Tag Archives: variation

Are Animals Doing the Wrong Thing?

The great tit (Parus major) needs to gain more than 10 % of its body weight in pure fat every evening, in order to survive a cold winter night (Image Credit: Ian Frank, CC BY 2.0)

Guest post by Thomas Haaland

Short-term insurance versus long-term bet-hedging strategies as adaptations to variable environments (2019). Haaland, T.R. et al., Evolution, 73, 145-157.

The Crux

Why do animals behave the way they do? Behavioral ecology is a field of research trying to explain the ecological rationale of animal decision making. But quite often, it turns out the animals are doing the ‘wrong’ thing. Why don’t all animals make the same choice, when there clearly is a best option? Why do animals consistently do too little or too much of something?

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Battle of the Sexes

If male and female predators like this newt hunt in different places, they may have different effects on prey communities. (Image Credit: Dave Huth, CC BY 2.0)
Sexual dimorphism in a top predator (Notophthalmus viridescens) drives aquatic prey community assembly (2018) Start & De Lisle, Proceedings B, doi:10.1098/rspb.2018.1717

The Crux

Ecology is a scientific discipline focused on the interactions between the biotic (living) and abiotic (non-living) parts of the environment, and within ecology the subdiscipline of community ecology focuses on how these biotic and abiotic parts interact to determine what species live where. When researchers investigate these relationships, they tend to only consider differences between species, instead of differences within a single species. This means that we are missing a big part of the picture, as differences within a single species can outnumber those between multiple species.

One of the most common differences within a species are those between males and females. Depending on the species in question, one sex can be bigger, eat more, live longer, or eat different things, and this can have an effect on the community that the species in question lives in. Despite these many differences between the sexes, there weren’t any direct empirical examples in the scientific literature of these differences affecting community dynamics. The authors of this paper were the first to use an experiment to investigate this phenomenon, using the red-spotted newt (Notophthalmus viridescens), which is an important predator in aquatic communities.

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