What Bugged the Dinosaurs?: Insects, Disease, and Death in the Cretaceous

6. Pollination

6. Pollination In a dark recess at the base of a fern, a tiny bee began the arduous duty of motherhood by constructing a nest. She first cleared a small area on the ground by using her toothed mandibles to remove, particle by particle, larger bits of soil, then began digging in earnest with both front and middle pairs of legs. As the small pile of excavated soil became larger, the busy animal gradually disappeared inside the tunnel until finally only the ejected soil particles revealed the hymenopteran ’s presence. Working day and night, the minute insect formed a cell that would serve as a nursery for its first progeny. She added the finishing touches by compacting the soil in the chamber with the tip of a blunt abdomen. With the first task completed, this mother now had to concentrate on the perilous duty of filling the cell with pollen for any offspring . In the dim light of the following morning, the solitary bee prepared to depart. Before that first foray away from the nest, she flew up and circled the area three or four times to memorize the location and then whisked off through the forest. Winding a tortuous way between the huge araucarian trees with their glistening resinspotted trunks and dodging the hanging lianas, the diminutive insect noticed some small, intricate white flowers wedged between clusters of blue-green leaves. An assortment of climbing and hovering insects was already busy feeding on the blooms. Metallic-colored beetles with comb-like antennae devoured the pollen while long-legged flies mopped up nectar and miniscule thrips with flashing silvery wings scraped tissue from the petals. Avoiding these, the little bee settled on a group of recently opened flowers and began transferring as much pollen as possible onto the stiff hairs of her hind legs. Even with a full load, she would still need to make another five or six trips before collecting enough pollen to nourish just one larva to adulthood. Arriving back at the nest, the female quickly entered the nursery cell and began scraping off the pollen. As she left, she blocked the nest entrance to foil any thieving insects that might be searching for a free meal by partially filling the entrance hole with a plug of dirt and then placing some debris on top as camaflougue. Then it was back to the forest to search for more flowers. The journey this time led to a clearing where there was already a tumult of activity, but not just from insects. Ceratopsians were grazing in the undergrowth, consuming everything in their path like lumbermen implementing a clear-cut operation. Browsing indiscriminately on ferns, cycads, horsetails, low-lying conifers, and shrubby angiosperms, the giant herbivores devoured the herbage and shrubs that had regrown since their last visit. Oblivious to any competition, the hymenopteran went from flower to flower collecting pollen, stopping now and then for a sip of nectar. Her hairy body was covered with pollen and with each visit to a neighboring blossom, some of these grains were left on the female flower parts. The simple act of cross-fertilization would insure that seeds would be set and a new generation would appear. This was a gift delivered in exchange for pollen and nectar that the bee needed for procreation. With hind legs loaded to capacity, the hardworking bee returned to the nest. Having now gathered enough provisions for one offspring, some nectar was added to the pollen grains and the mixture was shaped into a little ball. Care was taken to keep this resource from touching the moisture-laden earthen walls since an attack of mold could make it inedible for the young. When satisfied, the female turned and laid a pearly white egg on the top of the food mass, then hastily backed out of the chamber and closed the entry securely by tamping down a layer of soil particles over the hole. The most significant way insects aided the establishment and spread of flowering plants was by their pollination activities, something the dinosaurs were incapable of doing. Most of the 58 – CHAPTER SIX early plants were wind and water pollinated, and neither dinosaurs nor insects took an active part in this process. However, this did not keep any number of insects, from beetles and thrips to flies and wasps, from feeding on pollen from cycads, cycadeoids , and conifers. Those ancient associations may have been strictly one-sided, with the insects just eating...