Peggy S. M. Hill

Spontaneous flower constancy and learning in honey bees as a function of colour

When presented with an artificial flower patch of blue and yellow pedicellate flowers, individual honey bees, Apis mellifera L., became constant to one of the two flower colours, rarely even sampling the alternative colour. Some bees visited only blue flowers while others visited only yellow flowers. This paper describes the onset of constancy for bees that had had no experience with the experimental apparatus. In 3020 visits, bees failed to land on or drink from the flower colour on which they first landed only 17 times. This behaviour was not modified by quality or quantity of reward, training to the experimental site, group effects or presence of odour during trials. However, when we trained bees to a target painted with two colours and then forced them to sample monomorphic flower patches in sequence, all bees visited the only colour present: yellow or blue. When we subsequently offered these same bees yellow and blue flowers simultaneously (rewarded choices), they became constant. Eleven of 23 bees showed constancy to the less rewarding flower morph without even sampling the alternative. Those bees failed to sample even though they had previously been forced to visit the alternative flower morph, which offered a reward with twice the calories/volume. Constancy is thus spontaneous in honey bees, but it can be hidden by some experimental protocols designed to study learning.1997The Association for the Study of Animal Behaviour

How do animals use substrate-borne vibrations as an information source?

Animal communication is a dynamic field that promotes cross-disciplinary study of the complex mechanisms of sending and receiving signals, the neurobiology of signal detection and processing, and the behaviors of animals creating and responding to encoded messages. Alongside visual signals, songs, or pheromones exists another major communication channel that has been rather neglected until recent decades: substrate-borne vibration. Vibrations carried in the substrate are considered to provide a very old and apparently ubiquitous communication channel that is used alone or in combination with other information channels in multimodal signaling. The substrate could be ‘the ground’, or a plant leaf or stem, or the surface of water, or a spider’s web, or a honeybee’s honeycomb. Animals moving on these substrates typically create incidental vibrations that can alert others to their presence. They also may use behaviors to create vibrational waves that are employed in the contexts of mate location and identification, courtship and mating, maternal care and sibling interactions, predation, predator avoidance, foraging, and general recruitment of family members to work. In fact, animals use substrate-borne vibrations to signal in the same contexts that they use vision, hearing, touch, taste, or smell. Study of vibrational communication across animal taxa provides more than just a more complete story. Communication through substrate-borne vibration has its own constraints and opportunities not found in other signaling modalities. Here, I review the state of our understanding of information acquisition via substrate-borne vibrations with special attention to the most recent literature.

Vibration and Animal Communication: A Review

SYNOPSIS. Vibration through the substrate has likely been important to animals as a channel of communication for millions of years, but our awareness of vibration as biologically relevant information has a history of only the last 30 yr. Morphologists know that the jaw mechanism of early amphibians allowed them to perceive vibration through the substrate as their large heads lay on the ground. Although the exact mechanism of vibration production and the precise nature of the wave produced are not always understood, recent technical advances have given answers to increasingly sophisticated questions about how animals send and receive signals through the substrate. Some of us have been forced to explore the use of vibration when all other attempts to manipulate animals in the field have failed, while others began to think about vibration to explain some of the puzzling behaviors of species they were studying in other contexts. It has thus become clear that the use of vibration in animal communication is much more widespread than previously thought. We now know that vibration provides information used in predator-prey interactions, recruitment to food, mate choice, intrasexual competition and maternal/brood social interactions in a range of animals from insects to elephants.

