Details

Autor(en) / Beteiligte

• Trunschke, Judith
• Sletvold, Nina
• Ågren, Jon

Titel

Manipulation of trait expression and pollination regime reveals the adaptive significance of spur length

Ist Teil von

• Evolution, 2020-03, Vol.74 (3), p.597-609

Ort / Verlag

United States: Wiley

Erscheinungsjahr

2020

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• Understanding the mechanisms of adaptive population differentiation requires that both the functional and adaptive significance of divergent traits are characterized in contrasting environments. Here, we (a) determined the effects of floral spur length on pollen removal and receipt using plants with artificial spurs representing the species-wide variation in length, and (b) quantified pollinator-mediated selection on spur length and three traits contributing to floral display in two populations each of the shortspurred and the long-spurred ecotype of the orchid Platanthera bifolia. Both pollen receipt and removal reached a maximum at 28–29 mm long spurs in a short-spurred population visited by short-tongued moths. In contrast, pollen receipt increased linearly across the tested range (4–52 mm) and pollen removal was unrelated to spur length in a long-spurred population predominantly visited by a long-tongued moth. The experimentally documented effects on pollen transfer were not reflected in pollinatormediated selection through female fitness or pollen removal indicating that the natural within-population variation in spur length was insufficient to result in detectable variation in pollen limitation. Our study illustrates how combining trait manipulation with analysis of causes and strength of phenotypic selection can illuminate the functional and adaptive significance of trait expression when trait variation is limited.