Phenotypic Plasticity

The nymphalid above, the map butterfly Araschnia levana, produces multiple generations each year. Its pupae come in two forms, dark and light, the difference arising from varying melanin concentrations. These differences persist in the adult. Above you see the adult that emerged from a light pupa; below is the adult …

How do insects breathe? An outline of the tracheal system

Hexapods (including insects) have two pairs of openings on their thorax, called spiracles. These open into chitinous tubes called tracheae which then further subdivide until becoming less than 1 mm in diameter tracheoles, 2-3 µm away from metabolically-active tissues, forming a network all through the body of the insect, as …

Flatfish (Vertebrata: Pleuronectiformes)

Pleuronectiformes (flatfish) is an order composed of almost 800 species in 11 families (Eschemeyer & Fong, 2011), distributed cosmopolitanly in mostly marine waters, although some can also be found in freshwater. They’re most well-known from the edible flounders, turbots, halibuts, and soles, all of which have well-established aquaculture schemes. For …

“Gradients” and “Fields” in Developmental Biology: A history of the ideas

Anyone who’s taken a course in developmental biology will have heard of “developmental gradients” or “embryonic fields” or “morphogenetic fields”; I learned these in German, so the English names might be different (I’ve seen those three being used). This post is about the history of these ideas of fields and …

Regeneration

Note that I’m not referring to regeneration in the ecological sense (i.e. recovery of communities). I will also only talk about animals in this post, for the simple reason that regeneration in plants is commonplace and a routine part of their physiology. Of course, any animal with eyes also has …