Aptesis nigrocincta

(Gravenhorst, 1815)

Aptesis nigrocincta is a solitary that attacks of the apple (Hoplocampa testudinea). Females are nearly wingless and significantly smaller than males, an for searching soil at 10–25 cm depth. The is considered the most important mortality factor for apple sawfly cocoons in the studied orchard, achieving rates of 12.1–39.7% per .

Aptesis nigrocincta by (c) Owen Strickland, some rights reserved (CC BY), uploaded by Owen Strickland. Used under a CC-BY license.

Pronunciation

How to pronounce Aptesis nigrocincta: /æpˈtesɪs nɪɡrəʊˈsɪŋktə/

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Identification

Females nearly wingless and significantly smaller than males; this distinguishes A. nigrocincta from many other . The combination of reduced in females and association with apple in orchard soil provides field identification cues.

Images

Habitat

Soil at 10–25 cm depth in apple orchards; specifically documented from an organically managed apple orchard in Switzerland.

Distribution

Switzerland (field documented); Denmark, Norway, and Sweden (GBIF records).

Seasonality

(two per year).

Host Associations

  • Hoplocampa testudinea - of prepupal ; most important mortality factor in studied orchard

Life Cycle

; to development takes 38.0 days (males) to 39.6 days (females) at 20°C. Females emerge nearly wingless. Pre- period averages 5.8 days.

Behavior

Females locate by searching soil at 10–25 cm depth. After encountering a host, females require 19.9–29.3 minutes to an depending on temperature. Females mate immediately after ; copulation lasts approximately 21.7 seconds. Exhibits influenced by egg load and host encounter rate: accepts parasitized hosts at low encounter rates but rejects them when host availability is high and egg limitation is imminent. Food deprivation drastically reduces longevity and .

Ecological Role

of apple ; constitutes the most important mortality factor for Hoplocampa testudinea cocoons, with rates of 12.1–39.7% per in field studies.

Human Relevance

agent of apple (Hoplocampa testudinea), a pest of apple orchards.

Similar Taxa

  • Other Aptesis speciesLikely similar and ; A. nigrocincta distinguished by to apple and documented in orchard systems.

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Sources and further reading