Larval anatomy and intra-puparial development of the camel nasal bot fly, Cephalopina titillator (Diptera: Oestridae).

Larvae of the camel nasal bot fly, Cephalopina titillator (Diptera: Oestridae), cause nasopharyngeal myiasis in camels. This myiasis can be severe, even fatal. Here, the morphology of the main organs of second (L2) and third (L3) instar larvae and of the intra-puparial forms are described, using a combination of micro-computed tomography supported by routine histology. For this, L2 and L3 larvae were collected from the heads of slaughtered camels and were either killed and preserved or allowed to pupariate. Pupariated specimens were killed at intervals and larvae and puparia were prepared for micro-CT scanning. Additionally, freshly collected larval specimens were fixed, stained and examined by light microscopy. The most distinctive internal larval structures were the digestive organs, occupying almost 5 % of the internal larval volume. The larval salivary glands were enlarged, with a similar relative volume to other Oestrinae, but they were shorter and did not unite posteriorly in a "glandular band". The distal region of the Malpighian tubules was also enlarged as in other Oestrinae, but to a lesser degree. The intra-puparial forms showed a gradual reduction of the digestive tract, reflecting the non-feeding behaviour of adults, yet had highly developed reproductive organs facilitating mating soon after eclosion. The morphological and physiological adaptations to parasitism are discussed.