Abstracts

ABSTRACT

The normal development of empathy has been proposed to be imperative to the healthy emotional and social functioning of youths. In contrast, compromised levels of empathy have been linked to an increased propensity to engage in antisocial behaviors, including animal cruelty. Previous findings have revealed parent attachment to be intrinsically linked to the development of empathy. This association has been shown to play a role in predicting the expression of various outcome behaviors, including both those which are prosocial in nature, and those which are antisocial, and potentially aggressive. This study examines these associations in a sample of 281 12- to 18-year-old students. The aims included the investigation of the direct predictive roles played by attachment and empathy for prosocial and antisocial behaviors directed at both humans and animals. We also investigated the mediating role played by empathy in these relationships. Attachment and empathy significantly predicted prosocial and antisocial behaviors, both individually, and in combination. Furthermore, empathy was found to serve a mediating role in the associations between attachment and: human-directed prosocial behavior, the humane treatment of animals, and animal cruelty. These findings expand upon existing literature by demonstrating that it is, at least partially, through empathy that attachment to parents predicts prosocial and antisocial behaviors during adolescence. This is in contrast to the direction of relationships implied by some previous findings and proposals, which have suggested that treating animals humanely fosters the normal development of empathy, for example. Notwithstanding the promising findings revealed by the current study, we recommend that replicating this research using a larger sample will assist in addressing the limited generalizability identified in the current study. It is further proposed that the use of a lie scale could limit the influence of social desirability responding. Future research is also needed to determine the direction of the demonstrated relationships.     

Exotic grass invasion impacts fitness of an endangered prairie butterfly, <Emphasis Type="Italic">Icaricia icarioides fenderi</Emphasis>

Fender’s blue butterfly is an endangered species restricted to fragmented, grassland remnants that are becoming increasingly dominated by tall, invasive grasses in western Oregon, USA. I performed a removal experiment to assess the impacts of structural degradation accompanying the invasion of Arrhenatherum elatius, tall oat grass, on butterfly fitness and fitness related behaviors. Clipping of A. elatius to native grass sward height resulted in 2.5–5 times as many eggs laid per leaf of host plant. Both male and female butterflies basked more frequently in areas removed of A. elatius inflorescences and upon encountering the treatment edge butterflies had a high rate of return into a large area removed of the grass inflorescences. Although butterfly behavior appeared to be affected by the change in sward height on the treatment edge, there was no evidence for the edge causing a disproportionate egg load. Invasion and dominance by A. elatius appeared to diminish host plant apparency which may result in overloading of eggs on conspicuous host plants, increased incidence of emigration, and a decrease in the likelihood of colonization because female butterflies appeared indifferent to larval resources beneath A. elatius inflorescences. Dominance of natural shortgrass prairies by tall stature grasses like A. elatius may be an insidious form of habitat degradation for grassland Lepidoptera worldwide, but it may go largely unnoticed because larval and adult resources can persist under the unnaturally tall grass canopy.     

Differential Effects of Tachykinins Injected Intranigrally on Striatal Dopamine Metabolism

The effects of intranigral injection of kassinin, eledoisin, and substance P on striatal dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) contents as well as circling behavior were studied in rats. Kassinin and eledoisin produced a marked dose-dependent increase of DOPAC concentrations in the ipsilateral striatum, as well as in the number of contralateral circlings. Substance P produced a similar but weaker effect. At the larger dose (5 nmol), the three tachykinins also induced an increase of DA concentrations in the ipsilateral striatum. The rank order of activity was kassinin greater than eledoisin greater than substance P. These results suggest that tachykinins stimulated the nigro-striatal dopaminergic system by accelerating the dopamine metabolism in striatum.     

Reproductive behavior and social organization in the sand tilefish,Malacanthus plumieri

Synopsis Observations on the Caribbean sand tilefish, Malacanthus plumieri, were made during 3 dive trips in the Bahamas (Feb., 1986; July, 1986; Jan., 1987) at depths from 5 to 30 m. Eighteen mating groups contained 1 to 5 females (x = 2.9). Seven male home ranges (encompassing female ranges within mating groups) measured 250 to 700 m². Of 134 paired rises recorded between 1733 and 1925 h EST, 38 had an observed cloud of gametes. Mating times are presented in relation to time of sunset and depth of water. Courtship begins with conspicuous looping behavior of the male as he swims to a female. Close pairing, criss-crossing, and low rises (<1.5 m) often precede a high quivering upward swim (1.5 to 6 m) which culminates in the release of a cloud of gametes at the apex. M. plumieri is compared to the protogynous hermaphroditic razorfishes, Xyrichtys pentadactylus and X. martinicensis, with regard to social organization, size of male home ranges in exposed sandy habitats near coral reefs, sexual size dimorphism, and sex ratio.     

