|From left: Callophyrs augustinus and an empidid fly nectaring on Arctostaphylos viscida.|
Arctostaphylos viscida, a variant with white florets
|Arctostaphylos viscida flanks the northeastern rim of Upper Table Rock in Central Point, OR|
|Flowers of Arctostaphylos viscida with banded thrips, Aeolothrips sp.|
|Arctostaphylos viscida bark|
|From left: A. viscida berries, crushed dried berries, and seeds.|
|A honey bee, Apis mellifera, seeking nectar|
|A bumblebee queen, Bombus vosnesenskii, collecting nectar.|
The primary pollinators of manzanitas are typically medium and large bees which are capable of sonication, or buzz pollination. The bee lands on the flower and vibrates the flight muscles which releases a burst of pollen from the pores in the anthers. A positive electric charge (which all flighted insects generate) helps the pollen cling to the bee. Bumble bees (Bombus), mason bees (Osmia), digger bees (Anthophorini), and long-horned bees (Eucerini) are capable of sonication and I have observed all visiting A. viscida in my observations.
|Male Andrena sp., robbing nectar through a hole in the side of the flower.|
Many smaller bees visit the flowers, and in my observations many of them are nectar thieves. It's unclear who is chewing the holes in the flowers, but once they are there the flower has a low chance of getting pollinated since most of the visitors to those flowers bypass the reproductive structures and feed on nectar through the hole.
|A cuckoo bee, Nomada sp., robbing nectar from a hole in the floret.|
I have personally observed many types of small bees visiting A. viscida including mining bees (Andrena), small carpenter bees (Ceratina), and cuckoo bees (Nomada). Cuckoo bees are kleptoparasitoids, like cuckoo birds, who lay their eggs in the nests of other bees. Cuckoo bees forgo the creation of their own nests, and do not collect pollen. Instead, cuckoos rely on the provisions supplied by host species, usually other closely related bees. The invader sneaks into the nest while the host is out and lays an egg in a cell chamber. When the cuckoo bee larvae hatches, it kills the host larvae then feeds on the host provisions and develops in the host nest until adulthood. The genus Nomada, sometimes called nomad bees, are in the Apidae, the family that includes honey bees, bumble bees, digger bees, carpenter bees, and a few more. Mining bees, Andrena, are typical hosts for nomads, but others include Agepostemon (green metallic sweat bees) and a few others.
|From left: a mason bee, Osmia sp., perched on a leaf, and a paper wasp.|
|A parasitoid wasp, Ichneumonini|
Many parasitoid wasps congregate on and around A. viscida for nectar and honeydew, as well as to seek out hosts. I've observed ichneumonoids and chalcidoids either seeking hosts or seeking sustenance. Many suitable hosts are found on A. viscida, including many lepidopteran caterpillars.
|Male ant, Lasius sp., stuck to the sticky inflorescence.|
The sticky inflorescences of A. viscida trap many small insects, notably small flies and winged ants. Winged ants were one of the unfortunate insects to get stuck to the inflorescence. Ants in the genus Lasius are often attracted to honeydew, the frass of sap sucking insects like scale or aphids. Subterranean species of Lasius feed on the honeydew of root feeding aphids, forming mutualistic relationships.
|A bee fly, Bombylius major, feeding on nectar|
Flies visit A. viscida flowers frequently, and may also be gathering around the plants to mate or seek out prey (predatory species). More diverse and speciose than bees, flies are reliable pollinators in climatic conditions not accommodating to most bees. Many flies mimic bees and wasps, although flies are incapable of stinging. Bee flies, Bombyliidae, not only do a good job at mimicking bees, some are even parasitoids of ground nesting bees.
Dagger flies, or dance flies, are named for the long rigid proboscises they possess and the distinctive courting rituals performed by the males. Not all species have a long proboscis, but those that do use them to probe flowers for nectar. I have seen them visiting many early blooming trees such as Prunus and Salix, and early blooming ephemerals like Crocus and Muscari. They are also predatory, feeding on smaller flies, while larvae feed on decaying matter in the soil.
|Empididae infected with Entomophthora fungi|
I've seen several dead flies clinging to leaves and flowers, having been infected with the fungi Entomophthora. Spores are forcibly ejected from specialized structured grown by the fungus from membranous sections of the abdomen. Flies under or downwind may inadvertently catch a spore which proceeds to grow into the unsuspecting fly. The fungal hyphae gradually grow throughout the entire body, digesting the flies organs, and when it reaches the brain causes the fly to land and climb upwards. When the fly dies, after about a week from becoming infected, spores are produced and the cycle is renewed. Entomophthora isn't restricted to flies, some species infect aphids, mites, grasshoppers, and others.
