Summary: Ulyan et al. (2006)

Ulyan et al. (2006) evaluated the responses of group living capuchins (Cebus apella) to different feeding schedules. They fed animals a predictable schedule for 6 weeks, then an unpredictable schedule for another 6 weeks. They sampled behaviour using scan sampling (1 minute intervals) for 1 hour pre- and post-feed. Ulyan et al. (2006) hypothesized that behaviour and faecal cortisol concentration would be influenced by meal unpredictability. They did not find any major differences in behaviours typically associated with stress or anticipation, but suggest that differences in other behavioural measures indicates that predictable feeding regimes is better for the animals' well being. Their results suggest that the anticipation of feeding is pronounced when feeding time is delayed in an unpredictable manner and cortisol concentration increases during this time. Ulyan et al. (2006) propose that a predictable feeding schedule is more beneficial for the well being of captive capuchins.

Summary: Chapuis & Bshary (2010)

Signals alter the behaviour of receivers, thereby increasing the sender's fitness. When individuals interact cooperatively, signal strength may be linked to supply and demand (biological market theory). Hunger level in cleaner shrimps (Periclimenes longicarpus) is linked to advertisement of their services to client reef fish. To test more detailed predictions of biological market theory, Chapuis & Bshary (2010) investigated signalling by wild cleaner shrimps. Shrimps increased claw clapping when they were food deprived and were more likely to clean than non-clapping shrimp. Chapuis & Bshary (2010) however did not find evidence that signalling was target-specific to visiting client species, and shrimps signalled more frequently to predatory species. They conclude that signal conveys information about identity in order to avoid predation, rather than to attract choosy clients.

Summary: Stetina et al. (2011)

Recognition of emotions is required for interpersonal interactions and emotional competencies. Stetina et al. (2011) explored the possibility of enhancing emotion recognition of children (5-7 years) and adults (19-45 years) by using animal-assisted intervention, focusing on the emotional expression of dogs. Their results showed that the highest changes in both the adult and children groups related to the correct identification of fear and anger. Adults also showed an increase in the overall number of correctly identified facial expressions, as well as a decrease in the latency to respond. Children also increased their capacity for the recognition of disgust and neutral facial expressions, identified 5 more emotions correctly after training and decreased their response latency. Stetina et al. (2011) suggest that a generalization process from human-dog interaction to human-human interaction seems to occur. They indicate that the implied learning effects of animal-assisted interventions are a promising and essential aspect of psychological and psychosocial treatment.

Summary: Townsend & Moger (1987)

Male Puerto Rican frogs Eleutherodactylus coqui are paternal throughout embryonic development of the eggs. Males stop calling (which is necessary for attracting mates) and reduce egg cannibalism during this period. Townsend & Moger (1987) analyzed the relationship between parental behaviour and androgens by analysing blood plasma from males captured in the field. They found that paternal males had lower androgen levels than males that were nonpaternal, calling or amplectant. They noted that the decline in circulating androgens between the sexually active state and the paternal care state was rapid, but also that androgen levels did not differ between males that were at differing stages of the paternal care period. Townsend & Moger's (1987) results suggest a relationship between circulating androgen levels, mating behaviour and the development of paternal care.

Summary: Wainwright et al. (1999)

Linoleic acid and alpha-linoleic acid can not be synthesized by animals and must be obtained through their diet. These fatty acids are important for essential for growth and development. Wainwright et al. (1999) compared behavioural development of young born to female B6D2F1 mice that had been fed a diet with an imbalance of dietary essential fatty acids to pups that had been undernourished (through rearing in large litters). Some pregnant and lactating females were fed a diet with a very low (n-6):(n-3) ratio, in which the fatty acids were provided solely as linoleic acid and very high levels of docosahexaenoic acid. Wainwright et al. (1999) randomly established four groups of females : 2 groups were fed lab chow but varied in litter size (large vs. normal), and 2 groups were of normal litter size but varied in dietary ratio (low=0.32 vs. normal = 4.0). At 32 days post conception, offspring from both lab chow-fed large litters and low ratio normal litters had lower body weights and were behaviourally retarded. Wainwright et al.'s (1999) results show that growth retardation (offspring of dams fed a diet with low essential fatty acid ratio and very high levels of DHA) is accompanied by behavioural retardation similar to that seen in malnourished pups.

Summary: Moosman et al. (2009)

Animal signals evolve in a variety of contexts. Some male fireflies (Coleoptera: Lampyridae) produce bioluminescent courtship signals during mate searching, and these males are often chemically defended. These courtship signals may have consequences (positive/negative) that are unrelated to mating. Moosman et al. (2009) examined whether Photinus flash signals are aposematic signals for insectivorous bats. They observed four species of North American bats in the field, then conducted behavioural and diet experiments in the laboratory to assess taste responses to the fireflies. Interestingly, fireflies were not found in bat faeces, even though they co-occurred in the field. Bats found the taste of meal worms coated with homogenized fireflies aversive, but responded differentially to moving lures based on a combination of lure size and flash cues. Moosman et al. (2009) suggest that flash signals of Photinus fireflies probably act as aposematic warnings to the common bat Eptesicus fuscus. This indicates that bioluminescent courtship signalling in fireflies may operate under competing selective pressures.