SOCIAL SELECTION AND THE EVOLUTION OF ANIMAL SIGNALS

Social selection is presented here as a parallel theory to sexual selection and is defined as a selective force that occurs when individuals change their own social behaviors, responding to signals sent by conspecifics in a way to influence the other individuals' fitness. I analyze the joint evolution of a social signal and behavioral responsiveness to the signal by a quantitative-genetic model. The equilibria of average phenotypes maintained by a balance of social selection and natural selection and their stability are examined for two alternative assumptions on behavioral responsiveness, neutral and adaptive. When behavioral responsiveness is neutral on fitness, a rapid evolution by runaway selection occurs only with enough genetic covariance between the signal and responsiveness. The condition for rapid evolution also depends on natural selection and the number of interacting individuals. When signals convey some information on signalers (e.g., fighting ability), behavioral responsiveness is adaptive such that a receiver's fitness is also influenced by the signal. Here there is a single point of equilibrium. The equilibrium point and its stability do not depend on the genetic correlation. The condition needed for evolution is that the signal is beneficial for receivers, which results from reliability of the signal. Frequency-dependent selection on responsiveness has almost no influence on the equilibrium and the rate of evolution.     

The roles of ecological and behavioral observation in species recognition among primates

Closely related living mammal species present numerous difficulties of recognition and delineation, not least because populations as well as individual organisms fulfill both genetic and economic functions. However, since species are often distributed geographically across multiple ecosystems or environments, it is evident that species as wholes, except where coterminous with the local populations of which they are composed, cannot be said to play unitary ecological roles. Aspects of the economic activity of organisms thus may not be admitted as elements in species recognition. Those who study the behavior of mammals in their natural habitats must therefore focus upon behaviors which preserve the genetic integrity of species if they wish to contribute to the systematic question of species identification. «Isolation» concepts of species are not served by data of this kind, since they emphasize interspecies discontinuities; the «recognition» concept of species, however, specifically focuses upon behaviors of this kind as they contribute to the «Specific-Mate Recognition System». Among primates such behaviors are likely to involve signalling of various kinds; where this is visual it is reasonable to expect to find morphological or chromatic correlates; where such cues are auditory or, to a lesser extent, olfactory, it is less probable that such correlates will be found to exist.     

Dietary practices,site-specific tumors,and age-at-death relationships

When rats are given freedom of dietary choice, the quantity and composition of the diet selected varies from animal to animal, but the risk to the individual of developing a variety of neoplasms is greatly increased over that of rats fed fixed diets. The increase in frequency of tumors cannot be explained on the basis of the amount or the composition of the diet selected. However, the application of “variable selection” statistical procedures shows that there are combinations of temporal-specific interacting dietary and dietary-dependent variables that are closely linked with cancer mortality. The multi-variable statistical model for animals dying with one type of tumor is not applicable to those dying with tumors of other types or sites. In every case, the only data required to characterize the dates of death of tumor-bearing individuals are those describing the dietary practices and growth responses prior to maturity. The model for animals with pancreatic tumors is used to illustrate the extent to which dietary practices of early life are linked with the animals’ survival.     

The Social Environment of an Aggregating, Ant-Attended Treehopper (Hemiptera: Membracidae: Vanduzea arquata)

Many membracid treehoppers are attended by honeydew-harvesting ants. Ant mutualism often favors group living, which will in turn influence social interactios and communication. I investigated aspects of life history that underlie the social behavior of an aggregating, ant-attended treehopper. The number of adults, and their patterns of distribution, changes dramatically over the course of a season. Despite the relatively low vagility and high persistence in the same clump of host plants, individuals encounter a wide range of social environments. This aggregating species differs from solitary species in the clumped distribution of females, and possibly in the intensity of acoustic competition among males, but both aggregating and solitary species exhibit large temporal changes in density. A high degree of temporal and spatial variation in the social environment is probably characteristic of many insects and may be an important source of selection on insect communication.     

Differential Interactions Between an Aphid Endohyperparasitoid and Three Honeydew-Collecting Ant Species: A Field Study of Alloxysta brevis (Thomson) (Hymenoptera: Alloxystidae)

The behavioral interactions between the chemically protected aphid hyperparasitoid Alloxysta brevis and three trophobiotic ant species were examined in the field on thistles. The patterns were not essentially influenced by hyperparasitoid sex. Ants differed in their guarding behavior of aphids and their response toward A. brevis. Lasius niger attacked the hyperparasitoid more readily than Myrmica laevinodis, while aggression by Formica rufa was intermediate. Apart from applying chemical defense, A. brevis responded to ants by flying away (mainly at L. niger) or with avoidance behavior (mainly at M. laevinodis). Additionally, females might switch their tactics from flight to defense with increasing age. Females left the plant more often after encounters with L. niger or F. rufa than with M. laevinodis. Disturbance by any ant species affected the foraging activities, reducing oviposition success to nearly zero.