20th International Congress of Arachnology

DENVER MUSEUM OF NATURE & SCIENCE

REPORTS

No. 3, July 2, 2016

Cushing

of prey correlated with the time taken to catch the prey:

more consistent bold prey survived longer. This study

highlights 1) the importance of the joint effect of both

predator and prey personality on their interactions; and

2) the intra-individual variability (IIV) also plays a part

in a predator’s foraging success and prey survivorship.

Keywords: boldness, intra-individual variability,

jumping spider, predation

Student - oral presentation

Investigating resource contests with the

amblypygid

Phrynus longipes

*Kenneth Chapin

UCLA, Department of Ecology & Evolutionary Biology

621 Charles E. Young Drive, East Los Angeles, CA 90095-

7246, USA

chapinkj@gmail.com

Behavioral researchers using Amblypygi have noted

the regularity at which species engage in agonistic

interactions. Despite this, why agonistic interactions

occur and how they are resolved is unknown. I con-

ducted paired interactions of the amblypygid

Phrynus

longipes

in Puerto Rico to understand the dynamics of

agonistic interactions. Through a series of analyses, I

found that agonistic interactions are territory contests

common across the demographic range of the species.

Further, I decoded the strategy that opponents use to

negotiate contests, and used resource contests to explain

the peculiar pattern of cannibalism that this species

exhibits. I used these results to build an evolutionary

simulation model of contest strategies, with novel pre-

dictions for the evolution of unintuitive contest tactics.

Further, I identified variation in contests and other

behavioral phenotypes across cave and surface popula-

tions. Last, I discuss current work on understanding

the genetic mechanisms that maintain this behavioral

variation across environments. This research broadens

theory of resource contest evolution and behavioral

variation by investigating phenomena in a non-model

study system.

Keywords: behavioral ecology, territoriality, resource

contests, Amblypygi, population genetics

Oral presentation

Comparison of dragline silk gland mor-

phology and silk genes in two spiders

Crystal Chaw

, Peter Arensburger

, Marjorie Wimmer

Liliana Alaniz

, Cheryl Y. Hayashi

Department of Biology, University of California,

Riverside. Riverside, CA 92521 USA;

California State

Polytechnic University, Pomona. Pomona, CA 91768 USA

rcrystal@ucr.edu

Spiders spin an exceptional diversity of functionally

distinct silks, including silks for adhesion, egg-case

construction, and prey capture. An individual spider can

produce multiple task-specific silks from specialized

abdominal glands. Among araneomorph (true spiders)

species, silk glands can be grouped by morphology and

production of a unique silk type. For example, the Enteleg-

ynae have major ampullate silk glands, which are named

for their size and ampule-shape. Major ampullate glands

produce the proteins for dragline silk, and the glands can

be subdivided into three regions with different functions

and cell types. The Haplogynae also have ampule-shaped

glands that produce dragline silk proteins, but whether

the glands have differentiated regions is unknown. Major

ampullate gland spigots are defined by their location on

the anterior lateral spinneret, and the number of major

ampullate silk gland spigots among entelegyne and haplo-

gyne lineages suggests a complicated evolutionary history

of major ampullate gland gains and losses. Functionally,

ampullate glands from entelegyne and haplogyne spiders

manufacture dragline silk proteins but as with the spigot

evidence, the relationships of ampullate silk proteins sug-

gests a complicated evolutionary history with multiple

origins. Here, we study ampullate silk glands from the

entelegyne

Latrodectus hesperus

and the haplogyne

Holocnemus pluchei

. Using histology and immunohis-

tochemistry, we investigate the cells of

L. hesperus

major

ampullate and

H. pluchei

ampullate glands. We expect

that these glands will have three regions with different cell

types, suggesting that the cellular structure of dragline

silk glands is homologous and conserved. We also identify

H. pluchei

silk protein genes using deep sequencing and

determine their relationship to other silk genes.