Nature Blog Network

Friday, May 7, 2010

What in the larval world is this?

No one at Duke seems to know what this is. Southern Fried Scientist has allowed me to copy verbatim his post in the hopes that maybe someone out there in TO95's world knows what this is!

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The following photo was taken near the Yadkin River in Davie, North Carolina. According to observers, there were millions of them attached to the sides of trees and undersides of leaves throughout the region. In some places they were hanging so thick they looked like tiny bats. Does anyone know what they are?

photo by Gregory Bonito (click to embiggen)

~Southern Fried Scientist

Tuesday, April 6, 2010

Circus of the Spineless #49 is up!


Xenogere has the latest edition of the Circus of the Spineless up! Its nicely written and has lots of excellent links to invertagoodness in it!

Sunday, February 28, 2010

Monday, February 1, 2010

Circus of the Spineless #47 is up at Beetles in the Bush!


Beetles in the Bush has the 47th edition of the Circus of the Spineless up! A nicely laid out post with 16 fabulous submissions spanning a wide range of terrestrial, marine and aquatic critters.

Matthew Sarver from the Modern Naturalist
is hosting edition #48! You can submit entries via his contact page.

Friday, January 1, 2010

Circus of the Spineless #46 is up!

Great job to Kate who posted the latest installment of the Circus of the Spineless (#46!) up at Adventures of a Free Range Urban Primate. A fantastic edition, I'm glad to see new faces in there.

I'm looking for hosts for May and beyond. Leave a comment or send me an email if you'd like to host! Next month will be hosted by Ted at Beetles in the Bush, makes sure you get your submission in by January 30. You can contact him here.

Sunday, November 29, 2009

Cephalopod Inspired

Looking for something invertebrate inspired to give for Christmas, Cephalopodmas or Chanukah?

Noadi may very well have you covered. In her etsy store she has a variety of primarily cephalopod themed earrings and necklaces. A small sampling can be seen in the photo below:

Wednesday, October 28, 2009

Work with an Invert! - Amphipod Pop Gen

From EvolDir:

M.Sc. position: Marine invertebrate population genetics.

I seek a highly motivated and enthusiastic candidate to fill a fully funded MSc position in the Department of Biology at University of New Brunswick (Fredericton). The project will use DNA sequence variation to assess the level of genetic subdivision and patterns of gene flow among populations of the abundant marine amphipod Corophium volutator. The successful candidate will join a multi-disciplinary collaboration between researchers at UNB, Carleton University, and Mount Allison University. Our aim is to model the environmental interactions between climate driven processes and the population dynamics of C. volutator throughout the mudflats in the Bay of Fundy, Canada.

For more information about the Biology Department, see:
http://www.unb.ca/fredericton/science/biology/

For information about Graduate Studies at UNB, see:
http://www.unb.ca/gradschl/

For enquires, or to apply, email a CV or resume, a letter of interest, unofficial transcripts and contact information for 3 references to Jason Addison (jaddison at unb dot ca). The review of applications will begin immediately and will remain open until the position is filled. Work could potentially begin anytime, but admittance to the Graduate Studies program is expected in January, May, or September of 2010.

Monday, October 26, 2009

An Awesome Ocean Community

Just a quick note, a note of thanks!

The ocean blogging and ocean twitter communities really came through in a huge way today for Donors Choose. HP had an offer to put $2000 into the Oceans in the Classroom Initiative but only if the community could raise $2000 by midnight on Sunday the 25th. As late as 11pm it seemed a long shot with over $500 left to go. But it happened. With matching $$$ and swag from Kevin and Rick, it happened. Thanks to HP, the $2019 you all have contributed will now be doubled.

But...

There are still many more ocean themed projects out there to fund, so if you haven't yet donated, please do. We do so want to give some of these hundreds of kids the opportunity to get hooked on science and the ocean with all it marvels.

So now I still owe 2 more cards. Pick a card any card...

Sunday, October 25, 2009

Crepidula Fornicata

We've got two new Ocean Inspired Donors Choose projects that have been funded in the Oceans in the Classroom Challenge! The first one that was funded on Thursday was the awesome Invertebrates in my Tank project that will provide lots of kids with the opportunity to explore one of our favorite subjects: marine inverts!

The Inverts in my Tank card is the 6 of Spades — The Slipper Snail, Crepidula fornicata.

Classification for the Atlantic Slippersnail


Kingdom
Animalia

Phylum
Mollusca

Class
Gastropoda

Order
Littorinimorpha

Family
Calyptraeidae

Genus
Crepidula

Species
C. fornicata

I pulled this card for several reasons. First it has the cutest little veliger larvae. Second, it is all over the place here in Long Island Sound. And lastly, it is a prime example of a reproduction strategy that is comparatively rare in the animal world in general, but much less so in molluscs: protandrous sequential hermaphroditism. You may recall Dr. M's recent post, "Who likes protandric hermaphrodites?", in which he described the strategy, while reporting new findings about Idas washingtonia, a deep-sea clam.

Like I. washingtonia, the Atlantic Slippersnail (Crepidula fornicata), is a protandric sequential hermaphrodite. While they strongly resemble limpets externally, and are often called slipper limpets, they are indeed gastropods that are common inhabitants of the sub– to intertidal area of New England rocky coasts where they are often found in stacks, like the one pictured, from 3 to 20 individuals. Unfortunately, they are also an invasive species becoming all too common in areas outside its native range, where their filter feeding capabilities may negatively affect native and aquacultured filter feeding molluscs.