Summary: Paulisson (2008)

After long periods of training, lizards and snakes show spatial learning (an animal's ability to learn the location of resources for access in the future). It has been suggested that the natural environment is more conducive to spatial learning in squamates than the laboratory, as the animals become familiar with vital resources and landmarks within their home ranges. Paulisson (2008) hypothesised that spatial learning in little brown skinks (Scincella lateralis) can be improved with prior experience of a habitat. He subjected individual lizards to simulated predatory attacks and tested their ability a) to choose between 1 of 2 cardboard retreats (Experiment 1); 2) to choose a designated "correct" retreat without prior experience (Experiment 2); and 3) to choose the "correct" retreat after 48 hours of prior experience in the habitat (Experience 3). Paulisson (2008) found that little brown skinks learn to take refuge (Experiment 1), and experience leads them to choose the "correct" retreat in a short period of time (Experiment 3). He discusses the role of experience and the use of ecologically relevant landmarks in laboratory-based learning experiments.

Summary: Gerber et al. (2011)

Oceans are challenging areas for conservation, as large marine mammals move large distances, but are typically only protected in small areas. In 2006, the Papahānaumokuākea Marine National Monument (PMNM), one of the largest conservation areas in the world, was established with the primary aim of conserving marine wildlife. However, despite this goal, one of the endemic species of this area, the Hawaiian monk seal (Monachus schauinslandi) is declining as a result of high juvenile mortality. In contrast, populations outside of the protected area are increasing. The ecological drivers of the decline are currently unknown. Gerber et al. (2011) evaluated an intervention proposal by the Pacific Island Fisheries Science Centre. The benefits proposed included maintainance of subpopualtions in the Northwestern Hawaiian Islands through preservation of metapopulation structure. Gerber et al. (2011) indicate that this would provide more time for studies on the factors driving the population decline. They suggest that the inability of the PMNM to conserve monk seals reflects the differing ideals of conservation agendas, the necessity for understanding ecosystem and large-scale ecosystem interactions, and the necessity of adaptive management.

Summary: Kunc et al. (2006)

It is thought that overlapping of song in birds is a signal of immediate aggression. However, some evidence suggests that song overlapping may provide information to females about a male's quality, allowing them to make extrapair mating decisions based on male vocal performance (eavesdropping). Kunc et al. (2006) investigated how male behaviour (overlapping versus non-overlapping) influenced subsequent pairing status and how males respond to playbacks of vocalizations, using specific structural song components. They predicted that more successful males would overlap songs more if song is a signal of male quality. They found that males that mated during the breeding season overlapped their songs more to the playback than males that remained unpaired, suggesting that overlapping is a signal of male status. They also found that males adjusted the use of specific song components and decreased song rate, suggesting that flexibility of structural song components is more important than increasing song output. Since song overlapping may be a signal of aggression, Kunc et al. (2006) suggested that more aggressive males may have greater pairing success.

Summary: Sober & Brainard (2009)

Humans use vocal imitation from auditory feedback when learning to talk. Similarly, during the process of imprinting, young birds learn to imitate the songs of adults (tutors) through a reliance on auditory feedback. Initially discordant vocalizations are crystallized into mature song similar to their demonstrator's. During adulthood, humans continue to rely on auditory feedback to correct vocal errors. However, it is unclear whether parallel processes drive the stability of adult vocal behaviour. Sober & Brainard (2009) tested the hypothesis that adult Bengalese finches maintain vocal output by disturbing the pitch (fundamental frequency) of auditory feedback (using custom-designed headphones) and monitoring any resulting vocalization modifications. They predicted that shifts in auditory feedback pitch would cause birds to change their own song pitch in the direction opposite to the imposed feedback. They found that birds use auditory feedback and maintain their song vocalizations through a continual process of error correction. The birds adjusted their song pitch, thereby compensating for the auditory error imposed. Sober & Brainard's (2009) result show that error correction, even in adulthood, is a general principle of learned vocal behaviour.

Summary: Cardoso & Atwell 2011

Some oscines (songbirds) shift to singing at higher frequencies in urban areas (high noise-polluted areas), which has been interpreted as an adjustment to reduce acoustic masking by low-frequency man-made noise. Furthermore, they may also sing louder (i.e. higher amplitude) when exposed to noise and frequency shifting is thought to be less efficient than merely singing louder. Increasing vocalization amplitude in response to background noise is known as the Lombard effect. It has been suggested that high frequency singing might be a physiological consequence of louder singing, rather than just a a functional adjustment to noise. Cardoso & Atwell 2011 tested whether louder oscine songs are sung at higher frequency (central tenet of the hypothesis) using the dark-eyed junco, Junco hyemalis thurberi. The frequency bandwidth of songs and syllables increased with amplitude, involving lower minimum frequency in louder songs and syllables. Therefore, louder singing does not explain the higher minimum frequency of urban dark-eyed juncos. Amplitude and peak frequency were weakly positively related across but not within songs, suggesting that increased frequency is not an obligatory outcome of singing louder. Instead, birds may adjust both amplitude and frequency in response to changing noise or motivation across songs. Their results suggest that adjustments in song frequency and amplitude are largely independent and thus can be complementary rather than alternative vocal adjustments to noise. They discuss oscine vocal physiology and details of the behaviour of urban birds, both of which we argue are consistent with the increased frequency of urban birdsong generally being a functional adjustment to noise, rather than a consequence of singing louder.

