Physocephala Burgessi

physocephala burgessi

Physocephala burgessi, commonly known as a thick-headed fly, is a fascinating insect belonging to the family Conopidae. These flies are notable for their unique life cycle, where the larvae develop as internal parasitoids of other insects, primarily bees and wasps. While the adult flies are harmless nectar feeders, their reproductive strategy makes them an interesting component of their ecosystem, playing a role in regulating populations of their hosts. Often mistaken for wasps due to their striking mimicry, Physocephala burgessi are a testament to evolutionary adaptation. Their presence often indicates a healthy population of their host insects, as well as an abundance of flowering plants that provide nectar for the adults. They are an excellent example of the intricate and often hidden relationships within insect communities.

Habitat: Found in open, sunny areas such as meadows, gardens, field edges, and open woodlands where host insects and nectar-producing flowers are abundant.

Appearance

Physocephala burgessi exhibits a distinct wasp-like appearance, a form of Batesian mimicry that helps deter predators. Adults typically have slender, elongated bodies with a predominant black coloration, often adorned with contrasting yellow or reddish-brown markings, particularly on the abdomen. Their heads are relatively large and rounded ('thick-headed'), with prominent eyes. The wings are clear or slightly tinted, often with dark veins, and held in a characteristic manner over the body, further enhancing their resemblance to small wasps. Size-wise, they are medium-small flies, usually measuring between 10-15 mm in body length.

KingdomAnimaliaPhylumArthropodaClassInsectaOrderDipteraFamilyConopidaeGenusPhysocephala

Physocephala Burgessi

Interesting facts

Despite their wasp-like appearance, these flies are completely harmless to humans, feeding only on nectar as adults.

Female Physocephala burgessi often lay their eggs on host insects while the host is in flight, requiring incredible precision and timing.

The 'thick-headed' part of their common name refers to the distinctive broad head of flies in the Conopidae family.

The larvae of these flies are endoparasitoids, meaning they live and feed inside their host, eventually leading to the host's death.

Special abilities

Adult Physocephala burgessi closely mimic the appearance of wasps, featuring slender, banded bodies and often a buzzing flight. This mimicry provides protection from predators who avoid stinging insects.

The larval stage of this fly is a highly specialized internal parasitoid. Female flies lay eggs on or inside the bodies of live adult bees and wasps, with the developing larva consuming the host from within.

Adult female flies possess acute sensory abilities to locate suitable host insects, often identifying them in flight. They then swiftly deposit an egg with remarkable precision, ensuring the survival of their offspring.

Measurements & details

Length: 10-15 cm
Wingspan: 18-25 cm
Weight: 0.00005-0.0001 kg
Clutch Size: 100-500
Incubation: 3-7 days

Diet & Feeding

Adult Physocephala burgessi feed exclusively on nectar from various flowering plants, providing them with energy. In contrast, their larvae are obligate internal parasitoids, developing by consuming the tissues of their living insect hosts.

Age differences: Yes, adults are nectar-feeders, while larvae are internal parasitoids of other insects.