Collyria

Schiødte, 1839

Collyria is a of in the Collyriinae. within this genus are specialized of (), particularly those infesting cereal such as wheat. The genus includes species that have been investigated and employed as agents against pests in North America and Europe. Members exhibit with their , with typically emerging earlier than host , and demonstrate complex host discrimination behaviors including variable rates.

Collyria.coxator2.-.lindsey by James K. Lindsey. Used under a CC BY-SA 3.0 license.

Pronunciation

How to pronounce Collyria: /kəˈlɪriə/

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Identification

Collyria can be distinguished from other of by their placement in the Collyriinae. Specific morphological characters distinguishing Collyria from related are not detailed in the provided sources. Identification to species level requires examination of detailed morphological features not summarized here.

Images

Habitat

Agricultural fields, particularly wheat and other cereal systems where () occur. Associated with wheat stubble and stems where host develop and overwinter.

Distribution

to Europe (including England, Scandinavia: Denmark, Norway, Sweden) and Central Ciscaucasia (Russia). to North America (Canada: Ontario, Prairie Provinces; United States: western Montana considered as potential release area) as agent. One (C. catoptron) native to China.

Seasonality

emerge in summer, typically earlier than . period coincides with availability of host and young . Host larvae hibernate at base of wheat stems through winter, with development continuing within.

Host Associations

Cephus pygmaeus - ; primary for C. calcitrator
Cephus cinctus - North ; target of introductions
Cephus fumipennis - Chinese ; of C. catoptron, evaluated for control of C. cinctus
Cephus (Trachelus) tabidus - Additional for C. calcitrator

Life Cycle

-larval : eggs deposited into eggs or young , with development continuing through host larval stages. Host larvae overwinter at base of wheat stems with parasitoids inside. Single parasitoid develops per host (). emerge from host or pupal chambers.

Behavior

Females discriminate between healthy and parasitized , with probability of ( into already parasitized hosts) varying with proportion of parasitized hosts in . Superparasitism increases under host scarcity conditions. Only one individual successfully develops per host, with perishing.

Ecological Role

Specialized regulating of pests in cereal agroecosystems. Acts as agent reducing damage to wheat . Competes with other parasitoid such as Pediobius beneficus (formerly Pleurotropis benefica), which is intrinsically inferior competitor.

Human Relevance

Employed in programs against (Cephus cinctus in North America, C. pygmaeus in Ontario). Imported from Europe to Canada (1930–1939) and released in Prairie Provinces and Ontario. C. catoptron from China evaluated for potential release against C. cinctus in western Montana. Reduces to wheat production.

Similar Taxa

Pediobius beneficusAlso parasitizes Cephus ; formerly classified as Pleurotropis benefica; intrinsically inferior competitor to Collyria; may be mistaken for unparasitized in field

More Details

Superparasitism dynamics

Mathematical analysis of C. calcitrator showed that observed distributions in deviate significantly from random expectations, indicating active host discrimination. However, host shortage at peak parasite activity can cause high rates, potentially misleading assessment of discrimination ability.

Sampling considerations

Estimates of rates from wheat stubble may underestimate true parasitism because and their are removed with harvested straw, and because inferior competitor (Pediobius) must be accounted as unparasitized by Collyria.

Phenological matching

Development timing from termination of larval to varies by less than one day across C. catoptron and its C. fumipennis, and patterns are similar, facilitating successful .