Aptesis nigrocincta
(Gravenhorst, 1815)
Aptesis nigrocincta is a solitary ectoparasitoid that attacks cocoons of the apple sawfly (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 .
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 ichneumonids. The combination of reduced wings in females and association with apple sawfly cocoons 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 - cocoon Ectoparasitoid of prepupal cocoons; 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-oviposition period averages 5.8 days.
Behavior
Females locate cocoons by searching soil at 10–25 cm depth. After encountering a host, females require 19.9–29.3 minutes to deposit 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
Cocoon of apple sawfly; 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 sawfly (Hoplocampa testudinea), a pest of apple orchards.
Similar Taxa
- Other Aptesis speciesLikely similar and ; A. nigrocincta distinguished by specificity to apple sawfly and documented in orchard systems.
Sources and further reading
- BugGuide
- GBIF taxonomy match
- iNaturalist taxon
- NCBI Taxonomy
- Catalogue of Life
- Superparasitism in the solitary ectoparasitoid Aptesis nigrocincta: the influence of egg load and host encounter rate
- Life history ofAptesis nigrocincta(Hymenoptera: Ichneumonidae) a cocoon parasitoid of the apple sawfly,Hoplocampa testudinea(Hymenoptera: Tenthredinidae)