Palynivore

A honeybee collecting pollen from a flower
A pollen wasp (Jugurtia dispar), a type of wasp that exclusively feeds its larvae pollen. This is an example of a palynivore that is only a palynivore for part of its life span, as the adults of the species do not consume pollen

In zoology, a palynivore /pəˈlɪnəvɔːɹ/, meaning "pollen eater" (from Greek παλύνω palunō, "strew, sprinkle", and Latin, vorare, meaning "to devour") is an herbivorous animal which selectively eats the nutrient-rich pollen produced by angiosperms and gymnosperms.[1] Most true palynivores are insects or mites. The category in its strictest application includes most bees, and a few kinds of wasps,[2] as pollen is often the only solid food consumed by all life stages in these insects. However, the category can be extended to include more diverse species. For example, palynivorous mites and thrips typically feed on the liquid content of the pollen grains without actually consuming the exine, or the solid portion of the grain. Additionally, the list is expanded greatly if one takes into consideration species where either the larval or adult stage feeds on pollen, but not both. There are other wasps which are in this category, as well as many beetles,[3] flies, butterflies, and moths. One such example of a bee species that only consumes pollen in its larval stage is the Apis mellifera carnica.[4] There is a vast array of insects that will feed opportunistically on pollen, as will various birds, orb-weaving spiders[5] and other nectarivores.

Pollen consumption of the Hibiscus syriacus plant by the Bombus ruderatus (large garden bumblebee)

Pollen, the essential component of the palynivore diet, is a male gametophyte[6] that is formed in the anther, or the male part of the flower. Pollen is needed to fertilize the female part of the flower, or gynoecium, and has a long history of consumption by various species. There is evidence that suggests palynivory dates back to at least the Permian period.[7] It is likely that a coevolution has occurred between plants and palynivores in a form of mutualism, or the process by which two species individually benefit from the activity of the other. For example, palynivores benefit by receiving nutrients from the pollen, and thus the structure of the palynivore eye evolved to better interpret visual cues given by the pollen. Pollen benefits from the animal-plant interaction by being spread as the animal carries it from flower to flower, furthering the reproductive success of its respective flower. Thus, pollen has evolved to be more visually appealing to palynivores, and changed its surface texture to be more readily recognized by palynivore's tactile sensory receptors.[7]

Colorized electron micrograph of various types of pollen
  1. ^ Cembrowski, A. R.; Reurink, G.; Arcila Hernandez, L. M.; Sanders, J. G.; Youngerman, E.; Frederickson, M. E. (August 2015). "Sporadic pollen consumption among tropical ants". Insectes Sociaux. 62 (3): 379–382. doi:10.1007/s00040-015-0402-x. hdl:1807/110084. ISSN 0020-1812. S2CID 46421274.
  2. ^ Hunt, James H.; Brown, Peggy A.; Sago, Karen M.; Kerker, Jennifer A. (1991). "Vespid Wasps Eat Pollen (Hymenoptera: Vespidae)". Journal of the Kansas Entomological Society. 64 (2): 127–130. ISSN 0022-8567. JSTOR 25085261.
  3. ^ Samuelson, G. Allan (1994), Jolivet, P. H.; Cox, M. L.; Petitpierre, E. (eds.), "Pollen consumption and digestion by leaf beetles", Novel aspects of the biology of Chrysomelidae, Dordrecht: Springer Netherlands, pp. 179–183, doi:10.1007/978-94-011-1781-4_10, ISBN 978-94-010-4783-8, retrieved 2022-10-19
  4. ^ Szolderits, Maria Julia; Crailsheim, Karl (1993-10-01). "A comparison of pollen consumption and digestion in honeybee (Apis mellifera carnica) drones and workers". Journal of Insect Physiology. 39 (10): 877–881. Bibcode:1993JInsP..39..877S. doi:10.1016/0022-1910(93)90120-G. ISSN 0022-1910.
  5. ^ Eggs, Benjamin; Sanders, Dirk (2013-11-29). "Herbivory in Spiders: The Importance of Pollen for Orb-Weavers". PLOS ONE. 8 (11): e82637. Bibcode:2013PLoSO...882637E. doi:10.1371/journal.pone.0082637. ISSN 1932-6203. PMC 3843719. PMID 24312430.
  6. ^ McCormick, Sheila (2013-11-18). "Pollen". Current Biology. 23 (22): R988–R990. Bibcode:2013CBio...23.R988M. doi:10.1016/j.cub.2013.08.016. ISSN 0960-9822. PMID 24262831.
  7. ^ a b Krassilov, V.; Rasnitsyn, A. P.; Afonin, S. A. (April 2007). "Pollen eaters and pollen morphology: co-evolution through the Permian and Mesozoic" (PDF). African Invertebrates. 48 (1): 3–11.