Posts Tagged ‘laboratory research.’

19 January, 2013 — Spermcasting

Saturday, January 19th, 2013

Hi Folks,

The news of some days, of course, is better than on others. And the news of the January 16, 2013, was grand! It contained a term I had never seen, but one I will be sure to use whenever possible, “spermcasting”.  I have to admit, when I first read it, it conjured up visions of fly casting, but with some essential differences; such as the type of rod one uses…  Aaah…  But, let’s not go any further down that road. :-)

As the authors of the term meant it, in its basic form spermcasting would be seen in broadcast spawning animals such as many sessile marine invertebrates, and it would presumably have a feminine complement of ovacasting. In other words, “spermcasting” is the release of male gametes into the surrounding water as a means of reproduction. This type of reproduction is also seen in mobile animals such as echinodermsBroadcast spawning animals typically have simple reproductive systems, without any externally visible modifications.  The gametes are made and simply released through a “gonopore” into “the great outside world”.

A male sunflower star Pycnopodia helianthoides photographed  "spermcasting" otherwise known as "broadcast spawning" in Northern Puget Sound.

A male sunflower star Pycnopodia helianthoides photographed “spermcasting” otherwise known as “broadcast spawning” in Northern Puget Sound.

 

A close up of the animal in the previous image showing the sperm suspension being released from the gonopores.

A close up of the animal in the previous image showing the sperm suspension being released from the gonopores.

However, spermcasting is something that is not generally considered to be part of the reproductive behavior of animals with a penis. In fact, over the array of invertebrate animals, the variety of penises, receptacles, openings, and the behaviors to get them all together is truly amazing, but spermcasting has not been considered a part of that behavior.  And why should it?   Because a penis is used to place sperm in some sort of receptacle or opening in a female, spermcasting has been thought to be unnecessary.   

While obviously commonly occurring, the actual physical act of the male’s transferring sperm to the inside of a female’s genital tract, “copulation”, is actually seldom observed in marine animals.  The reason for this is obvious.  For many species where reproduction involves internal fertilization or union of their gametes, reproduction may be an intrinsically hazardous process; and its duration and frequency is often minimized.  Often, copulation involves the intimate meeting of two animals that may be predatory and dangerous to one another. The terrestrial examples of the preying mantis or spiders such as the Black Widow come to mind, but the marine environment also has its share of dangerous liaisons. In such animals copulation often requires all sorts of behavior to ensure that the predatory behavior of both parties is “defused”. Some of the best known examples of such behavior occur in octopuses.

A large individual of the Giant Pacific Octopus, Enteroctopus dofleini.   Highly predatory and cannibalistic, and reaching weights well in excess of 50 kg (110 pounds), precopulatory behavior that may last several hours is necessary  before the animals can safely remain in each other's proximity for reproduction.

A large individual of the Giant Pacific Octopus, Enteroctopus dofleini. Highly predatory and cannibalistic, and reaching weights well in excess of 50 kg (110 pounds), precopulatory behavior that may last several hours is necessary before the animals can safely remain in each other’s proximity for reproduction.

 Copulation may place the animals at risk of predation by animals other than a potential mate. When animals are copulating, their attention cannot be on predator avoidance.  Consequently, natural selection has forced the development of behavior that reduces the risk of being seen – and eaten – such as nocturnal or reclusive mating. In some other animals, the act is over so fast, that the odds of an observer even noticing it range between slim and none. Pairs of one nudibranch species, Hermissenda crassicornis, can “do the deed” in a few seconds. And in those animals the act is reciprocal, the partners are hermaphrodites so each one gives and receives.  However, the process is seldom seen, or if it is, it is seldom recognized for what it is.

Hermissenda crassicornis, the so-called "opalescent nudibranch".  Individuals of this hermaphroditic species reciprocally exchange sperm in some of the fastest copulations known.

Hermissenda crassicornis, the so-called “opalescent nudibranch”. Individuals of this hermaphroditic species reciprocally exchange sperm in some of the fastest copulations known.

As a result, generally, people have inferred internal fertilization or copulation by the presence of a penis and the associated female plumbing. And some animals are legendary in their endowment. Some of the best known in this regard are barnacles whose penises are often able to extend several times the length of the animal. Barnacles don’t actually copulate, relatively few crustaceans do, but they use the penis to deposit sperm in the females’ mantle cavities, and sperm behavior or the female partner ensures the gametes find their ultimate destination. However as the saying goes, this “pseudo-copulation” is “good enough for government work”.  Barnacles are sessile, glued to the substrate by glands in their head, consequently, their reproductive success, and their “evolutionary fitness”, depends on how far they can reach out to touch someone with their legendary penises. Fortunately, as they are hermaphroditic, any neighbor will do.

