The development of larval resistance to a nucleopolyhedrovirus is not accompanied by an increased virulence in the virus

Milks, ML Myers, JH

Ml. Milks et Jh. Myers, The development of larval resistance to a nucleopolyhedrovirus is not accompanied by an increased virulence in the virus, EVOL ECOL, 14(7), 2000, pp. 645-664

65

INGLESE

Article

Environment/Ecology

EVOLUTIONARY ECOLOGY

0269-7653 → ACNP

14

7

2000

645 - 664

ISI

0269-7653(2000)14:7<645:TDOLRT>2.0.ZU;2-6

Two laboratory experiments were conducted to examine the possible coevoluti on of cabbage loopers (Trichoplusia ni) and their S nucleopolyhedrovirus (T nSNPV). At the conclusion of Experiments 1 and 2, T. ni had respectively ev olved 4.4 x and 22 x resistance to TnSNPV. The higher level of resistance a chieved in Experiment 2 could be due to marginally stronger selection, poss ibly greater genetic variability in larval resistance to TnSNPV, or both. H owever, the evolution of resistance was not accompanied by an increased vir ulence of TnSNPV or a change in the restriction profile of the viral DNA wh en digested with BamHI, EcoRI, HindIII, PstI, SalI, SstI or XhoI. Little ge netic variability for virulence in the initial TnSNPV stocks, low mutation rates and possibly weak selection on the virus are some factors that may ha ve constrained the evolution of TnSNPV. We discuss our results in light of the geographic mosaic theory of coevolution and their implications for the use of TnSNPV as a biological control agent against T. ni.