Sperm precedence in two Diabrotica (Coleoptera: Chrysomelidae) subspecies demonstrated phenotypically and by random-amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR).

摘要

Using phenotypic characters and random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), sperm precedence was studied in two Diabrotica (Coleoptera: Chrysomelidae) subspecies: D. undecimpunctata howardi Barber, known as the spotted cucumber beetle (SCB), and D. undecimpunctata undecimpunctata Mannerheim, known as the western spotted cucumber beetle (WSCB). Through initial studies, baseline information needed to conduct the sperm precedence studies were generated.; The WSCB formed significantly more mating pairs than SCB (t-test: t = 11.94; P 0.0001). There was no difference between WSCB and SCB for time spent in copula (t-test; t = 0.24; P > 0.81) as recorded both visually and by video. WSCB females laid more eggs during a period of 28 days than SCB females (F_1,24 = 10.2: P 0.04).; In WSCB the abdomen is black but it is yellow in SCB. In all multiple matings, F₁ progeny had abdominal color exactly as the second male parent, demonstrating sperm precedence. The inheritance of body color in WSCB and SCB, appears to be governed by one gene and it is determined by the male.; RAPD-PCR was used to determine paternity of the F₁ progenies of multiple crosses in which the females of WSCB and SCB were mated with two males successively. Paternity was determined by the shared presence and the shared absence of bands from the gels and was calculated by the formula M = N_ab/N_T where N_ab is total number of matches in individuals a and b, and N_T is the total number of bands scored in the study. In all the crosses where the female mated with a second male, there were band matches between the second male and the F₁ progeny, ( M = 1), thus showing paternity of F₁ progeny and sperm precedence of the second male.; This model can be employed to determine if other members of this group of beetles are subspecies. It can also be used to study fitness between resistance and susceptible strains in corn rootworm.