Monthly Archives: November 2020

Pollinators and honey berries

This research from Lublin, Poland affirms the common knowledge about honey berries. They need insect pollination, and fruit size is related to the number of seeds per fruit. They are pollinated by honey bees, solitary bees and bumble bees. Flowers that were bagged and isolated showed less than 25% fruit set, whereas flowers exposed to insect pollinators had more than 88% fruit set. Interesting that honey bees don’t really enter the picture in Alaska because bloom time is so early, temperatures are still relatively cool, and honey bees are still shivering in their hives. Bumble bees, by far, are the most important pollinator in Alaska.

Bozek, M. 2012. The effect of pollinating insects on fruiting of two cultivars. Journal of Apicultural Science. 56(2):5-11.

S u m m a r y: In 2004 and 2006-2008, a study was conducted on the effect of pollinating insects on the fruit, seed set, and development of two cultivars of blue honeysuckle Lonicera caerulea (Sevast.) Pojark.: Atut andDuet”. The experiment was carried out in south-eastern Poland, at the Experimental Farm of the University of Life Sciences in Lublin, Poland. Flowers accessible to pollinating insects throughout the whole fl owering period, set fruit at a very high percentage. The study average was 90.57% for “Duet” and 88.08% for “Atut”. During self-pollination under isolation, on the other hand, the percentage of fruit-bearing fl owers was low. In the case of “Atut” the average was 9.37%, whereas for “Duet” it was 23.85%. Multiple fruits formed from isolated fl owers had a 45-50% lower weight, on average, than those developed from fl owers accessible to pollinating insects. The pollination mode was found to have a signifi cant effect on the number of seeds produced in the multiple fruit. Flowers which were isolated to prevent insect foraging did develop multiple fruits, characterized by a signifi cantly lower number of seeds. The recent studies confi rm that several cultivars should be planted on honeysuckle acreage. The presence of managed pollinators can increase quantity and improve quality of fruit yield in honeysuckle.

Spawning salmon increase fruit production of salmonberries

Researchers from Simon Fraser University Burnaby, BC studied the effects of spawning salmon species on fruiting of salmonberries, Rubus spectabilis. No surprise to anyone who has used fish guts, fish eggs and carcasses as fertilizer, the remnants of spawning salmon dragged or floated up on the banks of streams, adds a big fertilizer boost to salmonberries. These researchers studied 14 salmon streams and found that all that organic waste product promoted fruiting, and the density of chum salmon was correlated with increased fruit production. Pinks didn’t measure up. Seed count, fruit weight and sugar content were not correlated with salmon density. I’ll bet those traits are more related to bumble bee and other pollinator activity. Conclusion? Fish fertilizer makes great fertilizer!

 SIEMENS, L.D., A.M. DENNERT, D. S. OBRIST, J. D. REYNOLDS. Spawning salmon density influences fruit production ofsalmonberry (Rubus spectabilis). Ecosphere 11(11):e03282. 10.1002/ecs2.3282

 Abstract. Annual spawning migrations by Pacific salmon can provide substantial subsidies to nutrientlimited

Annual spawning migrations by Pacific salmon can provide substantial subsidies to nutrient-limited freshwater and riparian ecosystems, which can affect the abundance, diversity, and physical characteristics of plant and animal species in these habitats. Here, we provide the first investigation of how salmon subsidies affect reproductive output in plants, focusing on a common riparian shrub, salmonberry (Rubus spectabilis). We studied 14 streams with a range of spawning salmon densities on the central coast of British Columbia, Canada. We determined the effects of chum (Oncorhynchus keta), pink (O. gorbuscha), and total salmon spawning density on the number of fruits per shrub, number of seeds per fruit, fruit weight, and estimated sugar content (° Brix) of salmonberry fruits. We found that the number of fruits per salmonberry shrub increased with increasing salmon density. However, we found no effect of salmon density on the number of seeds per fruit, fruit weight, or sugar content. The effect of salmon density was species-dependent; the number of fruits per shrub increased with chum salmon density but was not affected by pink salmon density. This could be because chum salmon occur at higher densities and are transferred from water to land at higher rates than pink salmon in our study area. Higher salmonberry fruit production could lead to a larger input of salmonberry fruits to coastal food webs. These results demonstrate how salmon can cross ecological boundaries and influence reproductive output of terrestrial species.