Egg Chill Requirements

Research Issue

Diapause of the mature embryonic larva within the egg is a lengthy (8-9 mo/yr) and a critical portion of the life cycle of the nun moth.  Diapause enhances survival during the winter and synchronizes hatch with bud burst of preferred host plants in the spring.  The chill requirements for diapause completion and hatch of nun moths have not been investigated.  This information is required to parameterize predictive models and would be important for determining if eggs are laid on vessels or cargo would hatch in transit.  

Our Research

The hatch of eggs held for 0, 30, 60, 90, 120, 150, 180, and 210 days at 5 °C then incubated at 25 °C was evaluated.

Expected Outcomes

Knowledge of nun moth egg chill requirements required to make predictions of when eggs will hatch.

Research Results

Nun moth eggs have lower chill requirements for hatch than gypsy moths from the United States but require more chill than gypsy moth eggs from far east Russia to hatch.  Thus they could establish and may be able to adapt to a wide range of climates within the United States.

Research Participants

Principal Investigator

• Melody Keena, USDA Forest Service- Northern Research Station Research Entomologist

For further details log on website :
https://www.nrs.fs.fed.us/disturbance/invasive_species/nun_moth/biology_ecology/egg_chill/