My birthday was last week, and I had a great time! Although I don’t really have any insightful statements, I do have a lot of ecology to talk about. I celebrated by attending this year’s Ecology Conference at Massey University in Palmerston North. I was able to learn a great deal about New Zealand ecology by sitting in on some great talks as well as speaking with some inspiring scientists. I will be summarizing the highlights here.
I’ve always been fascinated by the trade-offs between sexual and asexual reproduction. Sexuality reaps the benefit of genetic diversity, but is a density dependent interaction (you need to be able to find a mate). Being able to do a direct comparison is difficult because species usually can’t do both – but some do! Like the NZ snail. It reproduces sexually in a diploid state, but is able to switch to diploid (3 or 4 sets of chromosomes) as subsequently reproduces asexually. Laboratory experiments demonstrated the the asexual snails outperform sexual snails in every fitness metric (growth rate, strength, reproduction time, and reproductive output), but are only found in watersheds that are high in nutrients. This suggests that polyploidy is a competitive advantage if there are enough resources for extra sets of chromosomes but is unable to persist in low nutrient conditions, driving asexual populations locally extinct. Mechanisms related to how this with is made remain, but it is certainly a line of research worth continuing.
One research lab investigated the flammability of different types of plants by putting them in a grill! (with standardized procedures)
Through analysis of a wealth of extraordinarily preserved fossils and amber specimens it has been shown that although New Zealand’s contemporary insect communities are quite disparate, in the past a wealth of invertebrate diversity existed on the islands. These specimens date to before the last ice age, and so it is likely that changing climates and range reductions drove many of them extinct.
In an amazing demonstration of stabilizing selection pressure, it was demonstrated that a serious NZ invasive weed, gorse, has evolved larger seeds outside of its home range. In Europe it is paracitized by a beetle larvae, which feasts upon its seeds when young. It prefers larger seeds because they contain more food, thus when the beetle is present it exerts a pressure for smaller seed size. When the beetle is removed from the equation when gorse is transported to new territory that pressure is removed, seed sizes become larger over a few generations as larger seeds mean greater survivability in general. Neat!
I can’t wait to be presenting my own exciting findings next year!