ABSTRACT
Chemical compounds play a key role in the communication systems of many living organisms. Information-carrying molecules, known as semiochemicals, have been classied into several groups, depending on the identities of the sender and recipient organisms and on who benets from the transmitted information (reviewed, e.g., in Howse et al. 1998; Wyatt 2003). In short, chemical signals that act within species, to induce either a specic behavior (releaser pheromones) or a developmental process (primer pheromones), are known collectively as pheromones, whereas semiochemicals that act between species are known as allelochemicals. There are three main types of allelochemicals, which can either (1) benet the receiver at the cost of the sender (kairomones), (2) benet the sender at the cost of the receiver (allomones), or (3) benet both sender and receiver alike (synomones). In addition to pheromones and allelochemicals, other chemical cues, which are not primarily emitted for the purpose of communication, can also act as a source of information for many animals, that way inuencing their behavior. Social insects are one of the best examples of a group of organisms whose daily lives depend heavily on chemical communication. Wilson (1990) estimated that for the vast majority, or if not all species of social insects, at least 90% of
Introduction .................................................................................................................................... 223 Food Odors .....................................................................................................................................224 Food Source Marking Volatiles ......................................................................................................226
