We Still Couldn't Cross Them-Here's Why

Genetic crosses of different fruit flies have not started yet, because virgin females of each phenotype had not been isolated. Today, we released all remaining adults, sorted the newly hatched flies, and isolated a small number of white-eyed and wild type females into new cultures. Hopefully there will be new flies present in the vestigal culture tomorrow.

Final Sexing Before Thanksgiving/Genetic Crosses

For the last sexing (Wednesday) before Thanksgiving break and the actual genetic crosses of the project, the cultures containing White eyed flies were focused on. Although the other cultures have seen hatchings, white eyed flies had the largest population growth that needed to be addressed in the shortened period.
37 new females and 21 males were accounted for.

For the vestigal flies, the tube containing the largest amount of slime mold was thrown out, because the contaminated food had begun to kill off the flies within that culture. However, the other vestigal culture is well, containing a healthy mixture of adult flies, larvae, and cacoons.

Hatching Update

This week, the fruit fly cultures were moved from the classroom environmental chamber to an incubator set at ____ degrees. This has resulted in an increase in the number of hatched flies per culture; especially with the white-eyed flies. The adults in separate cultures are still thriving, and laying eggs. Sexing information on the newly hatched flies will come in the next post.
Slime molds are still an issue within the cultures, but changes in the levels of food have not done anything to reduce their presence. More research will be done to evaluate this issue.
Next week, virgin flies will be taken from each culture to be used in the genetic crossings of each phenotype.

Second Generation

The eggs in our cultures have finally starting hatching. At this point, they have not been sexed.

• Wild Type
• Three flies hatched during the day--more had been retrieved earlier.
• Larvae are still crawling in the food and up the sides of the culture.
• White Eyed
• Small number of white-eyed (around 4) had hatched over the weekend; one hatched later today.
• larvae are still crawling in the food and up the sides of the culture.
• Vestigal
• Although food is infected, larvae are moving within it and stabilizing on the sides of the culture.
• 5 hatched during the course of the day, none from the weekend.

November 3 Update

Sexing of remaining vestigial adults:
20 females and 2 males.

Sexing the flies this time was easier, because another distinguishing trait between the two sexes was also used: male fruit flies have dark patches of sex combs on their upper limbs, while female fruit flies only have sparse hairs.

Observations of the other cultures:
Wild type eggs/larva--larvae are still present in the food, and chrysalises on the sides of the culture have still not hatched. Slight discoloration that can be attributed to slime mold growth is also present.
Wild type adults--only one is left alive (a male); more flies may need to be added into this culture.
Vestigial Developing flies--larvae are still digging tunnels in the food, and chrysalises on the sides of the culture have not yet hatched.
Vestigial Adults, previously sexed-- 11 have died, 10 are still alive, and there is no evidence of reproduction within the culture.
White eyed--the culture is still thriving overall, but a large number died in the last 24 hours (no sufficient time to get a count). Larvae are still burrowing in the food source.

**For future reference: When genetic crosses begin, females will have to be counted in the morning. If there are old females mixed in with males, they will need to be killed or released. Newly hatched females will be moved to a separate culture, because they are still virgins for their first 10 hours of life. If they are left to have sex after this time period, they are useless for genetic crosses, as they can store sperm from more than one parent and the specific genes that the offspring will have will not be evident.

Life Cycles: November 1

After a long weekend, many changes were noted in the cultures of fruit flies.

• Vestigal:
• Only two males were left alive in the vestigal culture. Because of this, we had to take flies out of the teacher's culture and add them to ours. Then, they were sexed in two groups. For the first group, there were 6 females and 10 males. For the second group, there were
• In the culture that had been contaminated with slime mold (which the adults had been separated from), metamorphic casings had appeared on the sides of the container and larvae were also visible within the food.
• Wild Type:
• Within the cultures for the wild type flies, the larvae had made metamorphic casings, while others were still scurrying around the food as worms.
• For the adults, only three were still alive, and had not laid any new eggs.
• White Eyed:
• The many adults that had been added to the white-eyed sample were still thriving, but had not laid any new larvae. Some were still visible in the food, but had not progressed to the stage where they made metamorphic casings

For future reference:
--While food should be kept in a one-to-one ratio, there should be less of the food and water added total. Because slime molds accumulate so quickly in the cultures, lessening the amounts of food might be beneficial to the prolonged survival of the flies.