© 2015 James Dale Our group seeks to address major questions in evolutionary ecology. These range from: How do global patterns of biodiversity and species life history traits inform us about evolutionary processes? What accounts for the diversity of sexual size dimorphism across different species? What is the function of bright coloration in animals? And how do hormonal and genetic mechanisms of colour development relate to their evolutionary function? The selected papers below illustrate the broad spectrum of interdisciplinary approaches we use to answer these questions. email: j.dale@massey.ac.nz ph: +64 9 2136612 Welcome to the lab of James Dale Evolutionary Ecology Group Institute of Natural & Mathematical Sciences Massey University, Auckland, New Zealand
Plumage coloration in male and female birds
By quantifying the colouration of all approximately 6,000 species of passerine birds, certain life-history traits such as large body size and tropical distribution are found to increase ornamentation in both male and female birds, whereas cooperative breeding increases it in females only, and sexual selection diminishes it in females more than it increases it in males

Nature      View Publication
J Dale, CJ Dey, K Delhey, B Kempenaers and M Valcu
Social selection for red beaks
We compared beak color in over 1600 species of birds to test alternative hypotheses of signal evolution. We found that red beak coloration co-evolved with traits related to social competition, not measures of sexual selection.

Journal of Evolutionary Biology      View Publication
CJ Dey, M Valcu, B Kempenaers & J Dale
Extra pair paternity in the size dimorphic Tui
We show that the tui, an iconic New Zealand endemic with extreme sexual size dimorphism, has one of the highest rates of extra-pair paternity (EPP) currently known ( 72% of broods and 57% of offspring). Both male body size and ornament size were strongly correlated to EPP.

Behavioral Ecology      View Publication
S. Wells, W. Ji, J. Dale, B. Jones and D. Gleeson
Predators predict longevity of birds
Life-span varies widely across animals. Across 1400 species of birds, we found that global variation in life-span can be explained by the species’ body mass, clutch size and the local diversity of predator species - confirming a key prediction of the classical evolutionary theory of ageing.

Ecography      View Publication
M Valcu, J Dale, M. Griesser, S. Nakagawa and B Kempenaers
Pukeko's game of angry birds
Dominant pukeko (purple swamphens) have larger frontal shield ornaments. We experimentally manipulated apparent shield size in pukekos to demonstrate a dynamic link between signal elaboration and social interactions. This study provides key evidence for the ‘integrative costs’ model of honest signaling.

Proceedings of the Royal Society of London, B      View Publication
C. J. Dey, J. Dale and J. Quinn
Carotenoid genetics in a wild bird
Knowledge of the genetic pathways that regulate carotenoid coloration is completely lacking. Here we identify candidate genes with potential roles in carotenoid coloration and examine their expression in wild red-billed queleas. This study provides a critical starting point for future work on carotenoid colour regulation.

Proceedings of the Royal Society of London, B      View Publication
N. Walsh, J. Dale, K. J. McGraw, M. A. Pointer and N. I. Mundy
rangeMapper software package
This paper introduces rangeMapper, an R package for the study of the macroecological patterns of life-history traits. Using three topical biogeographical case studies we make novel insights into key macroecological questions, generate elegant maps to illustrate these findings, and showcase a new and valuable tool for macroecological analysis.

Global Ecology and Biogeography      PDF       R-forge site       CRAN site
M. Valcu, J. Dale and B. Kempenaers
Testosterone-related signalling in House Sparrows
Badge size in House Sparrows has become a model example of a costly, testosterone-dependent indicator or quality. However, this detailed study indicates that bill coloration, not badge size, is the best ornamental indicator of a “running average” of male testosterone and therefore the best potential indicator of testosterone-related traits.

Behavioral Ecology and Sociobiology      View Publication
S. Laucht, B. Kempenaers and J. Dale
Individual recognition: it is good to be different
In this paper we provide an holistic synthesis of the concepts related to individual recognition from the perspective of both the recognizer and the recognized. We conclude that selection for traits that reveal individual identity represents an important and underappreciated force contributing to the evolution of genetic polymorphisms.

Trends in Ecology and Evolution      View Publication
E.A. Tibbetts and J. Dale
Sexual selection explains Rensch's rule
Across many taxa, sexual size dimorphism tends to increase with increasing body size. The cause of this allometric relationship, known as ‘Rensch’s rule’, has defied convincing explanation. We analyzed size dimorphism in over 5300 species of birds and demonstrated beyond any doubt that sexual selection for large body size is the chief architect behind this pattern.

Proceedings of the Royal Society of London, B      View Publication
J. Dale, P. Dunn, J. Figuerola, T. Lislevand, T Szeleky and L. Whittingham
Intraspecific variation in bird coloration
Why do some species show incredible variation in coloration while other species are remarkably uniform? In this comprehensive synthesis, I argue that intraspecific variability in coloration can be understood from a conceptual framework comprised of seven fundamental types of signals: quality, attractiveness, strategy, compatibility, kinship, individuality and presence.

Bird Coloration (vol 2): Function and Evolution      View Book Chapter
J. Dale
Badges of status in paper wasps
In paper wasps, facial markings are cheap 'status badges' that would seem to be susceptible to cheating. But wasps punish those whose markings lie. We show here how social competition can be a strong selective force acting on signal evolution.

Nature      View Publication
E. Tibbetts and J. Dale
Individual Recognition Model
We develop an evolutionary model that predicts the properties of signals of individual identity. Such signals are predicted to be highly variable, display polymodal distributions, be cheap, not be associated with fitness differences, exhibit independent assortment of component characters, and have a high degree of genetic determination.

American Naturalist      View Publication
J. Dale, D. Lank and H.K. Reeve
Carotenoids are not always quality signals
Carotenoid-based, sexually dichromatic breeding plumages are argued to signal male quality. However in red-billed queleas I demonstrate convincingly that such plumage can not function at signalling quality. I suggest instead that ornamental plumage facilitates individual recognition within neighbourhoods of nesting males.

Proceedings of the Royal Society of London, B      View Publication
J. Dale