Drafts

4) What do the researchers think that their findings mean (i.e. how do they interpret their findings)

    Ultimately, they determined that a cuckoo chick is able to predictably increase its call rate to offset its low gape area as these 2 features are the dominating factors that inform parents of nutritional needs. However, they are not fed as frequently as they would prefer and they suspect this is to avoid exhaustion of the host parents. Instead, they demand a similar amount of food as a standard warbler nest (4) for an extended duration.  This is counterintuitive as a cuckoo chick does not have any stake in the survive of the host parents, but they suspect that a constraint must prevent the cuckoo from the predicted optimal feeding rates.

Glycogen degradation and glycogen synthesis have many similarities and differences. The main difference between the two is degradation is a catabolic reaction while synthesis is an anabolic reaction. Although the catabolic and anabolic reactions are normally thought of as one releasing energy the other requiring energy, Glycogen degradation and synthesis is a coupled reaction therefore the overall reaction would be releasing energy to make it favorable. Another difference is the use of different enzymes. Degradation uses the enzyme phosphorylase that breaks only the bond between an alpha 1 and 4 bond. Synthesis forms bonds with glycogenin.

3) What, exactly, did the researchers find (i.e., what were their data)?

In regards to the call experiment noted above, the researchers observed that there was a linear correlation between brood size and call frequency. They then created several regression equations in an attempt to quantify the impact of each factor.  After manipulating the call rates of clutches they determined that the regression equation derived is: feeds delivered per hour = 2:28 (maximum number of gapes displayed) + 2.30 (maximum number of chicks calling) + 8.23. This equation was exclusive to 6-7 day old chicks so they manipulated the factors so that they could apply this to chicks of any age. The resulting regression equation thus derived was: feeds delivered per hour =0:0162 (gape area displayed (in mm2 )) + 0.178 (calls per 6 s) + 8.2. When analyzing the cuckoo chicks they determined that 1. A cuckoo chick intakes the amount that 4 warblers would normally require to survive and that a Cuckoo that is 6-8 days old has a call frequency that matches that of 4 warbler chicks. 2. This increased intake is not related to size,  as black birds and song thrushes, even with augmented warbler calls, did not receive the same amount of food. However, in the presence of a cuckoo call they did receive more food. They then used the equation 0162 (gape area displayed (in mm2 )) + 0.178 (calls per 6 s) + 8.23, to determine if the cuckoo’s reduced gape area would in turn increase their call frequency in a predictable fashion.

The traps used will be a version of the pitfall trap described by Youngman et. al., 2009. The trap design is a cup firmly planted in a hole dug in the ground, with a second cup of the same rim width resting inside. In the interior cup, a small amount of ethanol will be placed to kill/preserve the specimens collected. Each team will set three traps at their chosen location, with each trap being at least twenty feet apart from the others.

Highly branched glycogen structure is more efficient form of energy storage than an unbranched structure. Highly branched glycogens have a significant number of ends that can be added to or removed from. These branched glycogens have one end that is unable to reduce or add to. The other end of the branch is able to be reduced or added upon. The branching structure is optimal for the efficiency of storage and/ or release of glucose.

A coupled reaction is a series of connected reactions, which share products and substrates. The reactions increase efficiency of energy transfer, and allows more points of regulation. The regulation is important for conservation of energy and resources. In order for a coupled reaction to be favored the net delta G must be overall negative. This means the pathways cannot be direct opposites of each other because than the pathway would have a slightly positive making it unfavorable. Also the pathway would then be futile and waste energy.

1 gram of nutmeg was added to a round bottom Erlenmeyer flask and then 3 mL of TBME was added to the flask as well. The distillation process was then followed proceeded by a micro scale filtration that occurred pipet-full by pipet-full. 2 mL of TBME was then added again to the nutmeg and the filtration method was repeated. A light air stream was then run over the crude product and after a 5 minute drying period the weight was obtained. 12 mL of acetone was then added to the flask the solid was dissolved via a recrystallization process. The dissolved solution was cooled at room temperature and in an ice bath, the vacuum filtration method was then followed and the crystals were allowed to dry. A final weight and MP was then obtained. Following the filtration .072g of Trymyristin was then transferred to a round bottom flask. 2 mL of 6 M NaOH, 2 mL of 95% Ethanol and boiling chips were added to the flask. The solution was then refluxed for approximately 45 minutes. The remaining Trymyristin was then recrystallized and filtered a second time. The MP and final weight of the Trymyristin was recorded. After 45 minutes the refluxed solution was cooled at room temperature and transferred to a 50 mL beaker containing 8 mL of water. 2 mL of concentrated HCl was then added to the solution. The beaker was then cooled on ice while being stirred. The solid was collected via vacuum filtration and was allowed to dry overnight before obtaining a final weight and MP.

2) What, exactly, did the researchers do to try to answer their question?

They first used a regression equation to determine the independent effects of gaping and calling in regards to effect on parental care. They then correlated these 2 factors and determined that both factors in tandem appear to be the most optimized means of conveying nutritional needs. To determine the effect of the begging call they compared to responses of the parents subjected to 49 nests with either 2 or 4 chicks that were 6/7 days old. They then amplified the call in the experimental groups with either a playback of 1 or 4 additional chicks and compared these results to the control groups that did not have any vocal augmentation. Once they created a regression model that best quantified these results they then applied this formula to chicks of other ages.The compared the parental response by transposing blackbird and song thrush chicks into warblers nests as they rival the cuckoo chicks in size. They then tested the response of the parents in the presence of these experimental species performing their  natural displaying (large gaping) that was augmented by a cuckoo call.

1) What question were the researchers trying to answer?

The researchers were trying to discover why common cuckoo chicks are able to successfully parasitize warbler nests. Specifically,  they are researching the complex behavior that is displayed by the cuckoo and warbler chicks in an effort to quantify the effect each signal type (gaping displays and call frequency) has on the parental individuals in regards to how much food they provide. To begin,  they first tested the various impacts of different response levels and discovered that multiple signals offered more precise information regarding how much food the chicks required, the age of the individual as well as the size of the brood. However, they then transition to the effect of a cuckoo parasite on a nest of warblers and note that one cuckoo requires the nutrition needed for approximately 4 warbler chicks. They question how only a cuckoo chick, with its enormous size,  is able to trick the foster parents into continually bringing it large amount of food.

To confirm their suspected correlation between cooperative passerines and parasitic species they used phylogenetic comparisons of the fauna in the aforementioned areas. Their results showed that a large percentage of the species targeted by parasitic individuals in these areas were indeed cooperative breeders. Their theories were confirmed after comparing the growth rates of cuckoo (parasitic) chicks in biparnal and group care settings. In larger groups (3+) cuckoos grew at a faster rate with decreased levels of death due to smaller predation rates.  However, these potential benefits were seldom realized as larger groups were able to defend from parasitism more efficiently. Finally, they determine that cooperative behavior is driven by their increased reproductive success secondary to their defensive measures.