MS, University of Cincinnati, 2018, Arts and Sciences: Biological Sciences

Habitat structure can influence signaling efficacy, resulting in communication differences between species. Two closely related species, Schizocosa ocreata and S. rovneri, are similar in morphology, yet differ in courtship behaviors and microhabitat. Male S. ocreata use visual and vibratory courtship signals and occupy complex deciduous forest litter, whereas S. rovneri use higher amplitude vibratory signals and are found in the flattened litter of the floodplain. While previous studies have quantified the potential courtship signal active space (transmission distance) for S. ocreata in its native habitat, there is currently little data characterizing the active space for signals of S. rovneri. Therefore, this study sought to create a comprehensive comparison of the courtship signal active space of S. ocreata and S. rovneri to determine the impact of microhabitat choice on the efficacy of communication for these spiders. In their native field sites and in laboratory mesocosms representing these environments, no difference in potential active space (signal vanishing point) was found between species. This suggests that the different signaling strategies of these two species result in equal communication distance within the structure of their native microhabitat. However, in a laboratory reciprocal transplant, S. ocreata was found to have a significantly shorter orientation latency and longer orientation distance compared to S. rovneri regardless of mesocosm type, supporting the hypothesis that the multi-modal signals of S. ocreata act to increase courtship active space. Furthermore, the mating success of S. ocreata was not found to be impacted by substrate type, yet S. rovneri were seen to have higher mating success on substrates that better conduct vibrations. This study suggests that the signaling strategies of these species are influenced by microhabitat structure and may provide insight into how local environments can lead to differences in communication between s (open full item for complete abstract)

Committee: George Uetz Ph.D. (Committee Chair); Elke Buschbeck Ph.D. (Committee Member); Eric Maurer Ph.D. (Committee Member) Subjects: Biology

MS, University of Cincinnati, 2019, Arts and Sciences: Biological Sciences

Communication signals have evolved to convey information from a sender to a receiver through different sensory modalities. These signals may vary in their complexity to ensure successful transmission through the environment and enable receiver discrimination. Sibling wolf spider species, Schizocosa ocreata and S. rovneri, have recently diverged and are reproductively isolated by their behavior during courtship. Males of both species court females using multicomponent vibratory signals that vary in their complexity. The vibratory signal of male S. ocreata represents a complex pattern of stridulation and percussion components, compared to that of S. rovneri, which produces a regular pattern of brief pulses of nearly simultaneous (combined) stridulation and percussion components. I examined the role of signal complexity in species recognition and mate preference using vibratory playback via piezoelectric disc benders of separate individual components (percussion and stridulation) from each male signal. Female S. ocreata and S. rovneri were exposed to either conspecific or heterospecific signals within four treatment groups: complete signal, percussion only, stridulation only, or white noise. The number of female receptivity displays varied significantly among treatment groups for both S. ocreata and S. rovneri females, however there was no difference in female receptivity to individual components (stridulation and percussion) compared to complete signals. There were significant differences in the number of female receptivity displays for both S. ocreata and S. rovneri when presented with playback of complete conspecific vs. heterospecific vibration signals as females were more receptive to conspecific signals. Each focal species responded differently to treatment groups, with S. rovneri displaying significantly more receptivity displays compared to S. ocreata. I determined that individual signaling components are redundant and when combined in a complete signal they e (open full item for complete abstract)

Committee: George Uetz Ph.D. (Committee Chair); Elke Buschbeck Ph.D. (Committee Member); Nathan Morehouse (Committee Member) Subjects: Biology

MS, University of Cincinnati, 2017, Arts and Sciences: Biological Sciences

Recent interest in male mate choice has prompted a re-examination of widely held beliefs regarding sex roles in animal mating systems. It is now known that males can be choosy based on female quality – namely with regards to sperm competition and fecundity. However, studies which directly compare aspects of female quality and their influence on male mate choice are relatively rare. The brush-legged wolf spider Schizocosa ocreata (Hentz) has a well-studied, conspicuous male courtship display, within which can be seen evidence of male mate choice based on female mating history and foraging history, as well as possible effects of experience and rearing environment. This makes it an excellent system to compare the importance of these two female states and examine how the choice patterns they give rise to may be influenced by the environment. By examining male courtship and female behavior under different circumstances and across environmental experience conditions, the relative effects of these factors can be inferred. Evidence collected in this study suggests that female mating status is the dominant predictor of both male and female mate choice, with males most often courting virgin females more vigorously regardless of context, as well as females showing higher levels of receptivity when unmated. An important exception to this trend is seen in field-reared males and their female partners, who show no preference or behavioral differences based on female state, suggesting that this preference is not static and may be influenced by experience. Altogether these results fit within the general pattern of two-axis preference studies by showing a trend to the importance of mating status with lesser importance of feeding status. Therefore, these results may help to better understand the influence of male mate choice on female sexual selection across taxa.

