Proteomics is the large scale study of protein structure, function and expression in cells, tissues or body fluids. Recent technological advances have extended the applicability of proteomic techniques to species typically studied by behavioral ecologists. In this review we point out the advantages of proteomic approaches, suggest research topics best tackled by proteomics, and highlight some of the techniques available for the identification and quantification of proteins.
We found novel differences in the bills of female and male hummingbirds, and show that these differences are related to the males’ ability to defend territories necessary to attract females. Our findings contradict the traditional explanation that the differences in bill shape between the sexes are caused by differential feeding at dissimilar flower shapes. We provide the first evidence of weapons in bills and one of the few examples of male weaponry in birds.
It is believed that a bird’s energetic reserves determine when and for how long it incubates its eggs. We challenge this view for species where both parents incubate. We experimentally reduced the energetic demands of incubation by heating and insulating the nest. These treatments had no major effect on the length of incubation bouts.
Conspicuous red or yellow colors often act as a warning signal to predators, but conspicuous is in the eye of the beholder. Praying mantids, which are voracious insect predators, have monochromatic vision and are colorblind. To mantids, orange harlequin stinkbugs are cryptic against leaves, while individuals with iridescent patches are highly conspicuous. Future research should consider how predators with poor long-wavelength vision influence the evolution of warning coloration.
Cryptic moths are able to seek out locations and change their body orientations after landing on tree trunks to improve camouflage. Moths rest on backgrounds where they are often well camouflaged in terms of color, pattern matching, and disruptive coloration. Using image analysis of moth photos, we show that bark resting moths become more camouflaged in terms of color, luminance, pattern direction matching, and disruptive effect (concealing the outline of body) after they have landed and repositioned themselves.
The use and relative importance of intraspecific and interspecific social information in a bird community
Information from conspecifics outweighs other information sources for collared flycatchers making their nest site choices late in the spring. Collared flycatchers copy the nest site characteristics apparently chosen by earlier settled flycatchers and competing tits. When the apparent decisions of the fellow flycatchers and competing tits are in conflict, flycatchers copy conspecifics when conspecifics outnumber the competitors, which is the case late in the spring.
Telemetric and video assessment of female response to male vocal performance in a lek-mating manakin
Male vocalizations attract females, but the way we monitor male and female behavior can influence scientific results. We studied tropical manakins using both video recorders and a novel automated radio-tracking system. Videos showed that females visited males producing more frequent, more synchronous duets; radio-tracking revealed no such pattern. We explore possible explanations for this difference. We also show that diel variation in male and female behavior may be influenced by temperature extremes.
Using on-animal acoustical monitoring to study the behavior of terrestrial animals, we examine how the use of auditory vigilance in mule deer varies with landscape features. Deer used this antipredator strategy more when in forested cover and at night, where visual vigilance was likely to be less effective.
Warbler species produce 2 types of alarm calls: “general” calls, which are highly diverse across species, and scream-like “rasps.” General calls recruit a variety of surrounding birds to group attacks on widely threatening predators. By contrast, warblers use rasp calls when aggressively confronting cuckoos, which parasitize warbler nests, and these calls attract mostly other parasitized species. Rasp calls have scarcely changed over millions of years, which we attribute to their restricted context and message.
Individuals with different personalities may also differ in how they make decisions. We tested stickleback fish in a maze task and expected that bolder fish would make quicker but less accurate decisions. In fact, we found different personalities to be equally good at the task. This might explain why we often find bold leaders in fish shoals as they make both quick and accurate decisions.
It is beneficial to be bold when colonizing new habitats. Bold behavior, however, may be risky. We found that cane toads from introduced populations are less afraid of novelty than toads from native populations. Introduced toads are more willing to exploit novel food and eat familiar food by a novel object. Their bolder behavior facilitates their successful establishment. This is the first study to examine the role of neophobia at promoting invasions in anurans.
Do all individuals of a population adopt a similar pattern of habitat use or are there different tactics linked to an individual’s personality? We show that a priori more reactive individuals minimize risk by using safer habitats, thus gaining only limited access to forage-rich habitats, whereas less reactive individuals prioritize access to high-quality resources by using riskier open habitat, but may thus be subject to higher risk of predation. This suggests the existence of a risk management syndrome in wild populations.
