Quantifying division of labor: Borrowing tools from sociology, sociobiology, information theory, landscape ecology, and biogeography

How do we quantify division of labor? We review several fields (sociology, landscape ecology, statistics, information theory, and biogeography) that have been cognizant of these questions and been somewhat successful at answering them. We review fourteen indices for quantifying division of labor, sensu lato, which can be categorized into four families: Shannon's index/entropy, Simpson's index, geometric mean, and standard/absolute deviation (including coefficients of variation). We argue that those indices using matrix inputs will simultaneously quantify the interplay between all individuals and all tasks and will thus best capture the essence of division of labor

Swimming Eastern Chipmunks, Tamias striatus, and Hairy-tailed Mole, Parascalops breweri, in Kawartha Highlands Provincial Park, Ontario

We report swimming Eastern Chipmunks, Tamias striatus, and a swimming Hairy-tailed Mole, Parascalops breweri, in southern Ontario in Kawartha Highlands Provincial Park. Although naturally swimming Eastern Chipmunks have been seen before, they have never been previously documented in the literature. Ours appears to be the first photograph of a swimming Hairy-tailed Mole and the first report of one successfully and apparently voluntarily swimming

Abrupt shortening of bird W chromosomes in ancestral Neognathae

As a result of suppressed recombination, heterogametic sex chromosomes (either Y or W) are usually assumed to gradually shorten over evolutionary time as a way to remove accumulated mutations. However, suppressed recombination removes the most obvious mechanism for excising portions of sex chromosomes. We examined ratios of W/Z chromosome size across 224 bird species from 146 genera. Much of the data were obtained from a previous study (Rutkowska et al. 2012. Biology Letters 8: 636-638), who, similar to ourselves, found no gradual decrease in W chromosome length over evolutionary time. However, we show an abrupt decrease in W chromosome length at or just after the phylogenetic split between the two extant bird superorders, Paleognathae and Neognathae, indicating that the key to understanding sex chromosome evolution may have little to do with gradual suppression of recombination