Committee: George Uetz Ph.D. (Committee Chair); Eric Maurer Ph.D. (Committee Member); Andrew Roberts Ph.D. (Committee Member) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 2015, Evolution, Ecology and Organismal Biology

Communication between potential mates is of vital importance to the fitness of many taxa, allowing individuals to find one another, as well convey and receive information important in assessing a suitable mate. Signals involved in sexual communication can be transmitted through visual, vibrational and chemical modalities, with chemical communication being the oldest and most widespread. The ability to detect visual and vibrational cues often occurs across a range of inputs, while chemical communication has the potential for much higher specificity, as only those receivers possessing chemosensory cells attuned to the compounds used will be able to detect their presence. The detection and integration of multimodal signals into a behavioral response has been extensively studied in the Schizocosa ocreata (Hentz 1844) wolf spider (Lycosidae) model system. In this ground dwelling species, males respond to substrates containing female chemical signals with visual and vibratory courtship displays. While this response has been well characterized, the chemical identity of these signaling compounds is currently unknown, and pheromone identity has been understudied across spiders as a whole. The behavioral response of male S. ocreata to conspecific chemical signals has primarily been studied in the context of substrate bound female cues, though past studies have suggested that chemicals produced by conspecific male competitors may inhibit male courtship behavior, and have even suggested a role for olfaction.We further examined the role olfaction plays in male detection and location of females, and while we found no evidence that males are utilizing olfaction to find mates, we did observe behavioral changes to conspecifics of both sexes, and a reduction of activity in the presence of volatile cues from a predator. At levels of competitor cues that males are expected to encounter in nature, we found no evidence that male-male inhibition occurs in this species. In examining male r (open full item for complete abstract)

Committee: J. Andrew Roberts (Advisor); Susan Gershman (Committee Member); Roman Lanno (Committee Member) Subjects: Behavioral Sciences; Biology; Ecology

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

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

Condition dependence (CD) of animal behavior is an emerging avenue of study. Because many aspects of animal physiology and life history vary with environmental factors, a variable environment may influence phenotype expression, which may consequently be subject to sexual selection. However, under food limitation, potentially cannibalistic animals like spiders face condition-dependent trade-offs between sexual selection (mate choice) and natural selection (sexual cannibalism). This research investigated the relationship between female feeding history, mate choice, male courtship and reproductive timing in the wolf spider, Schizocosa ocreata (Lycosidae; Hentz). I tested the influence of long- and short-term food stress on female mate choice, by assessing female preference for condition dependent male visual signals – body size and sexual ornaments. Female preference for visual male traits varied as a function of feeding treatment and time post maturity. Females demonstrated different degrees and types of phenotypic selection on males, but ultimately males with relatively large ornaments were selected through mate choice. Male courtship investment also varied with female feeding treatment, as males courted female silk from well-fed, deprived and cannibalistic females differently. However, both male experience and female feeding treatment significantly impacted courtship investment, as male investment in courtship vigor in subsequent encounters depended on the type of female seen in a previous encounter. Emerging from these observations was support for differential male investment and preliminary support for male mate choice in a wolf spider. Feeding history significantly impacted spider growth and induced plastic developmental responses as females matured. Food limited females took longer to develop by adding additional instars and ultimately attained a smaller adult size. Female gonad development coincided with increased female receptivity in well-fed females, suggest (open full item for complete abstract)

Committee: George Uetz PhD (Committee Chair); John Layne PhD (Committee Member); Eric Maurer PhD (Committee Member); Elke Buschbeck PhD (Committee Member); Ann Rypstra PhD (Committee Member) Subjects: Biology

MS, University of Cincinnati, 2006, Arts and Sciences : Biological Sciences

I investigated the importance of the seismic component, substratum-borne vibrations, of the multimodal courtship display in the wolf spider Schizocosa ocreata (Hentz) (Araneae: Lycosidae). It is currently known that the visual signaling component of male multimodal courtship displays conveys condition-dependent information, and that females can use this signal alone in mate choice decisions. I found that isolated seismic signals are also used in mate choice, as females preferred males that were louder, higher pitched and with shorter signaling pulses. Results also showed that male seismic signals are dependent on current condition and may convey information about male size and body condition. Seismic signals and visual signals are likely redundant, although some aspects of seismic signals may convey different information, supporting both the redundant and multiple messages hypotheses.

Committee: Dr. George Uetz (Advisor) Subjects: