120 likes | 394 Views
Jewel Wasp Biology. Kadeen Johns Barry K. Rhoades. Nasonia Vitripennis Life Cycle. Characteristics of Nasonia vitripennis. Wasps are parasitoid on fly puparia Females oviposit up to 40 eggs Several host species, including Sarcophaga bulatta
E N D
Jewel Wasp Biology Kadeen Johns Barry K. Rhoades
Characteristics of Nasonia vitripennis • Wasps are parasitoid on fly puparia • Females oviposit up to 40 eggs • Several host species, including Sarcophaga bulatta • Complete metamorphosis with ~14 day developmental cycle • Jewel wasps are haplodiploid – gender determined by ploidy • Flightless, haploid males have short wings - mate at eclosion site • Diploid females have longer wings, larger bodies – locate and oviposit hosts • Mating takes place immediately after eclosion • Three different stock eye colors - wild, scarlet, and oyster
Nasonia vitripennis Reproduction • Female sex determination of offspring • Haplodiploid genetics of eye color Female Phenotypes: Wild ScarletOyster +.+/+.+ +.st/+.st oy.+/oy.+ +.+/+.st +.+/oy.+ +.st/oy.+ Male Phenotypes: Wild ScarletOyster +.+ +.st oy.+
Maternal Determination of Progeny Gender in Nasonia vitripennis • Female stores sperm after mating in spermatheca • Female can deposit either fertilized or unfertilized eggs • Female can detect prior ovipositions into host puparium and control sex ratio of offspring (F1) during oviposition • For single oviposition, females mate with brothers upon eclosion • Ideal F1 sex ratio differs depending on oviposition exclusivity and sequential order – facultative sex ratio adjustment • First wasp (primary oviposition) -> predominantly female progeny – maximizes # of F2 secnd generation female offspring • Subsequent wasps (superoviposition) -> relatively more males – outcompete primary wasp’s few male F1 progeny for reproductive access to F1 females • Multiple female wasps directly competing -> relative number of male progeny should increase with number of competing wasps
Distinguishing Females from Males sorting pupae – to isolate virgin females
Facultative Sex Ratio AdjustmentBased on Oviposition Sequence • Single fly puparium exposed sequentially to 2 female wasps • Day1 – female wasp 1, Day 2 – female wasp 2 • Purebred eyecolor stocks used to determine offspring parentage • Balanced design with repetitions • W1S2 x 4, S1W2 x4 – 4 groups • O1S2 x 4, S1O2 x 4 – 3 groups • Data included: • if and only if female progeny from both parental stocks • 16 out of 56 fly puparia -> 462 wasps • C2 = 36.5, d.f. = 1, p < .001
Facultative Sex Ratio Adjustment Based on Female Competition • Single fly puparium exposed to 1 or more female wasps concurrently • 1, 2, 4, or 8 female wasps – 4 day exposure • Repetitions – 7 sets x 4 conditions • Data included: • if and only if female progeny eclosed • 23 out of 28 fly puparia -> 1320 wasps • C2 = 26.1, d.f. = 3, p < .001