Investigation of cotton fleahoppers (Pseudatomoscelis seriatus) as pollinators of cotton

We have frequently observed cotton fleahoppers in cotton flowers with their legs and bodies dusted with cotton pollen grains.  Following these observations we asked can fleahoppers be minor pollinators of cotton?  To help answer this question we first quantified the frequency that fleahoppers visit flowers and the number of pollen grains that fleahoppers carry on their bodies.  We found fleahoppers at a quarter of all flowers surveyed and that fleahopper carry on average 25 pollen grains on their bodies.  Then, we tested the ability of fleahoppers dusted in flourscent powder to deposit the powder onto cotton flower stigmas.  We found that evidence that the fleahoppers left flourscent powder on 13% of the flowers in cages where they were released.  Given the large amount of flowers in each field cage, we believe this result suggests that fleahoppers remain mobile when carrying a powder load.  Other studies have found powder to be an appropriate pollen analog. Finally, to look at fleahopper pollination ability directly we tested the capability of fleahoppers to pollinate emasculated flowers.  We emasculated flowers to prevent self crossing by pouring water on the stigmas.  A previous study showed that dowsing stigmas in water causes pollen grains to burst due to osmosis and prevents selfing. We predicted that if fleahoppers could pollinate emasculated flowers, there should be decent fruit set on emasculated flowers where fleahoppers visited, comparable to the selfing flowers.  We found evidence that fleahoppers could do so, suggesting overall, that fleahoppers are minor pollinators of cotton.