INTRODUCTION

As the focus of ecological research has broadened from site-level observations and experiments to landscape-scale studies, interest among ecologists in connectivity among habitat patches has increased (Turner et al. 1995; Wiens 1995; Gustafson and Gardner 1996; Hanski and Gilpin 1997; Haddad and Baum 1999). From a conservation perspective, concern with the maintenance of connectivity has grown as habitat loss and fragmentation continue worldwide (Rosenberg et al. 1997; de Lima and Gascon 1999; Haddad and Baum 1999). Typically, both basic and applied studies consider connectivity among patches of the same habitat type, such as a set of forest fragments embedded in a matrix of agricultural land uses. These studies, reviewed throughout this volume, focus on measuring patch isolation and examining the utility of corridors to restore connectivity among patches.

However, another type of connectivity, although less well studied and understood, is of equal importance in these complex landscapes: the connectivity among patches of different habitat types (Daily et al. 2001; Ricketts et al. 2001; Talley et al. Chapter 5). Many species require different habitat types for different resources or life-history stages. The proximity and availability of different habitat types, therefore, can affect the population dynamics and persistence of individual species and the diversity of communities. For example, bees often nest in one habitat type (e.g, tree cavities in forest) but require other types for forage (e.g., wildflower meadows).

Animal pollination is a mixed blessing for angiosperms. Animals carry pollen readily because they are mobile and large relative to pollen grains. Furthermore, animals learn to associate floral signals with the presence of food and so move between conspecific plants relatively consistently (Chittka et al., this volume; Gegear & Laverty, this volume; Giurfa, this volume; Menzel, this volume). However, animals act in their own interests, which often conflict with successful pollen transport (e.g., only about 1% of a plant's pollen production reaches stigmas; Harder 2000). Consequently, manipulation of pollinator behavior to promote cross-pollination is a prevailing theme in the evolution of floral design (form, color, nectar, and fragrance production) and display (inflorescence size and architecture).

This chapter reviews three aspects of pollinator manipulation by plants and their effects on pollen dispersal. First, because pollen dispersal for most animal-pollinated plants depends on the general responses of feeding pollinators to their foraging environment, we consider the underlying economic principles that establish the opportunities for floral manipulation. Second, we outline influences on the typical pattern of pollen dispersal among flowers for plants with granular pollen, and summarize how flower design affects this pattern (for a review of dispersal of orchid pollen, see Harder 2000). Finally, because pollination and mating success are characteristics of entire plants, rather than individual flowers, we consider how floral display affects pollinator attraction and within-plant behavior to determine pollen dispersal.

A central theme in Vygotsky's development theory is that cognitive development can be understood as the transformation of basic, biologically determined processes into higher psychological functions. According to the theory, the human child is endowed by nature with a wide range of perceptual, attentional, and memory capacities, such as the capacity to perceive contrast and movement, the capacity for eidetic memory, and arousal/habituation responses to environmental stimuli, to name a few. Such basic processes (also referred to by Vygotsky as “biological,” “natural,” or “elementary”), however, are substantially transformed in the context of socialization and education, particularly through the use of language, to constitute the higher psychological functions or the unique forms of human cognition.

Our readings of Vygotsky suggest that this “transformation” from basic to higher functions consists mostly of an increasing self-regulation of processes and capacities that are originally bound to and controlled by the concrete, immediate stimulus field. In development, the infant's eidetic, rudimentary memory processes are gradually transformed into the capacity for voluntary memory and the use of mnemonic strategies; the capacity to perceive salient stimulus features develops into the capacity for selective attention; arousal/habituation patterns develop into the capacity for vigilance, concentration, and sustained attention. The common denominators of these transformations or developmental changes are the decreasing power of immediate environmental contingencies and the increasing role of self-formulated plans and goals in the regulation of behavior and cognitive activity.