Balanus nubilus, the giant "cloud" barnacle of the N. E. Pacific.  Large individuals reach up to about 15 cm (6 inches) wide at the base, and are often solitary or a relatively great distance from their neighbors.  Spermcasting would definitely benefit their reproduction.

Balanus nubilus, the giant “cloud” barnacle of the N. E. Pacific. Large individuals reach up to about 15 cm (6 inches) wide at the base, and are often solitary or a relatively great distance from their neighbors. Spermcasting would definitely benefit their reproduction.

The need for (pseudo-) copulation, inferred by the presence of a penis, in barnacles could present a significant limitation in their reproductive capability relative to broadcast spawning animals, and hence it could severely limit their evolutionary fitness. Nonetheless, as far as anybody knew, barnacles put their amazingly large “equipment” to good use, copulated, and “THAT” was “THAT”.

Except, as it turns out “THAT,” is not “THAT”.  In a paper published online on January 16, some scientists have shown, rather elegantly that at least one species of barnacles; the common gooseneck barnacle of the NE Pacific, Pollicipes polymerus, does things quite a bit differently. They spermcast…

They are apparently able to both throw caution to the winds – or their spermies to the seas – and, amazingly enough, have this result in successful fertilization. Using genetic markers and some elegant and careful work, the researchers, from Dr. A. Richard Palmer’s lab at the University of Alberta, have shown that spermcasting occurs commonly in the goose neck barnacle, and even occurs in animals that can reach a partner to mate in the “traditional” manner.

Such extraordinary findings really upset the traditional view of spawning and copulation. After all, if barnacles can spermcast… it certainly seems that other animals possessing normal copulatory organs may also be able to do this.  No longer is it possible to look at the anatomy of species wherein the males possess a penis, and blithely assume that they only reproduce by copulation. 

Of such uncertainty, good research is made, as people have to ascertain the mode of reproduction.

As the authors of this paper state in the abstract, “These observations (i) overturn over a century of beliefs about what barnacles can (or cannot) do in terms of sperm transfer, (ii) raise doubts about prior claims of self-fertilization in barnacles, (iii) raise interesting questions about the capacity for sperm capture in other species (particularly those with short penises), and (iv) show, we believe for the first time, that spermcast mating can occur in an aquatic arthropod.”

More later,

Cheers, Ron
 

More Scaphopod Information – Including Some Ancient Scaphopod Jewelry

Friday, August 26th, 2011

 Scaphopod Connections

Over the past few days, I have finished scanning my images of Native American scaphopod jewelry and decorated clothing, all of which were photographed in 1987 in the Burke Museum on the University of Washington campus in Seattle.  Some of the Native American dentalium jewelry/clothing images that I have are REALLY impressive, not only for the wealth they contained, but also for the tremendous skill of the remarkable women who made them.  Somehow, I wish I could find something like the shawl in the image below in an old trunk in my garage, and take it to the appraisers on The Antiques Roadshow.  It would get the attention it really deserved.  Ah… well.  All I am likely to find in old trunks in my garage is old trash covered in old dust.

 A shawl, made by a seamstress and master craftswomen from one of the Plains Tribes, in the mid-to-late 19th century.

This is a shoulder wrap or some sort of vestment, I neglected to photograph both sides in 1987, when I took the image.  I would estimate that there may be close to a 1000 Antalis pretiosum shells in this item.

Not surprisingly considering their shapes and durability,  scaphopod shells were widely used in ornamentation elsewhere and elsewhen throughout history.   The following image was taken by Don Hitchcock in from the Dolní Věstonice Museum in the Czech Republic, which has some wonderful artifacts recoverd from an ice age mammoth hunter’s site.  

dolniimg_2014b

A reconstructed necklace made from fossilized Dentalium badense shell fragment artifacts recovered at the Dolní Věstonice site in the Czech Republic.  The artifacts at this site have been dated with Carbon-14 to about 29,000 years ago.  Photo: Don Hitchcock donsmaps.com

In one of the more bizarre coincidences I have had recently, I found the above image and information with the assistance of Mr. Google and associates.  I hadn’t seen it prior to findinig on the web, but I knew that there should be ancient European, Asian or African dentalium work illustrated somewhere on the web, and charged ahead to find something I might use.  I found this image, and it fit the bill of what I wanted, and I went to track down some information about it, including where the Dolní Věstonice site (which, from reading the information at the site, I realized I must have read about it sometime ago, I recollected nothing at all about it ) is located. 