Immune system and sprint performance consume resources, and are under trade-off in lizards. We activated both male and female lizards’ immune system by inoculating them with an antigen, whereas a control group was injected with physiologically inactive saline solution. Then we calculated their speed. Males ran faster than females, but immune challenge reduced male speed. Interestingly, females remained unaffected by immune challenge.
Mating patterns of animal populations can be described as a sexual network, and this approach may provide insights on sperm competition. Studying an arachnid with alternative mating tactics, we showed that sperm competition is higher among males that sneak copulations. Moreover, aggregated harems are hotspots of sneaker invasions, suggesting that the spatial structure of harems has strong influence on the topology of the sexual network.
Hamilton’s rule in humans: in times of crisis people primarily rely on close relatives, or spouses, for support. Hamilton’s rule states that costly helping behaviors are more likely to evolve if they are directed toward genetically “closer” relatives. However, while this rule has been confirmed in non-humans, its application to humans is controversial. We confirm Hamilton’s rule using data on whom people anticipate they would obtain support in times of crisis.
Sociality increases juvenile survival after a catastrophic event in the feral horse ( Equus caballus )
We know group living benefits social animals. But could the number of “friends” an animal has help it survive a catastrophic event? We asked whether sociality affected foals’ ability to survive the removal of close associates. Foals with more associates after the removal were more likely to survive. Moreover, associations formed before the removal were critical to the survival of foals left without parents. Our results demonstrate another important link between sociality and animal survival.
We use hidden Markov models to evaluate behavioral states and their relation to environmental, seasonal, and social factors in the endangered red-cockaded woodpecker. Woodpeckers showed 2 distinct behavioral states, resting and foraging, which were related to habitat quality, season, and group size. Our results reveal insights into underlying motivations of a social bird under different contexts and demonstrate the flexibility and utility of new tools for analyzing high-resolution animal tracking data.
This is the first study to directly compare the signaling properties of the 3 major types of pigments: carotenoids, melanins, and pterins. While there have been many studies examining melanin and carotenoid, few studies have examined the signaling properties of pterins. In bluefin killifish, melanin predicts dominance and mating, whereas carotenoid and pterin predict health and mating. The elaborate colors used by male killifish potentially provide multiple messages to multiple receivers.
We asked how mating calls vary with the size of the male producing them. Call traits are magnified by large males if females prefer extreme values and if the traits closely reflect body condition. Call traits are produced evenly by large and small males if females prefer intermediate values and if the traits do not reflect body condition.
Fish living in stable, complex habitats rely on landmarks to navigate, whereas landmarks are both rare and unreliable cues in dynamic sandy habitats. We found that gobies from complex, stable rock pool habitats learned the solution to a spatial task much faster and made fewer errors than goby species from simple, dynamic sandy habitats. Rock-pool gobies tended to use multiple cues to solve the task, whereas sand-dwelling gobies relied significantly more on body-centred orientation.
The fear of unseen predators: ground squirrel tail flagging in the absence of snakes signals vigilance
Many studies report use of conspicuous antipredator displays in the absence of predators, but ours is the first to experimentally test their function. Squirrels that emit conspicuous antisnake displays in the absence of rattlesnakes are more successful at evading surprise attacks. Thus, although these displays have been shown to advertise predator detection, they can also honestly indicate vigilance when predators are undetected. The fear of attack from unseen predators may create fitness tradeoffs in prey.
The orchid mantis lures pollinators as prey by mimicking a flower and is more successful when surrounded by real flowers. This is likely due to the “magnet species effect”, whereby large numbers of flowers in the vicinity increase the overall amount of pollinator “traffic.” This same effect is known to influence the pollination success of deceptive flowers that attract pollinators but do not provide a nectar reward.
Male size predicts extrapair paternity in a socially monogamous bird with extreme sexual size dimorphism
The New Zealand tui is an iconic bird exhibiting extreme sexual size dimorphism. This is an unusual trait for a monogamous species and so we tested whether a male’s body size was related to his paternity success. First, we found that tūī had very high rates of extrapair paternity compared to other monogamous species. Second, larger males had higher paternity success. Thus, in contrast with previous studies, our results show that extrapair paternity can lead to the evolution of sexual size dimorphism.
