Asaphes suspensus

(Nees, 1834)

Asaphes suspensus is a common hyperparasitoid (Hymenoptera: Pteromalidae) that attacks aphidiine primary within mummified aphids. The exhibits sophisticated discrimination , including self-discrimination that favors unparasitized hosts over self-parasitized ones, but notably lacks interspecific discrimination against competitors. It employs ovicidal behavior as a competitive strategy, physically destroying competitor through distinctive concave puncture sites. This species has been recorded from multiple continents including Europe, South America, and North America.

Pronunciation

How to pronounce Asaphes suspensus: //əˈseɪfiːz sʌsˈpɛnsəs//

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Identification

Distinguished from other hyperparasitoids by its ovicidal pattern: females create concave puncture sites when destroying competitor , a trait shared with some congenerics but differing from Dendrocerus carpenteri which lacks this aggressive egg-destruction strategy. Self- discrimination allows females to avoid of their own offspring, but unlike some competitors, does not avoid hosts parasitized by other hyperparasitoid .

Habitat

Associated with agricultural and cultivated systems supporting ; found in environments where Aphis fabae and other aphid occur, including bean crops and related plants.

Distribution

Recorded from Brazil (Minas Gerais), Canada (Alberta, British Columbia, Manitoba), and Europe; widespread distribution across multiple continents suggesting adaptability to temperate and subtropical regions with availability.

Host Associations

Aphis fabae - secondary ( host of primary )Bean aphid; mummified individuals contain primary attacked by A. suspensus
aphidiine primary parasitoids - primary Primary of aphids within mummified
Dendrocerus carpenteri - competitorInterspecific competitor; are targeted for ovicide by A. suspensus

Behavior

Females exhibit self- discrimination, laying significantly more on unparasitized hosts than on hosts already parasitized by themselves. Lacks interspecific host discrimination: does not avoid oviposition on hosts parasitized by Dendrocerus carpenteri. Performs ovicidal , killing approximately 85% of competitor eggs through physical destruction, creating distinctive concave puncture sites on host mummies.

Ecological Role

hyperparasitoid that occupies the fourth in aphid- . Acts as a competitor with other hyperparasitoid through aggressive ovicide. Considered detrimental to programs because it reduces the of primary parasitoids of aphids; management strategies may target reducing hyperparasitoid viability to improve primary parasitoid effectiveness.

Human Relevance

Negative impact on of pests due to hyperparasitism of beneficial primary . Plant extracts including Azadirachta excelsa (EC50 3.6 ppm) and Xanthium italicum (EC50 22 ppm) show to this , suggesting potential for selective management to protect primary parasitoid in systems.

Similar Taxa

Dendrocerus carpenteriCo-occurring hyperparasitoid; distinguished by A. suspensus having self- discrimination and ovicidal , while D. carpenteri lacks these traits and shows different host discrimination patterns
Pachyneuron aphidisCo-occurring hyperparasitoid of Aphis fabae; distinguished by differential susceptibility to plant extracts and likely differences in discrimination