Predation risk and inter-population variation in antipredator behaviour in the three-spined stickleback, Gasterosteus aculeatus L.

Predation risk from fish and bird predators was assessed at seven Scottish Gasterosteus aculeatus L. sites. Samples of adult male and female sticklebacks and fry from each site were tested with either a model heron or a live pike to measure anti-predator responses. Principal Component Analyses were then used to describe the responses, the first factor to emerge from each multivariate analysis providing an index of overall level of response toward the predator. Significant sexual and inter-population differences in behaviour are described. Sticklebacks from populations at high risk from either predatory fish or birds showed higher fright response scores than fish from low risk sites. In general, adult male sticklebacks are bolder than adult females during interactions with predators.     

An investigation of the territorial behaviour of the three-spined stickleback (Gasterosteus aculeatus) using principal components analysis

The territorial responses of male three-spined sticklebacks to intruders of a variety of species were investigated. The results were subjected to a principal components analysis, followed by varimax rotation, methods whose general usefulness in analysing complex correlated responses are discussed. In all these tests, both when the subject had an empty nest and when they had newly hatched young, the factors which emerged were recognizable in terms of the major systems in which the behaviour of sticklebacks is usually discussed. Re-analysis of data from Cullen (1960) using principal components analysis confirmed her original conclusions and unearthed some undetected results.     

The disinhibition interpretation of the ‘displacement’ activities during courtship in the three-spined stickleback, Gasterosteus aculeatus

Further research was conducted on the ‘displacement’ nest activities occurring during the courtship of the male three-spined stickleback, Gasterosteus aculeatus. In several respects the results were found to be inconsistent with the widely accepted disinhibition explanation of displacement activities. One difficulty is that this theory ignores the possibility that the performance of the displacement act might itself play some causal role in motivational adjustment, as demonstrated in the present circumstances (Wilz 1970). In addition, the disinhibition hypothesis proposes that those behaviours prepotent in an animal's repertoire are those that are most likely to occur in the conflict situation of courtship. In the stickleback, however, it is not the most frequent behaviours prior to the conflict situation that occur most frequently during the ‘displacement’ contexts of courtship. Finally, the disinhibition view assumes functionally unrelated activities each have their own causal factors entirely separate from those of other behaviours, a view challenged by the present findings. All of these difficulties are considered in relation to the nature of stickleback courtship.     

Behind closed doors: use of visual cover by courting male three-spined stickleback, Gasterosteus aculeatus

Species that form breeding aggregations, such as the three-spined stickleback, have ample opportunity to observe and interact with others in their respective populations. This exposes courting pairs to distraction or disruption from onlooking individuals. Thus, courting inconspicuously could be beneficial to males. We tested whether males would court inconspicuously by housing them in individual tanks with visual access to a neighbouring male. A dummy of a gravid female three-spined stickleback was presented to a male in the front quadrant of the tank while screens concealed either the front quarter or front half of the tank from the neighbour. When a portion of the tank was concealed from a neighbouring rival, males courted more in the concealed areas than those that were exposed to a rival. Hence, in the presence of rivals, males can adjust their courtship behaviour in ways that could increase their mating success. Whether this reflects an active ‘strategy’ or a passive result of the male being less distracted by its neighbour is presently unknown.     

Aggression in the early phases of the reproductive cycle of the male three-spined stickleback (Gasterosteus aculeatus)

Male sticklebacks with nests were more aggressive towards other males than were males which had yet to build nests.Males with nests were more aggressive towards other males than towards non-gravid females. This was not true of fish that had yet to build nests.The increased aggression shown to other males by males with nests was reduced after gonadectomy to the level characteristic of fish that had yet to build nests. This reduction occurred in the first week after the operation. Gonadectomy had no immediate effect on the aggression shown to non-gravid females.The aggression of males that had still to build nests was not reduced by gonadectomy.Gonadectomy resulted in a complete absence of nest building and nest-directed behaviour.     