This Google Earth image shows where the Dolní Věstonice site is located.  The other site indicated, the Frydek-Mistek region, is  where my ancestors, at least back to before the mid-1700’s, lived. !!!  My great-great-grandfather was one of four brothers that migrated together from this area to the US (Texas) just after the Civil War.

Nobody knows, of course, what happened to the descendents of the people who made and used the scaphopod shell necklace, or even if they left descendents at all.   But I think it could be possible -stretching possibilities very thinly- if those descendents remained in that area, that maybe some of the genes of the person who made the scaphopod necklace may have decended to be in the genome – some 28,000 years later – that directed the growth of my scaphopod-studying body.

In closing this entry, I must thank Don Hitchcock for his gracious permission to use his fine image of the scaphopod necklace.  Don has an immense array of web information about the paleolithic period throughout the world, and I have linked to his site in my blogroll.  It is well worth a visit.

Until later,

Cheers,

Coral Problems

Friday, December 17th, 2010

Hi Folks,

A most interesting and interesting article discussing the problems with identifying stony corals, in particular, some species of Hawai’ian Montipora has recent been published.

The background for the article is that last year several parties petitioned to have 83 stony corals to be listed under the United States Endangered Species Act. The National Marine Fisheries Service (NMFS), a branch of the National Oceanic and Atmospheric Administration (NOAA) is charged with assessing the coral species in question to determine, among other things, if they actually are endangered.  If the corals are listed, the act is supposed to provide some more protection for the species, and probably most importantly, designate critical habitat for these corals.

Of course, the whole “assessment” process ultimately depends upon somebody’s ability to identify individual colonies of coral species in question and that, in turn, depends upon the validity scientific description of those species.  The basic fundamental issues are:

1) Is the given species well-enough described to be reliably identified?  Keep in mind, that by being listed on the petition, at least somebody thinks the indivual colonies in that species can be identified.

2) If the species is identifable, can it be assessed to determine if it is endangered?

The article discussed in the Coral feature was officially published on 2 December, 2010, in the electronic (online and free access) peer-reviewed journal, PLoS One:

 

Forsman ZH, Concepcion GT, Haverkort RD, Shaw RW, Maragos JE, et al. (2010) Ecomorph or Endangered Coral? DNA and Microstructure Reveal Hawaiian Species Complexes: Montipora dilatata/flabellata/turgescens & M. patula/verrilli PLoS ONE 5(12): e15021. doi:10.1371/journal.pone.

I urge you all to read, at least, the Abstract (= the authors’ short summery) of the article, but I am also a realist and realize that while a few of you will look at the Abstract, and some of you may actually read or download and save the article, most people who scan this blog probably won’t.

So…

Here is a brief summary of the summary – if you will, an abstracted abstract.  And if this is creative document would it then be “abstract art?”    Yeah, I know, “Boo!… hiss!”

The researchers examined the genetic codes for a relatively large number of well-known and well-characterised proteins found in the corals’ cells, as well, they also looked at how the subcellular structures called mitochondria vary genetically between the samples.  They also microscopically compared, in fine detail, some of the visible physical structures of each specimen.  

When added together, these different examinations revealed four distinct groupings of specimens (called “clades”), and when each specimen was identified with traditional taxonomic methods, the four clades contained these species: I) M. patula/M. verrilli, II) M. cf. incrassata, III) M. capitata, IV) M. dilatata/M. flabellata/M. cf. turgescens.  So, sophisticated statistical analyses of skeletal microstructure and genetics separated specimens of 7 “species,” based on traditional taxonomy, into 4 groups that represent -probably- actual groups.  I think whether or not one wants to consider that each of these groups represents a species is probably dependent on how one feels about this type of analysis.  To me, yup, I’ll buy in to consideration of each group as representation of a species.  The microcharacters of the size and shape of verrucae or papillae were the only reliable physical characters that could be used in identifying the groups, while gross features such as any aspect of colony-level morphology was so highly variable as to be useless.

The authors noted that previous studies on how observable structures in corals vary from specimen to specimen have revealed that fragments taken from the same colony can exhibit strikingly different growth forms if grown in different environments.   Additionally, the extent of both genetic and morphological intraspecific variation in corals is poorly understood. This is clearly creates problems for assessment of species in the context of the Endangered Species Act as  structurally-based taxonomy – not molecular or genetic information – is the current basis for estimating species distributions, abundance, and extinction risk.

