20th International Congress of Arachnology

DENVER MUSEUM OF NATURE & SCIENCE

REPORTS

No. 3, July 2, 2016

Cushing

Hawaiian Islands are particularly useful for examining

the ecological-evolutionary nexus because they display

an age chronology that allows analysis of communi-

ties that are just starting to establish, to more mature,

allowing insights into how early ecological processes give

way to longer term processes of adaptation and species

diversification. Focusing on different lineages of spiders,

I use the island chronosequence to examine the interplay

between ecological affinities and genetic differentiation

in fostering diversification. I highlight the importance of

fusion and fission in fostering diversification; variability

upon which selection can act; and selection and genetic

drift in generating diversity. I use genetic and genomic

tools to understand microevolutionary change in differ-

ent lineages of spiders. I couple these data with ecological

metrics across the chronosequence to uncover community

dynamics. Different spider lineages show different rates

and patterns of differentiation. One lineage shows “non-

adaptive” radiation, with multiple species in allopatry and

diversity increasing with island age. Another lineage shows

early diversification into different ecologically defined

taxa, and subsequent general progression down the island

chain of each species; here, species numbers are high even

on the youngest island, and seem to level off quickly on

the older islands. Other lineages show repeated evolution

of similar ecomorphs within islands; here, species numbers

increase early in the radiation, and then decrease. This

work highlights the interplay between rates of ecological

and genetic differentiation in shaping biodiversity.

Keywords: evolution, ecology, biodiversity, island bioge-

ography, phylogeography, community ecology

Student - Oral presentation

What makes males red-hot: mate choice

in the peacock spider,

Maratus volans

Madeline Girard

, Damian Elias

, Michael Kasumovic

1130 Mulford Hall, University of California Berke-

ley, Berkeley, CA 94720, USA;

Ecology and Evolution

Research Center, University of New South Wales, NSW

2052, Australia

maddiegirard34@berkeley.edu

Jumping spiders have long been renowned for their

specialized visual systems and colorful ornaments.

Surprisingly however, virtually no experimental work

has examined the importance of color as females select

among potential mates. We conducted experiments on the

exceptionally colorful peacock spider,

Maratus volans

, to

investigate the role of both visual and vibratory courtship

signals. By manipulating the visual and vibratory sensory

environments, we tested whether long wavelength and/

or vibratory signals were critical for male mating success.

Our results suggest that red ornaments are relatively more

important than vibratory signals for successful mating. We

discuss the evolution of red coloration in peacock spiders

and complex multimodal signaling across the group.

Keywords: sexual selection, jumping spider, multi-modal,

visual communication, color vision

Oral Presentation

The Opiliones Tree of Life: resolution of harvest-

men relationships through transcriptomics reflects

ancient regionalization of Pangea and multiple

instances of temperate Gondwanan vicariance

Gonzalo Giribet

, Rosa Fernández

, Ana L. M.

Tourinho

1,2

, Prashant Sharma

Museum of Comparative Zoology, Department of

Organismic and Evolutionary Biology, Harvard

University, 26 Oxford Street, Cambridge, Massachu-

setts, USAmerica;

Instituto Nacional de Pesquisas da

Amazônia, Coordenação de Biodiversidade (CBIO),

Avenida André Araújo, 2936, Aleixo, CEP 69011-970,

Manaus, Amazonas, Brazil;

Department of Zoology,

University of Wisconsin-Madison, 352 Birge Hall, 430

Lincoln Drive, Madison, Wisconsin 53706, USA

ggiribet@g.harvard.edu

Opiliones are iconic arachnids with an ancient origin and

a diversity that reflects ancient biogeographical patterns.

Due to interest in their diversity, ecology, evolution and

biogeography, their relationships have been thoroughly

studied using morphology and PCR-based approaches

to systematics. More recently, two studies utilized tran-

scriptomics-based phylogenomics to explore their basal

relationships and diversification, but sampling was limiting

for understanding more recent evolutionary patterns, as