Social foraging strategies and acquisition of novel foraging skills in cooperatively breeding Arabian babblers
This paper addresses cognitive questions concerning individual foraging strategies and learning abilities in a wild, free-living cooperative breeder. To our knowledge, this is the first time that experimental work on the producer-scrounger game and on the ability to acquire a novel foraging skills has been conducted on the same individuals from groups of different sizes in a wild population of cooperatively breeding birds. This research helps to shed a light on the advantages and on the constraints that high-level cooperation has on social foraging strategies and learning abilities. Our findings that subordinates scrounge (joins other who found food) more than dominant individuals but are more innovative when presented with a novel foraging skill are unique and may be both interesting and beneficial to a broad community of researchers varying from those who study social foraging and cognition to those who study the evolution of cooperation.
Three species of African ungulates, impala, wildebeest, and warthog, seem to have retained their ability to recognize their main predator, the African lion, following its extinction. Since the ecological impacts of large carnivores are partly determined by antipredator responses exhibited by their prey, this suggests that repatriations of African carnivores may result in rapid reconstruction of ecosystem function.
Engineers face the challenge of designing transportation networks that are robust against damage, cheap, and efficient. Unfortunately, these design criteria cannot be optimized simultaneously. Trail-making ants face a similar dilemma but must build networks without the aid of computers or centralized leadership. We find that meat ant trail networks are more efficient and less costly than random networks. However, networks were less robust than random, suggesting that meat ants prioritize efficiency and cost over robustness.
Quite a few animals are male and female at the same time, so they can choose to mate either as male or female on copulation. The decision to perform either sex role was known to be highly flexible depending on various, but often confounding, factors. For the pond snail, we report that young and small snails tend to mate as males first, though old and large snails do not seem to be better females.
Predators often prefer to attack prey that are different to the rest of the group (“odd”), as groups are often confusing to attack, but predators often also prefer to attack large prey as they provide a better meal. We find that stickleback predators prefer to attack large prey, especially when they are odd, but don’t attack small prey when they are odd. Thus, large and small prey should both benefit by grouping with large group mates.
We showed that puma foraging behaviors changed when American black bears stole their kills, and that puma kill rates were greater during the season when bears were active. Surprisingly, pumas did not utilize spatial refuges to mitigate competition with bears. Our results suggested predation needs to be studied within a community framework, and that animals that steal food instead of kill their own may indirectly impact prey populations through top predators.
Many parasites manipulate the behaviors of their hosts, yet understanding the evolutionary pathways leading to adaptive host manipulation remains unclear. Here, we support a recent hypothesis proposing that parasites can exploit host behaviors employed to compensate for the costs of infection. We demonstrate that by reducing the number of host offspring in parasitized nests, cowbirds increase the likelihood that parasitized female warblers will attempt a second brood, thereby increasing the opportunities for parasitism.
Fights to the death are rare in nature because the benefits of victory rarely outweigh the cost of losing. We used experiments and observations to show that female pollinating fig wasps kill competitors when resources essential for the survival of their offspring, fig flowers, are in short supply. When flowers are plentiful, wasps peacefully ignore each other, showing that under certain conditions competition can predict extreme aggression between female animals.
Cortisol in mother’s milk across lactation reflects maternal life history and predicts infant temperament
In monkeys, high cortisol and changes in cortisol levels in mother’s milk are associated with more nervous and less confident infants. Sons are more sensitive than are daughters to changes in cortisol in mother’s milk across lactation. Females that are earlier in their reproductive career tend to have higher cortisol in their milk. Mothers may be “programming” behaviorally cautious offspring that prioritize growth through cortisol signaling.
Behavior is flexible and flexibility depends on the cognitive mechanisms of decision making, which are often biased and sometimes irrational. From formal models of optimal (but biologically implausible) computation, I derive a simple, versatile and biologically plausible decision mechanism, which values options as deviations from an expected standard, weighted by assessment accuracy. I use this model to investigate the functional role of systematic errors in decision making.
Interactions with individuals of another species in an early life phase may have profound influence on social behavior in adulthood. Once independent, bats reared in groups of their own species will exhibit amicable interactions toward subjects from other species and persistent preference for former infant group mates regardless of their species identity. This phenomenon may have significant implications for the development and maintenance of mixed-species colonies in bats.