Managed bumble bees are viable as pollinators in netted kiwifruit orchards
Protected cropping can increase orchard productivity; however, enclosed environments can be disruptive to pollinators. Bumble bees (Bombus terrestris) forage under covers, but industries lack guidelines for using them as pollinators. Here conservative stocking rates for bumble bees in covered kiwifruit orchards were identified using empirical manipulation of bee density and theoretical calculations based on bee behaviour. Bumble bee pollination at two bee densities (24 and 72 colonies/ha) was assessed within two fully netted sections (1/25 ha each) in a Gold3 kiwifruit orchard. Predictive modelling was used to estimate total bees required for pollination while actual pollination in the two blocks was measured directly. There was no difference in flower visitation rate between stocking densities but a 20% increase in seed set was found at high bee density. It was estimated that 90% of a Gold3 crop could be pollinated by 914 foraging bees/ha, or between 22 and 48 colonies/ha at the strengths used in this study. Bumble bees are effective pollinators in protected cropping environments and provide a viable tool for managed pollination under nets. A theoretical approach to refining stocking rates is a good option when manipulating pollinator densities is not possible.
Castilla N 2002. Current situation and future prospects of protected crops in the Mediterranean region. Proceedings of the International Symposium on Mediterranean Horticulture: Issues and Prospects, pp. 135-147. <a href="https://doi.org/10.17660/ActaHortic.2002.582.11">https://doi.org/10.17660/ActaHortic.2002.582.11</a>
Cook R, Calvin L 2005. Greenhouse tomatoes change the dynamics of the North American fresh tomato industry. Economic Research Report No. ERR-2. United States Department of Agriculture. 86 p. <a href="https://www.ers.usda.gov/publications/pub-details/?pubid=45477">https://www.ers.usda.gov/publications/pub-details/?pubid=45477</a>
Dag A 2008. Bee pollination of crop plants under environmental conditions unique to enclosures. Journal of Apicultural Research 47: 162-165. <a href="https://doi.org/10.1080/00218839.2008.11101444">https://doi.org/10.1080/00218839.2008.11101444</a>
Evans E 2017. From humble bee to greenhouse pollination workhorse: can we mitigate risks for bumble bees? Bee World, 94: 34-41. <a href="https://doi.org/10.1080/0005772X.2017.1290892">https://doi.org/10.1080/0005772X.2017.1290892</a>
Hanan JJ, Holly WD, Goldsberry KL 1978. Greenhouse management. Springer Berlin. <a href="https://doi.org/10.1007/978-3-642-66778-7">https://doi.org/10.1007/978-3-642-66778-7</a>
Howlett BG, Read SFJ, Jesson LK, Benoist A, Evans LE, Pattemore DE 2017a. Diurnal insect visitation patterns to ‘Hayward’ kiwifruit flowers in New Zealand. New Zealand Plant Protection 70: 52-57. <a href="https://doi.org/10.30843/nzpp.2017.70.27">https://doi.org/10.30843/nzpp.2017.70.27</a>
Howlett BG, Evans LJ, Pattemore DE, Nelson WR 2017b. Stigmatic pollen delivery by flies and bees: Methods comparing multiple species within a pollinator community. Basic and Applied Ecology 19: 19-25. <a href="https://doi.org/10.1016/j.baae.2016.12.002">https://doi.org/10.1016/j.baae.2016.12.002</a>
Jones JB 2007. Tomato plant culture: In the field, greenhouse, and home garden. CRC Press, Boca Raton, Florida, 216 p. <a href="https://doi.org/10.1201/9781420007398">https://doi.org/10.1201/9781420007398</a>
Pomeroy N, Fisher RM 2012. Pollination of kiwifruit (<em>Actinidia deliciosa</em>) by bumble bees (<em>Bombus terrestris</em>): effects of bee density and patterns of flower visitation., New Zealand Entomologist, 25(1): 41-49 <a href="https://doi.org/10.1080/00779962.2002.9722093">https://doi.org/10.1080/00779962.2002.9722093</a>
Pomeroy N, Stoklosinski SR 1990. Measuring the foraging strength of bumble bee colonies. In: Shriva P ed. Proceedings of the XIth Congress of the International Union for the Study of Social Insects: 252-253. Bangalore, India.
Reddy PP 2016. Sustainable crop protection under protected cultivation. Springer, Singapore, 434 p. <a href="https://doi.org/10.1007/978-981-287-952-3">https://doi.org/10.1007/978-981-287-952-3</a>