A cytological description of Eusimulium vernum, E. decolletum, and the E. pugetense complex (Diptera: Simuliidae) in Alaska

Abstract

Larval populations of the black flies Eusimulium vernum, E. decolletum, and E. pugetense in Alaska were analyzed using polytene chromosome cytology. One cytotype ("Knebworth") of E. vernum was found and cytotypes A and B of E. pugetense were found, with cytotype B having distinct northern and southern variants. No fixed inversions were found between E. decolletum and E. vernum, an interpretation that differs from a previous publication. Eusimulium decolletum is characterized cytologically by its profile of polymorphisms, the lack of B chromosomes, and partial sex linkage of IIIL-1de. Detailed collection information is also presented for E. vernum, E. decolletum, and E. pugetense.Key words: black flies, cytogenetics, chromosomal inversions, evolution.