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Overwintering Physiology and Microhabitat Use of Phyllocnistis populiella (Lepidoptera: Gracilliariidae) in Interior Alaska
|Title||Overwintering Physiology and Microhabitat Use of Phyllocnistis populiella (Lepidoptera: Gracilliariidae) in Interior Alaska|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||Wagner, D, Doak, P, Sformo, T, Steiner, PM, Carlson, B|
We investigated the overwintering physiology and behavior of Phyllocnistis populiellaChambers, the aspen leaf miner, which has caused severe and widespread damage to aspen in Alaskaover the past 10 yr. Active P. populiella moths caught in spring and summer supercooled to an averagetemperature of 16C, whereas dormant moths excavated from hibernacula in the leaf litter duringfall and winter supercooled to an average of 32C. None of the moths survived freezing in thelaboratory. Counts of overwintering moths in leaf litter across microhabitats in interior Alaskademonstrated that moths occurred at signiÞcantly higher density beneath white spruce trees thanbeneath the aspen host, several other hardwood species, or in open areas among trees. During winter,the temperature 1Ð2 cm below the surface of the leaf litter beneath white spruce trees was on average7Ð9C colder than beneath aspen trees, and we estimate that during at least one period of the winterthe temperature under some white spruce trees may have been cold enough to cause mortality.However, the leaf litter under white spruce trees was signiÞcantly drier than the litter from othermicrohabitats, which may assist P. populiella moths to avoid inoculative freezing because of physicalcontact with ice. We conclude that in interior Alaska, P. populiella overwinter in a supercooled statewithin leaf litter mainly under nonhost trees, and may prefer relatively dry microhabitats over moisterones at the expense of lower environmental temperature.