Tachinidae

Thomas Bresson - Tachina fera (by)

10-Indian-Insect-Life - Harold Maxwell-Lefroy - Tachinidae

Tachinid eggs on Leptoglossus

Istocheta aldrichi egg on Japanese beetle

Tachinidae

Ormia ochracea (gravid female)

Tachinidae is a large family of flies belonging to the order Diptera, encompassing over 10,000 described species distributed worldwide. Tachinidae, commonly known as tachinid flies, are predominantly parasitoids or occasionally parasitic in nature, with their larvae developing inside the bodies of other arthropods, mainly Lepidoptera (moths and butterflies), but also within other groups such as Coleoptera (beetles), Hymenoptera (sawflies, bees, wasps, and ants), and other Diptera. Due to their parasitic lifestyle, many tachinid flies are considered important in the biological control of pest species.

Description

Tachinid flies are diverse in appearance, ranging in size from small to large, with body lengths varying from 2 to 20 mm. They often have a bristly appearance, with stout bodies and a significant variation in coloration, from dull to brightly colored. Key identifying features include a well-developed postscutellum, a unique structure not found in most other flies, and the presence of tachinid-specific bristles on the abdomen and legs.

Life Cycle

The life cycle of tachinid flies involves several stages: egg, larva, pupa, and adult. Females lay their eggs in various ways, depending on the species. Some deposit eggs directly onto the host, others inject eggs into the host's body, and a few species lay eggs in the environment, where the larvae then find and penetrate their hosts. Once inside, the larvae feed on the host's tissues, eventually leading to the host's death. The larval stage is followed by pupation, either inside or outside the host's body. The adult flies emerge from the pupae to continue the cycle.

Ecological Role

Tachinid flies play a significant role in the control of populations of many pest insects, making them allies in agriculture and forestry. Their parasitoid nature targets a wide range of host species, including many that are harmful to crops and trees. This has led to the intentional use of tachinid flies in biological control programs. However, their impact is complex, as they can also affect populations of non-target species, including beneficial insects.

Taxonomy and Classification

The family Tachinidae is divided into several subfamilies and numerous genera. The taxonomy is complex and continually evolving, with ongoing research and molecular studies revealing new insights into the relationships within this diverse group. The classification of Tachinidae into subfamilies and genera is based on morphological characteristics, such as the structure of the antennae, mouthparts, and wing venation, as well as larval and pupal features.

Research and Conservation

Research on Tachinidae encompasses various aspects, including their taxonomy, biology, ecology, and use in biological control. Conservation efforts for tachinid flies focus on maintaining habitat diversity to support their complex life cycles and the ecological services they provide. As with many insects, habitat loss, pesticide use, and climate change pose threats to their populations.