Acute exposure to offshore produced water has an effect on stress- and secondary stress responses in three-spined stickleback Gasterosteus aculeatus

Pollution is one of today's greatest problems, and the release of contaminants into the environment can cause adverse changes in vitally important biological pathways. In this study, we exposed three-spined stickleback Gasterosteus aculeatus to produced water (PW), i.e. wastewater from offshore petroleum production. PW contains substances such as alkylphenols (APs) and aromatic hydrocarbons (PAHs) known to induce toxicant stress and endocrine disruption in a variety of organisms. Following exposure to PW, a standardized confinement treatment was applied as a second stressor (PW-stress), testing how fish already under stress from the pollutant would respond to an additional stressor. The endpoint for analysis was a combination of blood levels of cortisol and glucose, in addition to transcribed levels of a set of genes related to toxicant stress, endocrine disruption and general stress. The findings of this study indicate that low doses of PW do not induce vitellogenin in immature female stickleback, but do cause an upregulation of cytochrome (CYP1A) and UDP-glucuronsyltransferase (UDP-GT), two biomarkers related to toxicant stress. However, when the second stressor was applied, both genes were downregulated, indicating that the confinement exposure had a suppressive effect on the expression of toxicant biomarkers (CYP1A and UDP-GT). Further, two of the stress related genes, heat shock protein 90 (HSP90) and stress-induced phosphoprotein (STIP), were upregulated in both PW- and PW-stress-treatment, but not in the water control confinement treatment, indicating that PW posed as a larger stress-factor than confinement for these genes. The confinement stressor caused an increased level of glucose in both control and PW-treated fish, indicating hyperglycemia, a commonly reported stress response in fish.     

Ultraviolet light and visual behaviour in the three-spined stickleback, Gasterosteus aculeatus

The ability of various vertebrates to perceive visual information in the ultraviolet region of the electromagnetic spectrum (300-400 nm) is receiving increasing interest. To date, many of these studies have concentrated on the role of ultraviolet perception in mate choice, yet there are several ways in which the ability to perceive ultraviolet information may affect other behaviours. Until now, it has been widely assumed that colour in the three-spined stickleback can be quantified by methods appropriate to the human visual system. However, evidence does exist that suggests that, in some populations, sticklebacks are capable of perceiving ultraviolet wavelengths. Using a behavioural technique, we tested the ability of the stickleback to perceive ultraviolet light under full-spectrum conditions to establish whether such wavelengths are utilised within their normal behavioural repertoire. We tested this ability by assessing whether subjects could locate hidden food in a foraging task where food position was indicated by the position of landmarks. These landmarks differed only in their ultraviolet content, appearing identical when viewed across the human visible region of the spectrum. We found that sticklebacks were able to use ultraviolet perception to locate a foraging patch under full-spectrum conditions.     

Development of the overhead fright response in wild and predator-naive three-spined sticklebacks, Gasterosteus aculeatus L.

Variation in the overhead fright response within populations between adult and juvenile sticklebacks and between juveniles from separate populations are described. The development of the response was measured experimentally in fish from two populations subject to avian predation and in predator-inexperienced fry from one of these populations. The response developed with age and/or body size. The even development of the response in a sample of laboratory-reared fry suggests that experience of predators is not necessary for the normal development of this behaviour.     

Territory quality,male quality,courtship intrusions,and female nest-choice in the threespine stickleback, Gasterosteus aculeatus

In a recent study (Sargent & Gebler 1980), we allowed male sticklebacks to compete for a limited number of clay flowerpots as nest sites in circular wading pools. Although the males who nested in post enjoyed higher reproductive success (Sargent & Gebler 1980), a further analysis of these data revealed the males in these two classes did not differ significantly with regard to territory size, total courtships, and female rejections of the nest. In the present study, for the first half of the experiment, flowerpots were assigned randomly to half of the males nesting in wading pools; the pots were later taken from those males who first had them and were given to the remaining males for the second half of the experiment. Using paired comparisons, each male's performance was examined with and without a flowerpot. The males received more female nest-choices, and fewer intrusions from other males, when their nests were in flowerpots; however, the females appeared to engage in courtships with males independently of the males' nest site concealment. For the two classes of nest site concealment, the males were not significantly heterogeneous for the number of nest-choices that they received: thus male quality did not appear to directly affect female nest-choice. These results suggest that territory quality, in the form of nest site concealment, was the most important determinant of female nest-choice and male reproductive success in the experiments of Sargent & Gebler (1980). Females appear to minimize the risk of egg-cannibalism by spawning with those males who experience the least amount of courtship interference.     

Migrations of three-spined stickleback, nine-spined stickleback, and pond smelt in the Chignik catchment, Alaska

Upstream spawning migrations of age-2 three-spined stickleback, nine-spined stickleback, and pond smelt, and subsequent downstream migrations of young-of-the-year and age-1 individuals are documented in Black River of the Chignik catchment, Alaska.     

