Summary: Wittkopp et al. (2009)

Intra- and interspecific phenotypic variation may be influenced by genetic mechanisms, but the allelic relationship underlying intraspecific polymorphism and interspecific divergence is unknown. Wittkopp et al. (2009) examined the genetic basis of variation in pigmentation within and between two closely related Drosophila species (D. americana and D. novamexicana) to investigate the relationship between intraspecific polymorphism and interspecific divergence. They found that changes linked to both the tan and ebony genes in closely related Drosophila species contributes to divergence in pigmentation. Furthermore, they found that the alleles linked to these two genes in one species contributed to the variation in the other species, suggesting the similar phenotypes in a population may have different underlying genotypes. The genetic variation present in the common ancestor of these two species likely gave rise to both intraspecific polymorphism and interspecific divergence, as the alleles appear to predate speciation.

Summary: Griggio et al. (2010)

Preening behaviour is important for plumage maintenance in birds but has received relatively little attention with respect to the role it plays in influencing plumage colouration. Furthermore, elaborate or colourful plumage is important in female mate choice assessment in birds, but few studies have investigated the costs associated with maintaining this trait in good condition (through preening behaviour). Griggio et al. (2010) investigated whether preening behaviour of captive-bred, wild-type budgerigars, Melopsittacus undulatus, changes plumage reflectance and whether females exercise a choice (in two-choice tests) for males that have higher plumage reflectance (i.e. whether female prefer males that were allowed to preen over those prevented from preening or those who could preen, but had plumage what was UV-blocked by UV-absorbing chemicals). Griggio et al. (2010) found that the plumage of unpreened birds showed lower UV reflectance and females showed a preference for preened males. However, when females were given a choice between unpreened and UV-blocked males, they did not show a preference. Their results show that preening mediates plumage colouration (in the UV range) and can convey honest information about a bird's present condition. Furthermore, females are able to exercise a choice based on the level of UV reflectance.

Summary: Yoon et al. (2008)

Humans have a remarkable ability to learn socially, and teaching is a specialised form of cooperative information transmission. It is dependent on the presence of benevolent communication and on the readiness of students to learn. Yoon et al. (2008) hypothesized that human infants should be biased to perceive and member referents of communication, if they are sensitive to those signals typically indicating communication. They tested this hypothesis using 9-month-old human infants, asking whether the infants could discriminate between communicative and noncommunicative social contexts and whether they retain qualitatively different information about novel objects in these contexts. Yoon et al.'s (2008) results show that 9-month-old infants remember the identity of novel objects, but not the location, in a communicative context, while they remember the location of novel objects, but not the identity, in a noncommunicative context. Yoon et al. (2008) propose that infants are sensitive to, and interpret social cues that indicate specific intentions and these represent important mechanisms of social learning, by which others can help determine what information observers retain in memory.

Summary: Martín et al. 2009

Predation risk can vary over a broad range of temporal patterns. As a result, prey may have difficulty assessing risk level and making decisions about how to allocate antipredator behaviour (which is costly) across time. Allocation of antipredator behaviour should depend on 1) the potential benefits gained in the short-term, 2) the costs reduced in the long-term and 3) prior experience of predation risk. Martín et al. (2009) tested how Iberian rock lizards, Iberolacerta cyreni, in the laboratory allocate antipredator behaviour over time when exposed to repeated predatory attacks of different intensity and temporal pattern. Through assessment of activity levels, time spent hidden in refugia after an attack and likelihood of hiding when predators are nearby, they found that antipredator responses increased when risk was high, but this depended on the temporal pattern of the associated risk. Prey activity did not change when predation risk was low or random. Martín et al. (2009) suggest that lizards can predict risk level, and modify their behaviour accordingly, when successive attacks have similar risk levels. However, when risk level is random, lizards adopt a conservative strategy and overestimate risk.