Chrysobothris femorata

(Olivier, 1790)

flatheaded appletree borer

Chrysobothris femorata is a metallic wood-boring in the , commonly known as the flatheaded appletree borer. It is a pest of fruit, , and nut trees in North America. The was historically a catch-all for a complex of closely related species, but was taxonomically revised in 2007 to define more precise species limits. are attracted to stressed or dying trees, where females oviposit in bark crevices and tunnel beneath the bark, potentially girdling and killing trees.

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Pronunciation

How to pronounce Chrysobothris femorata: //ˌkrɪsoʊˈbɒθrɪs ˌfɛmɔˈreɪtə//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Differs from related in the C. femorata species-group by the combination of: straight posterolateral elytral margins (versus arcuate in C. caddo), reddish elytral (versus bronze in C. caddo), shallowly impressed (versus deeply impressed in C. quadriimpressa), and lack of margin on pygidium (present in C. adelpha). Identification requires examination of multiple character suites; no single diagnostic character reliably separates it from all relatives.

Images

Appearance

are with characteristic body form—elongate, somewhat flattened, and streamlined. The have straight (not curved) posterolateral margins and distinctly reddish tips. Males possess a bright green , while females show reddish tinges behind the and on the . The ( abdominal tergite) is shallowly impressed on each side of the middle. Body length approximately 15–18 mm.

Habitat

Associated with deciduous in landscape, orchard, and forest settings. Most commonly encountered on stressed, dying, or recently windthrown trees. are and found on exposed trunks and logs in sunny conditions.

Distribution

North America, including all continental United States and Canada. More common east of the Continental Divide. Also reported from Central America.

Diet

feed phloeophagously (on inner bark and cambium) of trees. do not feed on material.

Host Associations

Acer - larval maple
Betula - larval birch
Crataegus - larval hawthorn
Malus - larval apple
Platanus occidentalis - larval sycamore
Populus - larval poplar, cottonwood
Prunus - larval cherry
Pyrus - larval pear

Life Cycle

. are deposited in bark crevices. hatch and tunnel beneath the bark, feeding on phloem and cambium. Larvae are flattened in form (giving rise to the

Behavior

are and active on sunny days. Males rapidly search up and down trunks seeking mates. Females bark cracks and crevices with their to locate -laying sites. Adults are visually oriented, with large adapted for . When disturbed, they exhibit rapid, erratic with flash coloration from the brilliant metallic -green surface. Attracted to violet and red wavelengths of light, as demonstrated in trapping studies.

Ecological Role

Primary colonizer of stressed and dying deciduous trees. Larval tunneling accelerates tree death by girdling trunks and branches. Contributes to by initiating wood decomposition. Serves as for insectivorous birds and other .

Human Relevance

Significant economic pest of nursery stock, fruit trees (apple, pear, cherry), and landscape trees. Larval boring weakens and kills young trees, particularly those stressed by transplanting, sunburn, or other factors. Management in commercial settings relies on protecting tree trunks and . No reliable monitoring methods existed until recent studies on color-based trapping.

Similar Taxa

Chrysobothris caddoFormerly confused under C. femorata; distinguished by arcuate (curved) posterolateral elytral margins and bronze (not reddish) elytral . Associated primarily with Celtis (hackberry) rather than rosaceous .
Chrysobothris shawneeFormerly confused under C. femorata; distinguished by larger, bronze-black callosities. Associated primarily with Quercus (oak).
Chrysobothris quadriimpressaFormerly confused under C. femorata; distinguished by shallowly impressed . Associated primarily with Quercus.
Chrysobothris maliSimilar (Pacific flatheaded borer) and biology; distinguished by geographic distribution (primarily western North America) and molecular/genitalic characters. Recently documented attacking pear fruit, a not previously recorded for the .

Misconceptions

Historically, C. femorata served as a catch-all for multiple cryptic . Many literature records of and distributions actually refer to other species in the complex, particularly records from Quercus and Celtis. The 2007 revision by Wellso and Manley clarified species limits, but specimens in older collections and literature may be misidentified.

More Details

Taxonomic history

The C. femorata -group was last revised by Fisher in 1942. Wellso and Manley (2007) revised the group, describing six new species (C. caddo, C. comanche, C. mescalero, C. seminole, C. shawnee, C. wintu), resurrecting C. quadriimpressa from synonymy, and designating for C. femorata, C. rugosiceps, and C. viridiceps. The revision doubled the number of described species in the group from six to twelve.

Color vision and trapping

Studies demonstrate attraction to violet-range and red wavelengths. Traps with hues between red and (higher b* values) capture more . This visual preference may relate to -location mechanisms, though ecological interpretation remains speculative.