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Posts Tagged ‘social behavior’


Seychelles Warbler Cooperative Breeding

July 2nd, 2014 by Alyson

This is my added edit to the Seychelles Warbler wikipedia page. I added the section for Cooperative Breeding that can be found here: https://en.wikipedia.org/wiki/Seychelles_Warbler#Cooperative_Breeding_Habits

Cooperative Breeding

Seychelles Warblers demonstrate cooperative breeding, a reproductive system in which adult male and female helpers assist the parents in providing care and feeding the young. The helpers may also aid in territory defense, predator mobbing, nest building, and incubation (females only).[1] Breeding pairs with helpers have increased reproductive success and produced more offspring that survived per year than breeding pairs with the helpers removed.[2] Helpers only feed the young of their parents or close relatives and do not feed unrelated young. This is evidence for the kin-selected adaptation of providing food for the young. The indirect fitness benefits gained by helping close kin are greater than the direct fitness benefits gained as a breeder. This could be evidence for the kin-selected adaptation of providing food for the young.

On high-quality territories where there is more insect prey available, young birds were more likely to stay as helpers rather than moving to low-quality territories as breeders.[3] On low quality territories, having a helper is unfavorable because of increased resource competition. Females are more likely to become helpers[4], which may explain the adaptive sex ratio bias seen in the Seychelles warblers. On high quality territories, females produce 90% daughters; on low quality territories, they produce 80% sons. Clutch sex ratio is skewed towards daughters overall.[5] When females are moved to higher quality territories, they produce two eggs in a clutch instead of a single egg, with both eggs skewed towards the production of females. This change suggests that Seychelles Warblers may have pre-ovulation control of offspring sex ratio, although the exact mechanism is unknown. (more…)

It’s Important to Be a Social Lizard

June 16th, 2014 by akm6

 

Image of a veiled chameleon by Geoff (CC BY-SA 3.0).

It is a well-known fact that people need constant interaction with others in order to grow up to become normal, healthy adults. But do all types of animals require group contact with other members of their species as we do? Ballen and colleagues were interested in the behavioral differences caused by raising a particular type of lizard, the veiled chameleon, in a group or in isolation. The findings of their paper were further brought to public attention by the science writer, Mary Bates, in her news article titled “Lizards Need Social Lives, Too.” Although the main message from these two pieces of literature is the same, Ballen and colleagues wrote for the scientific community and Bates wrote for a more general and wider audience.

Ballen and colleagues knew from previous studies that birds and mammals raised in isolation had problems with “social behavior, mental performance, and foraging behavior” (Ballen 2014). However, they were curious if reptiles were also negatively affected by being raised alone. Ballen found a type of lizard known to grow up with its siblings in its early life: the veiled chameleon. Ballen decided to test if isolation early in life affected the chameleon’s ability to forage for food and interact with members of its species later in life. To do this, Ballen incubated chameleon eggs until they hatched and then raised some of these hatchlings in groups and others in isolated enclosures. The chameleons’ foraging ability was then tested by measuring the amount of time an individual took to catch a cricket. The scientists tested social behavior by placing two chameleons of the same size and sex together and observing aggressiveness and submissiveness in social interactions. (more…)

The Elephant in the News: An Evaluation and Comparison between Two Articles

June 6th, 2014 by svn2

 

Media is always entertaining or informing us with new things. However, I have learned over time that media sometimes tends to sensationalize stories. Recently, I read an unbelievable report on how elephants can comfort each other. Wary about media sensationalization, I searched for the original research article.  After reading both the news report and research article, I evaluated each one and compared them with each other.

