Gene Flow by Hyles Lineata
Vegetable Crops Research Unit
2010 Annual Report
1a.Objectives (from AD-416)
The objective of this project is to successfully rear hawkmoths in the laboratory or the greenhouse in order to be able to complete some gene flow experiments using this pollinator in the greenhouse. We have been unable to date to do the experiments described in our parent project that involve doing the pollen carryover and pollinator shadow curves using hawkmoths. It has been too difficult to obtain hawkmoths from the field and match the stage of the moths (flying adults) to the timing of flowering of our plant species. However, if we rear the hawkmoths at UW-Madison we will be able to complete these experiments. These moths or a useful equivalent to do these experiments are not commercially available. Manduca sexta have too long a proboscis to be useful pollinators of our plant species, the rocky mountain columbine. Once Hyles lineata becomes available to us we will obtain the pollen carryover and paternity shadow curves described in our parent project. These curves are very useful measures to examine potential for gene flow by distinct pollinators. Having hawkmoths available will also allow us to do some choice experiments with these pollinators and help us determine how floral traits may differentially influence gene flow by distinct pollinators.
1b.Approach (from AD-416)
Eggs will be collected from wild Hyles lineata in Arizona. Collaborators in AZ will blacklight for hawkmoths, induce the hawkmoths to lay eggs and collect the eggs from a number of different wild hawkmoths. They will ship the eggs to Madison-Wisconsin. The eggs will be maintained at high humidity and at 72F until they hatch. The larvae will be trained to feed on an artificial diet typically used to rear Manduca sexta. The larvae will go through their five instars before they become pupae. The pupae will be allowed to bury themselves in dirt until they hatch. There will be a need to go through this cycle many times before we can successfully match the eclosure of adult Hyles lineata and the flowering of the rocky mountain columbine in the greenhouse. Once these two processes are matched experiments on hakwmoth choice for floral traits will be started. Examination of how the interaction between the proboscis length of the hawkmoth and the spur length of the flower affect pollen removal and deposition by hawkmoths will be examined. The influence of floral scent, flower color, nectar production, pollen production on pollinator choice of flowers will be started together with a determination of how the pollinators select for these floral traits. The latter will be examined using a phenotypic selection experiment. In addition we will be able to pursue the pollen carryover and paternity shadow curves by hawkmoths in the greenhouse described in the parent project.
We have succeeded in rearing the plant in fairly large numbers in the greenhouse and have examined the broad sense heritability of various floral traits, including floral scent. We have obtained larvae of Hyles lineata and started rearing them in the laboratory. We are still working on synchronizing the flowering of the plant with the emergence of the adult hawkmoth in order to pursue some of our gene flow experiments. All scientists on this project are located in the department of Entomology at the University of Wisconsin - Madison and monitoring of activities goes on periodically via discussions and meetings.