Circadian rhythms are endogenous cycles that control physiological and behavioral changes that can be affected by environmental factors which allow most eukaryotic organisms to synchronize their daily activities with the 24-hour day. Parasteatoda tepidariorum,the common house spider, demonstrates a short-period circadian clock averaging 21.6 hours when left in constant darkness, yet they are able to entrain to a 24-hour light cycle. We tested whether these spiders were able to use non-photic Zeitgebers to entrain to the 24-hour day. Periodic presentation of food and disturbance were not found to be effective cues for the spiders’ entrainment. A few individuals were clearly able to entrain to an 8 oC amplitude temperature cycle, while most did not.

An increased understanding of species-specific behavioral needs has lead zoos to focus on providing more naturalistic and stimulating environments. Scientific assessments of how changes in habitat affect animal behavior are necessary in improving overall animal welfare. This study examined the move of three orangutans housed at the Oregon Zoo into a new and innovative exhibit. Post-occupancy evaluation (POE), which offers systematic information regarding the success or failure of the built environment (Maple & Finlay, 1987), was utilized to effectively evaluate the results of the move. The collection of behavioral data and adrenal activity monitoring through collection of non-invasive saliva, urine and hair provided a comprehensive methodology for comparing changes in behavior and physiological functioning. Behavioral results showed that following the move to the new enclosure animals spent less time inactive, more time at higher elevations and utilized exhibit structures at a greater frequency. Hormonal results suggest that detection of cortisol in orangutan hair could be a useful tool for monitoring chronic stress.

ABSTRACT SALT DRIVE IN THE BEAVER (Castor canadensis): AN EXPERIMENTAL ASSESSMENT WITH FIELD FEEDING TRIALS SEPTEMBER 2012 JENNIFER E. STRULES, B.M. BERKLEE COLLEGE OF MUSIC M.S., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Stephen DeStefano Salt drive is a seasonal phenomenon common to several classes of wild herbivores. Coincident with shifts of nutrient quality when plants resume growth in the spring, sodium is secondarily lost as surplus potassium is excreted. The beaver (Castor canadensis) is an herbivore whose dietary niche closely follows that of other herbivores that are subject to salt drive, but no published studies to date have assessed the likelihood of its occurrence. To quantify if beavers experience seasonal salt drive, we designed a field experiment to measure the foraging responses of beavers to sodium-enhanced foods. We used sodium-treated (salted) and control food items (aspen [Populus tremuloides] and pine [Pinus spp.] sticks) during monthly feeding trials at beaver-occupied wetlands where water lily (Nymphaea spp. and Nuphar spp.) was present and where water lily was absent. If conventional ontogeny of salt drive was operant, we expected to observe greater utility of sodium-treated food items by beavers in May and June. Further, if water lilies supplied beavers with sodium to meet dietary requirements as is widely speculated, we expected foraging responses to sodium-treated food items at wetlands where water lilies were absent to be greater than at wetlands where water lily was present. Aspen was selected by beavers in significantly greater amounts than pine. There was no difference between the mean percent consumed of salted and control aspen sticks by beavers at lily and non-lily wetlands, and no differences in temporal consumption associated with salted or control pine sticks at either wetland type. Salted pine was consumed in greater amounts than unsalted pine. We propose that the gastrointestinal or renal physiology of beavers may predispose them to low solute loss, thereby preventing salt drive.

Forelimbs in many mammals are used in both locomotion and the acquisition of food. In bats, the forelimbs are highly specialized for flight, but the thumb is free to preform other functions. Using morphological data from museum specimens and field observations of feeding behavior, I documented how Neotropical leaf-nosed bats (family: Phyllostomidae) use their thumbs during feeding, and examined how thumb structure and function are linked with diet. I then used these data to test when changes in thumb morphology and feeding behaviour evolved, focusing on two specific time points: the evolution of frugivory in phyllostomids; and the diversification point at the base of the clade Stenodermatinae, which are hard canopy fruit specialists. I found that size-corrected thumb length was weakly associated with diet, but the frequency and duration of thumb use were higher in frugivorous species than in their insectivorous counterparts. Likewise, the function for which frugivores used their thumbs differed from insectivores, although variation in specific thumb movements could not be teased apart in the analyses. When I modeled selective regimes of diet, I found that species that consumed fruit showed selection for increased frequency and duration of thumb movements, but there was no evidence of selection for increased thumb length at either of the two evolutionary time points tested. This suggests that a shift in how thumbs are used during feeding, and not thumb morphology, may be linked to a transition from a mainly insectivorous diet to frugivory in phyllostomid bats.