As Dr. M described in his post, many protandrous sequential hermaphrodites change sex based on size. A prevailing theory (the size-advantage hypothesis) predicts that a species will change its sex at a particular size that allows the individual higher reproductive success. Generally, this means smaller Atlantic Slippersnails are males and larger ones are females. It is energetically expensive for females to produce large, energy–rich eggs. It is very common in the marine realm that older, larger females produce more eggs of larger size and higher quality with resultant higher success rates. For guys to produce sperm is a comparatively inexpensive expenditure of energy. Even a wee lad can produce enough sperm of suitable quality to reproduce successfully. (Whether or not a female will have him, of if his sperm can out compete a larger male's sperm, is a different issue.)

C. fornicata follows this trait — for the most part. When the planktonic veliger larvae metamorphose and settle to the bottom, they are attracted to chemical cues produced by the adults. This guides most settling juveniles to land on, or very near, existing individuals or stacks. They then make their way (ever slowly) to the top of the stack and mature into young males. In paternity studies the oldest, largest males (sometimes the same size as females) are responsible for the majority of the viable larvae from females in the stack (upwards of 83% of larvae coming from one father). Younger males further up the stack do have some successes, though, and the more males (and more larger males) in a stack the more sperm competition appears to play a significant role in each individual's success and the less dominant the dominant male becomes. At a certain point these large dominant males may be better off as females sharing the reproductive success among a few females instead of many highly competitive males.

If a settling juvenile misses the chemical cues or for some other reason does not stack onto an existing individual or group, it will mature through a very brief male phase then become female, hopefully attracting juveniles from the next batch to settle on to it. Given that there are solitary (small) post settlement females and that some older males in a stack are as big as their female stackmates, size is clearly not the sole cue for sex change in C. fornicata. There is some plasticity in the change and social interaction appears to play a strong role on the size of the individual undergoing sex change.

You can probably see why sequential hermaphroditism is such an interesting area of study. There are several general hypotheses, but there are also so many individual variations on those general themes, that it seems we will never run out of study material!

And now a word for our Challenge this month


If you have contributed to the Oceans in the Classroom Challenge - Thank you so much!! These posts and previews are for you! You have helped the Ocean Bloggers make a difference in at least 300 kids' lives. (More considering many projects have reusable multi-year assets!)

If you have not yet given to the Donors Choose Oceans in the Classroom Challenge, please consider giving today. I know times are tough. I am a grad student with a family to feed. Believe me, I get how tough it is. Still every amount is welcome and appreciated. For my family's donation it means I have to brown bag it for two weeks. But you know, that's a small price to pay in exchange for knowing that we are exposing hundreds of kids to the science of the ocean. There is even a kindergarten class project in there - Commotion in the Ocean. Talk about a great time to open a kid's mind to the ocean and science!! If 25 readers give just $10 each, we'll help a dedicated young teacher expose 18 high poverty area kindergarten kids to science and the ocean.

There is a chance, still, to get an additional $2,000 dollars of matching funds donated by HP, but it will only happen if we can get to $2,000 donated from the Ocean Bloggers readers today. It won't be easy, but it's a great chance to really increase our impact! Please give to the Challenge!


References


Proestou DA, Goldsmith MR, & Twombly S (2008). Patterns of male reproductive success in Crepidula fornicata provide new insight for sex allocation and optimal sex change. The Biological bulletin, 214 (2), 194-202 PMID: 18401001


Richard, J., Huet, M., Thouzeau, G., & Paulet, Y. (2006). Reproduction of the invasive slipper limpet, Crepidula fornicata, in the Bay of Brest, France Marine Biology, 149 (4), 789-801 DOI: 10.1007/s00227-005-0157-4

Saturday, October 17, 2009

Wading in with Urosalpinx cinerea

As we pull into NYC on the Amtrack for a science filled weekend, Mrs. S's class in Rhode Island have gotten fully funded for their new waders as part of the Oceans in the Classroom Challenge. Hopefully they are thinking about getting in some clamming very soon! While they are out there wading in the beautiful coastal waters of Rhode Isalnd, they will no doubt see many Atlantic Oyster Drills as well since Urosalpinx cinerea is a pretty common sight around here (here being eastern Connecticut and Rhode Island). Unfortunately it is also becoming more common on the west coast in areas like Puget Sound where it is an invasive species, as well as being a nuisance to oyster fisheries on both coasts.

Even though it is a nuisance to mollusc fisheries and aquaculture, I can't help but like this particular carnivorous gastropod. It lives in the harsh intertidal zone, an area where it may well probably the most effective hunter. It "smells" out it's prey in the water: young oysters, young clams, or the thinner shelled blue mussels. Once located the one inch predator climbs onto its prey and grabs it firmly with its foot. Then the drilling begins.

Using its radula, a ribbon like organ with rows of tiny teeth on it, the oyster drill rasps away at the shell, scraping bits of the calcium shell. After rasping for a time the oyster drill brings out its secret weapon, the accessory boring organ (ABO). The oyster drills use of the ABO was described originally by Mel Carriker while he was a graduate student in the late 1930's early 1940's, we have featured his video and explanation of the drilling before (highly recommended!). Between 1 minute raspings with the radula the drill presses the ABO against the drilling site for 30 minutes, releasing calcium dissolving acid to soften the next layer of shell and make the drilling easier. Depending on the thickness of the preys shell, the process may take upwards of a day to complete. Yes the oyster drill is persistent!

video

Once through the shell the oyster drill inserts its proboscis through the hole and releases digestive enzymes into the prey shell ans slurps the resulting liquefied meat back up through the hole via its proboscis.



Another cool detail about the oyster drill is that unlike most other gastropods, the oyster drill does not have a planktonic larval stage. The oyster drill lays its eggs that each have up to 12 young in them under rocks and shells. The young snails eat their way out of the eggs and look like miniature adults.