MS, University of Cincinnati, 2010, Arts and Sciences: Biological Sciences

In predatory animals such as spiders, females are often aggressive or potentially cannibalistic, and thus selection has favored males that recognize females and signal their identity and intent to mate at a distance. This often involves recognition of chemical cues or signals (pheromones) from females. Chemical communication is an important part of the mating process in the wolf spider Schizocosa ocreata, as cues associated with female silk are sufficient to elicit courtship from males. However, it is not known whether females also respond to chemical cues associated with male silk. Although responses of males to airborne chemical cues from females have been demonstrated in some spider species, this has not been well examined in S. ocreata. In this study, I examine how both male and female S. ocreata wolf spiders respond to silk-borne and airborne chemical cues from members of the same or opposite sex. I collected silk from mature males and females onto a piece of filter paper and recorded the amount of time that spiders spent in a stimulus chamber containing male silk, female silk, and no silk (control). Males spent more time on female silk, while females spent significantly less on female silk, but neither sex showed a significant difference between male silk and a control. In addition, I conducted studies in an olfactometer in which subjects were exposed to airborne chemical cues from a male spider, female spider, male silk, female silk, or a blank control. I scored the choice made as well as specific male courtship behaviors. Males and females showed no significant directional response to airborne cues from either sex, but males displayed courtship behaviors most often and at higher rates when exposed to airborne cues from females. Furthermore, I compared the rates of male courtship behaviors between airborne chemical cues and silk-borne cues from females and found that silk elicited higher rates of courtship than airborne chemical cues. I conclude that chemical (open full item for complete abstract)

Committee: George Uetz PhD (Committee Chair); Michal Polak PhD (Committee Member); Alan Cady PhD (Committee Member) Subjects: Biology

Master of Science (MS), Bowling Green State University, 2018, Biological Sciences

Prey often alter their morphology, physiology, and/or behavior when presented with predatory cues. Alteration in behaviors (i.e. habitat use, food consumption) are consequences of non-consumptive effects that can alter the dynamics of prey resources and cause changes in food web structures. One key factor in determining predation threat level by predators is the composition of the diet of the predator. We wanted to test the ability of prey to determine threat level based on cues produced by different predators on various diets. Odors from two different species of fish, bass (Micropterus salmoides), a natural predator of crayfish, and cichlid (Oreochromis aureus x Oreochromis niloticus), a non-natural predator of crayfish that were fed a vegetarian pellet, a protein diet, a heterospecific crayfish, and a conspecific crayfish were collected. Anti-predator behavior was tested by placing the prey, crayfish (Orconectes virilis), in a y-maze and analyzing the side of choice arena the crayfish spent time in, shelter usage of the crayfish, walking speed, walking forward and backward, climbing, and posture when presented with predator odors. Our results show that crayfish spent less time in odors containing conspecific diets, but when in this odor, crayfish spent most of the time hiding in the shelter when odors were emitted from a natural bass predator. However, these results were not present when exposed to non-predatory cichlid odors. Therefore, crayfish can determine different threat levels based off of chemical signals emitted from a potential or real threat, when paired with diet, eliciting predator avoidance behaviors.

Committee: Paul A. Moore Dr. (Advisor); Verner P. Bingman Dr. (Committee Member); Daniel D. Wiegmann Dr. (Committee Member) Subjects: Animals; Behavioral Sciences; Biology; Ecology; Freshwater Ecology

Master of Science, Miami University, 2007, Zoology

This study investigated the responses of red-backed salamanders ( Plethodon cinereus) to chemical cues from a predator (garter snake, Thamnophis sirtalis) and a competitor (centipede, Scolopocryptops sexspinosus). A trade-off was discovered between avoidance of both chemical cues and thermal preference. In a thermal gradient, presence of either cue caused P. cinereusto alter their thermal preference to avoid the cue. Forced locomotor speeds were increased and feeding rates were decreased by the presence of either chemical cue. Voluntary locomotor speeds and activity were not affected by the presence of either chemical cue, but an increase in temperature, from 15 °C to 25 °C, caused an 86% increase in voluntary speed. P. cinereustends to avoid both predator and competitor cues and favors predator and competitor avoidance over thermal selection when these two demands conflict.

Committee: Dennis Claussen (Advisor) Subjects:

Master of Science (MS), Bowling Green State University, 2012, Biological Sciences

The use of shelters by crayfish is influenced by the presence or absence of predatory cues. Crayfish are able to detect sensory cues in the environment and use the information gathered to make behavioral changes to reduce the risk of becoming a predator's next prey item. Factors such as mechanical cues or chemical cues in the water may determine the extent to which the crayfish alter not only the use of shelter, but also other behaviors, such as walking speed and exploratory behaviors. This thesis set out to address which factor elicits the strongest response in behavior alteration and use of shelter. To tease apart the mechanical and chemical cues, five sets of trials were conducted. The first set of trials acted as a control in which a baseline of behavior and shelter use could be determined. The second set of trials exposed the crayfish to the scent of a channel catfish (Ictalurus punctatus), but not to the mechanical cues of the predator. The third set of trials exposed the crayfish to the mechanical cues of a model channel catfish, but not the chemical cues. The fourth set of trials exposed the crayfish to the chemical cues of a channel catfish and mechanical cues of the model channel catfish simultaneously. The fifth and final set of trials exposed the crayfish to the chemical and mechanical cues of a channel catfish. By observing the behaviors under the various experimental designs, the research shows us that the mechanical cues of the model channel catfish had the greatest effects on the behaviors demonstrated by the crayfish. The results from these experiments show us that the crayfish relied more on the mechanical cues in the environment than the chemical cues when considering predator avoidance and behavior modification.

Committee: Paul Moore (Advisor); Robert McKay (Committee Member); Jeffrey Miner (Committee Member) Subjects: Animal Sciences; Aquatic Sciences; Behavioral Sciences; Biology