Honey bee development is a spectacular feat of biology. A bee begins its life as a tiny egg, about 1 mm long in the shape of a grain of rice. After 3 days, it hatches as a larva but is still so small that it’s barely visible to the naked eye. It will grow amazingly fast, eating constantly and virtually swimming in food for the first week of life, after which it weighs about as much as a full-grown bee. Then the larva’s body will completely rearrange to become a pupa, springing eyes and legs out of nowhere in a process called ‘metamorphosis’ (the same thing that happens to caterpillars when they become butterflies). On day 21, the bee emerges as an adult soon to get to work with its sisters in the hive.
A fact that still amazes me after so many years is that an egg is a single cell. Just one! This applies equally to a bee egg or an ostrich egg, which is the biggest animal cell in the world. But of course, soon after the egg is laid, the cell inside its case will rapidly start dividing to form the developing embryo. This can happen virtually before your eyes – after a couple days of looking at a bee egg under the microscope, I can see its little larva head wagging back and forth, eager to break free. I have spent a lot of time looking at bee eggs lately, waiting for them to hatch after I inject them using a microscopic glass needle. So what am I injecting them with, and why am I doing it?
One of the goals of my research is to better understand how hygienic behaviour works (see the ‘My Research’ section for more about this). It has to do with their sense of smell, but there’s still a lot about it that we don’t know. What I’m working on now is injecting bee eggs with the materials they need to make more proteins that are associated with perceiving smell – essentially giving them an olfactory boost (later on this will let me test these bees to see if they can smell some odors better than others, compared to bees that don’t get the boost). What might be surprising is that I also inject the eggs with the gene for green fluorescent protein (GFP).
GFP was originally isolated from a jellyfish; it’s the gene that lets them display the beautiful bioluminescence you can sometimes observe in the oceans at night. It turns out, this gene is also incredibly useful for molecular biology. Like most researchers, I use GFP as a ‘control’ – in other words, a tool to help me figure out if the technical aspects of my experiment worked or not. Think of the situation where I’ve (supposedly) given some bees their olfactory boost but then find that regular bees have just as good sniffers as the boosted ones. Is this a real result, or did the injections just not work? By including GFP, you can either say “Aha! My bee is green, so the injection must have worked and my results are real,” or if the bee is not green, “The methods didn’t work and I can’t trust my results.”
I’m not actually interested in making a bee glow green just because it looks cool (it’s safe to say that most people who use GFP as a tool aren’t). What I want to know is if I can decipher a bee’s olfactory system, and the green bee is just an intermediate step to this goal. But scientists are getting a bad reputation for this, adding to the ‘mad scientist’ image, like we’re ‘playing God’ by making ‘Franken-creatures.’ What I hope to do here is clarify that it is just a tool to meet an end, and not the end itself.