Absence of outer caudal setae on all larval instars of Phlebotomus tobbi from the Ionian Greek islands

Abstract

Larval instars 2, 3 and 4 of Phlebotomus tobbi Adler, Theodor & Lourie from the Greek islands of Corfu and Zakynthos were found to have two caudal setae instead of the four usually present on these instars of Phlebotomus larvae. In a scanning electron microscope comparison with larvae of P. papatasi (Scopoli), a sensillum was seen in place of each outer seta of P. tobbi larvae, suggesting secondary loss of the setae. As the larvae of less than a tenth of the species and subspecies of the genus Phlebotomus have been seen and described, it cannot be assumed that those of P. tobbi are unique in having only two caudal setae. However, four caudal setae in late instars can no longer be considered as a constant character of the genus Phlebotomus. Observations on the larvae of P. tobbi also raise the question of the unknown function of the caudal setae.

Human Urogenital Myiasis Caused by Psychoda Species Larvae: Report of Five Cases and Morphological Studies

“…According to Killick-Kendrick et al (1989) the function of these setae is obscure. The distinctive backand forth movement of the long setae of larvae and their fine hair suggest the presence of sensillae.…”

External morphology of sensory structures of fourth instar larvae of neotropical species of phlebotomine sand flies (Diptera: Psychodidae) under scanning electron microscopy

“…According to Killick-Kendrick et al (1989) the function of these setae is obscure, although they observed a basal sensilla on the probable points of one of the naturally absent pairs of caudal setae of P. tobbi. The distinctive back-andforth movement of the long setae of larvae of L. whitmani and L. intermedia led Barretto (1940), to suggest the presence of sensillae.…”

“…Up to that time, all descriptions and morphological observations were made by light microscopy. Studies of sand fly larvae with scanning electronic microscopy (SEM) were initiated by Killick-Kendrick et al (1989) on Old World species Phlebotomus tobbi. In South America, Willians (1996, 1997) described by SEM the larvae of fourth and first instar of L. longipalpis.…”

Morphology and ultrastructure of spiracles in phlebotomine sandfly larvae

“…Although the characteristics of insect pre‐imaginal stages are as important in taxonomy as those of adults ( van Emden 1957), the larvae of most sandfly species have never been described or observed and few morphological characteristics of taxonomic importance have been identified ( Killick‐Kendrick et al . 1989 ).…”