Exploring the function of greeting display in a long-term monogamous songbird, the Java sparrow

Exploratory behaviour is one of the best-investigated behavioural traits. However, little is known about the influence of personality on novel food preferences in the social context, i.e., whether knowledge and previous experience can influence individual preference or if the presence of conspecifics can alter their choice. In the present study, we examined in cinereous tit (Parus cinereus) whether individuals with different personality types in the social context will prefer their own previously chosen novel food or change their preference in the presence of conspecifics. Second, we studied how the presence and behaviour of conspecifics may mediate individual personality. We conducted a standardized personality assay (exploratory behaviour) to analyse the individual personality. Birds were trained and provided with three different types of novel human-derived materials in both asocial and social contexts (with a conspecific). We recorded the latency to feed, time spent at the feeder, and the number of visits by fast and slow explorers in the two contexts, i.e., asocial and social. After the analyses of experimental data, we found that fast-exploring cinereous tits preferred peanuts in an asocial context, while slow explorers consumed a greater amount of sunflower seeds. In the social context, individuals of both personality types preferred peanuts to sunflower seeds. Additionally, individuals took less latency to eat food, made more visits to the feeder, and spent more time at the feeder in the social context than in the asocial context. Our findings show that foraging success may be determined by personality and social context. However, personality traits may be subject to constraints arising from correlations with other behavioural traits, and it remains a major challenge to understand the functional significance of individual foraging strategies.

Social context is a powerful mediator of behavioral decisions across animal taxa, as the presence of conspecifics comes with both costs and benefits. In risky situations, the safety conferred by the presence of conspecifics can outweigh the costs of competition for resources. How the costs and benefits of grouping influence decisions among alternative antipredator behaviors remains largely unexplored. We took advantage of the Trinidadian guppy (Poecilia reticulata) to examine the influence of social context on alternative behavioral responses to threats. We compared the frequency of active (startle) versus passive (freeze) responses to sudden acoustic stimuli in the presence and absence of conspecifics. We found that fish were relatively less likely to startle and more likely to freeze when in a group than when alone, indicating that immediate social context modulates predator evasion strategy in guppies. We suggest that these social context‐dependent changes reflect trade‐offs between survival and energy expenditure. To our knowledge, an effect of immediate social environment on startle probability has not been previously demonstrated in a teleost.

In seasonally breeding birds, natural selection favors individuals that begin breeding earlier in a year because they produce more or higher quality offspring than those that begin breeding later. Among the factors that influence the timing of breeding, which include the age, health, competitive ability, or mate quality of individuals, is the longevity of the pair bond, with birds that remain mated across years initiating breeding earlier in the season than newly formed pairs. The behavioural interactions between pair members that may facilitate long-term pair bonding and early breeding onset have infrequently been studied, however. Here we report the relationship between male-female affiliative behaviour, pair-bond duration, and breeding date in house finches (Carpodacus mexicanus), a short-lived, socially monogamous passerine species in which the duration of pair bonds is highly variable within and among seasons. Finches that initiated breeding earliest in the season were those that had bred with one another in previous years. Early breeding males from returning pairs maintained significantly closer contact with their mate during the first egg-laying period of the year than did males from late-breeding, newly formed pairs. Similarly, early-breeding females from returning pairs followed their mate more closely in nest-vicinity flights during the fertile period than females from late-breeding, newly formed pairs. These results suggest that attributes of and interactions between both pair members may help to maintain stable breeding pairs and influence the timing of breeding in seasonally nesting, short-lived songbirds. Rather than advertising for or seeking extra-pair fertilization opportunities, high-quality pairs of finches may invest heavily in their mate to secure the pair bond and ensure high intrapair reproductive success.

Ontogenetic change in social context as a cue for a behavioural switch in spiderlings

Display in monogamous pairs: a review of empirical data and evolutionary explanations

Long-term maintenance and eventual extinction of preference for a mate’s call in the female budgerigar

Consistent individual differences in behaviour, or ‘personality’, are likely to be influenced by development, social context, and species ecology, though few comparative, longitudinal studies exist. Here, we investigated the role of development and social context on personality variation in two identically reared, social corvids: common ravens and carrion crows. We repeatedly presented subjects with a variety of novel food and objects, while alone and in a primarily sibling subgroup, from fledging to sub-adulthood. We predicted that consistent individual differences would emerge later in development, and that conspecific presence would facilitate behavioural similarities. In contrast to our predictions, we found that individuals of both species were highly inconsistent in their behavioural responses throughout the development period. In line with our predictions, though in the ravens only, conspecific presence promoted behavioural similarities as individuals were strongly shaped by their subgroup, and it is likely that these effects were driven by social context rather than relatedness. We discuss these findings in relation to developmental steps and the role of social relations in these species. Overall, our findings highlight that these two species are highly adaptable in their behaviour, and the ravens in particular are strongly influenced by their social environment, which may facilitate cooperation and social learning.

