(EE, pp ) Flies

Phylogeny of Hexapoda from p. 52 Diptera

Common name: Diptera (122,000 known world species (12.2%)) Derivation: Gk. di - two; pteron - a wing Size: Body length mm; wing span up to 75 mm Metamorphosis: Complete (egg, larva, pupa, adult) Distribution: Worldwide Number of families: 130

Key Features abundant and ubiquitous one pair of functional wings (although some wingless) some species have immense economic impact through disease transmission fourth largest order

beneficial to the function of ecosystems as  pollinators  parasites  predators  decomposition and recycling relatively few species have a great impact on humans (e.g. mosquitoes) Flies are very successful (they are one of the dominant insect orders in most habitats) Giant stinky flowers (Raffleisa) attract flies - which act as pollinators Parasitic flowers that weigh more than a bowling ball!

single pair of membranous front wings hind wings are reduced to form a pair of balancing organs called halteres (think of these as gyroscopes) halteres are beat at the same frequency as wings, but out of phase they provide vital information to the flight system to keep the insect flying straight Wings are a key feature (flies are incredible acrobats - wing morphology is largely responsible)  hover  fly backwards  360 degree turns  upside down flight and landing

adults feed on a range of liquids, including blood, nectar and the products of plant or animal decay two basic types - biting/sucking and licking/sponging Fly mouthparts (designed for the ingestion of liquid foods)

to penetrate the skin, stylet bundle is sawed through the tissue towards a blood vessel to allow deep stylet penetration, the labium folds back on itself Saliva is pumped down the hypopharynx and the blood meal is sucked back up the food canal Mosquito mouthparts (only females suck blood and have fully developed mouthparts)

extended by the means of muscles and haemolymph pressure paired labial palps, located at the end of the proboscis, form a sponge- like structure (the labellum) saliva pumped down the hypopharynx onto the underside of the labellum - it is then drawn back up into the food canal House fly mouthparts (made up from fusion of the clypeus, maxillae and labium) psuedotracheae direct saliva across the food

eggs generally hatch quickly fly larvae (or maggots as they are often called) are cylindrical and often elongate, grub-like or worm-like they all lack thoracic legs Fly eggs and larvae (most female flies lay eggs, which are laid in the vicinity of larval food) Nematoceran larvae - 4 instars Brachyceran larvae instars

Diptera Suborders (two suborders, with the derived group split into two divisions) Suborder Number of families Feeding habits Nematocera26 (primitive) thread-horned’ flies such as crane flies, mosquitoes, black flies, midges, and fungus gnats - larvae are mostly detrtivorous or filter feeders (but some are gall formers or predators) Brachycera (Orthorrhapha)19 horse flies, robber flies and long-legged flies - larvae are mostly predaceous or parasitic Brachycera (Cyclorrhapha)85 hover flies, house flies and blow flies - larvae feeding is highly varied, most species are saprophagous

larvae have a well-defined head capsule (eucephalic) and the mandibles move in a horizontal plane pupae not enclosed in larval cuticle Suborder Nematocera (the basal Diptera Suborder)

adults have thread-like antennae with at least 6 segments (usually a lot more) maxillary palps are long Suborder Nematocera (the basal Diptera Suborder)

larvae have a reduced head capsule (hemicephali c) and the mandible move in a vertical plane pupae are not enclosed in their larval cuticle Suborder Brachycera (Division Orthorrhapa)

adults have short antennae, less than 6 segments - last segment is elongate or with bristle-like arista maxillary palps are short Suborder Brachycera (Division Orthorrhapa)

head capsule is vestigial, retractable (acephalic) and the mandibles are absent (replaced with specialized mouth hooks) pupa enclosed in last larval cuticle (puparium) Suborder Brachycera (Division Cyclorrhapa) mouth hooks

adults have short antennae, less than 6 segments - the last segment is elongate or with bristle-like arista maxillary palps are short Suborder Brachycera (Division Cyclorrhapa) tachinid flyfruit fly (tiphritid)

Flies as parasitoids (20% of all fly species are parasitoids - usually other insects)

Flies that eat human flesh (the larvae twist inside of flesh and drink up necrotic tissue) big-headed fly (pipunculid)

Flies practice mimicry (some flies try to look like wasps and bees) mydas fly (mydid) robber fly (assilid) hover fly (syrphid) bee fly (bombyliid)