Oh, Deer: How Do Aspen Trees Survive Herbivory?

A White-tailed deer browsing in Duluth, Minnesota (Photo: DPR, 2012)

Because of their relative immobility, plants are often perceived as being largely defenseless against predators. This couldn't be further from the truth. Anyone who's watched Journey to the Center of the Earth or Jumanji has seen exaggerated fictional depictions of such plants as the Venus Flytrap or the Pitcher plant. But even these striking examples miss the more common, albeit much more subtle, mechanisms of plant defense. The goal of my graduate research over the next couple of years is to elucidate the joint costs and benefits, as well as the ecological implications of what we believe to be a multivariate defense system in aspen trees towards mammalian herbivores. Specifically, I will be examining how Quaking aspen trees (Populus tremuloides) balance three defense traits (resistance, tolerance, and escape) to survive herbivory by White-tailed deer (Odocoileus virginianus) at various stages in their life cycle. If they spoke English, I'm sure the deer would tell you that plants do, indeed, have active defense systems. Although, if you've ever gotten tangled in poison ivy, you should already know this!

The Alpine Salamander: Try Beating this Record

The Alpine Salamander (Photo credit: Herpetofauna of Europe)

As the name suggests, this small black salamander lives high in the Alps of central Europe. Living an average of 10 years and measuring 12 centimeters in length, the female typically gives birth to two young after a gestation period of up to three years, depending on its elevation. This is the longest known gestation period of any animal. As you might expect, the young are well developed and quite large, almost half the length of the adult. In the initial stages of embryonic development, one embryo in each uterus is nourished by its own yolk and the yolks of its not-so-fortunate siblings. Once this resource is depleted, the young eat the vitelline mass available in the uterus. And finally, their external gills are used to acquire nutrients from the maternal fluids. Surprisingly, with such a long pregnancy and small number of offspring, these peculiar amphibians are quite common in their current distribution.

Reference: A Compendium of Indispensable Facts (Ben Horslen, 2004)