Prionus laticollis

(Drury, 1773)

broad-necked root borer, broad necked prionus

Prionus laticollis, commonly known as the broad-necked root borer, is a large root-boring longhorn beetle native to eastern North America. The is a significant economic pest of apple orchards, where larvae tunnel through roots causing structural damage to trees. are primarily , with males attracted to lights and females using an elongated ovipositor to deposit in soil. The species exhibits strong , with females substantially larger than males. The spans 3-4 years, with larvae developing underground while feeding on tree roots.

Prionus laticollis by (c) Samuel Paul Galick, some rights reserved (CC BY), uploaded by Samuel Paul Galick. Used under a CC-BY license.

Prionus Laticollis with ovipositer extended laying eggs by Cute Little Sweet Rainbow Stag Beetles. Used under a CC BY-SA 4.0 license.

Three eggs laid by Prionus laticollis on July 18, 2017 by Cute Little Sweet Rainbow Stag Beetles. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Prionus laticollis: /ˈpriː.ə.nəs ˌlæ.tɪˈkoʊ.lɪs/

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

Identification

Distinguished from other eastern North American Prionus by the combination of -punctate (roughly wrinkled and pitted) elytral texture and with exactly 12 antennomeres. P. pocularis has simple punctate rather than rugose-punctate, and P. imbricornis has more than 12 antennomeres. Females are readily identified by their large size and prominent ovipositor. Males are smaller with less robust antennae compared to some .

Images

Habitat

Terrestrial with suitable trees; found in deciduous woodlands, forest edges, and agricultural settings including apple orchards. are often encountered at the base of oak trees and other host plants. Larval habitat is subterranean, within and around tree roots.

Distribution

Eastern North America, ranging from Quebec in northeastern Canada southward to Arkansas in the southwestern United States. Widespread throughout the eastern deciduous forest region.

Seasonality

are active primarily during summer months. Peak adult occurs June-July. Adults are , most active during dusk and at night. Males are frequently attracted to lights.

Diet

Larvae feed on roots of living, weakened, or dead trees and shrubs. Documented include apple (Malus), oak (Quercus), and various other hardwoods. Larvae initially feed on bark, then proceed to hollow out small roots and may excavate interior wood.

Host Associations

Malus - larval major economic ; larvae cause damage to apple tree roots in orchards
Quercus - larval frequently found at base of oak trees

Life Cycle

Complete with a 3- to 4-year . are deposited in soil or on soil surface in mid-summer. Larvae tunnel downward to feed on living roots, initially consuming bark before excavating wood. Larvae leave roots to pupate in soil at depths up to 84 cm. Prepupal stage occurs May-June, pupal stage June-July. emerge, live approximately one week, and mate multiple times.

Behavior

are predominantly and , hiding during daylight hours. Females exhibit a distinctive "shivering" while ovipositing, inserting the ovipositor into soil or under litter. are typically laid in groups of two to four. After egg deposition, females move the ovipositor up and down to fill the hole. Males are attracted to prionic acid-based lures and frequently fly to lights. Adults are capable burrowers and hide at the base of trees.

Ecological Role

Root-boring herbivore that contributes to tree stress and mortality, particularly in agricultural settings. Natural mortality factors include by tachinid flies, pathogenic microorganisms, larval , and freezing temperatures. The serves as a model organism for studying cerambycid and has facilitated development of monitoring tools for related species.

Human Relevance

Significant economic pest of apple orchards in the eastern United States, causing damage through root boring that can weaken or kill trees. The was instrumental in development of prionic acid lures, originally created for orchard monitoring and now widely used in research on related Prionus species. occasionally encountered by homeowners and naturalists due to their large size and attraction to lights.

Similar Taxa

Prionus pocularisAlso has 12 antennomeres, but distinguished by simple punctate (not -punctate)
Prionus imbricornisHas but possesses more than 12 antennomeres
Prionus integerGreat Plains with different preferences and distribution; males attracted to same lures but species distinguished by geography and associations

More Details

Pheromone biology

Females produce prionic acid as the principal component of their . This compound has been synthesized for commercial lures used in orchard monitoring. Males are strongly attracted to prionic acid but may require additional chemical cues to precisely locate females, as evidenced by their circling near lures without always finding trap entrances.

Egg characteristics

Freshly laid are pure white and glistening with moisture, changing to deep yellow after a period, then to light washed pink, and finally to ivory as larvae develop internally. Eggs are approximately the size of small rice grains. Larvae hatch by chewing through one of the elongated, pointed ends of the egg.

Larval adaptations

Larvae possess adapted for digging into soil and strong black for chewing roots. They are capable of feeding on both living and dead woody material, with a preference for softer food sources.