These are papers that may be of general interest published this week, with commentary as necessary. No specific case studies, overly specialised research, or taxonomic papers. Papers ordered only by their appearance in my inbox. For PDFs, e-mail me, I get most of them. You can request an in-depth analysis of any paper and I’ll do it as I get the time.
Open-access papers, those that are free to read/download even without an academic connection, are tagged with [OA] for easy finding with your browser’s text search (Ctrl+F).
11 papers this time.
I love these scattered reports of animals being able to sense light without specific photoreceptors. They give me ideas for superhero powers. There’s also the case of photoreceptors lying around in places where no light can reach them, like in the brain of birds, discussed in a paragraph here.
Asphondyliines are some of the best organisms to use for ecological and evolutionary research given some of their characteristics (e.g. extended diapause, host plant alternation, dimorphic gall induction), so if you’re looking for a new model organism, read this review and see if they strike your fancy.
Ecophylogenetics is similar to evolutionary ecology, in that they both seek to study ecology from an evolutionary perspective. I consider ecophylogenetics to be a subfield of evo-eco, and its main thrust is that phylogeny is key to understanding ecological patterns, especially those that concern biodiversity patterns. It thus encompasses biogeography and is of interest to conservation biology. This paper is a timely review of it. If you’re in any way interested in ecology or macroevolution, then you should read this to get some perspective.
- Why are defensive toxins so variable? An evolutionary perspective.
- Insect Herbivores Drive Real-Time Ecological and Evolutionary Change in Plant Populations.
The coevolution between insects and flowering plants is a well-known phenomenon, given that it’s what led to the bulk of today’s biodiversity. This paper goes to the population level of a coevolution, finding that plants have an evolutionary response to insect predation even on short-term ecological timescales (i.e. “immediately”). Very cool. See a commenatry on it here.
More Herefordshire awesomeness.
- Evidence for gill slits and a pharynx in Cambrian vetulicolians: Implications for the early evolution of deuterostomes. [OA]
Vetulicolians are some of the most vexing of the Cambrian problematica. They have a head shield at the front and a segmented body, much like an arthropod – and this was how they were first classified, as bivalved arthropods. However, it was then discovered that they have holes in their segmented body, which some authors have interpreted as gill slits, leading to an alternate classification as stem-group deuterostomes in their own phylum. Taking the deuterostome idea even further, some authors even suggested that they’re the sister group to the chordates, one of them labelling them as stem-group tunicates. However, these varied interpretations weren’t accepted universally, and more research led to the discovery of more arthropodan characters. So, long story short, we have no clue what these freaks were. Since deuterstomes and arthropods are on opposite ends of the animal phylogeny, vetulicolians being on a stem of those two groups is out of the question. This paper is just one more lantern thrown into the abyss of vetulicolian phylogeny, with a clear pro-deuterostome tangent. Personally, I also slant towards them being deuterostomes, but refuse to take a hard stand since I’ve never had any personal time with a vetulicolian fossil. I like tot alk to them and get to know them. It’s how palaeontologists work.
A cool new example of an obligate symbiosis, this time between siliceous sponges and calcifying bacteria. From the abstract:
Calcification is mediated by endosymbiotic bacteria (calcibacteria) located in archeocyte-like sponge cells. These calcibacteria are devoid of bacterial walls and divide within sponge cells until they became surrounded by a calcitic sheet, being subsequently extruded to the sponge subectosomal (subepithelial) zone. Thousands of bacteria-produced calcitic spherules cover the surface of the host sponges, forming a cortex-like structure that mimics a rudimentary peripheral skeleton. Calcibacteria are vertically transferred to the sponge larvae during embryogenesis.
Some good party trivia about the fat-tailed dwarf lemur to be found in this paper.
It’s rare for me to get excited about yet another animal getting its genome sequenced, but reading these findings triggered my sense of scientific curiosity. Among palaeontologists, it’s well known that every fossil tells a story (geologists say the same about rocks), and this is especially true for molluscs, where the animal’s entire life story is left behind on the shell for the detailed palaeontologist to decipher. I work a lot with oyster fossils from Cyprus (currently, it’s concentrated on the ecological interactions with epizoans that live on the shells, like barnacles and bryozoans), and one thing that’s interested me for the longest time is how each shell looks different even though they’re all the same species. There are different numbers of layers and varied shell orientations. With spiny oysters, you can have drastic differences between localities: in one locality, there are plenty of large spines, while in another locality, the spines are inconcspicuous. These differences are all caused by the environment: more spines = more predators around, so integrating such variability information gives you clues to the palaeoecology of a locality. The link to this paper is that from sequencing the genome, it turns out oysters have a lot of genes responsible for dealing with environmental stress – the genes that will be turned on when many predators are in the environment, for example. I’m wondering how to combine the insights from the genome sequencing with palaeontological life history reconstruction. It’s definitely possible at an intuitive level, but doing it scientifically is fairly tricky.