Summary: Choi & Bowles (2007)

As in paper:
"Altruism—benefiting fellow group members at a cost to oneself—and parochialism—hostility toward individuals not of one’s own ethnic, racial, or other group—are common human behaviors. The intersection of the two—which we term “parochial altruism”—is puzzling from an evolutionary perspective because altruistic or parochial behavior reduces one’s payoffs by comparison to what one would gain by eschewing these behaviors. But parochial altruism could have evolved if parochialism promoted intergroup hostilities and the combination of altruism and parochialism contributed to success in these conflicts. Our game-theoretic analysis and agent-based simulations show that under conditions likely to have been experienced by late Pleistocene and early Holocene humans, neither parochialism nor altruism would have been viable singly, but by promoting group conflict, they could have evolved jointly."

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.

Summary: Brandt & Macdonald (2011)

It is presently thought that "familiarity" can be used as a proxy of quality, as familiarity of potential mating partners can influence mate choice. Social rodent species tend to favour mating with unfamiliar males, while solitary species show a preference for familiar males. Brandt & Macdonald (2011) investigated the role of familiarity in female mate choice in the harvest mouse Micromys minutus, using a two-stage controlled choice experiment. When females were presented only with olfactory cues, they showed no preference for familiar or unfamiliar males. However, when females were presented with live males, oestrus females they showed a clear preference for familiar males, while dioestrus females favoured unfamiliar males. Brandt & Macdonald (2011) also found that male weight affected female response, with oestrus females favouring familiar males that were heavier. In contrast, dioestrus females reduced their preference for unfamiliar males if they were heavier than familiar males. This study provides support for the hypothesis that female harvest mice favour familiar males as mates. Brandt & Macdonald (2011) also note that male size and female reproductive state can influence female preferences.

Summary: Carnaval et al. (2009)

Regions with high species endemism and considered to be threatened (conservation priority) are categorised as biodiversity hotspots. In the face of rapid environmental change, effective conservation may be difficult because biodiversity distribution data are too sparse. Carnaval et al. (2009) suggest that late quaternary climate fluctuations helped to shape present-day diversity in temperate and boreal systems and provide a general context for understanding current patterns of endemism. They compared alternative hypotheses of assemblage-scale responses to late Quaternary climate change using frogs as indicator species, ecological niche models under palaeoclimates and simultaneous Bayesian analyses of multispecies molecular data. They suggest that a hotspot for conservation priority lies within the Brazilian Atlantic forest hotspot. Furthermore, they show that the southern Atlantic forest was climatically unstable relative to the central region, and it served as a large climatic refugium for neotropical species in the late Pleistocene. Carnaval et al. (2009) suggest that this sets new priorities for conservation in Brazil and establishes a validated approach to biodiversity prediction for other understudied, species-rich regions.

Summary: Schino & Marini (2011)

Group-living animals experience numerous conflicts of interests during social life and can minimize the costs of overt aggression through reconciliation. Patterns of reconciliation and their differential use vary and have rarely bee studied. Schino & Marini (2011) studied the postconflict behaviour of captive mandrills Mandrillus sphinx and found that animals use contact and noncontact postconflict affiliation differently depending on their former opponent. Manrills used contact affiliation to reconcile with relatives and the original aggressor (if it was of a lower rank), but were more likely to use noncontact affiliation when reconciling with "repeat-aggressor" opponents. The use of both types of affiliation reduced the likelihood of renewed aggression. Schino & Marini (2011) suggest that accessibility to individuals and danger (likelihood of receiving aggression) modulated the use of conciliatory patterns. They suggest that more studies of flexible conciliatory strategies are needed.

Summary: Akre et al. (2009)

Social behaviour of group-housed foxes at different ages can be influenced by social preference for conspecifics. It is important to understand how social preference changes in order to prevent exposure to possible social stressors. Akre et al. (2009) investigated how familiarity influences social preference and motivation to seek social contact in female silver foxes (Vulpes vulpes) at 9 and 24 weeks of age. Foxes were tested at both ages, and were given a choice between an empty cage, a cage with a familiar female and a cage with an unfamiliar female (same age). They predicted that young cubs would favour familiar social contact for reassurance in a novel situation, while motivation to disperse would weaken this preferencee in older females. They found that, at 9 weeks of age, cubs favoured contact with a conspecific, regardless of familiarity. This preference disappeared at 24 weeks of age, with females increasing aggression towards the unfamiliar animal. Akre et al. (2009) suggest that the motivation for cubs seeking contact with conspecifics is possibly play-related, while motivation for juveniles to increase aggression could be associated with competition.