Little is known about the behavioral patterns of honey bee queens. To determine if mated honey bee queens possess diel rhythmicity in behavior, we observed them in glass-sided observation hives using three types of observation regimes: focal studies consisting of 2-hour and 24-hour continuous observations as well as scan-sampling of multiple queens. All behaviors (active: walking, inspecting, egg-laying, begging for food, feeding, and grooming self; inactive: standing) occurred at all times of day and night, but no queen showed consistent diel rhythmicity in any of the individual behaviors. There were no consistent diel differences in active versus inactive behaviors or the number of bees in the queen's retinue. This arrhythmicity was unchanged despite daily changes in both light and temperature levels. The arrhythmic behavior observed by most of the honey bee queens inside the colony appears to be similar to that exhibited by worker bees before they initiate foraging behavior.

Anelosimus studiosus exhibits two behavioral phenotypes: subsocial and social. This is the only documented spider inhabiting a temperate climate exhibiting social behavior. While the subsocial phenotype is most common throughout the range, the social behavior occurs in isolated pockets in northern latitudes. This study examines the origins of the social phenotype within a segment of the spider's range. Two hypotheses are tested: 1) pockets of social behavior represent a single origin or 2) pockets of social behavior represent local evolutions, thus leading to multiple origins of evolution. Microsatellite loci were used to determine genetic structure of the population and to estimate the origins of social behavior. All loci showed lower observed than expected heterozygosities and all populations show indications of high levels of inbreeding. A phylogeny indicates four of the six populations fall out by location, not phenotype. We propose these results reflect multiple local evolutions of the social strategy.

Territoriality in the flesh fly, Sarcophaga crassipalpis (Diptera: Sarcophagidae) was studied in the laboratory. In rectangular enclosures, male flies exhibited a lower tolerance (occupation of the same physical space) of same-sex conspecifics than did female flies. In circular arenas, male flies showed significantly higher levels of spatial separation among themselves (as determined from nearest neighbor analyses) than did females: males were distributed uniformly whereas females were nearly random. The male spatial behavior occurred during the photophase but not the scotophase of light-dark cycles, suggesting that visual cues are required for maintenance of inter-individual spacing. No significant differences in male spacing behavior occurred between subjective day and subjective night in either constant dark or constant light conditions, suggesting that spatial patterning is not driven by a circadian rhythm.

Experiments were performed to determine the influence of the honey bee time-memory on a forager bee's sensitivity to recruitment. Two groups of foragers from one colony were trained to separate food stations at the same restricted time of day for several consecutive days. Feeding then was canceled at one station but continued for four more days at the other. Bees with more days of training at a non-productive source were significantly less likely than foragers with less training to be recruited to an alternative food source presented at the same time of day. Furthermore, the ability of a forager to be recruited recovered after several days, but this recovery period was longer for bees with greater experience. These findings demonstrate a long-term influence of time-memory on subsequent foraging behavior, in contrast to currently accepted models for the allocation and re-allocation of honey bee foragers to food patches in the environment.

Predator cues can influence how aquatic organisms respond to anthropogenic contaminants. This study examined the effects of predator cues on behavior, metabolic rate, and sulfate (as Na2SO4) toxicity in amphipods (Gammarus minus). Predator cues included alarm cue (macerated conspecifics) and kairomone from mosquitofish (Gambusia affinis). Amphipods decreased activity and increased time in refuge when exposed to alarm cue, and increased time in refuge when exposed to kairomone. While median lethal concentrations (96-h LC50) were not influenced by predator cues, analysis of dose response curves indicated that kairomone exposure increased amphipod sensitivity to mid-range concentrations of sulfate (500-1,000 mg/L). Amphipods increased oxygen consumption in response to kairomone but not alarm cue. The influence of predator cues on contaminant lethality can be dependent on the type of cue, and physiological endpoints such as metabolic rate may help explain the basis of observed interactions.

