Inclusive fitness

Many questions in inclusive fitness theory turn on whether and how animals distinguish genetic relatives from non-kin. Vertebrates, from fish to humans, use odors, in addition to cues in other sensory modalities, to recognize kin (Table 6.1). This recognition, in turn, may enable relatives to cooperate. 

Allomones are interspecific semiochemicals that primarily benefit the sender. Animals as well as plants defend themselves chemically against predators. Myriads of ways to deter predation have evolved. Many chemicals have more than one function, being aimed not only at predators but also at parasites, prey, or conspecific competitors. As common denominator of allomones we assume that the inclusive fitness of the sender - rather than the receiver - is enhanced. Chapter 10 deals with defenses by animals, and Chapter 11 with plant defenses against herbivores. 

Insects are the most diverse group animals on earth, with approximately five million species described to date (Novotny et al. 2002). Amidst this great diversity are adaptations common to all insects that maximize inclusive fitness in their respective habitats. One such fundamental adaptation is the ability to respond to cues in the environment, in particular the ability to detect external biological compounds via a chemical sensor. The sophisticated olfactory system of insects is able to sense volatile odorants derived from prey, host plants, and conspecific individuals. These compounds are detected by olfactory receptor neurons (ORNs) housed in the antennae, and these ORNs relay information about food sources, oviposition sites, and mates that leads to behavior based on neural responses mediated by the ORNs. The binding... 

The factors which permit altruistic behaviors to be differentially directed to kin and non-kin have aroused much interest. Hamilton s (1964) development of the concept of inclusive fitness allowed a rationale for the evolution of altruistic behavior. However, in order to evolve, such behaviors must be directed at kin, and thus kin and nonkin must be discriminated. Various means by which such discriminations take place have been elaborated by Alexander (1979), Blaustein (1983), Holmes and Sherman (1983) and others. One prominent issue is the extent to which phenotype matching (involving learning) and/or recognition alleles are involved in kin recognition. Here we consider this and other issues in the context of a specific set of studies that have explored a genetic basis for possible discriminations among individual... 

One way this problem could be avoided would be to have enzymes preferentially copy one another. Apparently altruistic traits, such as the replicase trait, can evolve when interactions among individuals are non-random. For example, an individual may display altruistic behavior preferentially toward a relative. The selection of these traits is based on including the fitness of genetically similar relatives with the fitness of the individual (inclusive fitness). According to W.D. Hamilton s rule [57], an altruistic trait is evolutionarUy favoured if the cost (c) of the behavior is less than the benefit b) to the relative, weighted by the coefficient of relatedness (r), summed over all the affected relatives ( ), or... 

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