Acoustic signals which are used in animal communication must carry a variety of information and are therefore highly flexible. Echolocation has probably such functions and could prove as flexible. Measurable variabitlity can indicate flexibility in a behaviour. To quantify variability in bat sonar and relate to behavioural and environmental factors, I recorded echolocation calls of Euderma maculatum, Eptesicus fuscus, Lasiurus borealis and L. cinereus while the bats hunted in their natural habitat. I analysed 3390 search phase calls emitted by 16 known and 16 unknown individuals foraging in different environmental and behvioural situations. All four species used mainly multiharmonic signals that showed considerable intra- and inter-individual variability in the five signal variables I analysed (call duration, call interval, highest and lowest frequency and frequency with maximum energy) and also in the shape of the sonagram. A nested multivariate analysis of variance identified the influences of individual, hunting site, close conspecifics and of each observation on the frequency with maximum energy in the calls, and on other variables measured. Individual bats differed in multiple comparisons, most often in the main call frequency and least often in call interval. In a discriminant function analysis with resubstitution, 56–76% of a species' calls were assigned to the correct individual. Distinct individual call patterns were recorded in special situations in all species and the size of foraging areas in forested areas influenced temporal and spectral call structure. Echolocation behaviour was influenced by the presence of conspecifics. When bats were hunting together, call duration decreased and call interval increased in all species, but spectral effects were less pronounced. The role of morphometric differences as the source of individually distinct vocalizations is discussed. I also examined signal adaptations to long range echolocation and the influence of obstacle distance on echolocation call design. My results allow to discuss the problems of echo recognition and jamming avoidance in vespertilionid bats.

Sexuality plays an important role in the lives of individuals throughout their lifespan, as it can be expressed and experienced in different ways. There is a common worldwide misconception that individuals become asexual as they get older, but an emerging body of evidence confirms that this is not true, and that their sexuality is likely to be misunderstood.Perceptions of sexuality, sexual desire as well as forms of sexual behaviour differ among older adults and are influenced by many factors, such as their state of health or existing illnesses as well as their social, cultural, and structural contexts. The definition of sexuality in older adults is much broader than that of the younger population and is not just limited to sexual intercourse. On the contrary, many older adults relate the positive emotions and close companionship associated with joy, love, happiness, cuddling, touching, and hugging to sexuality in older age.Many reports and empirical studies confirm that sexual intercourse and other types of sexual behaviours happen among the elderly, and that sexual experience is often seen as an important factor in their mental and physical health. Furthermore, irrespective of its form, positive sexual activity in older adults leads to greater enjoyment in life, higher levels of psychosocial satisfaction, increased physical activity, better health, and higher relationship satisfaction.However, for many older adults, their sexual needs and well-being are often ignored or met with disdain for various reasons. Apart from an increasing number of health issues, chronic diseases, and medication use in older adults, other factors that inevitably affect sexuality are related to their social, cultural, and structural contexts. A lack of interest or commitment in relationships, cultural differences as well as a lack of privacy in institutionalized contexts also determine how old-aged people express and experience sexuality. If these health and social contexts are not adequately addressed, their sexual perception and behaviours are likely to be negatively shaped.For this reason, healthcare practitioners and those who are in close interaction with the elderly should be aware of these barriers and be able to engage with them in discussions about sexuality. In order to better understand sexuality in older adults more cultural, ethnic, and religious sensitivity is needed. Further, education on older age sexuality as well as engaging in open discussions on sexuality with older adults is desirable.KeywordsOlder adultsPerceptions and sexual desireForms of sexualityPsychosocial benefitsSexual healthSocio-cultural contextStructural contextSexuality educationHealthcare practitioners

Dust bathing in laying hens: strain, proximity to, and number of conspecifics matter

