycoidea (including sphinx moths) 84, Geometroidea (including inchworm moths) 83, Noctuoidea (the enormous owlet moth group) 82, Tortricoidea (including leaf-folding caterpillars) 68. All these groups are represented by local species.

The Chicago region’s 17-year periodical cicadas: Magicicada septendecim, left, and M. cassini.

The Chicago region’s 17-year periodical cicadas: Magicicada septendecim, left, and M. cassini.

Sota, Teiji, Satoshi Yamamoto, John R. Cooley, Kathy B.R. Hill, Chris Simon, and Jin Yoshimura. 2013. Independent divergence of 13- and 17-y life cycles among three periodical cicada lineages. Proc. Nat. Acad. Sci. 110:6919-6924. They sequenced a number of genes from nuclear and mitochondrial DNA from all known species and broods, and estimated divergence times based on general research that has been done on insect mitochondria. There are three species groups (referred to as Decim, Cassini, and Decula), each of which contains northern 17-year species and southern 13-year species. In any location, the species in the different groups emerge at the same time. The results clearly separated the three groups, and tied together the species within each group (e.g., 13-year Decim are more closely related to 17-year Decim than to 13-year Cassini). Furthermore, each species group is divided into eastern, central and western genetic clusters (this pattern has been documented in other organisms as well; for the most part, Illinois cicadas are in western clusters, Indiana ones in central clusters). Each cluster contains both 13- and 17-year species, “suggesting that life cycle divergence occurred independently in the three regions.” Analyses estimated that the western Cassini divergence of 13-year and 17-year species took place 23,000 years ago, 10,000 years for Decim. Population sizes for both Decim and Cassini groups appear to have been small during the last glacial period, but expanded greatly starting 10,000 years ago. The sequence appears to have been allopatric speciation of the 3 ancestral species, with the species later becoming sympatric and independently splitting into 13- and 17-year cicadas. “Surprisingly, however, the divergence of 13- and 17-y cicadas was asynchronous among the species groups and occurred repeatedly even within a species group.” The implication is “that the three Magicicada groups shared multiple refugia during the last glacial maximum.” The 13-/17-year splits occurred after the last glacial maximum, within the last 23,000 years, “suggesting that the life cycle divergence in Magicicada is closely associated with global climatic fluctuations and shorter growing seasons in the north versus the south.” However, the species groups themselves separated in the Pliocene, and their shared long lives suggest that this did not originate because of glacial climate influences. This shifting between 13- and 17-year life cycles suggests a common genetic basis among the species, and indicates a somewhat plastic nature of this trait. The coordination among species at a given location seems best explained by the selective advantage of low numbers of an invading species into the range of another, surviving best when sheltered by the established species’ numbers.

Zhao, Z, et al. 2013. The mitochondrial genome of Elodia flavipalpis Aldrich (Diptera: Tachinidae) and the evolutionary timescale of tachinid flies. PLoS ONE 8(4): e61814. doi:10.1371/journal.pone.0061814  Their genomic study traced the evolutionary relationships of the parasitic fly family Tachinidae, and molecular clock analysis calibrated to the fossil record points to the middle Eocene as the time of the family’s origin.

Brewer, MS, and JE Bond. 2013. Ordinal-level phylogenomics of the arthropod class Diplopoda (millipedes) based on an analysis of 221 nuclear protein-coding loci generated using next-generation sequence analyses. PLoS ONE 8(11): e79935. doi:10.1371/journal.pone.0079935  They place the ancestral millipedes at 510mya (million years ago), with major groupings established by 200mya.

Lucky, A, MD Trautwein, BS Guénard, MD Weiser, RR Dunn. 2013. Tracing the rise of ants – out of the ground. PLoS ONE 8(12): e84012. doi:10.1371/journal.pone.0084012     A phylogenetic analysis points to soil rather than leaf litter as the nesting habitat for the earliest ant species.

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