Acrocerinae

Acrocerinae is a subfamily of acrocerid flies, commonly known as wasp flies. These are small to medium-sized flies that are obligate parasitoids of other insects, primarily spiders. The adults are generally short-lived and do not feed, relying on reserves built up during their larval stages. Acrocerinae are characterized by their short, stout bodies, large heads that often occupy a significant portion of the total body mass, and often reduced or absent wings. Their legs are typically short and robust.

The larvae of Acrocerinae are endoparasitoids. First-instar larvae are mobile and actively seek out a host spider. Once a host is found, the larva enters the spider and develops within its body. The larval development is characterized by several instars, with the larva consuming the host's tissues. The spider host usually dies before the fly larva pupates. Pupation typically occurs within the spider's remains or the surrounding substrate.

The adult flies are weak fliers and are often found in shaded, humid environments where their spider hosts are likely to be found. Acrocerinae are distributed worldwide, with species found in various habitats, including forests, grasslands, and deserts. Their life cycle is highly specialized, making them sensitive to environmental changes and habitat disturbance. Research on Acrocerinae has focused on their host-parasite interactions, larval morphology, and phylogenetic relationships within the Acroceridae family.