Dominance and anti-predator behaviour in blue tits (Parus caeruleus)

Evidence from captive flocks of blue tits (Parus caeruleus) suggests that following the appearance of a predator, socially dominant individuals are likely to wait until subordinate members of their flock resume feeding before doing so themselves. After a model sparrowhawk (Accipiter nisus) was flown over captive flocks of blue tits at a feeder, there was a significant negative correlation between sequence of return to the feeder and status within a linear dominance hierarchy. During this period, birds increased the proportion of their time budgets devoted to scanning for predators. These results suggest that during periods of danger, high-ranking individuals are able to be more cautious than are low-ranking individuals, possibly because their ability to control food resources reduces the energetic costs of their extra caution.     

Schooling affects growth in the three-spined stickleback, Gasterosteus aculeatus

Three-spined stickleback fry (mean length 20 mm, mean weight 14 mg) were reared for 14 days alone and in groups of six in a constant per capita water volume. The fish originated from two habitats (rock-pools, sea) of different predation pressure. The fry were fed nauplii of Artemia and commercial aquarium fish food ad libitum. Specific growth rates of solitary and schooling fry differed and were also affected by their origin. The specific growth rates of solitary fry from the sea averaged 1.0% day⁻¹ (length) and 6.0% day⁻¹ (weight) and those of solitary rock-pool fry 1.1 and 6.7%, respectively. For group-reared fish the corresponding values were 1.2% (length) and 6.6% (weight), and 1.3% (length) and 7.6% (weight). The finding that schooling sticklebacks grow faster than solitary ones implies that grouping enhances fitness in stickleback fry under the conditions of our experiments.     

Nursing behaviour and maternal aggression among Welsh ponies (Equus caballus)

Nursing behaviour and related aggression of mare-foal pairs was studied from birth (n = 21) to 24 weeks of age (n = 15) of the foal. Foals exhibited a decreasing length and frequency of nursing as they grew older. Mares rarely aggressed against their foals during nursing in the foal's first 4 weeks of life, but did so increasingly through Weeks 13–16, after which the rate of aggression during nursing decreased. Mares terminated nursing primarily by moving away, and were most likely to do so during the foal's first 4 weeks of life. They became gradually less likely to do so as the foal grew older. It was concluded that mares sometimes flex their hind limb on the side opposite the foal during nursing in order to conserve energy in a situation in which they would be remaining still anyway. There was no difference between colts and fillies in the frequency or duration of nursing or in the frequency with which their mothers aggressed against them or terminated nursing.     

Association patterns and shoal fidelity in the three-spined stickleback

We investigated pairwise association patterns and shoal fidelity in free-ranging, individual three-spine sticklebacks (Gasterosteus aculeatus) by capturing entire shoals of sticklebacks and tagging each shoal member with a unique individual mark before releasing the shoal at the point of capture. We recaptured tagged fishes in the study area on five subsequent days, noting their identity, their location and the individuals with which they were associated. Stable partner associations between fishes were observed which might provide the basis for shoal fidelity via social networks. These results suggest the potential for the kinds of inter-individual association patterns assumed by models of predator inspection and 'tit-for-tat' behaviours in free-ranging fishes.     

The relationship between locomotor activity and sexual behaviour in ebony strains of Drosophila melanogaster

Male flies homozygous for the ebony¹¹ mutant allele suffer a severe visual impairment and consequently show poor mating success. However, ebony males show improved mating in darkness because they initiate courtship more quickly than in the light. They also exhibit a competitive superiority over wild-type males under darkened conditoons that correlates with the observed increase in the mutant's locomotor activity. Locomotor activity levels were subsequently shown to correlate with several indices of mating success under both dark and illuminated conditions. The evolutionary implications of this relationship between the two characters are discussed.     

The relationship between violent video games,acculturation, and aggression among Latino adolescents

Multiple factors are involved in the occurrence of aggressive behavior. The purpose of this study was to evaluate the hypotheses that Latino middle school children exposed to higher levels of video game playing will exhibit a higher level of aggression and fighting compared to children exposed to lower levels and that the more acculturated middle school Latino children will play more video games and will prefer more violent video games compared to less acculturated middle school Latino children. This study involved 5,831 students attending eight public schools in Texas. A linear relationship was observed between the time spent playing video games and aggression scores. Higher aggression scores were significantly associated with heavier video playing for boys and girls (p < 0.0001). The more students played video games, the more they fought at school (p < 0.0001). As Latino middle school students were more acculturated, their preference for violent video game playing increased, as well as the amount of time they played video games. Students who reported speaking more Spanish at home and with their friends were less likely to spend large amounts of time playing video games and less likely to prefer violent video games (p < 0.05).