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Archive for June, 2014


How to Steal a Mate: Frog Edition

June 30th, 2014 by nyn1

 

When it comes to finding mates, that privilege is usually saved for the biggest, strongest, smartest, and whatever other positive adjective you might think of to describe the “perfect mate.” But that leaves you to wonder, what about those who aren’t necessarily the best at what they do, but still find a way to mate? The answer is simple: they’re the cheaters! The saying goes that “cheaters never win,” but in the case of this species of frog, that isn’t always necessarily the case.

A study was done on the European tree frog, Hyla arborea, to figure out why the males in this species choose to either seek out mates “traditionally” or “parasitically.” The traditional way would include actually going out and finding attracting or procuring a mate on their own, while parasitically involves using another competitors skills in order to procure a mate. They wanted to know if this behavior is caused by the size of the frog, or if it is caused by the energy cost that it would take to attract a mate. In order to test these two hypotheses, Brepson and his team set up an experiment in which they randomly caught 100 male frogs from a pond in France and emptied said frogs’ stomachs. The frogs were then split into two groups, one group was fed crickets and flies for seven days consecutively while the other group was starved for the same period of time. Then each frog was put into a container with two speakers, one in the center that played the “chorus” noise (mating calls at the average frequency of the male H. arborea’s croak), and one at the end of the container that played either “attractive” or “unattractive” mating calls for that species. A call was determined to be “attractive” or “unattractive” depending on how low or high the frequency of the call was as well as how often the call was played, with lower and more often was considered more “attractive.” The “satellite” zone was set at any point that was 10 cm or less from the speaker playing the mating calls as a standard for measuring levels of parasitism in this species. Males found in the satellite zone were identified to be acting more “parasitically” than “traditionally”. (more…)

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Manduca sexta

June 18th, 2014 by svn2

 

The Wikipedia article for Manduca sexta, or the tobacco hornworm, contained information about its lifecycle. However, no information was provided about its behavior even though there has been recent research about its behavior. I added a Behavior section in the Wikipedia article found here: https://en.wikipedia.org/wiki/Manduca_sexta.

Manduca sexta (Tobacco hornworm). Photo by Daniel Schwen (CC BY-SA 4.0).

Behavior

 Feeding

 Tobacco hornworms are facultative specialists; the larvae can grow and develop on any host-plants. However, the larvae prefer solanaceous plants, such as tobacco and tomato plants. On these types of plants, larvae grow and develop faster. The lateral and medial sensilla styloconia, which are sensory receptors, on their mouthparts help them to identify solanaceous plants by recognizing indioside D, a steroidal glycoside found in those particular plants (del Campo et al., 2001). [1] Tobacco hornworms are considered pests because they feed on the upper leaves of tobacco plants and leave green or black droppings on the plants. As adults, they do not damage the plants since they feed on nectar. [2]

Tobacco hornworm larvae prefer humid environments. When dehydrated, tobacco hornworm larvae will move towards a source of water or to an area with a high relative level of humidity. They use their antennae to locate water to drink (Rowley and Hanson, 2007). [3]

Defense

Nicotine is poisonous to most animals that use muscles to move because nicotine targets the acetylcholine receptor, an important neuromuscular junction. However, the tobacco hornworm is capable of metabolizing nicotine from the tobacco plant and using nicotine as a defense against predators. It possesses a gene called cytochrome P450 6B46 (CYP6B46) that converts nicotine into a metabolite. About 0.65% of nicotine metabolites are transported from the gut to the hemolymph, where they are reconverted to nicotine and released into the air from the tobacco hornworm’s spiracles. The emitted nicotine is used as a way to deter spiders, a practice known as “toxic halitosis.”  In one study, tobacco hornworms that fed from nicotine-deficient plants or expressed low levels of CYP6B46 were more susceptible to wolf spiders predation (Kumar et al., 2013). [4] (more…)

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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…)

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Feather Ruffling in Black-bellied Whistling Ducks

June 11th, 2014 by cer7

 

Birds do a variety of behaviors to keep warm, avoid predators, mate, and find food. In my observations, I watched the Black-bellied Whistling Duck, or Dendrocygna autumnalis. This bird is a type of waterfowl native to parts of Mexico and South America, although they can be seen in the southern United States during the summer (“Black-bellied Whistling-Duck”). The Black-bellied Whistling Duck is brown with a grey head and a black underbelly. Its feet and beak are pink. The Whistling Duck gets its name from the whistling noise it makes. I observed flock of these birds at around 4:30 pm on a rainy cold day in Herman Park. The temperature outside was about 40°F, and the rain was very light.

The flock of ducks I observed numbered about ten, and they were walking along the path by the large pond in Herman Park. The behavior I thought was interesting happened a few times during my time observing these ducks. First, a duck would get a little taller in stance, and hold its wings out to the side. Then it would flap its wings, put them down, and ruffle its feathers a little as its wings shifted back into place. I took the picture below while observing the initial states of this behavior. You can see the raised wings of the Whistling Duck right before it folds them in and ruffles its feathers.

Black-bellied whistling ducks. Photo by Clare Randolph.

This behavior could have a lot of explanations. (more…)

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Geophagy

June 9th, 2014 by asa4

 

Geophagy is the behavior of consuming earth, clay, or soil-like materials. This behavior has been noted in many species including humans. My contribution to the Wikipedia page on Geophagy (http://en.wikipedia.org/wiki/Geophagy) included specific behaviors of geophagy in primates and bats.

Many hypotheses exist to explain the importance of geophagy in bats and primates2,3. Some documented benefits of geophagy include nutrition, detoxification, and benefit as an antimicrobial and anti-parasitic agent; however, the reasons for geophagy are largely species specific1, 3.

PRIMATES:

Krishnamani and Mahaney evaluated various hypotheses that could lead to maintained geophagy in different species of primates including Japanese macaques and chimpanzees2. Reasons for geophagy are largely dependent on the species as well as the habitat. For instance, mountain gorillas demonstrate geophagy as a result of an increased need for iron.  Iron supplementation from the soil helps to meet the demands of decreased oxygen partial pressure at high altitudes2.

BATS:

There has been great debate over whether geophagy in bats is primarily motivated by nutritional supplementation or by detoxification. It is known that some species of bats regularly visit mineral or salt licks to increase mineral consumption. However, Voigt et al. 2008 demonstrated that both mineral- deficient and healthy bats visit salt licks at the same rate3. Therefore, it would seem that mineral supplementation is not the primary reason for geophagy in bats. Additionally, it was found that bat occurrence at salt licks increased during periods of high energy demand. Voigt et al. 2008 concluded that the primary purpose for bat presence at salt licks is for detoxification purposes, compensating for the increased consumption of toxic fruit and seeds3. This was shown to be especially evident in lactating and pregnant bats as their food intake increases to meet higher energy demands3. (more…)

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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…)

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Rice’s Pet Squirrels

June 4th, 2014 by nyn1

 

The gray squirrel, Sciurus carolinensis, is a creature that is very well known across Rice University for being a little too friendly with Rice students. The squirrels here seem to have habituated themselves to a certain lifestyle here that has reduced their levels of alertness and actually changed the way that the squirrels here on campus forage for food.

Rice Squirrel with a Waffle. Courtesy of ricesquirrels.tumblr.com

Upon watching the gray squirrels, I realized that the squirrels here at Rice are the same species of the squirrels that I have observed living around my home, which happens to be a mere 30 minutes from Rice, however, they have striking differences. The squirrels that I noticed here at Rice were very bold. (more…)

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