Managing Monarch butterfly overwintering groves: making room among the eucalyptus Proper management and conservation of the coastal California overwintering sites used by western Monarch butterflies (Danaus plexippus L.) is critical for continued use of these sites by monarchs. Many management efforts are currently concentrating on eucalyptus-only sites because of the prevailing notion that monarchs prefer eucalyptus over native tree species. Yet, whether a preference exists or not has never been tested. Herein, we test the “eucalyptus preference” hypothesis with data from five overwintering sites comprised of blue gum eucalyptus (Eucalyptus globulus) and at least one other native tree species from fall 2009 to spring 2012. We found that when monarchs clustered disproportionately on a tree species relative to its availability, they clustered significantly more than expected on native trees and significantly less than expected on eucalyptus. Also, in years when the overwintering population was highest, monarchs clustered disproportionately on native conifers, and they often switched from clustering on eucalyptus in the early winter to native conifers in the middle or late winter. Our results suggest that overwintering groves should be managed to include a mixture of tree species. We cannot recommend simply planting more eucalyptus. At overwintering sites in central coastal California, native conifers such as Monterey cypress (Hesperocyparis macrocarpa) and pitch canker-resistant Monterey pine (Pinus radiata) should be planted as replacements for blue gum eucalyptus in areas where trees are likely to fall, and around the perimeter of groves. Testing the Monarch butterfly eucalyptus preference hypothesis at California overwintering sites Western Monarch butterflies (Danaus plexippus L.) overwinter in groves of native and non-native trees along the California coast. Eucalyptus is abundant in coastal counties, and overwintering monarchs utilize this type of tree more than any other. This has led to the belief that monarchs prefer eucalyptus. Yet whether a preference exists has never been tested. We tested the “eucalyptus preference” hypothesis at five California overwintering sites with canopies comprised of eucalyptus and at least one native conifer species. We found that at no time over the course of three years did monarchs cluster on trees in proportion to their availability in the canopy. Overall, they did not cluster on one tree species significantly more frequently than another, indicating that monarchs do not prefer eucalyptus—or any tree species—all of the time. However, more often than not monarchs clustered significantly more than expected on native trees, particularly at midseason when the weather was most inclement. They also clustered disproportionately on native conifers when the overwintering population size was highest. At most sites monarchs exhibited tree switching, shifting from eucalyptus to native conifers in the middle or late winter. Based on these results, we reject the “eucalyptus preference” hypothesis. In its place, we propose the “conditional preference hypothesis”, wherein monarchs are predicted to prefer cluster trees according to microclimate conditions and prefer alternate trees within a site as climatic conditions change. Rejection of the eucalyptus preference hypothesis suggests that sites comprised exclusively of eucalyptus may not offer monarchs a suitable range of microhabitats, and further suggests we should rethink “eucalyptus-centric” management. Monarch butterflies overwintering in coastal California: low site fidelity and high intersite movement Western monarch butterflies (Danaus plexippus L.) overwinter in large aggregations at hundreds of sites along the California coast. Management plans and census methods are both founded on the assumption that individual monarchs arrive at an overwintering site in the fall and stay at that site for the winter. Though populations potentially coalesce en masse from autumnal sites onto climax overwintering sites, very little individual movement between sites is inferred. Monarch movement is therefore thought to be primarily into sites (as opposed to out of or among them). We refer to this assumption and inference as the accrual hypothesis. In light of previous studies that provide evidence for movement among sites, we propose that overwintering monarchs may belong to a superpopulation. The existence of a superpopulation comprised of individuals moving in and out of sites would force us to rethink our ideas of landscape-level resource use by monarchs, our site-centric (rather than landscape-level) management strategies, and our abundance estimation techniques, which employ closed population models. We tested the closed population model, the accrual hypothesis, and the superpopulation model at three California overwintering sites using a mark-resight study design. We found that a large proportion of the monarchs at a site moved among (into and out of) monitored sites, both while the population size increased in October and November, and while the population appeared to exhibit an equilibrium winter maximum. The pattern of abundance of both tagged and untagged monarchs at monitored sites leads us to reject the closed population model and the accrual hypothesis. We found that monarchs at all three study sites are part of a larger superpopulation, though the sites do not contribute to the superpopulation equally. We determined that mark-resight is a viable alternative to existing population estimation techniques, though mark-resight methods would need to be explored further before being applied routinely. Our results suggest we need to move away from site-based management and manage instead for landscape-level overwintering (superpopulation) dynamics.