Some fly drawings. This is a stage 14 embryo, about 11 hours old, in the middle of a process called dorsal closure. At this stage there is basically a hole in the dorsal side of the fly that eventually closes as the embryo continues development. Anterior is to the left (the head is tucked inside), posterior on the right (the two dots are called the filzkorper, part of the tracheal system), ventral side down (where our lab studies wound healing, which is remarkably similar to dorsal closure), dorsal up (where the guy is pulling out DNA).
In June or so I was reading about oogenesis in fruit flies, and thought their ovaries were good for at least a few comics.
Comic 1. First, an ovary dissection. Public disclaimer: female mutilation is not humorous. When I do a testes dissection I'll draw some morbid male scientist comic to round things out. But until then, enjoy.
Things to keep in mind: 1) some mutant flies won't lay eggs, so in order to study what's happening genetically and molecularly we need to get at the ovaries, using watchmaker forceps. To make these females as happy as possible, so that their ovaries are as happy as possible, we keep them in bottles with yeast at twenty-five degrees celcius. And, 2) flies don't have blood, they have hemolymph.
Comic 2. Other things to consider before reading: A fly ovary looks kind of like a flower that hasn't bloomed (see Figure 1). One of the green leaves that protect the petals and stamen and pistil and those other important flower parts are analogous to one fly ovariole (though the ovarioles aren't concealing anything if you peel them back but more ovarioles, the whole bunch being an ovary). An ovariole is a series of maturing egg chambers--youngest at the tip (germarium), oldest, which will be dumped into the oviduct to be layed, near the stalk.
Figure 1. An ovary and ovariole.
If the female flies aren't happy (not at twenty-five degrees, or not fed well with yeast) they won't lay eggs. The eggs will back-up in their ovarioles. So if you want your fly to lay, you need to feed her. Enjoy. Oh yeah, flies probably don't smoke, and they probably don't drink either, because we dump them in ethanol to kill them.
Recently I wanted to draw a farmer. This turned into a cool series: