Getting clear about what behavioral scientists mean when they invoke content presupposing concepts, like information, is necessary for understanding how humanity’s own behavioral capacities do or do not relate to those of non-human animals. Yet, producing a general naturalistic definition for representational content has proven notoriously difficult. Some have argued that Claude Shannon’s formal, mathematically defined notion of information is the proper starting point for building a biological theory of content. Others have sought to define content presupposing concepts in terms of the historical selection processes that drive evolution. However, neither approach has produced definitions that capture the way successful researchers in the behavioral sciences use content-presupposing concepts. In this dissertation, I examine an ethological tradition of insect navigation research that has consistently ascribed content to insects. To clarify the meaning of such ascriptions, I analyze the practices scientists use to justify new attributions of content and the way new attributions of content guide scientists’ future research activities. In chapter 1, I examine a series of insect navigation experiments performed in 2006–2007 that led to a novel ascription of content. I argue that researchers ascribe content to insects’ navigation behaviors when those behaviors reliably accomplish a difficult goal-directed function. I also argue that ascriptions of content help researchers achieve their epistemic aims by guiding hypothesis formation and aiding comparative theorizing. In chapter 2, I trace the history of the experimental strategy analyzed above back to the work of Karl von Frisch in the early 20th century. I argue that von Frisch has a complicated and understudied relationship to the discipline of ethology. I support that argument by highlighting features of von Frisch’s research that both comported with and differed from the program of classical ethology. In chapter 3, I examine the cognitive map debate in insects. I argue that the debate stems from competing research groups’ endorsement of different norms for justifying claims about the dynamics of representational contents. I then situate these different norms historically to show how the cognitive map debate is a continuation of longstanding divisions within the history of animal behavior research.

Much like neighboring nations, living in close proximity can often lead to conflict over limited resources for social insect colonies. As with warring nations, conflicts among insect societies can also result in one colony attempting to invade the other. Though emigrations are common and well understood in social insects, the process of emigration in the context of conflict is not known. During emigrations of the ant Temnothorax rugatulus, colonies first employ the use of scouts, who search for new nest locations. These scouts then recruit naïve workers to these nests resulting in a ‘voting’ process through which colonies can collectively choose the best nest site. Once the decision is made, the selected nest is rapidly populated by workers who physically carry the queen(s), brood, and remaining naïve ants to the new nest. Invasions occurring during inter-colony conflicts bear a striking resemblance to this process. The state of the final nest suggested merged colonies, and statistical models were used to test for the likelihood of this. Here we test whether colonies of T. rugatulus use the same mechanisms during invasions as those used in emigrations by observing conflicts between colonies of T. rugatulus ants and tracking instances of scouting and recruitment, transport and changes in populations in each nest. Our results support the predicted order of behaviors starting with scouting, followed by recruitment and transport last. In addition, presence of the quorum rule, which determines the switch from recruitment to transport, is confirmed. Furthermore, evidence showed that the colonies were merged at the time of transport. While ant emigration patterns are well understood, there is a gap in understanding conflict driven emigrations/invasions. Our results serve to better understand conflict in social insects by further understanding the mechanisms used during conflicts.

Olfactory discrimination tasks can provide useful information about how olfaction may have evolved by demonstrating which types of compounds animals will detect and respond to. Ants discriminate between nestmates and non-nestmates by using olfaction to detect the cuticular hydrocarbons on other ants, and Camponotus floridanus have particularly clear and aggressive responses to non-nestmates. A new method of adding hydrocarbons to ants, the “Snow Globe” method was further optimized and tested on C. floridanus. It involves adding hydrocarbons and a solvent to a vial of water, vortexing it, suspending hydrocarbon droplets throughout the solution, and then dipping a narcotized ant in. It is hoped this method can evenly coat ants in hydrocarbon. Ants were treated with heptacosane (C27), nonacosane (C29), hentriacontane (C31), a mixture of C27/C29/C31, 2-methyltriacontane (2MeC30), S-3-methylhentriacontane (SMeC31), and R-3-methylhentriacontane (RMeC31). These were chosen to see how ants reacted in a nestmate recognition context to methyl-branched hydrocarbons, R and S enantiomers, and to multiple added alkanes. Behavior assays were performed on treated ants, as well as two untreated controls, a foreign ant and a nestmate ant. There were 15 replicates of each condition, using 15 different queenright colonies. The Snow Globe method successfully transfers hydrocarbons, as confirmed by solid phase microextraction (SPME) done on treated ants, and the behavior assay data shows the foreign control, SMeC31, and the mixture of C27/29/31 were all statistically significant in their differences from the native control. The multiple alkane mixture received a significant response while single alkanes did not, which supports the idea that larger variations in hydrocarbon profile are needed for an ant to be perceived as foreign. The response to SMeC31 shows C. floridanus can respond during nestmate recognition to hydrocarbons that are not naturally occurring, and it indicates the nestmate recognition process may simply be responding to any compounds not found in the colony profile and rather than detecting particular foreign compounds.

