When a moth's diet consists of one of the most abundant trees on the continent, it is no surprise to find them everywhere.
The Oak Besma is a common moth in North America, but not well known. It is sexually dimorphic, so males look different from females. Pale brown males have a thin, dark brown line crossing all the wings, creating a curve when they are flat and open. A dark patch sits below it. A shorter brown line hugs the moth's 'shoulders'. A small black dot sits between these lines. Hindwings also have a black dot just above the brown line. There is some variation among males, and varying shades of brown bands may be present as well as mottled markings. Females are pale yellow. The face and hairy thorax are bright yellow. The curved line across the female's wings is lighter, but still obvious. Both male and female are covered in fine freckles or specks that give it the appearance of woodgrain. Like many Geometer moths, the edges of the wings are wavy, or ruffled, and come to points.
Despite its name and love for oak leaves, caterpillars of the Oak Besma also eat from birch, poplar, willow, and white spruce. Two broods are produced each year.
Scientific Name: Besma quercivoraria
Butterfly or Moth
Size (Adult; Length): 27mm to 41mm (1.05in to 1.60in)
Colors: brown; yellow
Descriptors: single line; pale yellow; ruffled edge wings; dark patches; black dots; woodgrain; flying
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Butterfly and Moth Anatomy
Antennae: Butterflies and Moths have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and proboscis.
Thorax: Home to the three pairs of legs as well as vital internal organs.
Abdomen: Contains vital internal organs such as the heart(s) and reproduction facilities.
Forewing: The upper, forward wing pair used for flying.
Hindwing: The lower, rearward wing pair used for flying.
NOTE: Butterflies and Moths are part of the Lepidopteran order as they share many similarities.