Field Season

I’m studying isopods (pic) and a parasite that uses them as intermediate host. I collect these isopods from two different sites in Jyväskylä. One is Lake Jyväsjärvi and the other is Lake/Pond Niemisjärvi. The parasite isn’t found in Niemisjärvi because the fish definitive host can’t live there; the pond is too small. From Jyväsjärvi, I can collect infected isopods. Around this time of the year, the isopods are small but growing, and they are just starting to get infected with parasites. For my research, I need to collect infected individuals. This is far more difficult than you’d expect. From the number of worms you find in fish, you would think that there must be thousands of infected isopods. While this is probably true, they are not so easy to find amongst the hundreds of thousands of uninfected isopods in the lake. Today I probably looked at 300-400 isopods from Jyväsjärvi, and none were infected. Wasted hours? It sure feels like it. The other frustrating thing is that the isopods aren’t big enough yet. I visited Niemisjärvi today for the first time in about a year, and the isopods are there, but they’re tiny. A colleague and I are planning to do an experimental infection of isopods (i.e. give uninfected isopods parasite eggs to eat), but we know that the small, juveniles don’t get infected. Thus, we just have to wait for the isopods from the lakes to grow. We have to hope for warm weather, because animals grow faster at higher temps (there’s a limit, of course, and the rule doesn’t apply to endotherms [birds and mammals]). Also, if it is warmer, the isopods will eat more and probably get infected more frequently. Let’s hope, for the sake of my sanity, that Nature cooperates. Unfortunately, Nature rarely fits a predictable schedule. If it did, my life would be too easy. This is also why ecology is much more difficult than, say, molecular biology. Anyways, it seems like these little creatures are gonna cause me a lot of stress over the next 2 months.

Dan