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Data from: Colonization of marginal host plants by Callosobruchus seed beetles (Coleoptera: Chrysomelidae): effects of geographic source and genetic admixture

Citation

Gompert, Zachariah; Messina, Frank; Lish, Alexandra; Springer, Amy (2021), Data from: Colonization of marginal host plants by Callosobruchus seed beetles (Coleoptera: Chrysomelidae): effects of geographic source and genetic admixture, Dryad, Dataset, https://doi.org/10.5061/dryad.1jwstqjrq

Abstract

The ability to adapt to a novel host plant may vary among insect populations with different genetic histories, and colonization of a marginal host may be facilitated by genetic admixture of disparate populations. We assembled populations of the seed beetle, Callosobruchus maculatus, from four continents, and compared their ability to infest two hosts, lentil and pea. We also formed two cross-continent hybrids (Africa x N.A and Africa x S.A.). In pre-selection assays, survival was only ~3% in lentil and ~40% in pea. For three populations per line, colonization success on lentil was measured as cumulative exit holes after 75-175 days. On pea, we estimated the change in larval survival after five generations of selection. Females in all lines laid few eggs on lentil, and survival of F1 larvae was uniformly <5%. Subsequently, however, the lines diverged considerably in population growth. Performance on lentil was highest in the Africa x N.A. hybrid, which produced far more adults (mean >11000) than either parental line. At the other extreme, Asian populations on lentil appeared to have gone extinct. The Africa x N.A. line also exhibited the highest survival on pea, and again performed better than either parent line. However, no line displayed a rapid increase in survival on pea, as is sometimes observed on lentil. Our results demonstrate that geographic populations can vary substantially in their responses to the same novel resource. In addition, genetic admixtures (potentially caused by long-distance transport of infested seeds) may facilitate colonization of an initially poor host.

Methods

We assembled populations of the cowpea seed beetle, Callosobruchus maculatus, from four continents, and compared their ability to infest two novel hosts, lentil and pea. We also formed cross-continent hybrids (Africa x N.A and Africa x S.A.) to determine whether genetic admixture could facilitate adaptation. In pre-selection assays, survival was only ~3% in lentil and ~40% in pea. For three replicate populations per line, colonization success on lentil was measured as cumulative exit holes after 75 to 175 days. On pea, we instead estimated the change in larval survival after five discrete generations of selection.

Usage Notes

This data submission includes two data files, two R scripts, and two associated JAGS models:

1. lentil_exit_holes.csv = data file with lentil exit hold data. Columns denote the source population or cross type (LINE), how many seesds had 0, 1, 2, 3 or 4 exit holes, and the timing of the assay in days.

2. pea_exit_f5.csv = =data file  with pea assay data. Columns denote the source popualtion or cross type (Line), replicate, number of seeds and number of beetles that successfully emerged (Emerge).

3. commands_simple.R = R script to fit the Bayesian model for the lentil analysis.

4. pea_survival.R = R script to fit the Bayesian model for the pea survival analysis.

5. model_simple.txt = JAGS specification of the Bayesian model for the lentil analysis.

6. pea_model = JAGS specification of the Bayesian model for the pea survival analysis.

Funding

Utah Agricultural Experiment Station