In the original research article, researchers Joshua Plotnik and Frans de Waal (2014) studied Asian elephants’ tendency to console distressed members of their group. Consolation is usually defined as “affiliative physical contact from an uninvolved bystander directed toward a recipient of aggression” (Plotnik and de Waal, 2014). It is demonstrated in only a few species since most animals are not thought to have the cognitive capability for consolation. The researchers believed that elephants are capable of reassurance due to being social creatures with strong bonds to their families. In their research, Plotnik and de Waal studied 26 elephants at Elephant Nature Park in Thailand for several months. They collected data in two groups: post-distress and matched-control. In the post-distress condition, the researchers identified a distressed individual based on certain behaviors (e.g. erecting the tail, extending the ear, and roaring) in response to negative stimuli (e.g. aggression, group separation, and environmental threats). They observed nearby bystanders for 10 minutes. They compared these observations with those of the matched-control condition, in which the same elephants were observed at a different time with similar conditions but no distress stimuli. The researchers found that bystanders were quicker to interact with the upset individual in the post-distress condition compared to the matched-control. These bystanders tended to associate with the individual by touching the individual on the mouth and genitals with their trunks. Furthermore, they vocally responded to the individual with unique sounds, which were not made in the control condition. The researchers also discovered that bystanders would touch other bystanders, and surround their young, a behavior called “bunching.” These results suggest that elephants may have a more developed cognition than some animals since consolation is regulated by complex cognitive mechanisms. Because chimpanzees have similar reassurance behaviors and social relationships, the researchers suggested that convergent evolution may have occurred between elephants and chimpanzees in terms of cognition, a possibility to explore with more research.

An Asian elephant comforting another elephant. Photo by E. Gilchrist.

An Asian elephant comforting another elephant. Photo by E. Gilchrist (Think Elephants International, Inc. CC BY SA).

I have always been interested in human and animal behavior, so I enjoyed reading the research, and learning about the psychology of elephants, creatures that I never recognized were highly intelligent. (more…)

Kiss and Make Up – Reconciliation in Wombats

May 28th, 2014 by rsg4

 

Competition for limited resources has fueled physical conflict in mammals and other animals. While some physical conflicts result in death of a competitor, individuals often return to peaceful living through reconciliation. Reconciliation is defined as “the first exchange of affinitive behavior between opponents after conflict” (de Waal and van Roosmaleen, 1979). Examples of affinitive behavior include sharing resources, feeding each other, and cuddling (Cordoni and Norscia, 2014). Many mammals follow the Valuable Relationship Hypothesis, which states that kin demonstrate reconciliation more often than unrelated individuals, assuming a previously cordial relationship (Cordoni and Norscia, 2014). Reconciliation reduces stress and aggression, and maintains high-value relationships (such as those with kin) in wild chimpanzees and other mammals (Wittig and Boesch, 2005). I reviewed a study by Giada Cordoni and Ivan Norscia of the University of Pisa involving red-necked wallabies (Macropus rufogriseus) and reconciliation. This was the first study conducted to provide evidence of reconciliation in marsupials. (more…)

Social Learning in Humpback Whales

May 2nd, 2014 by clk5

Sometimes, natural events happen that lay a great backdrop for scientists to learn more about the natural world. In 2007, New England’s humpback whales all across the population were preforming a new technique that had originated only 27 years earlier. Jenny Allen and her colleagues took this opportunity to determine how behaviors are spread through a population. In April of 2013, these scientists published a report called “Network-Based Diffusion Analysis Reveals Cultural Transmission of Lobtail Feeding in Humpback Whales” in Science, which looked into this new behavior and how it became so widespread in the New England humpback whale population.

Before 1980, the humpback whales of the New England area primarily preyed on herring. When the herring population crashed in this area in the early 1980’s, the whales turned to a new fish as their primary prey: the sand lance. After this change in primary prey, a whale was seen preforming an all-new foraging technique, wherein it slapped the surface of the water right before eating. This technique creates bubbles underwater that group the sand lance together into a cluster, which makes it easier for the whales to hunt them. By 2007, forty percent of the population was using this technique. Allen and her colleagues hypothesized that the high prevalence of the technique was due to either social learning or widespread individual discovery. (more…)