Foraging decisions in nectarivores: unexpected interactions between flower constancy and energetic rewards

Foraging decisions are based on a suite of choices that include energetics and physiological constraints. Although travelling farther to harvest a greater net energetic reward is beneficial, many animals opt for a smaller net reward that requires less travel. Recent discoveries of a visual basis for flower constancy in the honeybee, Apis mellifera, led us to examine older reports that colour cues are superceded by energetic considerations. Here we show that when individual bees foraged on pedicellate artificial flowers varying in colour and interfloral distance, their behaviour depended on the colours in the choice test. Colours of similar spectral reflectance (blue versus white), that would be clustered in the bees visual colour space, elicited more visits to the closest flower when rewards were equal, but individuals travelled a greater distance to harvest a higher energetic reward when reward quality varied. Bees chose the closest flower more often when reward volume decreased while quality remained constant. Yet, even when all flowers were identical (morphology and reward), and only interfloral distance varied, bees did not always visit the closest flower. A dramatic difference was seen when the dimorphism was yellow-blue, colours quite separate in the bee colour space and known to elicit constancy behaviour. Here, bees visited the closest flower only 5% of the time, and varying reward volume did not elicit different behaviour. Animals thus display differential foraging behaviour with respect to environmental cues that must be considered when asking questions about other behavioural parameters.

Nectarivore foraging ecology: rewards differing in sugar types

Abstract. 1 Honey bees, visiting artificial flower patches, were used as a model system to study the effects of sugar type (sucrose, glucose, fructose, and mixed monosaccharide), caloric reward, and floral colour on nectarivore foraging behaviour. Observed behaviour was compared to the predictions of various (sometimes contradictory) foraging models. 2 Bees drank indiscriminately from flowers in patches with a blue‐white flower dimorphism when caloric values of rewards were equal (e.g. 1M sucrose in both colours; 1 M sucrose versus 2 M monosaccharide of either type), but when nectar caloric rewards were unequal, they switched to the flower colour with the calorically greater reward. 3 In yellow‐blue dimorphic flower patches, on the other hand, bees did not maximize caloric reward. Rather, bees were individually constant, some to blue, others to yellow, regardless of the sugar types or energy content of the rewards provided in the two flower morphs. 4 The results suggest that optimal foraging theory (maximization of net caloric gain per unit time) is a robust predictor of behaviour with regard to the sugar types common to nectars; such optimal foraging is, however, limited by a superstructure of individual constancy.

Studying Vibrational Communication

Vibrational communication holds the unique position of being one of the most ancient and widespread forms of animal communication and yet the most poorly known. The long evolutionary history of vibrational communication, the remarkable diversity of species in which it occurs, and its central role in biotic interactions provide unparalleled opportunities for addressing general questions. Vibrational communication has also proven to be a key to understanding the behavior of individual species, across much of the tree of life. The goal of Studying Vibrational Communication is to inspire research into this important and fascinating communication modality by providing state-of-the-field reviews, historical perspectives, and technical advice and by suggesting new directions for groundbreaking studies. We also hope to convince those new to the field that studying this communication modality is surprisingly accessible, even for those with no prior experience. R. B. Cocroft (&) University of Missouri, Columbia, MO, USA e-mail: cocroftr@missouri.edu M. Gogala Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia e-mail: matija.gogala@guest.arnes.si P. S. M. Hill University of Tulsa, Tulsa, OK, USA e-mail: peggy-hill@utulsa.edu A. Wessel Museum für Naturkunde—Leibniz-Institut für Evolutionsund Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Invalidenstraße 43, 10115 Berlin, Germany e-mail: andreas.wessel@mfn-berlin.de A. Wessel Zoologisches Museum, Universität Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany R. B. Cocroft et al. (eds.), Studying Vibrational Communication, Animal Signals and Communication 3, DOI: 10.1007/978-3-662-43607-3_1, Springer-Verlag Berlin Heidelberg 2014 3

Morphology and calling song characteristics in Gryllotalpa major Saussure (Orthoptera: Gryllotalpidae)

Abstract The prairie mole cricket (Gryllotalpa major Saussure) is a native of the tallgrass prairie ecosystem of the south central United States. The largest of North American crickets, its populations have declined with the reduced availability of suitable grassland habitat. Prairie mole cricket populations were surveyed at The Nature Conservancys Tallgrass Prairie Preserve in Oklahoma in the spring of 2005. We located 95 acoustic burrows occupied by calling males and recorded the calling songs of 55. We measured 3 morphological characters for 8 of these field-recorded males and characterized each males calling song for 7 key acoustic variables. Statistically significant relationships were discovered between male body length and 2 song parameters: syllables chirp−1 and dominant frequency.