This study identified no fixed genetic or fine-scale morphological differences between M. flabellata, M. cf. turgescens, and M. dilatata, or between M. patula and M. verilli; in other words, these 5 named species appear to be only 2 natural species.  The authors noted that the geographic ranges of these groups are likely to extend beyond Hawai’i into the central Pacific and that individuals within “species” of these complexes are either actively interbreeding (which means they are not separate species), or they are from separate species that are very closely related (e.g., evolutionarily separated within the last one million years) and cannot be distinguished from one another.  Now that these complexes have been identified, work is needed to determine if the nominal species within each complex freely interbreed.

Finally, the authors note:

Unfortunately, this study provides little guidance for determining if these specific species are valid and should be listed under the ESA, but perhaps more importantly; it highlights major gaps in the present understanding of species as opposed to population-level variation in corals. This study is an example of how knowledge of species boundaries in corals is not only necessary for understanding patterns and processes of biodiversity and evolution, but is essential for conservation.

In short, the article is a “fun read.” 

One of the many take home messages is obviously that corals are exceptionally difficult critters to identify.  Generally, if we choose the proper characters, we can identify them to genus.  Beyond that… don’t even try.  As it stands now, we have so few data across the range of most tropical stony reef-forming (and presumably, non-reef forming as well) corals, that distinguishing any specific species is an impossible task. 

Enjoy the article!!

Cheers,

Diodogorgia Behavior

Monday, September 13th, 2010

I have been burning the proverbial solidified lipid light source at the proverbial points of illumination as of late, working on preparing my manuscript of my first Diodogorgia feeding behavior manuscript.  I am opting to try to place it in one of the most widely read journals; a journal with a very significant rejection rate.   This is a generalized journal and very widely read and it gets a lot of manuscripts submitted to it.  Having a finite – and relatively small –  size, this means most manuscripts are rejected, but fortunately, they are rejected “without” prejudice, so they can be submitted elsewhere, and most are and probably most get published.    So, I have the customary backup plan: “B,” for the almost certain rejection.  I have heard the odds of success are about 1 in 20, so…   I am trying to convince myself that my work will not get accepted and that I shouldn’t be too upset with that likely outcome.  

Oh, yeah… THAT will work. 

I want this thing to be published in this journal so badly I can taste it, so the inevitable rejection will hurt.   I am old enough, and my research is limited enough, that my odds of ever doing some more work that I would think would be of suffiicent importance to even try to place in such a journal again are so small as to be non-existant.  It will be this time, or never.  You may have noticed I haven’t mentioned the name of the journal, either.  Some readers can probalby guess which journal I am shooting for, but I don’t want to jinx the process by naming the journal. 

Jinxing…  What a funny thing, I am absolutely certain that my mentioning the journal’s name will have no effect on the process whatsoever – still, a primal part of my reptilian soul tells me not to mention what journal it is.   Sooner or later, I will let the readers of this blog in on my first choice of journals, probably after I have submitted it to the next choice. 

 At least, I should be able to turn the work around into a different manuscript for another journal relatively rapidly.   And I think my second choice – probably the specialized journal, Invertebrate Biology –  will accept my stuff without any qualms. 

For the last few days I have been making illustrations.  A number of these have been almagamations of images made from sequential video frames to show some of the behavioral processes of food capture or rejection.   And all of these have to be within a specific size category and most of them should be grayscale.  Even though I knew that such an outcome was likely, it is amazing how much information disappears along with the color.  I probably will submit both color and gray-scale versions of the same image.  Perhaps the reviewers will opt for one over the other.   However, color images cost a lot more, and that money comes from the author.

Argh… the cost issues are awful.  My readers – if there are any – in the scientific realm will realize this, but most other folks probalby don’t know that the costs for publication in these peer-reviewed journals are, at least on paper, borne by the authors.  Often there are other sources that will help an impoverished author like myself, but unlike the commercial press that I normally write for, not only is the submission and selection process anguishing, you get to pay for the whole thing – or at least part of it, just to make you feel worse, I suppose.

Well, at least most journals will publish accepted papers regardless of the author’s ability to pay.  Which is good, ’cause I have NO ability to pay.

I suppose it is time to get back to the process, so I will try to periodically keep you posted here.

Until next time,

Cheers,