Feeding mechanisms of Diptera
The morphology of the mouthparts of insects are a result of their feeding habits, and as such, carrion feeding Diptera have modifications to allow them to pierce vertebrate skin and draw organic matter into their mouth (Gullan & Cranston, 2010). The mouth parts of adult Diptera flies are designed mainly for suction, with an elongated labrum which forms a tubular sucking organ (a proboscis) (Meeuse, 1988). Some also have modified mouthparts for piercing skin, with sharply pointed mouthhooks (Barker, 2004). These morphologies make them well equipped to feed on decaying human bodies (Barker, 2004).
Chemoreception
Insects can perceive chemical signals through the use of chemoreceptors found on various parts of their body (Gullan & Cranston, 2010). These chemical signals can be divided into taste or smell, depending on whether the signal is aqueous or air-borne, respectively (Gullan & Cranston, 2010). Chemoreceptors are sensory organs (sensilla) with one or many pores, and can exist as hairs, pegs, plates or simply pores, occurring on the antennae, legs (particularly the tarsi) or the mouth parts of insects (Gullan & Cranston, 2010). The sensilla trap chemical molecules, then transport these to a recognition site, where they stimulate a nerve impulse by depolarizing a membrane (Gullan & Cranston, 2010). Diptera, in particular the Calliphoridae family, have adapted highly sensitive chemoreceptive sensors, which is why blow flies (Calliphoridae), are one of the first of the insect families to arrive on a corpse (Huntington & Higley, 2010).
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