The larger sex shows increased body size plasticity

Patrick T. Rohner, Tiit Teder, Toomas Esperk, Stefan Lüpold and Wolf U. Blanckenhorn Being large can boost an individual’s reproductive success if larger body size increases strength in competition for mates, attractiveness to potential mates, or defense against predators and parasites. Animals should thus attain the largest size possible. In insects, however, the hard outer…

Competition induces increased toxin production in toad larvae without allelopathic effects on heterospecific tadpoles

Veronika Bókony, Bálint Üveges, Ágnes M. Móricz and Attila Hettyey  Animals and plants often respond to biological threats by inducible defences: plants produce toxic chemicals to deter herbivores; animals grow spines and helmets or change their behaviour to evade predators. Such defences, however, usually come at a cost: they make the individual less efficient in…

Leukocyte profiles are associated with longevity and survival, but not migratory effort: a comparative analysis of shorebirds

Piotr Minias, Radosław Włodarczyk, Włodzimierz Meissner At each life stage, all animals face some risk of death or injury. However, certain life-history strategies or environments can be more risky that the others. In general, species that are exposed to greater environmental or social risks are expected to show lower annual survival and lifespan, but they…

Darwin’s finches use their bills as heat radiators too!

Glenn J. Tattersall, Jaime A. Chaves, Raymond M. Danner Bird bills are important for feeding, but recent research has shown that the bird bill can also act like a radiator to help release extra body heat.  We studied this idea in Darwin’s finches, which have been the source of transformative findings about the evolution of animals….

Insulin-like growth factor 1 and life-history evolution of passerine birds

Jaanis Lodjak, Raivo Mänd, Marko Mägi How to grow, how to reproduce and how long to live? Organisms have been facing these vital questions throughout their evolutionary history, resulting in a diversity of ways that animals live their lives. Since the possible courses that the evolution of different traits can take is limited by various…

A hormone in feathers can detect elevated energy demands

David Johns, Tracy Marchant, Graham Fairhurst, John Speakman, and Robert Clark Animals must constantly balance their energy use to maintain physiological stability in the face of various daily challenges, ranging from the predictable (e.g., finding food) to unpredictable (e.g., enduring a storm, escaping a predator). The hormone corticosterone (or cortisol in humans) has a critical…

Do body temperatures of desert lizards fit a “normal” distribution?

Raymond B. Huey and Eric R. Pianka When physiological ecologists evaluate whether body temperatures of lizards and other ectotherms (such as insects, fishes) are “normally distributed,” they are not referring to whether a lizard’s body temperature averages 98.6°F, a so-called “normal” body temperature for a human.   Rather they are discussing whether the shape of the…

Host responses to parasites shape costs of infection

Sarah A. Budischak, Dawn O’Neal, Anna E. Jolles and Vanessa O. Ezenwa Parasites, by definition, steal resources from their hosts, but how infection relates to host fitness is not well understood, particularly in wild populations. We combine experimental deworming and a 4-year study in African buffalo to better quantify fitness costs of infection and examine…