Summary: Guttridge et al. (2009)

Sharks are often seen to associate in groups, but the structure (composition and organization) of these groups is unknown. Guttridge et al. (2009) aimed to quantify the social preferences of juvenile lemon sharks Negaprion brevirostris that live in close association with heterospecific nurse sharks Ginglymostoma cirratum. Juvenile lemon sharks associated with conspecifics in binary choice field experiments. Guttridge et al. (2009) found that 2-3 year old lemon sharks preferred groups of size-matched individuals and associated with conspecifics more than with heterospecifics. Their study provides further information on group-joining decisions and suggest that active mechanisms play a role in shark group formation and structure. Furthermore, shark associations provide opportunities for investigating social learning and cooperation in these fish.

Summary: Kim et al. (2011)

Gene-environment interactions influence the evolution of begging displays in bird chicks. The strength (intensity) of within-brood sibling competition, one mechanism thought to influence evolution of begging display, can cause begging behaviour to vary in response to environmental conditions experienced by offspring. Kim et al. (2011) broke down the the begging display of yellow-legged gull (Larus michahelis)chicks into 2 different functional components: 1) pecks (associated with pee calls) = begging for food; and 2) chatter calls = attention-seeking behaviour. They found, using a begging test, that males and chicks in poor-body condition begged at higher rates, while chicks from male-biased broods begged less frequently. Furthermore, chicks from larger broods begged more frequently. Their results suggest that chicks adjust their individual begging efforts to the strength of of sibling competition, if begging is costly. They also found that genetic origin had a significant effect on the frequency of chatter calls, but not on begging. Frequency of chatter calls also varied with sex, chick order within a brood and body condition. Kim et al. (2011) suggest that chatter calls can be subject to evolution under directional selection and that different begging components may have evolved through different evolutionary pathways.

Summary: Dormann et al. (2010)

It has been suggested that closely related species share similar climate niches. To test this hypothesis, Dormann et al. (2010) used distribution data for 140 European mammal species, together with climate, land cover and topographical data (to fit species distribution models) in order to derive an estimate of the mammals realised climate niches and to investigate their degree of overlap. They compared climate niche overlap of species pairs and found that closely related species differed in their climate niches, but display high climate niche distances. Dormann et al. (2010) interpret this finding as a strong interspecific competitive constraint on the fundamental niche. Their results imply a flexibility of realised climate niches that are independent of phylogenetic distance. Furthermore, the suggest that climate niche models may not be particularly useful for the prediction of future mammal distributions.

Summary: Hilário & Ferrari (2010)

Infanticide is a common phenomenon, usually caused by polygynous males taking over a harem with unrelated infants. Hilário & Ferrari (2010) describe rwo incidences of infanticide in a free-ranging group of
buffy-head marmosets (Callithrix flaviceps) in 2008, the first observed incidence in this species. Over a 10-day period, 4 females within the group gave birth, with the infanticides occurring on the third and sixth days. The perpetrator in the first incident was unknown, but the socially dominant breeding female is likely to have caused both as she was observed ingesting the second infant's head. The behaviour appears typical of marmosets in general. The strategy of the socially dominant breeding female attacking offspring of subordinates is likely aimed at reducing competition for caregivers.

Summary: Bartsch et al. (2010)

The hippocampus is an important structure for the processing of place learning tasks and topographical memory. Cells in the cormu ammonis 1 (CA1) sector of the hippocampus in rodents and primates have been shown to play an important part in place learning, specifically with regards to navigation and consolidation of spatial memory. However, it is unknown what role these cells play in the human hippocampus. Transient global amnesia (TGA) is a rare, self-limiting dysfunction of the hippocampus. Using a virtual Morris water maze, Bartsch et al. (2010) investigated 14 patients with TGA (selective and focal lesions in the CA1 sector of the hippocampus) to determine the role of CA1 cells in place learning. All individuals showed a profound impairment in place learning, with lesion size and TGA duration correlated with decreased performance. Bartsch et al. (2010) results indicate that, like rodents and primates, cells in this area of the hippocampus (CA1) play an important in place learning in humans.

Summary: Hourigan & Reese (1987)

The Hawaiian archipelago is an extremely isolated island group. Hourigan & Reese (1987) noted that the Hawaiian fish fauna is derived from, and has close affinities with, the Indo-west Pacific fauna. However, while it has many endemic species (30% of inshore fishes), there is low species diversity (depauperate). There is local adaptation, but no species radiation. These trends may have been caused by: (1) geographic isolation and current patterns; (2) life history characteristics, particularly dispersal ability, of the fishes; and (3) the extent of adaptive differentiation. Hourigan & Reese (1987) suggested that the isolation of Hawaii is due to its location with respect to unfavourable pacific current patterns, which in turn, determines the marine faunal source.

