Nectar is the most important reward offered by plants to pollinating animals. This book is a modern and interdisciplinary text on nectar and nectaries, prompted by the expansion of knowledge in ecological and molecular fields, and the strong recent interest in pollination biology. The topics covered vary widely: they include historical aspects, the structure and ultrastructure of nectaries and relationships to plant systematics, the dynamics of nectar secretion, nectar chemistry and the molecular biology of defence proteins, and more.

The number of currently known, described and accepted plant species is ca 374,000, of which approximately 295,00 (79%) are angiosperms. Almost 90% of this huge number of flowering plants is pollinated by animals (mostly insects) via nectar-mediated interactions. Notably, three-fourths of the leading global crop plants produce nectar and are animal pollinated, which is estimated to account for one-third of human food resources. Nectar can also be produced on tissues outside of flowers, by so-called extrafloral nectaries, and commonly mediate interactions with ‘body-guard’ ants and other pugnacious insects that defend the plant from herbivores. Extrafloral nectar is present in almost 4,000 plant species, a majority of them in the angiosperms. This brief summary on the occurrence of nectar in the plant kingdom is just to highlight that nectar has a fundamental role in two basal functions that allow the maintenance of our ecosystems: sexual plant reproduction and protection of plants from herbivory. Despite playing essential ecological and evolutionary functions, our current knowledge about nectar is largely incomplete; however, new research directions and perspectives on nectaries and nectars have arisen in recent years. In the last two decades, there were only a few ‘moments’ in which nectar was the main character in international meetings or in published books. In 2002, the first (and only) international meeting “Nectar and nectary: from biology to biotechnology” dedicated exclusively to nectar and nectaries was held in Italy (Montalcino, Siena) and in 2003 the proceedings were published in a special volume of Plant Systematics and Evolution (238, issue 1-4). In 2007, the book Nectar and Nectaries was published (Springer) with most of the contributions provided by authors that attended the meeting in Italy. Another book dedicated to nectar was published in 2015 (Nectar: Production, Chemical Composition and Benefits to Animals and Plants, Nova Science Publishers) covering aspects mainly related to nectar chemical composition and plant-pollinator interactions. Similarly, symposia focused on nectar have been organized within the International Botanical Congress in 2011 and 2017. Considering that the last few years has yielded essential developments in the understanding of nectar biology, we thought now is the moment to further stimulate research on this important topic. This aim has been met through 18 papers published in our Research Topic New Perspectives on the Biology of Nectaries and Nectars, with subjects spanning evolution and ecology to nectar chemistry and nectary structure.

Feeding on Non-Prey Resources by Natural Enemies Moshe Coll Reports on the consumption of non-prey food sources, particularly plant materials, by predators and parasitoids are common throughout the literature (reviewed recently by Naranjo and Gibson 1996, Coll 1998a, Coll and Guershon, 2002). Predators belonging to a variety of orders and families are known to feed on pollen and nectar, and adult parasitoids acquire nutrients from honeydew and floral and extrafloral nectar. A recent publication by Wäckers et al. (2005) discusses the p- visioning of plant resources to natural enemies from the perspective of the plant, exploring the evolutionary possibility that plants enhance their defenses by recru- ing enemies to food sources. The present volume, in contrast, presents primarily the enemies’ perspective, and as such is the first comprehensive review of the nut- tional importance of non-prey foods for insect predators and parasitoids. Although the ecological significance of feeding on non-prey foods has long been underappreciated, attempts have been made to manipulate nectar and pollen ava- ability in crop fields in order to enhance levels of biological pest control by natural enemies (van Emden, 1965; Hagen, 1986; Coll, 1998a). The importance of n- prey foods for the management of pest populations is also discussed in the book.

Tremendous progress has been made during the past decade in the burgeoning field of plant reproductive biology. A number of quantitative and technical breakthroughs, such as horizontal starch-gel electrophoresis, have resulted in a revolution in our thinking. The study of breeding systems, which used to be marked by a rather static focus on pollination and self-incompatibility, has been transformed by dynamic models of transitional pathways, and investigators are looking not only into genetic factors but ecological ones as well. Workers in the field have recently produced detailed accounts of mating success and the relative fitness of plants as male and female parents, thus testing the applicability of sexual selection theory to plants. Ecology and Evolution of Plant Reproduction surveys recent advances in the field of plant reproductive biology and identifies fruitful avenues for future research. The contributors are well known in the fields of morphology, systematics, genetics, cell biology, and ecology, representing the full spectrum of approaches that contribute vigor to this emerging field. This new work will benefit professionals and graduate students in plant science and plant breeding, evolutionary ecology, genetics, and reproductive biology.

These volumes are an exhaustive source of information on the control and regulation of flowering. They present data on the factors controlling flower induction and how they may be affected by climate and chemical treatments. For each plant, specific information is provided on all aspects of flower development, including sex expression, requirements for flowering initiation and development, photoperiod, light density, vernalization, and other temperature effects and interactions. Individual species are described from the standpoint of juvenility and maturation, morphology, induction and morphogenesis to anthesis. All information is presented alphabetically for easy reference

This book, first published in 2005, addresses food-mediated interactions, focusing on how plants employ foods to recruit arthropod 'bodyguards' as a protection against herbivores.