This paper is a survey of the Oribatid mites of the North American deserts. It contains four chapters. Chapter 1 gives an overview of the biology of mites and oribatids. I talk about their phylogeny, body parts, food sources, habitats, and lifecycle. In Chapter 2, I identify a group of 59 oribatid species with cosmopolitan or semi-cosmopolitan distributions and examine how the number of biogeographical regions where a species has been detected relates to body length and to reproductive mode (sexual or parthenogenetic). I also present an illustrated guide (File S1) to 58 of these species for use in identifying cosmopolitan species in oribatid surveys. Chapter 3 describes the current state of knowledge of oribatid diversity in the southwestern US and northern Mexico. In total, I was able to find records for 340 oribatid species from this region in the published literature and museum collections. However, we can see that some states, such as Arizona and Sonora, do not have many published records and that further studies are needed to more fully characterize oribatid diversity within this region. Finally, Chapter 4 describes some preliminary efforts to culture oribatid mites sampled from oak woodland in the Santa Rita Mountains of southeast Arizona. Although this work was interrupted by the COVID-19 crisis, I was able to keep three oribatid species in captivity long enough for them to lay eggs and for some of these eggs to hatch.

Across the animal kingdom, communication serves a vital purpose. The transfer of information between and among species is often paramount to many behaviors including mating, collaboration, and defense. While research has provided tremendous insight into animal communication and interaction, there is still much that we have yet to understand. Due to their reliance on interactions that maximize efficiency within their complicated colony structure and array of member roles, eusocial insects serve as an excellent model for animal communication. Among eusocial insects, ants are some of the most heavily researched, with a tremendous amount of literature focused on their cuticular hydrocarbons. Along with serving as a waterproofing agent, cuticular hydrocarbons also play a major role in recognition and communication in these insects. By studying the importance of hydrocarbons in ant social structure, their tremendously specialized olfactory system, and the use of learning assays in its study, parallels between communication in ants and other animals are revealed, demonstrating how ants serve as a relevant model for animal communication as a whole.

The desert ant, Novomessor albisetosus, is an ideal model system for studying collective transport in ants and self-organized cooperation in natural systems. Small teams collect and stabilize around objects encountered by these colonies in the field, and the teams carry them in straight paths at a regulated velocity back to nearby nest entrances. The puzzling finding that teams are slower than individuals contrasts other cases of cooperative transport in ants. The statistical distribution of speeds has been found to be consistent with the slowest-ant model, but the key assumption that individual ants consistently vary in speed has not been tested. To test this, information is needed about the natural distribution of individual ant speeds in colonies and whether some ants are intrinsically slow or fast. To investigate the natural, individual-level variation in ants carrying loads, data were collected on single workers carrying fig seeds in arenas separated from other workers. Using three separate, small arenas, the instantaneous speed of each seed-laden worker was recorded when she picked up a fig seed and transported within the arena. Instantaneous speeds were measured by dividing the distance traveled in each frame by how much time had passed.
There were nine ants who transported a fig seed numerous times and there was a clear variation in their average instantaneous speed. Within an ant, slightly varying speeds were found as well, but within-ant speeds were not as varied as speed across ants. These results support the conclusion that there is intrinsic variation in the speed of an individual which supports the slowest-ant model, but this may require further experimentation to test thoroughly. This information aids in the understanding of the natural variation of ants cooperatively carrying larger loads in groups.

Social animals benefit from the aggregation of knowledge and cognitive processing power. Part of this benefit comes from individual heterogeneity, which provides the basis to group-level strategies, such as division of labor and collective intelligence. In turn, the outcomes of collective choices, as well as the needs of the society at large, influence the behavior of individuals within it. My dissertation research addresses how the feedback between individual and group-level behavior affects individuals and promotes collective change. I study this question in the context of seed selection in the seed harvester ant, Pogonomyrmex californicus. I use both field and laboratory studies to explore questions relating to individual behavior: how forager decision-making is affected through information available in the nest and at the seed pile; how workers interact with seeds in the nest; and how forager preferences diverge from each other’s and the colony’s preference. I also explore the integration between individual and colony behavior, specifically: how interactions between the foraging and processing tasks affect colony collection behavior; how individual behavior changes affect colony preference changes and whether colony preference changes can be considered learning behavior. To answer these questions, I provided colonies with binary choices between seeds of unequal or similar quality, and measured individual, task group, and colony-level behavior. I found that colonies are capable of learning to discriminate between seeds, and learned information lasts at least one month without seed interaction outside of the nest. I also found that colony learning was coordinated by foragers receiving updated information from seeds in the nest to better discriminate and make choices between seed quality during searches for seeds outside of the nest. My results show that seed processing is essential for stimulating collection of novel seeds, and that foraging and processing are conducted by behaviorally and spatially overlapping but distinct groups of workers. Finally, I found that foragers’ preferences are diverse yet flexible, even when colonies are consistent in their preference at the population level. These combined experiments generate a more detailed and complete understanding of the mechanisms behind the flexibility of collective colony choices, how colonies incorporate new information, and how workers individually and collectively make foraging decisions for the colony in a decentralized manner.

