Animal Sciences Commons^™

Eight Legged Encounters, Eileen A. Hebets

Eileen Hebets Publications

This program was funded in part by a National Science Foundation grant (DRL–1241482 to EAH). Material was developed in collaboration with Marie- Claire Chelini, Jessie Rose Storz, Cody Storz, and Malcolm Rosenthal. Steven Schwartz, Jason Stafstrom, Kathy French, Priscilla Grew, and Judy Diamond were all extremely helpful in grant writing, facilitating the first live event, and/or discussions. Pawl Tisdale (artist) was phenomenal to work with on all aspects of the project!

TABLE OF CONTENTS

CLASSIFICATION & TAXONOMY STATIONS
I. WHAT IS AN ARTHROPOD? page 4 a. The goal of this station is to introduce the audience to some basic information …

Multimodal Sensory Reliance In The Nocturnal Homing Of The Amblypygid Phrynus Pseudoparvulus (Class Arachnida, Order Amblypygi)?, Eileen A. Hebets, Alfonso Aceves-Aparicio, Samuel Aguilar-Argüello, Verner P. Bingman, Ignacio Escalante, Eben J. Gering, David R. Nelson, Jennifer Rivera, José Ángel Sánchez-Ruiz, Laura Segura-Hernández, Virginia Settepani, Daniel D. Wiegmann, Jay A. Stafstrom

Eileen Hebets Publications

Like many other nocturnal arthropods, the amblypygid Phrynus pseudoparvulus is capable of homing. The environment through which these predators navigate is a dense and heterogeneous tropical forest understory and the mechanism(s) underlying their putatively complex navigational abilities are presently unknown. This study explores the sensory inputs that might facilitate nocturnal navigation in the amblypygid P. pseudoparvulus. Specifically, we use sensory system manipulations in conjunction with field displacements to examine the potential involvement of multimodal—olfactory and visual—stimuli in P. pseudoparvulus’ homing behavior. In a first experiment, we deprived individuals of their olfactory capacity and displaced them to the opposite side of …

Dangerous Mating Systems: Signal Complexity, Signal Content And Neural Capacity In Spiders, Marie E. Herberstein, Anne E. Wignall, Eileen Hebets, Jutta M. Schneider

Eileen Hebets Publications

Spiders are highly efficient predators in possession of exquisite sensory capacities for ambushing prey, combined with machinery for launching rapid and determined attacks. As a consequence, any sexually motivated approach carries a risk of ending up as prey rather than as a mate. Sexual selection has shaped courtship to effectively communicate the presence, identity, motivation and/or quality of potential mates, which help ameliorate these risks. Spiders communicate this information via several sensory channels, including mechanical (e.g. vibrational), visual and/or chemical, with examples of multimodal signaling beginning to emerge in the literature. The diverse environments that spiders inhabit have further shaped …

Obligate Male Death And Sexual Cannibalism In Dark Fishing Spiders, Steven Schwartz, William E. Wagner, Eileen A. Hebets

Eileen Hebets Publications

Male dark fishing spiders (Dolomedes tenebrosus Araneae, Pisauridae) always die during their first and only copulation, making all males monogynous. Such obligate male death can be adaptive if it facilitates sexual cannibalism, and if sexual cannibalism results in male reproductive benefits, such as an advantage in sperm competition through reduced female remating. We first conducted an experiment to determine the extent to which D. tenebrosus (1) males are cannibalized by females and (2) females engage in remating, both of which are prerequisites for several adaptive hypotheses of male self-sacrifice. We then conducted an experiment to test the hypothesis that …

A Male Spider’S Ornamentation Polymorphism Maintained By Opposing Selection With Two Niches, Bo Deng, Alex Estes, Brett Grieb, Douglas Richard, Brittney Hinds, Eileen Hebets

Eileen Hebets Publications

The Levene mechanism to maintain genotypic polymorphism by opposing selection on genotypes in multiple niches was proposed 60 years ago, and yet no systems were found to satisfy the mechanisms rather restrictive conditions. Reported here is such an example that a wolf spider population lives in a habitat of mixed rocks and leafy litter for which the females are phenotypically indistinguishable and the males have two distinct phenotypes subject to opposing selection with respect to the substrates. Census data is best-fitted to a population genetics model of the Levene type. A majority of the best fit support polymorphism, with many …

Tactical Adjustment Of Signaling Leads To Increased Mating Success And Survival, Laura Sullivan-Beckers, Eileen A. Hebets

Eileen Hebets Publications

Most sexually reproducing animals overcome the challenge of searching for and attracting mates by utilizing signals that are broadcast through a spatially and temporally varying environment. A diverse suite of behavioral solutions exist for overcoming such environmental variability, including the adjustment of signaling behavior based upon receiver feedback. Few studies have directly examined the relationship between such tactical signaling adjustments and proxies of male fitness; the few that have, failed to find a relationship. Using the wolf spider, Schizocosa rovneri, we set out to first quantify among-male variation in the form and degree of responsiveness to female feedback. Following …

Nocturnal Homing In The Tropical Amblypygid Phrynus Pseudoparvulus (Class Arachnida, Order Amblypygi), Eileen Hebets, E.J. Gering, Verner P. Bingman, Daniel D. Wiegmann

Eileen Hebets Publications

Arthropods are renowned for their navigational capabilities, with numerous examples known from insects and crustaceans. Early studies of amblypygids (Class Arachnida, Order Amblypygi) also suggest complex nocturnal navigation, despite their apparent lack of visual adaptations to the low-light conditions of a tropical understory. In a series of two studies, we use the tropical amblypygid, Phrynus pseudoparvulus, to assess their nocturnal homing ability. Our first experiment displaced and tracked resident and nonresident individuals. Resident individuals, displaced up to 4.5 m from their home refuges and released onto their home tree, were more likely to return to their previously occupied refuge than …

Detection Of Predator Cues Alters Mating Tactics In Male Wolf Spiders, Dustin J. Wilgers, Daniel Wickwire, Eileen Hebets

Eileen Hebets Publications

Males of the wolf spider, Rabidosa punctulata, exhibit condition-dependent alternative mating tactics, whereby small, poor condition males engage in multimodal courtship while large, good condition males adopt a direct mount tactic that forgoes courtship. This study explores the possibility that tactic-specific costs can help explain this unintuitive pattern of mating tactic expression. Specifically, we hypothesize that courtship signaling is costly with respect to eavesdropping by predators and that males can alter their tactic expression based upon the perceived environmental predation risk. We test this by first examining the risk of predation associated with different mating tactics. We use a …