In the April 2008 Mothly Newsletter I (Bill Oehlke) encouraged members to do some experimentation with egg chilling to see how long fresh eggs could be
chilled to delay development without permanent death or injury to developing larvae.
Dirk Bayer writes, "Do you remember that experiment (spring 2008) where I refrigerated some cecropia eggs for up to 10 days?
"Out of thirty-six eggs, eight spun cocoons, and all have hatched (March-April 2009) 3 females and 5 males.
"Two of the females attracted males and laid eggs that hatched. The larva are thriving on sumac. I released the other female after 3 days, only to have a male hatch the next day.
"Some of the larva from the egg experiment were eaten by spiders, and a lizard had a meal of one batch. I don't believe any of the losses were a result of the refrigeration. I used 4 eggs for each batch only because that is all I had at the time."
Batch 1: four eggs deposited May 7, refrigerated for two days, all hatched May 19, twelve days after deposition, one cocoon.
Batch 2: four eggs deposited May 7, refrigerated for three days, all hatched May 20, thirteen days after deposition, two cocoons.
Batch 3: four eggs deposited May 7, refrigerated for five days, all hatched May 22, fifteen days after deposition, one cocoon.
Batch 4: four eggs deposited May 7, refrigerated for six days, all hatched May 23, sixteen days after deposition, one cocoon.
Batch 5: four eggs deposited May 7, refrigerated for ten days, all hatched May 27, twenty days after deposition, two cocoons.
Batch 6: four eggs deposited May 7, refrigerated for eleven days, all hatched May 28, twenty-one days after deposition, one cocoon.
Many thanks to Dirk for his experimentation and reporting. I encourage others to do similar experiments with excess eggs during spring/summer of 2009.
It would appear that fresh cecropia eggs can be refrigerator chilled for at least eleven consecutive days without adverse effects.
Here is the challenge as issued in May 2008.
I (Bill Oehlke) am going to be doing some egg cooling experiments in June, 2008. I want to determine how long freshly deposited Antheraea polyphemus eggs can be chilled and kept cool without adversely affecting hatch rate and subsequent development of larvae into mature adults. I invite others to participate with this species and/or with other common Saturniidae.
I get many polyphemus pairings between wild males and females from my overwintered cocoons. I intend to place approximately 100 eggs in groups of 12 eggs each in a closed plastic container to be kept in my refrigerator crisper. All eggs, from the same female and same deposition date, will be placed in cold storage (fridge crisper, temperature about 36-38F) at around 8:00 am the morning after deposition.
Twenty-four hours later, a first batch of a dozen eggs will be removed from cold storage and will be kept under same indoor conditions as control group of unchilled eggs from the same female, deposited on same date as chilled eggs. Each batch of 12 chilled eggs will be removed from cold storage at 24 hour intervals so that I will have egg batches chilled from one to seven days to compare to unchilled eggs. Records will be kept to see if chilled eggs hatch, and, if they do hatch, how much of a delay there is.
During spring/summer of 2008, I experimented with polyphemus eggs, also using smaller batches than I had initially recommended. I went with seven batches of six eggs each.
Eggs were harvested from brown paper bag on the morning after deposition. Forty-two eggs, all from the same female with same date of deposition,
were put into refrigerator cold storage in sealed plastic tubs. Six eggs/day were removed after 1-6 days of storage and were placed in
labelled hatching tubs. One batch was kept in storage for a full month. Larvae from the first six egg batches emerged, fed, developed and spun cocoons as per unchilled eggs.
No larvae emerged from the eggs that were chilled for a full month.
My recollection is that the eggs that were chilled for up to five and six days showed sporadic hatching results, ie., they did not all hatch on the same date, and some hatched as
many as four days apart despite identical conditions of storage and non chilled incubation.
At any rate, it appears that fresh polyphemus eggs can be cold delayed for at least six days without adverse conditions, and cecropia eggs can be cold stored
for at least eleven days. I will probably try more polyphemus in June of 2009 for seven to twelve days in cold storage and will also do some experiments with chilling
luna, cecropia and columbia as well.
Use your browser "Back" button to return to the previous page.