Summary: Skelhorn (2011)

Noxious prey may use conspicuous colour patterns to advertise their defences (chemical or physical) to predators (aposematic colouring) and predators may show unlearned biases against these warning colours. Predators may use additional signals (.e.g sounds and odours) to determine attack rate and may decreases attack rates when the risk of ingestion toxic prey is perceived to be high. If a cue reliably signals prey defense, this should incite biases by predators against warningly coloured food. Skelhorn (2011) tested whether observation of a conspecific's distaste response to a bitter-tasting solution (e.g. beak wiping, head shaking) caused chicks (Gallus gallus) to bias their foraging decisions away from warningly colour prey. Chicks that observed a distaste reaction attacked fewer red and yellow crumbs, and more green crumbs. Observing a disgust response caused observers to bias their foraging preferences away from warningly coloured food. Skelhorn (2011) suggests that a predator's social system may be important in the evolution of prey defences.

Summary: Li & Zhang (2010)

In 1964, Hamilton suggested that kin recognition might be important for mediating the evolution of altruistic behaviour. Li & Zhang (2010) investigated amicable and agonistic social behaviours in Brandt's voles (Lasiopodomys brandti) to determine the mechanism of parent-offspring recognition (prior association / familiarity vs. phenotypic matching). Familiarity involves identification of kin by prior association with them, while phenotypic matching involves identification of kin based on shared family characteristics. Li & Zhang (2010) first examined whether parents could distinguish own from alien offspring, and found that both males and females showed more agonistic behaviour to alien young, indicating discrimination of young. They then used a cross fostering paradigm to investigate the underlying recognition mechanism. They found that parents are more amicable to familiar offspring and more agonistic to unfamiliar offspring (both accounts regardless of relation). Their results suggest that the most likely recognition mechanism in Brandt's voles is familiarity.

Summary: Edvardsson & Arnqvist (2000)

To stimulate females, males may engage in courtship behaviours during and after copulation. When females impose biases on postmating paternity success, thereby varying male reproductive success, these behaviours may evolve by cryptic female choice. Edvardsson & Arnqvist (2000) maniuplated female perception of male courtship behaviour in the red flour beetle Tribolium castaneum by male tarsal ablation (males could still perform courtship behaviour but could not stimulate females) and quantified male copulatory behaviour to determine whether females cause positive relationships between male copulatory courtship behaviour and relative fertilization success. They found that leg manipulation did not impair male vigour or number of sperm transferred. However, they did find a positive relationship between intensity of courtship and relative fertilization success: manipulated males had lower fertilization success. Female perception of male courtship behaviour, rather than actual male behaviour, governs sperm competition, showing that females impose biases on postmating paternity success and that copulatory courtship is under sexual selection (typically concerned with precopulatory processes and variance in male mating success) by cryptic female choice.

Summary: Bos et al. (2009)

Mate selection is important in many organisms and occurs through multiple trait assessment in a context or condition-dependent manner. Theoretically, mate choice may be based on an individual's genotype, but this requires organisms to self-reference their own genotype. MHC genes may be used in self-referencing as they can be assessed through ligand binding in the vomeronasal organ. Due to overdominance, major histocmpatibility complex (MHC) alleles are likely to be adaptive and there is likely to be negative assoratative mating between individuals. Bos et al. (2009) assessed MHC-based mating preferences in wild, outbred eastern tiger salamanders (Ambystoma tigrinum tigrinum) by genotyping adults and larvae at microsatellite and MHC loci. They aimed to address 4 questions about MHC-based mate choice: 1) Do morphological characteristics increase reproductive success? 2) Is reproductive success in males mediated by the MHC? 3) If yes, are the mating patterns context-dependent? 4) If yes (2 and 3), is variation in male reproductive success linked to MHC-based cues only when large differences are apparent? Bos et al. (2009) found that male reproductive success was positively correlated with increased tail length.They found that MHC-similar males (to females) sired more offspring, indicating that negative assortative mating is not occurring in the population and that MHC-diverent males may be at a reproductive disadvantage. Bos et al. (2009) suggest that MHC-based choice is likely to be influenced by many factors.

Summary: Honda-Sumi (2005)

Cricket songs are species-specific signals important for species recognition, mate choice and male advertisement. Honda-Sumi (2005) compared the calling songs of 3 Japanese crickets to validate the function of acoustic signals (i.e. calling song) as a premating isolation mechanism between sympatric species using playback experiments. Teleogryllus emma is widely distributed and is sympatric with both T. yezoemma (North) and T. taiwanemma (South), while T. yezoemma and T. taiwanemma are allopatric. Hondu-Sumi (2005) compared three temporal parameters, 1 frequency parameter and two structural parameters to test for species divergence in signals and also tested whether female T. taiwanemma distinguish conspecific males. Sympatric species had divergent songs, while allopatric species had similar songs. T. taiwanemma females could discriminate conspecifics (i.e. showed positive phonotaxis). This suggests that, where hybridization is costly, calling song is an important premating isolation barrier in sympatric Teleogryllus species.