The formation of long-term pair bonds in marine fish has elicited much empirical study. However, the evolutionary mechanisms involved remain contested and previous theoretical frameworks developed to explain monogamy in birds and mammals are not applicable to many cases of monogamy in marine fish. In this review, we summarise all reported occurrences of social monogamy in marine fish, which has so far been observed in 18 fish families. We test quantitatively the role of ecological and behavioural traits previously suggested to be important for the evolution of monogamy and show that monogamous species occur primarily in the tropics and are associated with coral reef environments in which territory defence and site attachment is facilitated. However, there is little evidence that obligately monogamous species are smaller in body size than species that can adopt a polygynous mating system. We review the evidence pertaining to six hypotheses suggested for the evolution of monogamous pair bonds: (1) biparental care, (2) habitat limitation, (3) low population density/low mate availability/low mobility, (4) increased reproductive efficiency, (5) territory defence, and (6) net benefit of single mate sequestration. We outline predictions and associated empirical tests that can distinguish between these hypotheses, and assess how generally each hypothesis explains monogamy within and between breeding periods for species with different types of territories (i.e. feeding only or feeding and breeding). Hypotheses (1) and (2) have limited applicability to marine fishes, while hypotheses (3)-(5) have little empirical support beyond the species for which they were designed. However, the role of paternal care in promoting monogamous pair bonds is not explicit in these hypotheses, yet paternal care has been reported in more than 70 monogamous marine fish. We show that paternal care may act to increase the likelihood of monogamy in combination with each of the proposed hypotheses through decreased benefits to males from searching for additional mates or increased advantages to females from sequestering a single high-quality mate. Among species defending breeding and feeding territories, the benefits, both within and between reproductive periods, of sequestering a single high-quality mate (hypothesis 6) appear to be the best explanation for socially monogamous pairs. For species without parental care (i.e. holding only feeding territories), territory defence (hypothesis 5) in combination with the benefits of guarding a large mate (hypothesis 6) could potentially explain most instances of monogamy. Empirical studies of marine fishes over the past two decades are therefore slowly changing the view of monogamy from a mating system imposed upon species by environmental constraints to one with direct benefits to both sexes.

In a monogamous species two partners contribute to the breeding process. We study pair formation as well as the effect of pair bond length and age on breeding performance, incorporating individual heterogeneity, based on a high-quality dataset of a long-lived seabird, the common tern (Sterna hirundo). To handle missing information and model the complicated processes driving reproduction, we use a hierarchical Bayesian model of the steps that lead to the number of fledglings, including processes at the individual and the pair level. The results show that the age of both partners is important for reproductive performance, with similar patterns for both sexes and individual heterogeneity in reproductive performance, but pair bond length is not. The terns are more likely to choose a former partner independent of the previous breeding outcome with that partner, which suggests a tendency to retain the partner chosen at the beginning of the breeding career.

Testosterone (T) can be released by stimuli such as social interactions, and thereby influence future social behaviours. Because the reinforcing effects of T can induce preferences for specific environmental locations, T has the potential to alter behaviour through space use. In a monogamous species, this T pulse may contribute differently to space use in sexually naive (SN) and pair-bonded (PB) males: SN males may be more likely to explore new areas to set up a territory than PB males, which are more likely to defend an existing, established territory. In this study, we test for variation in T-driven space use by examining variation in the formation of conditioned place preferences (CPPs) in SN and PB male California mice. In the three-chambered CPP apparatus, subcutaneous administrations of physiological levels of T were used to repeatedly condition SN and PB males to a side chamber, which is an unfamiliar/neutral environment. The final tests revealed that T-induced CPPs in the side chamber are developed in SN, but not PB males. This study fills a gap in our knowledge about plasticity in the rewarding nature of T pulses, based on past social experience.

Intranasal oxytocin reduces weight gain in diet-induced obese prairie voles

The acoustic behaviour of the European spiny lobster Palinurus elephas (Fabricius, 1787) was examined in the absence or presence of predators or conspecifics. Observations were conducted in a tank equipped with digital video and acoustic monitoring and recording systems using 25 adult lobsters and 5 common octopuses Octopus vulgaris. Single lobsters or groups of 4 lobsters were studied for 2 h. These were left alone during the first hour and exposed to a single specimen of the common octopus during the second hour. The lobsters' signals were acoustically analysed. Signal duration, number of pulses per signal, pulse rate, bandwidth, peak intensity, and peak frequency were measured. Single lobsters emitted a higher number of signals than lobsters belonging to a group. The signal (rasp) was audible to humans only in the presence of a predator and was always associated with specific behavioural events. In the absence of a predator, the lobsters produced ultrasound signals (screech) having lower duration, number of pulses per signal, bandwidth, and peak intensity and higher pulse rate and peak frequency. Audible rasps were produced in an anti-predator context, whereas the ultrasound screeches were also emitted under non-stressful conditions. Thus, these signals may play a role in intraspecific communication.