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Procedure:

Fifty eggs were placed into each of three treatment environments (as seen in Figure 3): a warm treatment that fluctuated between 22°C and 32°C during night and day respectively, a cold treatment that fluctuated from 6°C to 16°C, and a control treatment that fluctuated between 17°C and 27°C. The ten degrees of fluctuation mimicked a twenty-four hour day where the lighting in the treatments were programmed to be on during the day and off during the night hours. "Day" lasted from 5:00 A.M. until 9:00 P.M.

Figure 3

A larvae cage in a cooler

The development of monarchs was monitored from the egg stage to the full adult. The eggs were monitored from the time they hatched until the point at which they emerged from the chrysalis.  

Figure 4	Figure 5
Measuring the length of a larva	Weighing a larva

Ten larvae were randomly selected from each treatment environment (warm 22-32°C, cold 6-16°C, and control 17-27°C), their instar was determined [as according to A Field Guide to Monarch Caterpillars (Danaus plexippus)] and recorded. Then, as seen in Figures 4 and 5, each larva was weighed on an electronic balance and measured with digital calipers (length from the head capsule to the anterior end not including the tentacles). The masses and lengths of the ten larvae were averaged and recorded. All larvae present in each treatment were counted to determine the number that died. Once all the larvae in a treatment had reached the fifth instar level, the color of the ten random larvae was quantified, using the following unique presence absence method, as seen in Figures 6, 7,  8, 9, and 10. The larva was placed on a post-it note and allowed to straighten. A small ruler was placed beside the larva, and the number of millimeters that contain black stripes, the number of millimeters that contain yellow stripes, and the number of millimeters that contain white stripes were counted and recorded.  This was repeated for all ten larvae.

Figure 6

This figure shows how the color measurements took place. Black would be recorded as 10 mm, yellow would be recorded as 9 mm, and white would be recorded as 6 mm.

Figure 7	Figure 8
A larva on a Post-it note, ready to have its color measured	The color measurements being taken
Figure 9	Figure 10
A finished Post-it note	An adult monarch having its wings measured

As the butterflies emerged, their treatment, gender, personal identification number, and date of emergence (D.O.E.) were recorded. After all information was recorded, adults were released into the wild. Finally, mortality rates, color ratios, and development rates in the different treatments were analyzed and studied.

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