A handful of moths in the Noctuidae and Geometridae use A. viscida as a host plant. Caterpillars are often difficult to see unless one is seeking them out, due to their drab colors and patterns. Adult moths of various types visit the flowers for nectar.
During warm weather, butterflies visit the flowers. I have found this to be true only in clearings with a lot of direct sunlight. Manzanitas that receive only filtered light appear to be less attractive to butterflies. Adult butterflies were seen sunbathing as well as nectaring, while on a few occasions males attempted to defend their territory from other species. I suspect courtship may also occur in the vicinity as well, though I didn't observe it directly. California tortoiseshells, Nymphalis californica, overwinter as adults and benefit from access to early nectar sources such as A. viscida.
|A mayfly, Ephemeroptera|
Mayflies live for about a day as adults, and are incapable of eating. Thus, a mayflies presence on A. viscida flowers was purely coincidental. Mayflies spend one to several years as aquatic nymphs before reaching adulthood, feeding on algae and detritus from under rocks at the bottom of streams, rivers, and occasionally lakes.
|Banded thrips, Aeolothrips sp.|
Acsai, Jan, and David L. Largent. "Fungi Associated with Arbutus Menziesii, Arctostaphylos Manzanita, and Arctostaphylos Uva-ursi in Central and Northern California." Mycologia 75.3 (1983): 544.http://goo.gl/x2fXFD
Armstrong, W. P. "Termite, Winged Ant, Small Wasp or Gnat?" Ant Genera Index. Wayne's Word, 2013. Web. http://waynesword.palomar.edu/AntGenera.htm.http://goo.gl/rlkVld
"Calflora: Arctostaphylos Viscida." Calflora: Information on California Plants for Education, Research and Conservation, with Data Contributed by Public and Private Institutions and Individuals, including the Consortium of California Herbaria. 2016.http://goo.gl/vbJaA
Clarke, D., H. Whitney, G. Sutton, and D. Robert. "Detection and Learning of Floral Electric Fields by Bumblebees." Science 340.6128 (2013): 66-69. Web.https://goo.gl/T6P02x
Eliyahu, Dorit, Andrew C. McCall, Marina Lauck, and Ana Trakhtenbrot. "Florivory and Nectar-robbing Perforations in Flowers of Pointleaf Manzanita Arctostaphylos Pungens (Ericaceae) and Their Effects on Plant Reproductive Success." Arthropod-Plant Interactions 9.6 (2015): 613-22. Web.
Eliyahu, Dorit, McCall C. Andrew, Lauck Marina, Ana Trakhenbrot, and Judith L. Bronstein. "Minute Pollinators: The Role of Thrips (Thysanoptera) as Pollinators of Pointleaf Manzanita, Arctostaphylos Pungens (Ericaceae)." J Pollinat Ecol. 16 (2015): 64-71. Web.http://goo.gl/aghCgK
Fryer, Janet L. 2015. Arctostaphylos viscida, sticky whiteleaf manzanita. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Missoula Fire Sciences Laboratory (Producer).http://goo.gl/IDAtp4
Horton, Thomas R., Thomas D. Bruns, and V. Thomas Parker. "Ectomycorrhizal Fungi Associated with Arctostaphylos Contribute to Pseudotsuga Menziesii Establishment." Can. J. Bot. Canadian Journal of Botany 77.1 (1999): 93-102.http://goo.gl/Wzdt0G
Lewis, Donald. "Why Do Some Ants Have Wings?" ISU Extension News Release. ISU, 22 July 2002. Web.http://goo.gl/7AUR7V
Moncada, Roberto. "Pollinators and Nectar Robbers on Manzanita (Arctostaphylos Sp.)." Amateur Biology Blog. 07 Feb. 2013. Web.http://goo.gl/ZtRAvw
Rostás, Michael, and Jürgen Tautz. "Ants as Pollinators of Plants and the Role of Floral Scents." All Flesh Is Grass Cellular Origin, Life in Extreme Habitats and Astrobiology (2010): 149-61. Webhttp://goo.gl/KXDd5t
Shirley, C. 2011. "Plant Guide for sticky whiteleaf manzanita (Arctostaphylos viscida)". USDA-Natural Resources Conservation Service, California Plant Materials Center, Lockeford, CA 95237http://goo.gl/dckZS5
Turner, Mark. "Arctostaphylos Viscida | Sticky Whiteleaf Manzanita." Wildflowers of the Pacific Northwest. Web.http://goo.gl/ekPEz2