Summary: Ahearn et al. 1974

Ahearn et al. (1974) identified two kinds of reproductive isolating mechanisms: 1) premating isolation barriers (in the form of behavioural/ethological isolation); and 2) postmating isolation barriers (male hybrid sterility). They suggest that reproductive isolation arises as a by-product of genetic divergence or is induced by natural selection as a gene exchange barrier. Thus, premating isolation should occur more often between sympatric species. Drosophila heteroneura and D. silvestris are sympatric fly species on the island of Hawaii, while D. planitibia is allopatric on nearby Maui. Ahearn et al. (1974) found pronounced behavioural isolation between the sympatric, but not the allopatric, species. They did note that D. planitibia females do discriminate against D. heteroneura males. Male bybrid sterility is seen in allopatric crosses and is not correlated with behavioural isolation. They suggest that this is expected if premating isolation between closely related species is an ad hoc production of natural selection, while postmating isolation is an incidental result of genetic divergence.

Summary: Olsson et al. (2005)

Animals can learn to associate negative events with environmental stimuli (classical fear conditioning). Race bias and fear condition potentially rely on overlapping neural systems. Therefore, Olsson et al. (2005) aimed to further understanding of basic learning theory and social group interaction by investigating how the mechanisms of fear conditioning apply when humans learn by classical fear conditioning in a sociocultural context. They also assessed whether a bias in fear conditioning extends to social groups defined by race. Prepared fear learning is generally demonstrated as persistence to fear-relevant conditioned stimuli in the learned fear response. They conducted two experiments to test whether fear responses acquired to outgroup and ingroup faces persists during extinction (relative to each other). Their results show that individuals from a racial outgroup are more readily associated with an aversive stimulus. However, Olsson et al. (2005) indicate that this response might be reduced by close, positive interracial contact. They postulate that humans might have evolved a more general preparedness to fear others who are dissimilar to themselves or their social group because such individuals were, historically, more likely to pose a threat.

Summary: Hughes et al. (2010)

It is thought that the human Y chromosome evolved a sex-determining function millions of years ago by gene loss. Given this, theories of decelerating decay predicts that chimpanzee and human male-specific regions on the Y-chromosome (MSY) should not show much divergence. Hughes et al. (2010) accurately and completely sequenced the MSY in the chimpanzee, using large-insert bacterial artificial chromosome clones and iterative mapping and sequencing strategies, in order to compare it to the human MSY. They found differences in sequence structure and gene content, suggesting rapid evolution within the last 6 million years, contrary to the prediction that much divergence should be unlikely. They found that both human and chimp MSY euchromatin is largely comprised of ampliconic and X-degenerate sequence classes but noticed that, while humans have less massive palindromes than chimps, chimps have lost large portions of MSY protein-coding genes and gene families. Hughes et al. (2010) suggest that this divergence in chimp and human MSYs could be driven by four synergistic factors: (1) MSY's role in sperm production; (2) "genetic hitchhiking"; (3) frequent ectopic recombination; and (4) mating behaviour differences. They favour (3): that ectopic recombination between MSY amplicons has sped up MSY structural remodelling in both species. This study is the first to fully compared the Y chromosomes from two closely related species. The importance is two-fold: (1) it provides empirical insight into the evolution of the Y-chromosome; and (2) it provides a test of decelerating decay theories.

Summary: Koboroff et al. (2008)

The two hemispheres of the brain are able to conduct different functions, an ability known as brain lateralization. In birds, brain lateralization has been inferred when a preference to observe a stimulus with one eye ("lateral monocular visual field" is observed. Koboroff et al. (2008) considered that Australian magpies (Gymnorhina tibicen) would show eye preferences when performing anti-predator response. Constant assessment is needed during mobbing behaviour, to make decisions regarding approach, mob or withdraw. They speculated that the left hemisphere would control approach, while the right hemisphere would control withdrawal. However, since mobbing is considered a strong agonistic response, this could be controlled by the right hemisphere (controls intense emotion). Monocular fixations prior to or during performance of mobbing activity in response to perceived predation threat were video recorded. Koboroff et al. (2008) found that, prior to withdrawal, magpies favoured the left eye (85%), while prior to approach, magpies favoured the right eye (72%). Hence, approach in magpies is controlled by the left hemisphere, while withdrawal is favoured by the right hemisphere. They speculate that the left hemisphere is used to process visual inputs prior to approach and the right hemisphere prior to withdrawal. Their results are consistent with hemispheric specialisation in other species, including humans. The relationship between predator-prey interactions and the right hemisphere suggest that the right hemisphere may have, over evolutionary time, organised various anti-predator strategies.

