True grasses (Poaceae) are typically wind-pollinated plants. From their tall flower heads they cast pollen containing male gametes into the breeze. Some of the pollen may land on the female parts of flowers, resulting in fertilization. Although insects aren’t necessary for their reproduction, the copious amount of pollen occasionally attracts them.
The other day I noticed a number of syrphid flies (Diptera: Syrphidae) crawling all over the flower heads of this unknown grass. With relatively few plants flowering at this location this time of year, the abundant grass pollen must have presented a welcome food source for these flies.