In many plant-pollinator interactions the pollinator gets something for its trouble - usually nectar, but sometimes a tithe of the pollen. Bees get both.
In other plant-pollinator interactions the pollinator doesn’t benefit. (And arguably loses because of the energy wasted on a fruitless visit to a flower.) Short of a careful read of the scientific literature examples of such would be carrion odours (e.g. Rafflesia), visual and scent insect mimicry (e.g. Ophrys), and visual flower mimicry with nectar production.
In geological time, I’d guess that the originally pollinators were non-biotic processes, mostly wind. (Though modern anemophily is often secondary.) The earliest insect pollinators are thought to have been beetles using pollen as a food source. This just turned out to benefit the plants by improving the efficiency of pollination.
My opinion of a “better pollinator” is a bit of a toss-up because of all of the specialization that occurs. Some bee species are able to access trapped/concealed pollen through sonication which is an incredible advantage or how some species of moths have near exclusive access to some flowers due to specialized mouthparts.
We could also consider aquatic vectors which I believe may have pre-dated terrestrial pollination by insects. Red algae produce sticky, non-swimming male sex cells called spermatia. As tiny isopods (such as Idotea balthica) crawl across the algae to feed and seek shelter, these sticky cells attach to their shells and are carried to female reproductive organs of the red algae. I’d also be interested in forms of seagrass-bed mutualism that may serve similar functions analogous to pollination.
@lavateraguy Beat me to it mentioning pollinator syndrome, here is a small table from the USDA outlining some of these traits with additional links for more information at the bottom for anyone interested.
I would respectfully suggest that Odonata (Dragon- and Damselflies) probably don’t belong on the list.
I spend a great deal of time every year stalking them with the camera. I also document bees, butterflies, flies, moths, hoverflies, and wasps, but odes are my particular passion.
Every pollenator insect that I’ve seen has some way of transfering pollen grains; usually by being fuzzy to one degree or another. Dragonflies are predators. Every part of their bodies is adapted and evolved for the purpose of pursuing, trapping, and eating prey. Their legs, for instance, have spines that form a lattice or basket, to hold captured prey. Their bodies are pretty smooth; some are almost metallically shiny. While some species do have fuzz in places, it’s not really in the right places for pollen collection and deposition. What it does do is assist with relaying informaton about wind speed and direction.
Then there’s a move documented in a number of species called the splash-dunk / spin-dry. Dragonflies and damselflies are pretty serious about cleaning dust and dirt off of their wings. I don’t know how many species have been documented performing the maneuver, but I accidentally got a series of shots where a Halloween Pennant was demonstrating his technique. I’ve also seen Bluets and Forktails flying through fountain spray, garden misters, and sprinklers—presumably to clean off without having to court the danger of a full bath. Any pollen that happens to get deposited on them isn’t likely to end up on a plant.
Shorter version: dragonflies are really inefficient pollenators because they aren’t pollenators. But they do eat a whole lot of crop pests.
Relatively heavy, closed flowers like the larger ones in the legume (pea) family limit what insects can get to the nectar. Most of those insects are strong ones like bumblebees that push their heads inside and inevitably carry away pollen. However, a butterfly can cheat. I have photos of skippers (small butterflies) perched on the side of such flowers and slipping their long proboscis in between the petals, reaching inside to suck out the nectar while removing little or no pollen. Nectar theft indeed.
There are other wasps that have evolved to feed on plants as well; I used to watch various members of Torymidae in my other garden on the Ficus maxima that grew.
Zosteraceae are at least mostly hypohydrophilous and epihydrophilous.
Pollination strictly speaking applies only spermatophytes, but the press reports of biotic sperm dispersal in Gracilaria by Idotea mostly use the word, though some do include scare-quotes. However reading those articles leads me to reports of biotic pollination in turtle grass (Thalassia testudinarum), with varied agents.
There are reports of seed dispersal by woodlice, though there isn’t a single word for this process. (If you search in Google for isopodochory the AI overview will explain it, but there are no actual search results; onisc(i)ochory doesn’t even get an AI overview.)
A search for pollination by woodlice finds one paper on “background pollination”, i.e. pollination caused by incidental contact between animals and flowers. It mentions camel crickets as a taxon observed to be involved.
To address the question in the title directly, it isn’t a question that makes any sense to me. It feels like one of those, “Who would win a fight, a space marine, T. Rex, or one trillion bees?” questions. What does it mean to be a “better pollinator?” Under what circumstances are they pollinating? What plant(s) are around, what season is it, are we involved in agriculture, what time of day? Is there any context to the question?
I guess the determining factors would be something like this.
Specificity. That is the pollinator targets a limited number of plant species, meaning that collected pollen has a high chance of being deposited in a flower of the same species.
load capacity. The pollinator is able to carry substantial amounts of pollen. Bumblebees have been mentioned in a post above. Because of their relatively large hairy bodies and their strength at accessing flowers these insects are beloved by gardeners and orchardists.
Range. The further a pollinator travels to collect pollen the better chance of introducing diverse genetic material to the receiving flower. My apiarist friend tells me that honeybees will travel about 7 km from their hive to collect pollen. Studies here in Australia indicate that the grey-headed fruit bat will travel more than 100 km in a night to feed on Eucalypt nectar.
Hylaeus beg to differ, as do the numerous cuckoo bee species (many of them largely hairless) who do not collect pollen.
On the other hand, Megachilidae (bees in this family have a scopa on the underside of the abdomen) are often very efficient pollinators, to the extent that they are increasingly being used instead of honeybees for some crops (though efficiency is likely not the only factor in their use in agriculture – I imagine solitary bees with a short flight period that corresponds with the blooming period of the crop have the advantage that they don’t require much maintenance or a source of flowers during the rest of the growing season, as would be the case for a honeybee colony.)
In other words, “bees” are not a monolithic group any more than “pollinators” are.
I spent a while on my balcony this summer watching a tiny sweat bee trying to push apart the lips of a snapdragon-type flower – while the flower was quite small, she was even smaller and certainly nowhere near large enough to manipulate the opening mechanism. She was quite persistent, however, and eventually managed to squeeze her way inside (and emerged safely a little while later – apparently triumphantly, because she proceeded to repeat the procedure on neighboring blossoms).
I don’t know if it was purely a nectar run or whether she collected pollen while she was at it, but I imagine it is quite easy for the tiny bees to bypass the anthers of many flowers if they choose.
I was so fascinated by what I was watching that I didn’t think to grab my camera until it was basically too late!
The flower was Linaria repens or similar, so about 1 cm with a long spur, much smaller than Antirrhinum majus. Snapdragons are popular here with Xylocopa and Bombus; the other species in this tribe don’t seem to get a lot of attention from bees except for robbers interested in the nectar in the spur. This sort of flower also presents challenges for bee photography, as the photographer is likely to get a photo of little more than a butt disappearing into the flower.
I didn’t anticipate how extensive non-traditional pollination systems could be. It’s a fascinating area of study that’s now on my radar and something new to consider while observing, though I don’t want to derail the main thread any further from the focus of true pollination. Thankyou for sharing!!