Summary: Sigmund et al. (2010)

Players incur costs when imposing fines on exploiters in 'public goods games'. Even the threat of punishment can increase average pro-social contribution and promote collaborative efforts, yet emergence and stability of costly punishment are problematic. Sigmund et al. (2010) designed a model to compare peer-punishment with pool-punishment, which facilitates the sanctioning of second-order free-riders (those who do not punish exploiters), to determine the most beneficial reward system. The systems are expensive ways to encourage free-riders to cooperate. Spread of second-order free-riders can cause cooperation collapse. Without second-order punishment, the peer-punishment is optimal, but in the presence of second-order punishment, pool-punishers do better. Efficiency is traded for stability. Emergence and stability of costly punishing systems, which regulate common group resources and enforce collaborative efforts, do not require group selection or higher authority prescription. While Sigmund et al. (2010)'s model is minimialistic, it is sound in principle.

Summary: Butlin (1995)

The reinforcement hypothesis suggests that natural selection favours an increase in assortative mating (and thus progress towards speciation, if two divergent populations produce low fitness hybrids in the zone of contact. Butlin (1995) briefly reviews a model proposed by Liou & Price (1994) and an empirical study by Noor (1994). Liou & Price's (1994) study considered secondary contact in sympatry of two divergent stickleback populations, with three possible model outcomes (extinction of one population, permanent mixing of the gene pools or reinforcement and speciation). The model suggested  that reinforcement is likely because the diluting effects of gene flow are absent. Butlin (1995) notes, however, that Liou and Price (1995) did not distinguish between the conditions of zero hybrid fitness and reinforcement and argues that the most questionable aspect of this model is the genetic basis of selection against hybrids. Noor's (1994) study addresses the situation where there is a very low level of gene exchange between two species of Drosophila, finding that hybrid males were sterile but hybrid females were fertile. Noor (1994) found evidence for reinforcement, however, Butlin (1995) notes that, while the result is exciting because of testability, the observation is no stronger evidence for reinforcement than other examples. He does agree that this approach could provide more discriminating predictions, but a larger number of localities has to be examined. Finally, Butlin (1995) indicates that reinforcement is potentially important evolutionary process and suggests that further work will identify it's actual importance.

Summary: Kalueff & Tuohimaa (2005)

Grooming is an innate behaviour represented across most animal species. It is a rich source of behavioural and biological information and forms an important part of the rodent behavioural repertoire. Mice show strain differences in their behavioural phenotypes, particularly in grooming behaviour. Various stressors and genetic manipulations alter mouse grooming. Kalueff & Tuohimaa (2005) defined behavioural differences and organisation in spontaneous grooming activity (novelty-induced) between three strains (129S1, NMRI, BALB/c) of laboratory mice. All three strains showed contrasting grooming phenotypes. 129S1 showed lower grooming activity and impaired microstructure, accompanied by lower vertical exploration. BALB/c and NMRI mice showed higher vertical activity and unimpaired grooming microstructure, and BALB/c mice showed higher grooming levels. Kalueff & Tuohimaa's (2005) study suggests that contrasting grooming phenotypes may not be due to strain differences in their sensory abilities, general activity levels, brain anatomy or aggressiveness, but rather reflects a complex interplay between anxiety, motor and displacement activity in these strains. They suggest that an in-depth ethological analysis of mouse grooming may be a useful tool in neurobehavioural research and could contribute to our understanding of behavioural disorders in humans.

Summary: Dingemanse et al. (2007)

Animal populations show individual differences in suites of correlated behaviours ("temperament", "animal personality") across different contexts ("behavioural syndromes"). Population variation in behavioural syndrome may exist for two reasons: 1) natural selection favours covariance in a trait and syndromes will evolve in response ("adaptive hypothesis"); and 2) stochastic processes (e.g. mutation, drift, founder effects, gene flow) maintain variation. Dingemanse et al. (2007) examined the adaptive hypothesis using a comparative approach. They measured 5 different behaviours (categories: aggression, general activity, exploration-avoidance-novel foods, novel or altered environments) across 12 different populations (6 predator-sympatric, 6 predator-naive) of three-spined stickleback (Gasterosteus aculeatus) and assessed whether the differences in behaviour varied consistently depending on the environment. Their results confirm the prediction of the adaptive hypothesis. They found that behavioural syndromes are not always the same in different types of population, implying that population variation in behavioural syndromes is not a result of stochastic evolutionary processes. They suggest that, in sticklebacks, behavioural syndromes are correlated with the presence of predators. Dingemanse et al. (2007) suggest that behavioural syndromes are not fixed according to physiological or genetic constraints and arise from adaptive evolution, where a behaviour is favoured because it is the most optimal trait in that environment.