The Effect of Fire on Spatial Distributions of Male Mating Aggregations in Gryllotalpa Major Saussure (Orthoptera: Gryllotalpidae) at The Nature Conservancy's Tallgrass Prairie Preserve in Oklahoma: Evidence of a Fire-dependent Species

Abstract The prairie mole cricket (Gryllotalpa major Saussure) is a native of the tallgrass prairie ecosystem of the south central United States. Its populations have dwindled with the reduced availability of suitable grassland habitat. Populations are known to occupy relict prairie sites in Oklahoma, Kansas, Arkansas and Missouri. The Nature Conservancys Tallgrass Prairie Preserve in north central Oklahoma is the largest continuous tract of tallgrass prairie remaining (about 16,100 ha). The long-term management plan for this property includes the utilization of prescribed burns, bison grazing, cattle grazing and limited mowing to restore a functional tallgrass prairie landscape. Prairie mole cricket populations were surveyed at the site during the years 1993, 1994, 1998, and by our research team in 2005, using the male crickets acoustic call as a discrete presence indicator. Records from these surveys were integrated with prescribed burn maps to identify spatial distribution patterns of the calling aggregations at the preserve. These data were then analyzed to determine the randomness of spatial distributions with regard to pasture burn regimes. Results revealed a non-random distribution of prairie mole cricket calling sites, with advertising males found in higher numbers on sites that had been more recently burned. Analysis of soil temperature data taken from both burned and unburned prairie patches at White Oak Prairie in Oklahoma revealed no difference between the two treatments. The results of this study indicate that prairie mole cricket lek sites are somewhat transient within a broader prairie mosaic in which fire is a regular disturbance factor and tend to emerge on more recently burned patches. This information is being utilized in constructing habitat models and resource management plans for this preserve as well as other sites harboring Gryllotalpa major populations.

Singing from a constructed burrow: why vary the shape of the burrow mouth?

Abstract Male prairie mole crickets, Gryllotalpa major Saussure, studied in Oklahoma, sing sexual advertisement songs from constructed burrows in the soil. Here we report on variation in shape of the acoustic burrow mouth not previously described for this or other mole cricket species. We have identified six distinct shapes, of which only the ‘slit’ form has been previously described. Since the surface opening acts as the system ‘radiator’, we hypothesized that variation in the shape would account for at least some of the measured variation documented since 1993 in the songs produced by the population studied. We looked for patterns in the variation of dominant frequency of advertisement calls and maximum amplitude of calls that were linked to shape of burrow openings, but found none. Future work will focus on the role of previously documented weak higher harmonics in the G. major calling song, which might vary with differences in burrow mouth shape.

Life Expectancy in a Tulsa Cemetery: Growth and Population Structure of the Lichen Xanthoparmelia cumberlandia

-The demographics of a population of the foliose lichen Xanthoparmelia cumberlandia growing on gravestones in a Tulsa cemetery are presented. Because of the regular layout of granitic gravestones, the cemetery acted as a mechanism for generating experimental replicates and as a control for habitat variability. The lichen population was multi-modal, based on age classes. Thalli within each age class approximated a normal distribution of size. Age classes were separated by several years. Growth rates of thalli within age classes were independent of size, but growth was dependent on age class. Thallus growth varied among the months, and was correlated with precipitation but uncorrelated with temperature. Mortality rate was greatest in age class III, and lowest in class I (I youngest-III oldest thalli). A population model of the species showed that recruitment has been sporadic, yet highly successful when it did occur. The model depicts growth rates as independent of size within, but not among, the three age classes.