Larvae are approximately 11-15 mm in length and are bright green with a black head. The black head is lost in the final instar, where both the head and prothoracic shield are brown. An anal comb is present with 6-10 teeth.
Acleris variana completes one generation per year. Adults are present in August and September. The A. variana life cycle is nearly identical to that of Acleris gloverana.
Females lay eggs on the underside of needles in the upper section of host trees. Eggs overwinter until the following spring, and larvae hatch starting in mid-May. First intars feed inside opening buds, mid-instars web together needles to create a nest, and last instars are free-feeding. Males and 50% of females complete 4 larval instars while the remaining females complete 5 instars. Pupation occurs in webbed needles. Adults eclose in approximately two weeks.
Larval damage is similar to that of Acleris gloverana, although outbreaks of A. variana do not tend to cause tree mortality. Periods of low rainfall tend to trigger increases in A. variana populations.
Acleris variana attacks primarily fir and spruce. It has been recorded from the following hosts:
|Family ||Genus/species ||Common name|
|Cupressaceae ||Thuja plicata Donn ex D. Don ||western redcedar|
|Pinaceae ||Abies alba Mill. ||silver fir|
|Pinaceae ||Abies amabilis (Douglas ex Louden) Douglas ex Forbes ||Pacific silver fir|
|Pinaceae ||Abies balsamea (L.) Mill. ||balsam fir|
|Pinaceae ||Abies grandis (Douglas ex D. Don) Lindl. ||grand fir|
|Pinaceae ||Abies lasiocarpa (Hook.) Nutt. ||subalpine fir|
|Pinaceae ||Abies Mill. ||fir|
|Pinaceae ||Larix Mill. ||larch|
|Pinaceae ||Larix occidentalis Nutt. ||western larch|
|Pinaceae ||Picea A. Dietr. ||spruce|
|Pinaceae ||Picea abies (L.) Karst. ||Norway spruce|
|Pinaceae ||Picea engelmannii Parry ex Engelm. ||Engelmann spruce|
|Pinaceae ||Picea glauca (Moench) Voss ||white spruce|
|Pinaceae ||Picea mariana (Mill.) Britton, Sterns & Poggenb. ||black spruce|
|Pinaceae ||Picea pungens Engelm. ||blue spruce|
|Pinaceae ||Picea rubens Sarg. ||red spruce|
|Pinaceae ||Picea sitchensis (Bong.) Carriere ||Sitka spruce|
|Pinaceae ||Pinus contorta Douglas ex Loudon ||lodgepole pine|
|Pinaceae ||Pseudostuga Carriere ||Douglas-fir|
|Pinaceae ||Pseudotsuga menziesii (Mirb.) Franco ||Douglas-fir|
|Pinaceae ||Tsuga canadensis (L.) Carriere ||eastern hemlock|
|Pinaceae ||Tsuga heterophylla (Raf.) Sarg. ||western hemlock|
|Pinaceae ||Tsuga mertensiana (Bong.) Carriere ||mountain hemlock|
|Salicaceae ||Populus balsamifera L. ||balsam poplar|
Acleris variana is distributed in coniferous forests from eastern Canada and the northeastern United States west to Alberta.
Fig. 7: Rick West, Canadian Forest Service, Bugwood.org
Fig. 8: Connecticut Agricultural Experiment Station Archive, Connecticut Agricultural Experiment Station, Bugwood.org