Ant colonies provide numerous opportunities to study communication systems that maintain the cohesion of eusocial groups. In many ant species, workers have retained their ovaries and the ability to produce male offspring; however, they generally refrain from producing their own sons when a fertile queen is present in the colony. Although mechanisms that facilitate the communication of the presence of a fertile queen to all members of the colony have been highly studied, those studies have often overlooked the added challenge faced by polydomous species, which divide their nests across as many as one hundred satellite nests resulting in workers potentially having infrequent contact with the queen. In these polydomous contexts, regulatory phenotypes must extend beyond the immediate spatial influence of the queen.

This work investigates mechanisms that can extend the spatial reach of fertility signaling and reproductive regulation in three polydomous ant species. In Novomessor cockerelli, the presence of larvae but not eggs is shown to inhibit worker reproduction. Then, in Camponotus floridanus, 3-methylheptacosane found on the queen cuticle and queen-laid eggs is verified as a releaser pheromone sufficient to disrupt normally occurring aggressive behavior toward foreign workers. Finally, the volatile and cuticular hydrocarbon pheromones present on the cuticle of Oecophylla smaragdina queens are shown to release strong attraction response by workers; when coupled with previous work, this result suggests that these chemicals may underly both the formation of a worker retinue around the queen as well as egg-located mechanisms of reproductive regulation in distant satellite nests. Whereas most previous studies have focused on the short-range role of hydrocarbons on the cuticle of the queen, these studies demonstrate that eusocial insects may employ longer range regulatory mechanisms. Both queen volatiles and distributed brood can extend the range of queen fertility signaling, and the use of larvae for fertility signaling suggest that feeding itself may be a non-chemical mechanism for reproductive regulation. Although trail laying in mass-recruiting ants is often used as an example of complex communication, reproductive regulation in ants may be a similarly complex example of insect communication, especially in the case of large, polydomous ant colonies.

Emerging infectious diseases (EIDs) in vulnerable populations are a proposed cause of reduced global biodiversity due to local and regional extinctions. Chytridiomycosis, a fungal disease caused by Batrachochytrium dendrobatidis (Bd), is affecting amphibian populations worldwide.

Chapter 1 of this thesis reports using lab-raised larval tiger salamanders (Ambystoma tigrinum nebulosum), collected as eggs, to test if Bd infects them. Bd infects metamorphosed tiger salamanders; however, it is currently unknown if larvae can be infected by Bd. Adult frogs tend to host Bd on ventral surfaces and hind legs while tadpoles host Bd in keratinized mouthparts. No research has considered differences in infection between life stages of salamanders. It was hypothesized that Bd can colonize larvae in the same manner as metamorphosed animals. Larval salamanders were inoculated to test if Bd concentrations differ among body regions in larvae compared to metamorphosed salamanders. Larvae can carry Bd with the concentration of Bd varying between body region.

Chapter 2 report using native tiger salamanders (Ambystoma tigrinum nebulosum), from northern Arizona and Bd as a study system to test if Bd is native or introduced to Arizona. It was hypothesized that Bd is not endemic to Arizona, but is introduced. There are multiple hypotheses regarding potential routes Bd may have traveled through Arizona and into Mexico. These hypotheses were tested using the Kaibab Plateau in Coconino County, Arizona, as a study site. The plateau is isolated from surrounding areas by the Grand Canyon to the south and the Vermillion Cliffs to the north serving as major biogeographical barriers. It is hypothesized that tiger salamanders are not dispersing into or out of the Kaibab Plateau due to geological restrictions. Bd, therefore, should not be present on salamanders on the Kaibab Plateau due to geological restriction. Tiger salamanders in stock tanks located on the Kaibab as well as preserved museum specimens housed in the Arizona State University Natural History Collection were sampled. The results indicate that Bd occurs at low levels on Kaibab Plateau tiger salamanders.

When ants encounter liquid food, they have two options of transporting that food to their nests. The first is the social bucket method in which liquid is carried in the mandibles of the workers back to the nest. The second is trophallaxis in which liquid is imbibed and then transported inside the ant back to the nest. The liquid is then regurgitated to fellow nestmates. Ectatomma have been observed using the social bucket method of transport and were considered members of the Ponerine family. However, a new phylogeny created by Borowiec and Rabeling places Ectatomma near to Formecinae and Myrmicinae, both know for practicing trophallaxis. This seems to suggest either Ectatomma is able to utilize trophallaxis as well or that the evolutionary practice of trophallaxis is more plastic than previously believed. The ability of Ectatomma ruidum to utilize trophallaxis was examined in two experiments. The first experiment examined E. ruidum’s ability to practice worker to worker trophallaxis and the second examined E. ruidum’s ability to perform worker to larva trophallaxis. The results of both experiments indicated that E. ruidum cannot utilize trophallaxis but the larva of E. ruidum may be able to regurgitate to the workers. These results in turn seem to suggest that trophallaxis is a bit more plastic than originally thought.