Anthropology - Butler University

signaler or another individual. In many species, social interactions play a key role in deciding the
allocation of different resources. Crayfish use aggression as a mechanism to become
dominant. In crayfish, dominance structures and hierarchies are formed by dyadic interactions.
Concerning invertebrates, crustaceans are considered to be ideal models of aggression and
extensive work has provided an insight to the physiological and social effects on
aggression. Previous research has shown that in crayfish eavesdroppers are more likely to lose a
contest after watching an aggressive interaction. This suggests that crayfish are making
behavioral decisions based on the observations made during an eavesdropping event. In this
experiment we set up an interaction arena where two crayfish fought to establish a social
hierarchy, while three crayfish observed the interaction, receiving only visual cues. The three
eavesdropping crayfish were isolated in individual compartments that were built into the
arena. After the first encounter, a second fight was carried out to re-establish social status, in
which one eavesdropper fought the winner, the second eavesdropper fought the loser, and the
third eavesdropper fought a naïve crayfish. This was done to determine if the crayfish were
involved in making behavioral decisions based on observations during eavesdropping
interactions. Our research shows that crayfish with information gained when they observed an
aggressive interaction are more likely to win future aggressive encounters.
Hormonal Consequences of Eavesdropping in the Crayfish Procambarus clarkii
Brandon Quinby, Melody Palmer, Olivia Rivera & Jose Haro, Faculty Sponsor: Vanessa Quinn,
Purdue North Central
Aggressive behavior is speculated to an action of the amine hormone serotonin many species of
crustaceans. In the crayfish Procambarus clarkii exogenous serotonin increases rates of an
aggressive display, the meral spread. Serotonin injection has also been demonstrated to affect
rates, intensity, and duration of aggressive encounters. In our research we examined the affect of
eavesdropping on natural serotonin levels in P. clarkii. Eavesdropping occurs when an individual
observes but does not take part in an aggressive encounter. If eavesdropping provides behavioral
information to an individual we predicted that serotonin would also be altered. We measured
serotonin levels in crayfish that were engaged in an aggressive encounter as well as individual
observing the encounter. Our results show that serotonin is elevated both in the eavesdropping
and interacting crayfish. Thus, eavesdropping can lead to differences in both behavioral and
physiological contexts.
Copperhead Snakes as a Host and the Identification of Host Cues (Kairomones) for Larvae
of Ticks that Transmit Lyme Disease
Benjamin Rausch, Patrick Tomko & Andrew Jajack, Faculty Sponsors: Kevin Gribbins & Jay
Yoder, Wittenberg University
During numerous field encounters with Southern and Northern Copperheads, Agkistrodon
contortrix and mokasen, in locations across eastern United States, we observed larval ticks,
Ixodes scapularis, crawling and feeding on these pit vipers. Larval ticks were attached mainly
between the scales of the head and cloaca, and nymph and adult ticks were rarely associated with
wild Copperheads. To explore chemical cues that immature ticks may use to find snakes, we
determined attraction potentials of larvae to samples of Copperhead and four other snake species'
excreta (feces, uric acid), shed skins, and squalene (common snake skin lipid) in short-range