Category Archives: Adaptations

Adult fly mimics ant larva

This is the kind of stuff I love to find in my inbox in the morning.  I work on flies, and I’ve never seen or heard of these ones until Matthew Cobb posted about them in his email Z-letter this morning. Look at the creature in the top photo.  Looks like a larva, right? In […]

Bad breath fells aphids

Friday science quickie:  a new paper in Current Biology reports an intriguing adaptation: the breath of mammalian herbivores induces aphids to drop off plants, saving them from being eaten along with the leaves. Three biologists at the University of Haifa in Israel noticed that two species of aphids, the pea aphid (Acyrthosiphon pisum) and Uroleucon […]

Why eyespots?

While listening to talks at the evolution meetings, I’ve mentally divided them into two groups: what I call “general” versus “anecdotal” research.  The former seeks general laws of evolution that apply across diverse species.  “Haldane’s rule” is one example:  the observation that if, in a cross between two species, only of the two sexes of hybrid […]

Polymorphism in vertebrates

by Greg Mayer Darwin’s theory of evolution (and ours), unlike that of Lamarck, is variational, rather than transformational: the process of evolution is a change in frequency of different variants within a population, not a transformation of the individuals.  Darwin thus made the origin, nature, and inheritance of variation key problems for biology; indeed, for […]

March is the cruelest month…

by Greg Mayer …breeding mulleins out of the dead land. During a visit to the Washington, DC, area last weekend I made a point of looking at how advanced the spring greening was. Despite  the east coast’s hard winter, and the mild winter in the midwest (and 2010 in general is starting off quite warm), […]

How old are mammalian pheromones?

by Matthew Cobb Sex pheromones are widely used by mammals to communicate and detect the sexual status of a potential mate. This is particularly the case with female mammals, whose pheromones are primarily detected by a structure known as the vomeronasal organ (VNO), which is in the base of the nose/roof of the mouth. (And […]

Sharks with head claspers (sort of)

by Greg Mayer In my post on the genitalia of ratfish (which are shark relatives), I noted that although no extant sharks had similar structures, some fossil ones did, so here are what two species of these sharks looked like. Both are members of the family Stethacanthidae, known for its sexual dimorphism.Fig. 1. Female (above) […]

That’s not ratfish genitalia. That’s ratfish genitalia.

by Greg Mayer Over at Pharyngula, PZ has linked to a story at Deep Sea News about the description of a new species of ratfish with “forehead genitals”. While it’s a great concept, the tentaculum, or cephalic claspers, of ratfish are not genitals. Fig. 1. That’s not ratfish genitalia. A male ratfish (family Chimaeridae) showing […]

What frogs go through for their tadpoles

by Greg Mayer Matthew has once again given me a hot tip: the BBC has a video of a mountain chicken, Leptodactylus fallax, feeding its developing tadpoles with unfertilized eggs. (I am unable to embed the video– do click through to watch). The mountain chicken is actually a large frog (so named because they are […]

How the tapir got his spots III

by Greg Mayer The two great classes of phenomena that Darwin set out to explain were those of adaptation– the fit between an organism’s features (structure, behavior, etc.) and its conditions of existence; and unity of type — the similarities of basic structure among organisms in diverse conditions of existence (e.g., the one bone-two bones-many […]