Question

Blue-green eggshells. It is hypothesized that the blue-green color of the eggshells of many avian species represents an informational signal as to the health of the female that laid the eggs. To investigate this hypothesis, researchers conducted a study in which birds assigned to the treatment group were provided with supplementary food before and during laying; they predict that if eggshell coloration is related to female health at laying, females given supplementary food will lay more intensely blue-green eggs than control females. Nests were paired according to when nest construction began, and the study examined 16 nest pairs.

The blue-green chroma (BGC) of eggs was measured on the day of laying; BGC refers to the proportion of total reflectance that is in the blue-green region of the spectrum, with a higher value representing a deeper blue-green color. In the food-supplemented group, BGC chroma had xˉ=0.594 and s=0.010; in the control group, BGC chroma had xˉ=0.586 and s=0.009. A paired t-test resulted in t=2.28 and p=0.038. Interpret the results in the context of the data.

Answer 1

The study found that supplementary feeding resulted in more intensely blue-green eggshells in birds, with a significant p-value of 0.038, supporting the hypothesis that eggshell coloration is an informational signal of the female bird's health.

Step-by-step explanation:

Researchers conducted a study to determine if the blue-green chroma (BGC) of avian eggshells is related to the health of the female bird.

They hypothesized that females with supplementary food would lay eggs with higher BGC, indicating better health.

The study involved 16 nest pairs where the treatment group had an average BGC of 0.594 and the control group had 0.586.

The paired t-test yielded a t-value of 2.28 and a p-value of 0.038, which supports the hypothesis because the p-value is less than the typical threshold of 0.05, implying that there is a statistically significant difference between the two groups.

Bird eggs come in various colors and patterns, serving different evolutionary purposes such as camouflaging or signaling the health of the laying female.

The coloration may protect offspring from predation or provide information for intraspecies communication regarding mate selection.

This study's findings suggest that supplementary feeding, and by extension potentially better health or nutritional status, can influence the color intensity of eggshells in birds.

This could represent an evolutionary informational signal about the laying female's health, potentially affecting mating and reproductive success.