Summary: Merkle & Wehner (2009)

Foraging desert ants, Cataglyphis fortis, do not rely on chemical cues when searching for their nest, but rather navigate using path integration. In this process, all directions steered and covered for all movements are summed, providing ants with a home vector that leads them back to the nest on a straight path. Ants also use landmark information to adjust their movements as the path integrator is prone to error. Ants engage in systematic search behaviour if they do not encounter the nest entrance at the position suggested by the path integrator. Merkle & Wehner (2009) investigated whether additional cues influence the systematic search patterns of desert ants or whether this is exclusively determined by distance travelled. They captured ants at different points during inbound journeys or when about to enter the nest. Ants were then transferred to an unfamiliar test area and their paths recorded. Merkle & Wehner (2009) found that searches were influenced by distance covered, as well as other factors, but certainty of nest location increased with closeness to the nest. Most inbound ants, regardless of distance, continued the remaining part of their runs and then commenced their nest search, whereas those captured at the nest entrance started searching for the nest immediately. They suggest that the ants' systematic search behaviour does not depend only on the length of the foraging trip, but is more flexible than previously thought.

Summary: Bonato et al. (2009)

Female birds invest more in reproduction than males, due to egg production. Therefore, females should change their investment in any one breeding attempt in relation to the probability of it succeeding. Females of many species favour mating with males that show elaborate ornamentation, possibly because ornamentation is an indicator of male quality. Thus, females should invest more in more ornamented males. Egg size is a good indicator of maternal investment and chicks hatched from larger eggs growth faster and have a higher chance of survival. Bonato et al. (2009) investigated the relationship between male colouration (measured using UV-visible range spectrophotometry) and egg mass in male ostriches (Struthio camelus). They assessed paternity of eggs using microsatellite markers. Female ostriches discriminate between males on the basis of ornamentation and some features of male colouration (neck colour, white and black body feathers and brightness of black feathers) are good predictors of egg mass. Bonato et al. (2009) suggest that these visual cues influence female perception of male quality and females adjust their level of maternal investment as a result. Their study has important implications for the ostrich farming industry, where hatching success is notoriously low.

Summary: Adams & Rohlf (2000)

Ecological character displacement describes the differences in morphology that occur between sympatric species due to interspecific competition, which allows them to coexist. In this study, Adams & Rohlf (2000) describe ecological character displacement between 2 terrestrial salamander species, Plethodon cinereus and P. hoffmani from two geographic transects in the USA. They quantified morphology of individuals from both allopatric and sympatric populations using linear measurements and landmark-based geometric morphometric methods. They also quantified food resource use by assaying stomach contents. Adams and Rohlf (2000) found morphological differences between sympatric, but not allopatric, populations in terms of prey consumption and segregation of prey according to size, although the resource bases for each population were similar. The reduction in prey consumption implied competition for food resources. The major anatomical difference was in relation to the functional and biomechanical properties of jaw closure. P. hoffmani has a faster, but weaker, jaw in contrast to P. cinereus, which has a slower but more powerful jaw. Adams & Rohlf's (2000) findings provide evidence that character displacement could the causal mechanism driving morphological differences between sympatric populations and provides an example of how anatomical differences can be identified among populations using geometric morphometrics.

Summary: Makowska et al. (2009)

Laboratory mice are the most commonly used species in biomedical research and are most commonly euthensased with carbon dioxide, which they may find aversive, as has been shown in rats. In many countries, Animal care policies generally require death to be painless and there should be minimal fear and anxiety. Makowska et al. (2009) assessed male CD-1 mouse aversion to CO2 usuing approach-avoidance testing in response to CO2 and 4 alternatives (argon, CO, halothane and isoflurane). Mouse motivation to avoid gas exposure was measured against motiavtion to assess a highly palatable sweet food reward. During preliminary testing, they recorded time to recumbency and concentration of gas at recumbency. Mice were trained to enter the test chamber through provision of a piece of sweetened shredded coconut as a reward presented in response to gentle tapping of the cage. When exposed to CO2, argon and CO, mice always left the test cage before losing consciousness, showing that mice forego access to a preferred food reward in the presence of the gas. In most cases, when exposed to halothane and isoflurane, mice also left the test cage before losing consciousness, however motivation to avoid isoflurance appeared weaker. Makowska et al. (2009) suggest that dyspnea is the cause of the aversion to CO2. Furthermore, they suggest that all substances tested were aversive to mice, therefore the test for a non-aversive agent should continue. They also suggest that, as isoflurane appears to be the least aversive, it should be used (at least in the interim) as the preferred alternative to CO2 or other gases.

Summary: Wiltgen et al. 2010

The hippocampus is important for the temporary formation and retrieval of episodic and contextual memories. Damage to this area produces amnesia for new memories. Wiltgen et al. (2010) examined the relationship between memory quality and hippocampus dependency, hypothesizing that memory quality may be critical for determining whether the hippocampus is essential for memory retrieval. Using immediate early gene expression (as measured by RT-PCR), they monitored hippocampal activity in mice during memory retrieval and found that detailed memories require the hippocampus, whereas memories that lose precision do not. The dorsal hippocampus is preferentially activated by retrieval of detailed contextual fear memories and is necessary for the retrieval of detailed memories using a context-generalization procedure. Wiltgen et al. (2010) suggest that detailed contextual memories require the hippocampus, providing a new framework for understanding memory consolidation. Their data help to establish the precise role of the hippocampus in memory retrieval.